source: src/linux/universal/linux-3.18/kernel/trace/ftrace.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 3 months ago

update

File size: 130.1 KB
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1/*
2 * Infrastructure for profiling code inserted by 'gcc -pg'.
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally ported from the -rt patch by:
8 *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code in the latency_tracer, that is:
11 *
12 *  Copyright (C) 2004-2006 Ingo Molnar
13 *  Copyright (C) 2004 Nadia Yvette Chambers
14 */
15
16#include <linux/stop_machine.h>
17#include <linux/clocksource.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/suspend.h>
21#include <linux/debugfs.h>
22#include <linux/hardirq.h>
23#include <linux/kthread.h>
24#include <linux/uaccess.h>
25#include <linux/bsearch.h>
26#include <linux/module.h>
27#include <linux/ftrace.h>
28#include <linux/sysctl.h>
29#include <linux/slab.h>
30#include <linux/ctype.h>
31#include <linux/sort.h>
32#include <linux/list.h>
33#include <linux/hash.h>
34#include <linux/rcupdate.h>
35
36#include <trace/events/sched.h>
37
38#include <asm/setup.h>
39
40#include "trace_output.h"
41#include "trace_stat.h"
42
43#define FTRACE_WARN_ON(cond)                    \
44        ({                                      \
45                int ___r = cond;                \
46                if (WARN_ON(___r))              \
47                        ftrace_kill();          \
48                ___r;                           \
49        })
50
51#define FTRACE_WARN_ON_ONCE(cond)               \
52        ({                                      \
53                int ___r = cond;                \
54                if (WARN_ON_ONCE(___r))         \
55                        ftrace_kill();          \
56                ___r;                           \
57        })
58
59/* hash bits for specific function selection */
60#define FTRACE_HASH_BITS 7
61#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
62#define FTRACE_HASH_DEFAULT_BITS 10
63#define FTRACE_HASH_MAX_BITS 12
64
65#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
66
67#ifdef CONFIG_DYNAMIC_FTRACE
68#define INIT_OPS_HASH(opsname)  \
69        .func_hash              = &opsname.local_hash,                  \
70        .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
71#define ASSIGN_OPS_HASH(opsname, val) \
72        .func_hash              = val, \
73        .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
74#else
75#define INIT_OPS_HASH(opsname)
76#define ASSIGN_OPS_HASH(opsname, val)
77#endif
78
79static struct ftrace_ops ftrace_list_end __read_mostly = {
80        .func           = ftrace_stub,
81        .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
82        INIT_OPS_HASH(ftrace_list_end)
83};
84
85/* ftrace_enabled is a method to turn ftrace on or off */
86int ftrace_enabled __read_mostly;
87static int last_ftrace_enabled;
88
89/* Current function tracing op */
90struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
91/* What to set function_trace_op to */
92static struct ftrace_ops *set_function_trace_op;
93
94/* List for set_ftrace_pid's pids. */
95LIST_HEAD(ftrace_pids);
96struct ftrace_pid {
97        struct list_head list;
98        struct pid *pid;
99};
100
101/*
102 * ftrace_disabled is set when an anomaly is discovered.
103 * ftrace_disabled is much stronger than ftrace_enabled.
104 */
105static int ftrace_disabled __read_mostly;
106
107static DEFINE_MUTEX(ftrace_lock);
108
109static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
110static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
111ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
112ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
113static struct ftrace_ops global_ops;
114static struct ftrace_ops control_ops;
115
116static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
117                                   struct ftrace_ops *op, struct pt_regs *regs);
118
119#if ARCH_SUPPORTS_FTRACE_OPS
120static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
121                                 struct ftrace_ops *op, struct pt_regs *regs);
122#else
123/* See comment below, where ftrace_ops_list_func is defined */
124static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
125#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
126#endif
127
128/*
129 * Traverse the ftrace_global_list, invoking all entries.  The reason that we
130 * can use rcu_dereference_raw_notrace() is that elements removed from this list
131 * are simply leaked, so there is no need to interact with a grace-period
132 * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
133 * concurrent insertions into the ftrace_global_list.
134 *
135 * Silly Alpha and silly pointer-speculation compiler optimizations!
136 */
137#define do_for_each_ftrace_op(op, list)                 \
138        op = rcu_dereference_raw_notrace(list);                 \
139        do
140
141/*
142 * Optimized for just a single item in the list (as that is the normal case).
143 */
144#define while_for_each_ftrace_op(op)                            \
145        while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&  \
146               unlikely((op) != &ftrace_list_end))
147
148static inline void ftrace_ops_init(struct ftrace_ops *ops)
149{
150#ifdef CONFIG_DYNAMIC_FTRACE
151        if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
152                mutex_init(&ops->local_hash.regex_lock);
153                ops->func_hash = &ops->local_hash;
154                ops->flags |= FTRACE_OPS_FL_INITIALIZED;
155        }
156#endif
157}
158
159/**
160 * ftrace_nr_registered_ops - return number of ops registered
161 *
162 * Returns the number of ftrace_ops registered and tracing functions
163 */
164int ftrace_nr_registered_ops(void)
165{
166        struct ftrace_ops *ops;
167        int cnt = 0;
168
169        mutex_lock(&ftrace_lock);
170
171        for (ops = ftrace_ops_list;
172             ops != &ftrace_list_end; ops = ops->next)
173                cnt++;
174
175        mutex_unlock(&ftrace_lock);
176
177        return cnt;
178}
179
180static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
181                            struct ftrace_ops *op, struct pt_regs *regs)
182{
183        if (!test_tsk_trace_trace(current))
184                return;
185
186        ftrace_pid_function(ip, parent_ip, op, regs);
187}
188
189static void set_ftrace_pid_function(ftrace_func_t func)
190{
191        /* do not set ftrace_pid_function to itself! */
192        if (func != ftrace_pid_func)
193                ftrace_pid_function = func;
194}
195
196/**
197 * clear_ftrace_function - reset the ftrace function
198 *
199 * This NULLs the ftrace function and in essence stops
200 * tracing.  There may be lag
201 */
202void clear_ftrace_function(void)
203{
204        ftrace_trace_function = ftrace_stub;
205        ftrace_pid_function = ftrace_stub;
206}
207
208static void control_ops_disable_all(struct ftrace_ops *ops)
209{
210        int cpu;
211
212        for_each_possible_cpu(cpu)
213                *per_cpu_ptr(ops->disabled, cpu) = 1;
214}
215
216static int control_ops_alloc(struct ftrace_ops *ops)
217{
218        int __percpu *disabled;
219
220        disabled = alloc_percpu(int);
221        if (!disabled)
222                return -ENOMEM;
223
224        ops->disabled = disabled;
225        control_ops_disable_all(ops);
226        return 0;
227}
228
229static void ftrace_sync(struct work_struct *work)
230{
231        /*
232         * This function is just a stub to implement a hard force
233         * of synchronize_sched(). This requires synchronizing
234         * tasks even in userspace and idle.
235         *
236         * Yes, function tracing is rude.
237         */
238}
239
240static void ftrace_sync_ipi(void *data)
241{
242        /* Probably not needed, but do it anyway */
243        smp_rmb();
244}
245
246#ifdef CONFIG_FUNCTION_GRAPH_TRACER
247static void update_function_graph_func(void);
248#else
249static inline void update_function_graph_func(void) { }
250#endif
251
252static void update_ftrace_function(void)
253{
254        ftrace_func_t func;
255
256        /*
257         * Prepare the ftrace_ops that the arch callback will use.
258         * If there's only one ftrace_ops registered, the ftrace_ops_list
259         * will point to the ops we want.
260         */
261        set_function_trace_op = ftrace_ops_list;
262
263        /* If there's no ftrace_ops registered, just call the stub function */
264        if (ftrace_ops_list == &ftrace_list_end) {
265                func = ftrace_stub;
266
267        /*
268         * If we are at the end of the list and this ops is
269         * recursion safe and not dynamic and the arch supports passing ops,
270         * then have the mcount trampoline call the function directly.
271         */
272        } else if (ftrace_ops_list->next == &ftrace_list_end) {
273                func = ftrace_ops_get_func(ftrace_ops_list);
274
275        } else {
276                /* Just use the default ftrace_ops */
277                set_function_trace_op = &ftrace_list_end;
278                func = ftrace_ops_list_func;
279        }
280
281        update_function_graph_func();
282
283        /* If there's no change, then do nothing more here */
284        if (ftrace_trace_function == func)
285                return;
286
287        /*
288         * If we are using the list function, it doesn't care
289         * about the function_trace_ops.
290         */
291        if (func == ftrace_ops_list_func) {
292                ftrace_trace_function = func;
293                /*
294                 * Don't even bother setting function_trace_ops,
295                 * it would be racy to do so anyway.
296                 */
297                return;
298        }
299
300#ifndef CONFIG_DYNAMIC_FTRACE
301        /*
302         * For static tracing, we need to be a bit more careful.
303         * The function change takes affect immediately. Thus,
304         * we need to coorditate the setting of the function_trace_ops
305         * with the setting of the ftrace_trace_function.
306         *
307         * Set the function to the list ops, which will call the
308         * function we want, albeit indirectly, but it handles the
309         * ftrace_ops and doesn't depend on function_trace_op.
310         */
311        ftrace_trace_function = ftrace_ops_list_func;
312        /*
313         * Make sure all CPUs see this. Yes this is slow, but static
314         * tracing is slow and nasty to have enabled.
315         */
316        schedule_on_each_cpu(ftrace_sync);
317        /* Now all cpus are using the list ops. */
318        function_trace_op = set_function_trace_op;
319        /* Make sure the function_trace_op is visible on all CPUs */
320        smp_wmb();
321        /* Nasty way to force a rmb on all cpus */
322        smp_call_function(ftrace_sync_ipi, NULL, 1);
323        /* OK, we are all set to update the ftrace_trace_function now! */
324#endif /* !CONFIG_DYNAMIC_FTRACE */
325
326        ftrace_trace_function = func;
327}
328
329int using_ftrace_ops_list_func(void)
330{
331        return ftrace_trace_function == ftrace_ops_list_func;
332}
333
334static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
335{
336        ops->next = *list;
337        /*
338         * We are entering ops into the list but another
339         * CPU might be walking that list. We need to make sure
340         * the ops->next pointer is valid before another CPU sees
341         * the ops pointer included into the list.
342         */
343        rcu_assign_pointer(*list, ops);
344}
345
346static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
347{
348        struct ftrace_ops **p;
349
350        /*
351         * If we are removing the last function, then simply point
352         * to the ftrace_stub.
353         */
354        if (*list == ops && ops->next == &ftrace_list_end) {
355                *list = &ftrace_list_end;
356                return 0;
357        }
358
359        for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
360                if (*p == ops)
361                        break;
362
363        if (*p != ops)
364                return -1;
365
366        *p = (*p)->next;
367        return 0;
368}
369
370static void add_ftrace_list_ops(struct ftrace_ops **list,
371                                struct ftrace_ops *main_ops,
372                                struct ftrace_ops *ops)
373{
374        int first = *list == &ftrace_list_end;
375        add_ftrace_ops(list, ops);
376        if (first)
377                add_ftrace_ops(&ftrace_ops_list, main_ops);
378}
379
380static int remove_ftrace_list_ops(struct ftrace_ops **list,
381                                  struct ftrace_ops *main_ops,
382                                  struct ftrace_ops *ops)
383{
384        int ret = remove_ftrace_ops(list, ops);
385        if (!ret && *list == &ftrace_list_end)
386                ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
387        return ret;
388}
389
390static int __register_ftrace_function(struct ftrace_ops *ops)
391{
392        if (ops->flags & FTRACE_OPS_FL_DELETED)
393                return -EINVAL;
394
395        if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
396                return -EBUSY;
397
398#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
399        /*
400         * If the ftrace_ops specifies SAVE_REGS, then it only can be used
401         * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
402         * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
403         */
404        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
405            !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
406                return -EINVAL;
407
408        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
409                ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
410#endif
411
412        if (!core_kernel_data((unsigned long)ops))
413                ops->flags |= FTRACE_OPS_FL_DYNAMIC;
414
415        if (ops->flags & FTRACE_OPS_FL_CONTROL) {
416                if (control_ops_alloc(ops))
417                        return -ENOMEM;
418                add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
419        } else
420                add_ftrace_ops(&ftrace_ops_list, ops);
421
422        if (ftrace_enabled)
423                update_ftrace_function();
424
425        return 0;
426}
427
428static int __unregister_ftrace_function(struct ftrace_ops *ops)
429{
430        int ret;
431
432        if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
433                return -EBUSY;
434
435        if (ops->flags & FTRACE_OPS_FL_CONTROL) {
436                ret = remove_ftrace_list_ops(&ftrace_control_list,
437                                             &control_ops, ops);
438        } else
439                ret = remove_ftrace_ops(&ftrace_ops_list, ops);
440
441        if (ret < 0)
442                return ret;
443
444        if (ftrace_enabled)
445                update_ftrace_function();
446
447        return 0;
448}
449
450static void ftrace_update_pid_func(void)
451{
452        /* Only do something if we are tracing something */
453        if (ftrace_trace_function == ftrace_stub)
454                return;
455
456        update_ftrace_function();
457}
458
459#ifdef CONFIG_FUNCTION_PROFILER
460struct ftrace_profile {
461        struct hlist_node               node;
462        unsigned long                   ip;
463        unsigned long                   counter;
464#ifdef CONFIG_FUNCTION_GRAPH_TRACER
465        unsigned long long              time;
466        unsigned long long              time_squared;
467#endif
468};
469
470struct ftrace_profile_page {
471        struct ftrace_profile_page      *next;
472        unsigned long                   index;
473        struct ftrace_profile           records[];
474};
475
476struct ftrace_profile_stat {
477        atomic_t                        disabled;
478        struct hlist_head               *hash;
479        struct ftrace_profile_page      *pages;
480        struct ftrace_profile_page      *start;
481        struct tracer_stat              stat;
482};
483
484#define PROFILE_RECORDS_SIZE                                            \
485        (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
486
487#define PROFILES_PER_PAGE                                       \
488        (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
489
490static int ftrace_profile_enabled __read_mostly;
491
492/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
493static DEFINE_MUTEX(ftrace_profile_lock);
494
495static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
496
497#define FTRACE_PROFILE_HASH_BITS 10
498#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
499
500static void *
501function_stat_next(void *v, int idx)
502{
503        struct ftrace_profile *rec = v;
504        struct ftrace_profile_page *pg;
505
506        pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
507
508 again:
509        if (idx != 0)
510                rec++;
511
512        if ((void *)rec >= (void *)&pg->records[pg->index]) {
513                pg = pg->next;
514                if (!pg)
515                        return NULL;
516                rec = &pg->records[0];
517                if (!rec->counter)
518                        goto again;
519        }
520
521        return rec;
522}
523
524static void *function_stat_start(struct tracer_stat *trace)
525{
526        struct ftrace_profile_stat *stat =
527                container_of(trace, struct ftrace_profile_stat, stat);
528
529        if (!stat || !stat->start)
530                return NULL;
531
532        return function_stat_next(&stat->start->records[0], 0);
533}
534
535#ifdef CONFIG_FUNCTION_GRAPH_TRACER
536/* function graph compares on total time */
537static int function_stat_cmp(void *p1, void *p2)
538{
539        struct ftrace_profile *a = p1;
540        struct ftrace_profile *b = p2;
541
542        if (a->time < b->time)
543                return -1;
544        if (a->time > b->time)
545                return 1;
546        else
547                return 0;
548}
549#else
550/* not function graph compares against hits */
551static int function_stat_cmp(void *p1, void *p2)
552{
553        struct ftrace_profile *a = p1;
554        struct ftrace_profile *b = p2;
555
556        if (a->counter < b->counter)
557                return -1;
558        if (a->counter > b->counter)
559                return 1;
560        else
561                return 0;
562}
563#endif
564
565static int function_stat_headers(struct seq_file *m)
566{
567#ifdef CONFIG_FUNCTION_GRAPH_TRACER
568        seq_printf(m, "  Function                               "
569                   "Hit    Time            Avg             s^2\n"
570                      "  --------                               "
571                   "---    ----            ---             ---\n");
572#else
573        seq_printf(m, "  Function                               Hit\n"
574                      "  --------                               ---\n");
575#endif
576        return 0;
577}
578
579static int function_stat_show(struct seq_file *m, void *v)
580{
581        struct ftrace_profile *rec = v;
582        char str[KSYM_SYMBOL_LEN];
583        int ret = 0;
584#ifdef CONFIG_FUNCTION_GRAPH_TRACER
585        static struct trace_seq s;
586        unsigned long long avg;
587        unsigned long long stddev;
588#endif
589        mutex_lock(&ftrace_profile_lock);
590
591        /* we raced with function_profile_reset() */
592        if (unlikely(rec->counter == 0)) {
593                ret = -EBUSY;
594                goto out;
595        }
596
597        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
598        seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
599
600#ifdef CONFIG_FUNCTION_GRAPH_TRACER
601        seq_printf(m, "    ");
602        avg = rec->time;
603        do_div(avg, rec->counter);
604
605        /* Sample standard deviation (s^2) */
606        if (rec->counter <= 1)
607                stddev = 0;
608        else {
609                /*
610                 * Apply Welford's method:
611                 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
612                 */
613                stddev = rec->counter * rec->time_squared -
614                         rec->time * rec->time;
615
616                /*
617                 * Divide only 1000 for ns^2 -> us^2 conversion.
618                 * trace_print_graph_duration will divide 1000 again.
619                 */
620                do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
621        }
622
623        trace_seq_init(&s);
624        trace_print_graph_duration(rec->time, &s);
625        trace_seq_puts(&s, "    ");
626        trace_print_graph_duration(avg, &s);
627        trace_seq_puts(&s, "    ");
628        trace_print_graph_duration(stddev, &s);
629        trace_print_seq(m, &s);
630#endif
631        seq_putc(m, '\n');
632out:
633        mutex_unlock(&ftrace_profile_lock);
634
635        return ret;
636}
637
638static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
639{
640        struct ftrace_profile_page *pg;
641
642        pg = stat->pages = stat->start;
643
644        while (pg) {
645                memset(pg->records, 0, PROFILE_RECORDS_SIZE);
646                pg->index = 0;
647                pg = pg->next;
648        }
649
650        memset(stat->hash, 0,
651               FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
652}
653
654int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
655{
656        struct ftrace_profile_page *pg;
657        int functions;
658        int pages;
659        int i;
660
661        /* If we already allocated, do nothing */
662        if (stat->pages)
663                return 0;
664
665        stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
666        if (!stat->pages)
667                return -ENOMEM;
668
669#ifdef CONFIG_DYNAMIC_FTRACE
670        functions = ftrace_update_tot_cnt;
671#else
672        /*
673         * We do not know the number of functions that exist because
674         * dynamic tracing is what counts them. With past experience
675         * we have around 20K functions. That should be more than enough.
676         * It is highly unlikely we will execute every function in
677         * the kernel.
678         */
679        functions = 20000;
680#endif
681
682        pg = stat->start = stat->pages;
683
684        pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
685
686        for (i = 1; i < pages; i++) {
687                pg->next = (void *)get_zeroed_page(GFP_KERNEL);
688                if (!pg->next)
689                        goto out_free;
690                pg = pg->next;
691        }
692
693        return 0;
694
695 out_free:
696        pg = stat->start;
697        while (pg) {
698                unsigned long tmp = (unsigned long)pg;
699
700                pg = pg->next;
701                free_page(tmp);
702        }
703
704        stat->pages = NULL;
705        stat->start = NULL;
706
707        return -ENOMEM;
708}
709
710static int ftrace_profile_init_cpu(int cpu)
711{
712        struct ftrace_profile_stat *stat;
713        int size;
714
715        stat = &per_cpu(ftrace_profile_stats, cpu);
716
717        if (stat->hash) {
718                /* If the profile is already created, simply reset it */
719                ftrace_profile_reset(stat);
720                return 0;
721        }
722
723        /*
724         * We are profiling all functions, but usually only a few thousand
725         * functions are hit. We'll make a hash of 1024 items.
726         */
727        size = FTRACE_PROFILE_HASH_SIZE;
728
729        stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
730
731        if (!stat->hash)
732                return -ENOMEM;
733
734        /* Preallocate the function profiling pages */
735        if (ftrace_profile_pages_init(stat) < 0) {
736                kfree(stat->hash);
737                stat->hash = NULL;
738                return -ENOMEM;
739        }
740
741        return 0;
742}
743
744static int ftrace_profile_init(void)
745{
746        int cpu;
747        int ret = 0;
748
749        for_each_possible_cpu(cpu) {
750                ret = ftrace_profile_init_cpu(cpu);
751                if (ret)
752                        break;
753        }
754
755        return ret;
756}
757
758/* interrupts must be disabled */
759static struct ftrace_profile *
760ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
761{
762        struct ftrace_profile *rec;
763        struct hlist_head *hhd;
764        unsigned long key;
765
766        key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
767        hhd = &stat->hash[key];
768
769        if (hlist_empty(hhd))
770                return NULL;
771
772        hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
773                if (rec->ip == ip)
774                        return rec;
775        }
776
777        return NULL;
778}
779
780static void ftrace_add_profile(struct ftrace_profile_stat *stat,
781                               struct ftrace_profile *rec)
782{
783        unsigned long key;
784
785        key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
786        hlist_add_head_rcu(&rec->node, &stat->hash[key]);
787}
788
789/*
790 * The memory is already allocated, this simply finds a new record to use.
791 */
792static struct ftrace_profile *
793ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
794{
795        struct ftrace_profile *rec = NULL;
796
797        /* prevent recursion (from NMIs) */
798        if (atomic_inc_return(&stat->disabled) != 1)
799                goto out;
800
801        /*
802         * Try to find the function again since an NMI
803         * could have added it
804         */
805        rec = ftrace_find_profiled_func(stat, ip);
806        if (rec)
807                goto out;
808
809        if (stat->pages->index == PROFILES_PER_PAGE) {
810                if (!stat->pages->next)
811                        goto out;
812                stat->pages = stat->pages->next;
813        }
814
815        rec = &stat->pages->records[stat->pages->index++];
816        rec->ip = ip;
817        ftrace_add_profile(stat, rec);
818
819 out:
820        atomic_dec(&stat->disabled);
821
822        return rec;
823}
824
825static void
826function_profile_call(unsigned long ip, unsigned long parent_ip,
827                      struct ftrace_ops *ops, struct pt_regs *regs)
828{
829        struct ftrace_profile_stat *stat;
830        struct ftrace_profile *rec;
831        unsigned long flags;
832
833        if (!ftrace_profile_enabled)
834                return;
835
836        local_irq_save(flags);
837
838        stat = this_cpu_ptr(&ftrace_profile_stats);
839        if (!stat->hash || !ftrace_profile_enabled)
840                goto out;
841
842        rec = ftrace_find_profiled_func(stat, ip);
843        if (!rec) {
844                rec = ftrace_profile_alloc(stat, ip);
845                if (!rec)
846                        goto out;
847        }
848
849        rec->counter++;
850 out:
851        local_irq_restore(flags);
852}
853
854#ifdef CONFIG_FUNCTION_GRAPH_TRACER
855static int profile_graph_entry(struct ftrace_graph_ent *trace)
856{
857        function_profile_call(trace->func, 0, NULL, NULL);
858        return 1;
859}
860
861static void profile_graph_return(struct ftrace_graph_ret *trace)
862{
863        struct ftrace_profile_stat *stat;
864        unsigned long long calltime;
865        struct ftrace_profile *rec;
866        unsigned long flags;
867
868        local_irq_save(flags);
869        stat = this_cpu_ptr(&ftrace_profile_stats);
870        if (!stat->hash || !ftrace_profile_enabled)
871                goto out;
872
873        /* If the calltime was zero'd ignore it */
874        if (!trace->calltime)
875                goto out;
876
877        calltime = trace->rettime - trace->calltime;
878
879        if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
880                int index;
881
882                index = trace->depth;
883
884                /* Append this call time to the parent time to subtract */
885                if (index)
886                        current->ret_stack[index - 1].subtime += calltime;
887
888                if (current->ret_stack[index].subtime < calltime)
889                        calltime -= current->ret_stack[index].subtime;
890                else
891                        calltime = 0;
892        }
893
894        rec = ftrace_find_profiled_func(stat, trace->func);
895        if (rec) {
896                rec->time += calltime;
897                rec->time_squared += calltime * calltime;
898        }
899
900 out:
901        local_irq_restore(flags);
902}
903
904static int register_ftrace_profiler(void)
905{
906        return register_ftrace_graph(&profile_graph_return,
907                                     &profile_graph_entry);
908}
909
910static void unregister_ftrace_profiler(void)
911{
912        unregister_ftrace_graph();
913}
914#else
915static struct ftrace_ops ftrace_profile_ops __read_mostly = {
916        .func           = function_profile_call,
917        .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
918        INIT_OPS_HASH(ftrace_profile_ops)
919};
920
921static int register_ftrace_profiler(void)
922{
923        return register_ftrace_function(&ftrace_profile_ops);
924}
925
926static void unregister_ftrace_profiler(void)
927{
928        unregister_ftrace_function(&ftrace_profile_ops);
929}
930#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
931
932static ssize_t
933ftrace_profile_write(struct file *filp, const char __user *ubuf,
934                     size_t cnt, loff_t *ppos)
935{
936        unsigned long val;
937        int ret;
938
939        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
940        if (ret)
941                return ret;
942
943        val = !!val;
944
945        mutex_lock(&ftrace_profile_lock);
946        if (ftrace_profile_enabled ^ val) {
947                if (val) {
948                        ret = ftrace_profile_init();
949                        if (ret < 0) {
950                                cnt = ret;
951                                goto out;
952                        }
953
954                        ret = register_ftrace_profiler();
955                        if (ret < 0) {
956                                cnt = ret;
957                                goto out;
958                        }
959                        ftrace_profile_enabled = 1;
960                } else {
961                        ftrace_profile_enabled = 0;
962                        /*
963                         * unregister_ftrace_profiler calls stop_machine
964                         * so this acts like an synchronize_sched.
965                         */
966                        unregister_ftrace_profiler();
967                }
968        }
969 out:
970        mutex_unlock(&ftrace_profile_lock);
971
972        *ppos += cnt;
973
974        return cnt;
975}
976
977static ssize_t
978ftrace_profile_read(struct file *filp, char __user *ubuf,
979                     size_t cnt, loff_t *ppos)
980{
981        char buf[64];           /* big enough to hold a number */
982        int r;
983
984        r = sprintf(buf, "%u\n", ftrace_profile_enabled);
985        return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
986}
987
988static const struct file_operations ftrace_profile_fops = {
989        .open           = tracing_open_generic,
990        .read           = ftrace_profile_read,
991        .write          = ftrace_profile_write,
992        .llseek         = default_llseek,
993};
994
995/* used to initialize the real stat files */
996static struct tracer_stat function_stats __initdata = {
997        .name           = "functions",
998        .stat_start     = function_stat_start,
999        .stat_next      = function_stat_next,
1000        .stat_cmp       = function_stat_cmp,
1001        .stat_headers   = function_stat_headers,
1002        .stat_show      = function_stat_show
1003};
1004
1005static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1006{
1007        struct ftrace_profile_stat *stat;
1008        struct dentry *entry;
1009        char *name;
1010        int ret;
1011        int cpu;
1012
1013        for_each_possible_cpu(cpu) {
1014                stat = &per_cpu(ftrace_profile_stats, cpu);
1015
1016                /* allocate enough for function name + cpu number */
1017                name = kmalloc(32, GFP_KERNEL);
1018                if (!name) {
1019                        /*
1020                         * The files created are permanent, if something happens
1021                         * we still do not free memory.
1022                         */
1023                        WARN(1,
1024                             "Could not allocate stat file for cpu %d\n",
1025                             cpu);
1026                        return;
1027                }
1028                stat->stat = function_stats;
1029                snprintf(name, 32, "function%d", cpu);
1030                stat->stat.name = name;
1031                ret = register_stat_tracer(&stat->stat);
1032                if (ret) {
1033                        WARN(1,
1034                             "Could not register function stat for cpu %d\n",
1035                             cpu);
1036                        kfree(name);
1037                        return;
1038                }
1039        }
1040
1041        entry = debugfs_create_file("function_profile_enabled", 0644,
1042                                    d_tracer, NULL, &ftrace_profile_fops);
1043        if (!entry)
1044                pr_warning("Could not create debugfs "
1045                           "'function_profile_enabled' entry\n");
1046}
1047
1048#else /* CONFIG_FUNCTION_PROFILER */
1049static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
1050{
1051}
1052#endif /* CONFIG_FUNCTION_PROFILER */
1053
1054static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1055
1056#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1057static int ftrace_graph_active;
1058#else
1059# define ftrace_graph_active 0
1060#endif
1061
1062#ifdef CONFIG_DYNAMIC_FTRACE
1063
1064static struct ftrace_ops *removed_ops;
1065
1066/*
1067 * Set when doing a global update, like enabling all recs or disabling them.
1068 * It is not set when just updating a single ftrace_ops.
1069 */
1070static bool update_all_ops;
1071
1072#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1073# error Dynamic ftrace depends on MCOUNT_RECORD
1074#endif
1075
1076static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1077
1078struct ftrace_func_probe {
1079        struct hlist_node       node;
1080        struct ftrace_probe_ops *ops;
1081        unsigned long           flags;
1082        unsigned long           ip;
1083        void                    *data;
1084        struct list_head        free_list;
1085};
1086
1087struct ftrace_func_entry {
1088        struct hlist_node hlist;
1089        unsigned long ip;
1090};
1091
1092struct ftrace_hash {
1093        unsigned long           size_bits;
1094        struct hlist_head       *buckets;
1095        unsigned long           count;
1096        struct rcu_head         rcu;
1097};
1098
1099/*
1100 * We make these constant because no one should touch them,
1101 * but they are used as the default "empty hash", to avoid allocating
1102 * it all the time. These are in a read only section such that if
1103 * anyone does try to modify it, it will cause an exception.
1104 */
1105static const struct hlist_head empty_buckets[1];
1106static const struct ftrace_hash empty_hash = {
1107        .buckets = (struct hlist_head *)empty_buckets,
1108};
1109#define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
1110
1111static struct ftrace_ops global_ops = {
1112        .func                           = ftrace_stub,
1113        .local_hash.notrace_hash        = EMPTY_HASH,
1114        .local_hash.filter_hash         = EMPTY_HASH,
1115        INIT_OPS_HASH(global_ops)
1116        .flags                          = FTRACE_OPS_FL_RECURSION_SAFE |
1117                                          FTRACE_OPS_FL_INITIALIZED,
1118};
1119
1120struct ftrace_page {
1121        struct ftrace_page      *next;
1122        struct dyn_ftrace       *records;
1123        int                     index;
1124        int                     size;
1125};
1126
1127#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1128#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1129
1130/* estimate from running different kernels */
1131#define NR_TO_INIT              10000
1132
1133static struct ftrace_page       *ftrace_pages_start;
1134static struct ftrace_page       *ftrace_pages;
1135
1136static bool __always_inline ftrace_hash_empty(struct ftrace_hash *hash)
1137{
1138        return !hash || !hash->count;
1139}
1140
1141static struct ftrace_func_entry *
1142ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1143{
1144        unsigned long key;
1145        struct ftrace_func_entry *entry;
1146        struct hlist_head *hhd;
1147
1148        if (ftrace_hash_empty(hash))
1149                return NULL;
1150
1151        if (hash->size_bits > 0)
1152                key = hash_long(ip, hash->size_bits);
1153        else
1154                key = 0;
1155
1156        hhd = &hash->buckets[key];
1157
1158        hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1159                if (entry->ip == ip)
1160                        return entry;
1161        }
1162        return NULL;
1163}
1164
1165static void __add_hash_entry(struct ftrace_hash *hash,
1166                             struct ftrace_func_entry *entry)
1167{
1168        struct hlist_head *hhd;
1169        unsigned long key;
1170
1171        if (hash->size_bits)
1172                key = hash_long(entry->ip, hash->size_bits);
1173        else
1174                key = 0;
1175
1176        hhd = &hash->buckets[key];
1177        hlist_add_head(&entry->hlist, hhd);
1178        hash->count++;
1179}
1180
1181static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1182{
1183        struct ftrace_func_entry *entry;
1184
1185        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1186        if (!entry)
1187                return -ENOMEM;
1188
1189        entry->ip = ip;
1190        __add_hash_entry(hash, entry);
1191
1192        return 0;
1193}
1194
1195static void
1196free_hash_entry(struct ftrace_hash *hash,
1197                  struct ftrace_func_entry *entry)
1198{
1199        hlist_del(&entry->hlist);
1200        kfree(entry);
1201        hash->count--;
1202}
1203
1204static void
1205remove_hash_entry(struct ftrace_hash *hash,
1206                  struct ftrace_func_entry *entry)
1207{
1208        hlist_del(&entry->hlist);
1209        hash->count--;
1210}
1211
1212static void ftrace_hash_clear(struct ftrace_hash *hash)
1213{
1214        struct hlist_head *hhd;
1215        struct hlist_node *tn;
1216        struct ftrace_func_entry *entry;
1217        int size = 1 << hash->size_bits;
1218        int i;
1219
1220        if (!hash->count)
1221                return;
1222
1223        for (i = 0; i < size; i++) {
1224                hhd = &hash->buckets[i];
1225                hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1226                        free_hash_entry(hash, entry);
1227        }
1228        FTRACE_WARN_ON(hash->count);
1229}
1230
1231static void free_ftrace_hash(struct ftrace_hash *hash)
1232{
1233        if (!hash || hash == EMPTY_HASH)
1234                return;
1235        ftrace_hash_clear(hash);
1236        kfree(hash->buckets);
1237        kfree(hash);
1238}
1239
1240static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1241{
1242        struct ftrace_hash *hash;
1243
1244        hash = container_of(rcu, struct ftrace_hash, rcu);
1245        free_ftrace_hash(hash);
1246}
1247
1248static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1249{
1250        if (!hash || hash == EMPTY_HASH)
1251                return;
1252        call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1253}
1254
1255void ftrace_free_filter(struct ftrace_ops *ops)
1256{
1257        ftrace_ops_init(ops);
1258        free_ftrace_hash(ops->func_hash->filter_hash);
1259        free_ftrace_hash(ops->func_hash->notrace_hash);
1260}
1261
1262static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1263{
1264        struct ftrace_hash *hash;
1265        int size;
1266
1267        hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1268        if (!hash)
1269                return NULL;
1270
1271        size = 1 << size_bits;
1272        hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1273
1274        if (!hash->buckets) {
1275                kfree(hash);
1276                return NULL;
1277        }
1278
1279        hash->size_bits = size_bits;
1280
1281        return hash;
1282}
1283
1284static struct ftrace_hash *
1285alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1286{
1287        struct ftrace_func_entry *entry;
1288        struct ftrace_hash *new_hash;
1289        int size;
1290        int ret;
1291        int i;
1292
1293        new_hash = alloc_ftrace_hash(size_bits);
1294        if (!new_hash)
1295                return NULL;
1296
1297        /* Empty hash? */
1298        if (ftrace_hash_empty(hash))
1299                return new_hash;
1300
1301        size = 1 << hash->size_bits;
1302        for (i = 0; i < size; i++) {
1303                hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1304                        ret = add_hash_entry(new_hash, entry->ip);
1305                        if (ret < 0)
1306                                goto free_hash;
1307                }
1308        }
1309
1310        FTRACE_WARN_ON(new_hash->count != hash->count);
1311
1312        return new_hash;
1313
1314 free_hash:
1315        free_ftrace_hash(new_hash);
1316        return NULL;
1317}
1318
1319static void
1320ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1321static void
1322ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1323
1324static int
1325ftrace_hash_move(struct ftrace_ops *ops, int enable,
1326                 struct ftrace_hash **dst, struct ftrace_hash *src)
1327{
1328        struct ftrace_func_entry *entry;
1329        struct hlist_node *tn;
1330        struct hlist_head *hhd;
1331        struct ftrace_hash *new_hash;
1332        int size = src->count;
1333        int bits = 0;
1334        int i;
1335
1336        /*
1337         * If the new source is empty, just free dst and assign it
1338         * the empty_hash.
1339         */
1340        if (!src->count) {
1341                new_hash = EMPTY_HASH;
1342                goto update;
1343        }
1344
1345        /*
1346         * Make the hash size about 1/2 the # found
1347         */
1348        for (size /= 2; size; size >>= 1)
1349                bits++;
1350
1351        /* Don't allocate too much */
1352        if (bits > FTRACE_HASH_MAX_BITS)
1353                bits = FTRACE_HASH_MAX_BITS;
1354
1355        new_hash = alloc_ftrace_hash(bits);
1356        if (!new_hash)
1357                return -ENOMEM;
1358
1359        size = 1 << src->size_bits;
1360        for (i = 0; i < size; i++) {
1361                hhd = &src->buckets[i];
1362                hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1363                        remove_hash_entry(src, entry);
1364                        __add_hash_entry(new_hash, entry);
1365                }
1366        }
1367
1368update:
1369        /*
1370         * Remove the current set, update the hash and add
1371         * them back.
1372         */
1373        ftrace_hash_rec_disable_modify(ops, enable);
1374
1375        rcu_assign_pointer(*dst, new_hash);
1376
1377        ftrace_hash_rec_enable_modify(ops, enable);
1378
1379        return 0;
1380}
1381
1382static bool hash_contains_ip(unsigned long ip,
1383                             struct ftrace_ops_hash *hash)
1384{
1385        /*
1386         * The function record is a match if it exists in the filter
1387         * hash and not in the notrace hash. Note, an emty hash is
1388         * considered a match for the filter hash, but an empty
1389         * notrace hash is considered not in the notrace hash.
1390         */
1391        return (ftrace_hash_empty(hash->filter_hash) ||
1392                ftrace_lookup_ip(hash->filter_hash, ip)) &&
1393                (ftrace_hash_empty(hash->notrace_hash) ||
1394                 !ftrace_lookup_ip(hash->notrace_hash, ip));
1395}
1396
1397/*
1398 * Test the hashes for this ops to see if we want to call
1399 * the ops->func or not.
1400 *
1401 * It's a match if the ip is in the ops->filter_hash or
1402 * the filter_hash does not exist or is empty,
1403 *  AND
1404 * the ip is not in the ops->notrace_hash.
1405 *
1406 * This needs to be called with preemption disabled as
1407 * the hashes are freed with call_rcu_sched().
1408 */
1409static int
1410ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1411{
1412        struct ftrace_ops_hash hash;
1413        int ret;
1414
1415#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1416        /*
1417         * There's a small race when adding ops that the ftrace handler
1418         * that wants regs, may be called without them. We can not
1419         * allow that handler to be called if regs is NULL.
1420         */
1421        if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1422                return 0;
1423#endif
1424
1425        hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash);
1426        hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash);
1427
1428        if (hash_contains_ip(ip, &hash))
1429                ret = 1;
1430        else
1431                ret = 0;
1432
1433        return ret;
1434}
1435
1436/*
1437 * This is a double for. Do not use 'break' to break out of the loop,
1438 * you must use a goto.
1439 */
1440#define do_for_each_ftrace_rec(pg, rec)                                 \
1441        for (pg = ftrace_pages_start; pg; pg = pg->next) {              \
1442                int _____i;                                             \
1443                for (_____i = 0; _____i < pg->index; _____i++) {        \
1444                        rec = &pg->records[_____i];
1445
1446#define while_for_each_ftrace_rec()             \
1447                }                               \
1448        }
1449
1450
1451static int ftrace_cmp_recs(const void *a, const void *b)
1452{
1453        const struct dyn_ftrace *key = a;
1454        const struct dyn_ftrace *rec = b;
1455
1456        if (key->flags < rec->ip)
1457                return -1;
1458        if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1459                return 1;
1460        return 0;
1461}
1462
1463static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1464{
1465        struct ftrace_page *pg;
1466        struct dyn_ftrace *rec;
1467        struct dyn_ftrace key;
1468
1469        key.ip = start;
1470        key.flags = end;        /* overload flags, as it is unsigned long */
1471
1472        for (pg = ftrace_pages_start; pg; pg = pg->next) {
1473                if (end < pg->records[0].ip ||
1474                    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1475                        continue;
1476                rec = bsearch(&key, pg->records, pg->index,
1477                              sizeof(struct dyn_ftrace),
1478                              ftrace_cmp_recs);
1479                if (rec)
1480                        return rec->ip;
1481        }
1482
1483        return 0;
1484}
1485
1486/**
1487 * ftrace_location - return true if the ip giving is a traced location
1488 * @ip: the instruction pointer to check
1489 *
1490 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1491 * That is, the instruction that is either a NOP or call to
1492 * the function tracer. It checks the ftrace internal tables to
1493 * determine if the address belongs or not.
1494 */
1495unsigned long ftrace_location(unsigned long ip)
1496{
1497        return ftrace_location_range(ip, ip);
1498}
1499
1500/**
1501 * ftrace_text_reserved - return true if range contains an ftrace location
1502 * @start: start of range to search
1503 * @end: end of range to search (inclusive). @end points to the last byte to check.
1504 *
1505 * Returns 1 if @start and @end contains a ftrace location.
1506 * That is, the instruction that is either a NOP or call to
1507 * the function tracer. It checks the ftrace internal tables to
1508 * determine if the address belongs or not.
1509 */
1510int ftrace_text_reserved(const void *start, const void *end)
1511{
1512        unsigned long ret;
1513
1514        ret = ftrace_location_range((unsigned long)start,
1515                                    (unsigned long)end);
1516
1517        return (int)!!ret;
1518}
1519
1520/* Test if ops registered to this rec needs regs */
1521static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1522{
1523        struct ftrace_ops *ops;
1524        bool keep_regs = false;
1525
1526        for (ops = ftrace_ops_list;
1527             ops != &ftrace_list_end; ops = ops->next) {
1528                /* pass rec in as regs to have non-NULL val */
1529                if (ftrace_ops_test(ops, rec->ip, rec)) {
1530                        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1531                                keep_regs = true;
1532                                break;
1533                        }
1534                }
1535        }
1536
1537        return  keep_regs;
1538}
1539
1540static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
1541                                     int filter_hash,
1542                                     bool inc)
1543{
1544        struct ftrace_hash *hash;
1545        struct ftrace_hash *other_hash;
1546        struct ftrace_page *pg;
1547        struct dyn_ftrace *rec;
1548        int count = 0;
1549        int all = 0;
1550
1551        /* Only update if the ops has been registered */
1552        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1553                return;
1554
1555        /*
1556         * In the filter_hash case:
1557         *   If the count is zero, we update all records.
1558         *   Otherwise we just update the items in the hash.
1559         *
1560         * In the notrace_hash case:
1561         *   We enable the update in the hash.
1562         *   As disabling notrace means enabling the tracing,
1563         *   and enabling notrace means disabling, the inc variable
1564         *   gets inversed.
1565         */
1566        if (filter_hash) {
1567                hash = ops->func_hash->filter_hash;
1568                other_hash = ops->func_hash->notrace_hash;
1569                if (ftrace_hash_empty(hash))
1570                        all = 1;
1571        } else {
1572                inc = !inc;
1573                hash = ops->func_hash->notrace_hash;
1574                other_hash = ops->func_hash->filter_hash;
1575                /*
1576                 * If the notrace hash has no items,
1577                 * then there's nothing to do.
1578                 */
1579                if (ftrace_hash_empty(hash))
1580                        return;
1581        }
1582
1583        do_for_each_ftrace_rec(pg, rec) {
1584                int in_other_hash = 0;
1585                int in_hash = 0;
1586                int match = 0;
1587
1588                if (all) {
1589                        /*
1590                         * Only the filter_hash affects all records.
1591                         * Update if the record is not in the notrace hash.
1592                         */
1593                        if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1594                                match = 1;
1595                } else {
1596                        in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1597                        in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1598
1599                        /*
1600                         * If filter_hash is set, we want to match all functions
1601                         * that are in the hash but not in the other hash.
1602                         *
1603                         * If filter_hash is not set, then we are decrementing.
1604                         * That means we match anything that is in the hash
1605                         * and also in the other_hash. That is, we need to turn
1606                         * off functions in the other hash because they are disabled
1607                         * by this hash.
1608                         */
1609                        if (filter_hash && in_hash && !in_other_hash)
1610                                match = 1;
1611                        else if (!filter_hash && in_hash &&
1612                                 (in_other_hash || ftrace_hash_empty(other_hash)))
1613                                match = 1;
1614                }
1615                if (!match)
1616                        continue;
1617
1618                if (inc) {
1619                        rec->flags++;
1620                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1621                                return;
1622
1623                        /*
1624                         * If there's only a single callback registered to a
1625                         * function, and the ops has a trampoline registered
1626                         * for it, then we can call it directly.
1627                         */
1628                        if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1629                                rec->flags |= FTRACE_FL_TRAMP;
1630                        else
1631                                /*
1632                                 * If we are adding another function callback
1633                                 * to this function, and the previous had a
1634                                 * custom trampoline in use, then we need to go
1635                                 * back to the default trampoline.
1636                                 */
1637                                rec->flags &= ~FTRACE_FL_TRAMP;
1638
1639                        /*
1640                         * If any ops wants regs saved for this function
1641                         * then all ops will get saved regs.
1642                         */
1643                        if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1644                                rec->flags |= FTRACE_FL_REGS;
1645                } else {
1646                        if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1647                                return;
1648                        rec->flags--;
1649
1650                        /*
1651                         * If the rec had REGS enabled and the ops that is
1652                         * being removed had REGS set, then see if there is
1653                         * still any ops for this record that wants regs.
1654                         * If not, we can stop recording them.
1655                         */
1656                        if (ftrace_rec_count(rec) > 0 &&
1657                            rec->flags & FTRACE_FL_REGS &&
1658                            ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1659                                if (!test_rec_ops_needs_regs(rec))
1660                                        rec->flags &= ~FTRACE_FL_REGS;
1661                        }
1662
1663                        /*
1664                         * If the rec had TRAMP enabled, then it needs to
1665                         * be cleared. As TRAMP can only be enabled iff
1666                         * there is only a single ops attached to it.
1667                         * In otherwords, always disable it on decrementing.
1668                         * In the future, we may set it if rec count is
1669                         * decremented to one, and the ops that is left
1670                         * has a trampoline.
1671                         */
1672                        rec->flags &= ~FTRACE_FL_TRAMP;
1673
1674                        /*
1675                         * flags will be cleared in ftrace_check_record()
1676                         * if rec count is zero.
1677                         */
1678                }
1679                count++;
1680                /* Shortcut, if we handled all records, we are done. */
1681                if (!all && count == hash->count)
1682                        return;
1683        } while_for_each_ftrace_rec();
1684}
1685
1686static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1687                                    int filter_hash)
1688{
1689        __ftrace_hash_rec_update(ops, filter_hash, 0);
1690}
1691
1692static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1693                                   int filter_hash)
1694{
1695        __ftrace_hash_rec_update(ops, filter_hash, 1);
1696}
1697
1698static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1699                                          int filter_hash, int inc)
1700{
1701        struct ftrace_ops *op;
1702
1703        __ftrace_hash_rec_update(ops, filter_hash, inc);
1704
1705        if (ops->func_hash != &global_ops.local_hash)
1706                return;
1707
1708        /*
1709         * If the ops shares the global_ops hash, then we need to update
1710         * all ops that are enabled and use this hash.
1711         */
1712        do_for_each_ftrace_op(op, ftrace_ops_list) {
1713                /* Already done */
1714                if (op == ops)
1715                        continue;
1716                if (op->func_hash == &global_ops.local_hash)
1717                        __ftrace_hash_rec_update(op, filter_hash, inc);
1718        } while_for_each_ftrace_op(op);
1719}
1720
1721static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1722                                           int filter_hash)
1723{
1724        ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1725}
1726
1727static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1728                                          int filter_hash)
1729{
1730        ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1731}
1732
1733static void print_ip_ins(const char *fmt, unsigned char *p)
1734{
1735        int i;
1736
1737        printk(KERN_CONT "%s", fmt);
1738
1739        for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1740                printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1741}
1742
1743/**
1744 * ftrace_bug - report and shutdown function tracer
1745 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1746 * @ip: The address that failed
1747 *
1748 * The arch code that enables or disables the function tracing
1749 * can call ftrace_bug() when it has detected a problem in
1750 * modifying the code. @failed should be one of either:
1751 * EFAULT - if the problem happens on reading the @ip address
1752 * EINVAL - if what is read at @ip is not what was expected
1753 * EPERM - if the problem happens on writting to the @ip address
1754 */
1755void ftrace_bug(int failed, unsigned long ip)
1756{
1757        switch (failed) {
1758        case -EFAULT:
1759                FTRACE_WARN_ON_ONCE(1);
1760                pr_info("ftrace faulted on modifying ");
1761                print_ip_sym(ip);
1762                break;
1763        case -EINVAL:
1764                FTRACE_WARN_ON_ONCE(1);
1765                pr_info("ftrace failed to modify ");
1766                print_ip_sym(ip);
1767                print_ip_ins(" actual: ", (unsigned char *)ip);
1768                printk(KERN_CONT "\n");
1769                break;
1770        case -EPERM:
1771                FTRACE_WARN_ON_ONCE(1);
1772                pr_info("ftrace faulted on writing ");
1773                print_ip_sym(ip);
1774                break;
1775        default:
1776                FTRACE_WARN_ON_ONCE(1);
1777                pr_info("ftrace faulted on unknown error ");
1778                print_ip_sym(ip);
1779        }
1780}
1781
1782static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1783{
1784        unsigned long flag = 0UL;
1785
1786        /*
1787         * If we are updating calls:
1788         *
1789         *   If the record has a ref count, then we need to enable it
1790         *   because someone is using it.
1791         *
1792         *   Otherwise we make sure its disabled.
1793         *
1794         * If we are disabling calls, then disable all records that
1795         * are enabled.
1796         */
1797        if (enable && ftrace_rec_count(rec))
1798                flag = FTRACE_FL_ENABLED;
1799
1800        /*
1801         * If enabling and the REGS flag does not match the REGS_EN, or
1802         * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
1803         * this record. Set flags to fail the compare against ENABLED.
1804         */
1805        if (flag) {
1806                if (!(rec->flags & FTRACE_FL_REGS) !=
1807                    !(rec->flags & FTRACE_FL_REGS_EN))
1808                        flag |= FTRACE_FL_REGS;
1809
1810                if (!(rec->flags & FTRACE_FL_TRAMP) !=
1811                    !(rec->flags & FTRACE_FL_TRAMP_EN))
1812                        flag |= FTRACE_FL_TRAMP;
1813        }
1814
1815        /* If the state of this record hasn't changed, then do nothing */
1816        if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1817                return FTRACE_UPDATE_IGNORE;
1818
1819        if (flag) {
1820                /* Save off if rec is being enabled (for return value) */
1821                flag ^= rec->flags & FTRACE_FL_ENABLED;
1822
1823                if (update) {
1824                        rec->flags |= FTRACE_FL_ENABLED;
1825                        if (flag & FTRACE_FL_REGS) {
1826                                if (rec->flags & FTRACE_FL_REGS)
1827                                        rec->flags |= FTRACE_FL_REGS_EN;
1828                                else
1829                                        rec->flags &= ~FTRACE_FL_REGS_EN;
1830                        }
1831                        if (flag & FTRACE_FL_TRAMP) {
1832                                if (rec->flags & FTRACE_FL_TRAMP)
1833                                        rec->flags |= FTRACE_FL_TRAMP_EN;
1834                                else
1835                                        rec->flags &= ~FTRACE_FL_TRAMP_EN;
1836                        }
1837                }
1838
1839                /*
1840                 * If this record is being updated from a nop, then
1841                 *   return UPDATE_MAKE_CALL.
1842                 * Otherwise,
1843                 *   return UPDATE_MODIFY_CALL to tell the caller to convert
1844                 *   from the save regs, to a non-save regs function or
1845                 *   vice versa, or from a trampoline call.
1846                 */
1847                if (flag & FTRACE_FL_ENABLED)
1848                        return FTRACE_UPDATE_MAKE_CALL;
1849
1850                return FTRACE_UPDATE_MODIFY_CALL;
1851        }
1852
1853        if (update) {
1854                /* If there's no more users, clear all flags */
1855                if (!ftrace_rec_count(rec))
1856                        rec->flags = 0;
1857                else
1858                        /*
1859                         * Just disable the record, but keep the ops TRAMP
1860                         * and REGS states. The _EN flags must be disabled though.
1861                         */
1862                        rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
1863                                        FTRACE_FL_REGS_EN);
1864        }
1865
1866        return FTRACE_UPDATE_MAKE_NOP;
1867}
1868
1869/**
1870 * ftrace_update_record, set a record that now is tracing or not
1871 * @rec: the record to update
1872 * @enable: set to 1 if the record is tracing, zero to force disable
1873 *
1874 * The records that represent all functions that can be traced need
1875 * to be updated when tracing has been enabled.
1876 */
1877int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1878{
1879        return ftrace_check_record(rec, enable, 1);
1880}
1881
1882/**
1883 * ftrace_test_record, check if the record has been enabled or not
1884 * @rec: the record to test
1885 * @enable: set to 1 to check if enabled, 0 if it is disabled
1886 *
1887 * The arch code may need to test if a record is already set to
1888 * tracing to determine how to modify the function code that it
1889 * represents.
1890 */
1891int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1892{
1893        return ftrace_check_record(rec, enable, 0);
1894}
1895
1896static struct ftrace_ops *
1897ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
1898{
1899        struct ftrace_ops *op;
1900        unsigned long ip = rec->ip;
1901
1902        do_for_each_ftrace_op(op, ftrace_ops_list) {
1903
1904                if (!op->trampoline)
1905                        continue;
1906
1907                if (hash_contains_ip(ip, op->func_hash))
1908                        return op;
1909        } while_for_each_ftrace_op(op);
1910
1911        return NULL;
1912}
1913
1914static struct ftrace_ops *
1915ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
1916{
1917        struct ftrace_ops *op;
1918        unsigned long ip = rec->ip;
1919
1920        /*
1921         * Need to check removed ops first.
1922         * If they are being removed, and this rec has a tramp,
1923         * and this rec is in the ops list, then it would be the
1924         * one with the tramp.
1925         */
1926        if (removed_ops) {
1927                if (hash_contains_ip(ip, &removed_ops->old_hash))
1928                        return removed_ops;
1929        }
1930
1931        /*
1932         * Need to find the current trampoline for a rec.
1933         * Now, a trampoline is only attached to a rec if there
1934         * was a single 'ops' attached to it. But this can be called
1935         * when we are adding another op to the rec or removing the
1936         * current one. Thus, if the op is being added, we can
1937         * ignore it because it hasn't attached itself to the rec
1938         * yet.
1939         *
1940         * If an ops is being modified (hooking to different functions)
1941         * then we don't care about the new functions that are being
1942         * added, just the old ones (that are probably being removed).
1943         *
1944         * If we are adding an ops to a function that already is using
1945         * a trampoline, it needs to be removed (trampolines are only
1946         * for single ops connected), then an ops that is not being
1947         * modified also needs to be checked.
1948         */
1949        do_for_each_ftrace_op(op, ftrace_ops_list) {
1950
1951                if (!op->trampoline)
1952                        continue;
1953
1954                /*
1955                 * If the ops is being added, it hasn't gotten to
1956                 * the point to be removed from this tree yet.
1957                 */
1958                if (op->flags & FTRACE_OPS_FL_ADDING)
1959                        continue;
1960
1961
1962                /*
1963                 * If the ops is being modified and is in the old
1964                 * hash, then it is probably being removed from this
1965                 * function.
1966                 */
1967                if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
1968                    hash_contains_ip(ip, &op->old_hash))
1969                        return op;
1970                /*
1971                 * If the ops is not being added or modified, and it's
1972                 * in its normal filter hash, then this must be the one
1973                 * we want!
1974                 */
1975                if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
1976                    hash_contains_ip(ip, op->func_hash))
1977                        return op;
1978
1979        } while_for_each_ftrace_op(op);
1980
1981        return NULL;
1982}
1983
1984static struct ftrace_ops *
1985ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
1986{
1987        struct ftrace_ops *op;
1988        unsigned long ip = rec->ip;
1989
1990        do_for_each_ftrace_op(op, ftrace_ops_list) {
1991                /* pass rec in as regs to have non-NULL val */
1992                if (hash_contains_ip(ip, op->func_hash))
1993                        return op;
1994        } while_for_each_ftrace_op(op);
1995
1996        return NULL;
1997}
1998
1999/**
2000 * ftrace_get_addr_new - Get the call address to set to
2001 * @rec:  The ftrace record descriptor
2002 *
2003 * If the record has the FTRACE_FL_REGS set, that means that it
2004 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2005 * is not not set, then it wants to convert to the normal callback.
2006 *
2007 * Returns the address of the trampoline to set to
2008 */
2009unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2010{
2011        struct ftrace_ops *ops;
2012
2013        /* Trampolines take precedence over regs */
2014        if (rec->flags & FTRACE_FL_TRAMP) {
2015                ops = ftrace_find_tramp_ops_new(rec);
2016                if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2017                        pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2018                                (void *)rec->ip, (void *)rec->ip, rec->flags);
2019                        /* Ftrace is shutting down, return anything */
2020                        return (unsigned long)FTRACE_ADDR;
2021                }
2022                return ops->trampoline;
2023        }
2024
2025        if (rec->flags & FTRACE_FL_REGS)
2026                return (unsigned long)FTRACE_REGS_ADDR;
2027        else
2028                return (unsigned long)FTRACE_ADDR;
2029}
2030
2031/**
2032 * ftrace_get_addr_curr - Get the call address that is already there
2033 * @rec:  The ftrace record descriptor
2034 *
2035 * The FTRACE_FL_REGS_EN is set when the record already points to
2036 * a function that saves all the regs. Basically the '_EN' version
2037 * represents the current state of the function.
2038 *
2039 * Returns the address of the trampoline that is currently being called
2040 */
2041unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2042{
2043        struct ftrace_ops *ops;
2044
2045        /* Trampolines take precedence over regs */
2046        if (rec->flags & FTRACE_FL_TRAMP_EN) {
2047                ops = ftrace_find_tramp_ops_curr(rec);
2048                if (FTRACE_WARN_ON(!ops)) {
2049                        pr_warning("Bad trampoline accounting at: %p (%pS)\n",
2050                                    (void *)rec->ip, (void *)rec->ip);
2051                        /* Ftrace is shutting down, return anything */
2052                        return (unsigned long)FTRACE_ADDR;
2053                }
2054                return ops->trampoline;
2055        }
2056
2057        if (rec->flags & FTRACE_FL_REGS_EN)
2058                return (unsigned long)FTRACE_REGS_ADDR;
2059        else
2060                return (unsigned long)FTRACE_ADDR;
2061}
2062
2063static int
2064__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
2065{
2066        unsigned long ftrace_old_addr;
2067        unsigned long ftrace_addr;
2068        int ret;
2069
2070        ftrace_addr = ftrace_get_addr_new(rec);
2071
2072        /* This needs to be done before we call ftrace_update_record */
2073        ftrace_old_addr = ftrace_get_addr_curr(rec);
2074
2075        ret = ftrace_update_record(rec, enable);
2076
2077        switch (ret) {
2078        case FTRACE_UPDATE_IGNORE:
2079                return 0;
2080
2081        case FTRACE_UPDATE_MAKE_CALL:
2082                return ftrace_make_call(rec, ftrace_addr);
2083
2084        case FTRACE_UPDATE_MAKE_NOP:
2085                return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2086
2087        case FTRACE_UPDATE_MODIFY_CALL:
2088                return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2089        }
2090
2091        return -1; /* unknow ftrace bug */
2092}
2093
2094void __weak ftrace_replace_code(int enable)
2095{
2096        struct dyn_ftrace *rec;
2097        struct ftrace_page *pg;
2098        int failed;
2099
2100        if (unlikely(ftrace_disabled))
2101                return;
2102
2103        do_for_each_ftrace_rec(pg, rec) {
2104                failed = __ftrace_replace_code(rec, enable);
2105                if (failed) {
2106                        ftrace_bug(failed, rec->ip);
2107                        /* Stop processing */
2108                        return;
2109                }
2110        } while_for_each_ftrace_rec();
2111}
2112
2113struct ftrace_rec_iter {
2114        struct ftrace_page      *pg;
2115        int                     index;
2116};
2117
2118/**
2119 * ftrace_rec_iter_start, start up iterating over traced functions
2120 *
2121 * Returns an iterator handle that is used to iterate over all
2122 * the records that represent address locations where functions
2123 * are traced.
2124 *
2125 * May return NULL if no records are available.
2126 */
2127struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2128{
2129        /*
2130         * We only use a single iterator.
2131         * Protected by the ftrace_lock mutex.
2132         */
2133        static struct ftrace_rec_iter ftrace_rec_iter;
2134        struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2135
2136        iter->pg = ftrace_pages_start;
2137        iter->index = 0;
2138
2139        /* Could have empty pages */
2140        while (iter->pg && !iter->pg->index)
2141                iter->pg = iter->pg->next;
2142
2143        if (!iter->pg)
2144                return NULL;
2145
2146        return iter;
2147}
2148
2149/**
2150 * ftrace_rec_iter_next, get the next record to process.
2151 * @iter: The handle to the iterator.
2152 *
2153 * Returns the next iterator after the given iterator @iter.
2154 */
2155struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2156{
2157        iter->index++;
2158
2159        if (iter->index >= iter->pg->index) {
2160                iter->pg = iter->pg->next;
2161                iter->index = 0;
2162
2163                /* Could have empty pages */
2164                while (iter->pg && !iter->pg->index)
2165                        iter->pg = iter->pg->next;
2166        }
2167
2168        if (!iter->pg)
2169                return NULL;
2170
2171        return iter;
2172}
2173
2174/**
2175 * ftrace_rec_iter_record, get the record at the iterator location
2176 * @iter: The current iterator location
2177 *
2178 * Returns the record that the current @iter is at.
2179 */
2180struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2181{
2182        return &iter->pg->records[iter->index];
2183}
2184
2185static int
2186ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2187{
2188        unsigned long ip;
2189        int ret;
2190
2191        ip = rec->ip;
2192
2193        if (unlikely(ftrace_disabled))
2194                return 0;
2195
2196        ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2197        if (ret) {
2198                ftrace_bug(ret, ip);
2199                return 0;
2200        }
2201        return 1;
2202}
2203
2204/*
2205 * archs can override this function if they must do something
2206 * before the modifying code is performed.
2207 */
2208int __weak ftrace_arch_code_modify_prepare(void)
2209{
2210        return 0;
2211}
2212
2213/*
2214 * archs can override this function if they must do something
2215 * after the modifying code is performed.
2216 */
2217int __weak ftrace_arch_code_modify_post_process(void)
2218{
2219        return 0;
2220}
2221
2222void ftrace_modify_all_code(int command)
2223{
2224        int update = command & FTRACE_UPDATE_TRACE_FUNC;
2225        int err = 0;
2226
2227        /*
2228         * If the ftrace_caller calls a ftrace_ops func directly,
2229         * we need to make sure that it only traces functions it
2230         * expects to trace. When doing the switch of functions,
2231         * we need to update to the ftrace_ops_list_func first
2232         * before the transition between old and new calls are set,
2233         * as the ftrace_ops_list_func will check the ops hashes
2234         * to make sure the ops are having the right functions
2235         * traced.
2236         */
2237        if (update) {
2238                err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2239                if (FTRACE_WARN_ON(err))
2240                        return;
2241        }
2242
2243        if (command & FTRACE_UPDATE_CALLS)
2244                ftrace_replace_code(1);
2245        else if (command & FTRACE_DISABLE_CALLS)
2246                ftrace_replace_code(0);
2247
2248        if (update && ftrace_trace_function != ftrace_ops_list_func) {
2249                function_trace_op = set_function_trace_op;
2250                smp_wmb();
2251                /* If irqs are disabled, we are in stop machine */
2252                if (!irqs_disabled())
2253                        smp_call_function(ftrace_sync_ipi, NULL, 1);
2254                err = ftrace_update_ftrace_func(ftrace_trace_function);
2255                if (FTRACE_WARN_ON(err))
2256                        return;
2257        }
2258
2259        if (command & FTRACE_START_FUNC_RET)
2260                err = ftrace_enable_ftrace_graph_caller();
2261        else if (command & FTRACE_STOP_FUNC_RET)
2262                err = ftrace_disable_ftrace_graph_caller();
2263        FTRACE_WARN_ON(err);
2264}
2265
2266static int __ftrace_modify_code(void *data)
2267{
2268        int *command = data;
2269
2270        ftrace_modify_all_code(*command);
2271
2272        return 0;
2273}
2274
2275/**
2276 * ftrace_run_stop_machine, go back to the stop machine method
2277 * @command: The command to tell ftrace what to do
2278 *
2279 * If an arch needs to fall back to the stop machine method, the
2280 * it can call this function.
2281 */
2282void ftrace_run_stop_machine(int command)
2283{
2284        stop_machine(__ftrace_modify_code, &command, NULL);
2285}
2286
2287/**
2288 * arch_ftrace_update_code, modify the code to trace or not trace
2289 * @command: The command that needs to be done
2290 *
2291 * Archs can override this function if it does not need to
2292 * run stop_machine() to modify code.
2293 */
2294void __weak arch_ftrace_update_code(int command)
2295{
2296        ftrace_run_stop_machine(command);
2297}
2298
2299static void ftrace_run_update_code(int command)
2300{
2301        int ret;
2302
2303        ret = ftrace_arch_code_modify_prepare();
2304        FTRACE_WARN_ON(ret);
2305        if (ret)
2306                return;
2307
2308        /*
2309         * By default we use stop_machine() to modify the code.
2310         * But archs can do what ever they want as long as it
2311         * is safe. The stop_machine() is the safest, but also
2312         * produces the most overhead.
2313         */
2314        arch_ftrace_update_code(command);
2315
2316        ret = ftrace_arch_code_modify_post_process();
2317        FTRACE_WARN_ON(ret);
2318}
2319
2320static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2321                                   struct ftrace_ops_hash *old_hash)
2322{
2323        ops->flags |= FTRACE_OPS_FL_MODIFYING;
2324        ops->old_hash.filter_hash = old_hash->filter_hash;
2325        ops->old_hash.notrace_hash = old_hash->notrace_hash;
2326        ftrace_run_update_code(command);
2327        ops->old_hash.filter_hash = NULL;
2328        ops->old_hash.notrace_hash = NULL;
2329        ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2330}
2331
2332static ftrace_func_t saved_ftrace_func;
2333static int ftrace_start_up;
2334
2335static void control_ops_free(struct ftrace_ops *ops)
2336{
2337        free_percpu(ops->disabled);
2338}
2339
2340static void ftrace_startup_enable(int command)
2341{
2342        if (saved_ftrace_func != ftrace_trace_function) {
2343                saved_ftrace_func = ftrace_trace_function;
2344                command |= FTRACE_UPDATE_TRACE_FUNC;
2345        }
2346
2347        if (!command || !ftrace_enabled)
2348                return;
2349
2350        ftrace_run_update_code(command);
2351}
2352
2353static void ftrace_startup_all(int command)
2354{
2355        update_all_ops = true;
2356        ftrace_startup_enable(command);
2357        update_all_ops = false;
2358}
2359
2360static int ftrace_startup(struct ftrace_ops *ops, int command)
2361{
2362        int ret;
2363
2364        if (unlikely(ftrace_disabled))
2365                return -ENODEV;
2366
2367        ret = __register_ftrace_function(ops);
2368        if (ret)
2369                return ret;
2370
2371        ftrace_start_up++;
2372        command |= FTRACE_UPDATE_CALLS;
2373
2374        /*
2375         * Note that ftrace probes uses this to start up
2376         * and modify functions it will probe. But we still
2377         * set the ADDING flag for modification, as probes
2378         * do not have trampolines. If they add them in the
2379         * future, then the probes will need to distinguish
2380         * between adding and updating probes.
2381         */
2382        ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2383
2384        ftrace_hash_rec_enable(ops, 1);
2385
2386        ftrace_startup_enable(command);
2387
2388        ops->flags &= ~FTRACE_OPS_FL_ADDING;
2389
2390        return 0;
2391}
2392
2393static int ftrace_shutdown(struct ftrace_ops *ops, int command)
2394{
2395        int ret;
2396
2397        if (unlikely(ftrace_disabled))
2398                return -ENODEV;
2399
2400        ret = __unregister_ftrace_function(ops);
2401        if (ret)
2402                return ret;
2403
2404        ftrace_start_up--;
2405        /*
2406         * Just warn in case of unbalance, no need to kill ftrace, it's not
2407         * critical but the ftrace_call callers may be never nopped again after
2408         * further ftrace uses.
2409         */
2410        WARN_ON_ONCE(ftrace_start_up < 0);
2411
2412        ftrace_hash_rec_disable(ops, 1);
2413
2414        ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2415
2416        command |= FTRACE_UPDATE_CALLS;
2417
2418        if (saved_ftrace_func != ftrace_trace_function) {
2419                saved_ftrace_func = ftrace_trace_function;
2420                command |= FTRACE_UPDATE_TRACE_FUNC;
2421        }
2422
2423        if (!command || !ftrace_enabled) {
2424                /*
2425                 * If these are control ops, they still need their
2426                 * per_cpu field freed. Since, function tracing is
2427                 * not currently active, we can just free them
2428                 * without synchronizing all CPUs.
2429                 */
2430                if (ops->flags & FTRACE_OPS_FL_CONTROL)
2431                        control_ops_free(ops);
2432                return 0;
2433        }
2434
2435        /*
2436         * If the ops uses a trampoline, then it needs to be
2437         * tested first on update.
2438         */
2439        ops->flags |= FTRACE_OPS_FL_REMOVING;
2440        removed_ops = ops;
2441
2442        /* The trampoline logic checks the old hashes */
2443        ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2444        ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2445
2446        ftrace_run_update_code(command);
2447
2448        /*
2449         * If there's no more ops registered with ftrace, run a
2450         * sanity check to make sure all rec flags are cleared.
2451         */
2452        if (ftrace_ops_list == &ftrace_list_end) {
2453                struct ftrace_page *pg;
2454                struct dyn_ftrace *rec;
2455
2456                do_for_each_ftrace_rec(pg, rec) {
2457                        if (FTRACE_WARN_ON_ONCE(rec->flags))
2458                                pr_warn("  %pS flags:%lx\n",
2459                                        (void *)rec->ip, rec->flags);
2460                } while_for_each_ftrace_rec();
2461        }
2462
2463        ops->old_hash.filter_hash = NULL;
2464        ops->old_hash.notrace_hash = NULL;
2465
2466        removed_ops = NULL;
2467        ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2468
2469        /*
2470         * Dynamic ops may be freed, we must make sure that all
2471         * callers are done before leaving this function.
2472         * The same goes for freeing the per_cpu data of the control
2473         * ops.
2474         *
2475         * Again, normal synchronize_sched() is not good enough.
2476         * We need to do a hard force of sched synchronization.
2477         * This is because we use preempt_disable() to do RCU, but
2478         * the function tracers can be called where RCU is not watching
2479         * (like before user_exit()). We can not rely on the RCU
2480         * infrastructure to do the synchronization, thus we must do it
2481         * ourselves.
2482         */
2483        if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
2484                schedule_on_each_cpu(ftrace_sync);
2485
2486                if (ops->flags & FTRACE_OPS_FL_CONTROL)
2487                        control_ops_free(ops);
2488        }
2489
2490        return 0;
2491}
2492
2493static void ftrace_startup_sysctl(void)
2494{
2495        int command;
2496
2497        if (unlikely(ftrace_disabled))
2498                return;
2499
2500        /* Force update next time */
2501        saved_ftrace_func = NULL;
2502        /* ftrace_start_up is true if we want ftrace running */
2503        if (ftrace_start_up) {
2504                command = FTRACE_UPDATE_CALLS;
2505                if (ftrace_graph_active)
2506                        command |= FTRACE_START_FUNC_RET;
2507                ftrace_startup_enable(command);
2508        }
2509}
2510
2511static void ftrace_shutdown_sysctl(void)
2512{
2513        int command;
2514
2515        if (unlikely(ftrace_disabled))
2516                return;
2517
2518        /* ftrace_start_up is true if ftrace is running */
2519        if (ftrace_start_up) {
2520                command = FTRACE_DISABLE_CALLS;
2521                if (ftrace_graph_active)
2522                        command |= FTRACE_STOP_FUNC_RET;
2523                ftrace_run_update_code(command);
2524        }
2525}
2526
2527static cycle_t          ftrace_update_time;
2528unsigned long           ftrace_update_tot_cnt;
2529
2530static inline int ops_traces_mod(struct ftrace_ops *ops)
2531{
2532        /*
2533         * Filter_hash being empty will default to trace module.
2534         * But notrace hash requires a test of individual module functions.
2535         */
2536        return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2537                ftrace_hash_empty(ops->func_hash->notrace_hash);
2538}
2539
2540/*
2541 * Check if the current ops references the record.
2542 *
2543 * If the ops traces all functions, then it was already accounted for.
2544 * If the ops does not trace the current record function, skip it.
2545 * If the ops ignores the function via notrace filter, skip it.
2546 */
2547static inline bool
2548ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2549{
2550        /* If ops isn't enabled, ignore it */
2551        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2552                return 0;
2553
2554        /* If ops traces all mods, we already accounted for it */
2555        if (ops_traces_mod(ops))
2556                return 0;
2557
2558        /* The function must be in the filter */
2559        if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2560            !ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2561                return 0;
2562
2563        /* If in notrace hash, we ignore it too */
2564        if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2565                return 0;
2566
2567        return 1;
2568}
2569
2570static int referenced_filters(struct dyn_ftrace *rec)
2571{
2572        struct ftrace_ops *ops;
2573        int cnt = 0;
2574
2575        for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
2576                if (ops_references_rec(ops, rec))
2577                    cnt++;
2578        }
2579
2580        return cnt;
2581}
2582
2583static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2584{
2585        struct ftrace_page *pg;
2586        struct dyn_ftrace *p;
2587        cycle_t start, stop;
2588        unsigned long update_cnt = 0;
2589        unsigned long ref = 0;
2590        bool test = false;
2591        int i;
2592
2593        /*
2594         * When adding a module, we need to check if tracers are
2595         * currently enabled and if they are set to trace all functions.
2596         * If they are, we need to enable the module functions as well
2597         * as update the reference counts for those function records.
2598         */
2599        if (mod) {
2600                struct ftrace_ops *ops;
2601
2602                for (ops = ftrace_ops_list;
2603                     ops != &ftrace_list_end; ops = ops->next) {
2604                        if (ops->flags & FTRACE_OPS_FL_ENABLED) {
2605                                if (ops_traces_mod(ops))
2606                                        ref++;
2607                                else
2608                                        test = true;
2609                        }
2610                }
2611        }
2612
2613        start = ftrace_now(raw_smp_processor_id());
2614
2615        for (pg = new_pgs; pg; pg = pg->next) {
2616
2617                for (i = 0; i < pg->index; i++) {
2618                        int cnt = ref;
2619
2620                        /* If something went wrong, bail without enabling anything */
2621                        if (unlikely(ftrace_disabled))
2622                                return -1;
2623
2624                        p = &pg->records[i];
2625                        if (test)
2626                                cnt += referenced_filters(p);
2627                        p->flags = cnt;
2628
2629                        /*
2630                         * Do the initial record conversion from mcount jump
2631                         * to the NOP instructions.
2632                         */
2633                        if (!ftrace_code_disable(mod, p))
2634                                break;
2635
2636                        update_cnt++;
2637
2638                        /*
2639                         * If the tracing is enabled, go ahead and enable the record.
2640                         *
2641                         * The reason not to enable the record immediatelly is the
2642                         * inherent check of ftrace_make_nop/ftrace_make_call for
2643                         * correct previous instructions.  Making first the NOP
2644                         * conversion puts the module to the correct state, thus
2645                         * passing the ftrace_make_call check.
2646                         */
2647                        if (ftrace_start_up && cnt) {
2648                                int failed = __ftrace_replace_code(p, 1);
2649                                if (failed)
2650                                        ftrace_bug(failed, p->ip);
2651                        }
2652                }
2653        }
2654
2655        stop = ftrace_now(raw_smp_processor_id());
2656        ftrace_update_time = stop - start;
2657        ftrace_update_tot_cnt += update_cnt;
2658
2659        return 0;
2660}
2661
2662static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2663{
2664        int order;
2665        int cnt;
2666
2667        if (WARN_ON(!count))
2668                return -EINVAL;
2669
2670        order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2671
2672        /*
2673         * We want to fill as much as possible. No more than a page
2674         * may be empty.
2675         */
2676        while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2677                order--;
2678
2679 again:
2680        pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2681
2682        if (!pg->records) {
2683                /* if we can't allocate this size, try something smaller */
2684                if (!order)
2685                        return -ENOMEM;
2686                order >>= 1;
2687                goto again;
2688        }
2689
2690        cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2691        pg->size = cnt;
2692
2693        if (cnt > count)
2694                cnt = count;
2695
2696        return cnt;
2697}
2698
2699static struct ftrace_page *
2700ftrace_allocate_pages(unsigned long num_to_init)
2701{
2702        struct ftrace_page *start_pg;
2703        struct ftrace_page *pg;
2704        int order;
2705        int cnt;
2706
2707        if (!num_to_init)
2708                return 0;
2709
2710        start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2711        if (!pg)
2712                return NULL;
2713
2714        /*
2715         * Try to allocate as much as possible in one continues
2716         * location that fills in all of the space. We want to
2717         * waste as little space as possible.
2718         */
2719        for (;;) {
2720                cnt = ftrace_allocate_records(pg, num_to_init);
2721                if (cnt < 0)
2722                        goto free_pages;
2723
2724                num_to_init -= cnt;
2725                if (!num_to_init)
2726                        break;
2727
2728                pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2729                if (!pg->next)
2730                        goto free_pages;
2731
2732                pg = pg->next;
2733        }
2734
2735        return start_pg;
2736
2737 free_pages:
2738        pg = start_pg;
2739        while (pg) {
2740                order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2741                free_pages((unsigned long)pg->records, order);
2742                start_pg = pg->next;
2743                kfree(pg);
2744                pg = start_pg;
2745        }
2746        pr_info("ftrace: FAILED to allocate memory for functions\n");
2747        return NULL;
2748}
2749
2750#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2751
2752struct ftrace_iterator {
2753        loff_t                          pos;
2754        loff_t                          func_pos;
2755        struct ftrace_page              *pg;
2756        struct dyn_ftrace               *func;
2757        struct ftrace_func_probe        *probe;
2758        struct trace_parser             parser;
2759        struct ftrace_hash              *hash;
2760        struct ftrace_ops               *ops;
2761        int                             hidx;
2762        int                             idx;
2763        unsigned                        flags;
2764};
2765
2766static void *
2767t_hash_next(struct seq_file *m, loff_t *pos)
2768{
2769        struct ftrace_iterator *iter = m->private;
2770        struct hlist_node *hnd = NULL;
2771        struct hlist_head *hhd;
2772
2773        (*pos)++;
2774        iter->pos = *pos;
2775
2776        if (iter->probe)
2777                hnd = &iter->probe->node;
2778 retry:
2779        if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
2780                return NULL;
2781
2782        hhd = &ftrace_func_hash[iter->hidx];
2783
2784        if (hlist_empty(hhd)) {
2785                iter->hidx++;
2786                hnd = NULL;
2787                goto retry;
2788        }
2789
2790        if (!hnd)
2791                hnd = hhd->first;
2792        else {
2793                hnd = hnd->next;
2794                if (!hnd) {
2795                        iter->hidx++;
2796                        goto retry;
2797                }
2798        }
2799
2800        if (WARN_ON_ONCE(!hnd))
2801                return NULL;
2802
2803        iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2804
2805        return iter;
2806}
2807
2808static void *t_hash_start(struct seq_file *m, loff_t *pos)
2809{
2810        struct ftrace_iterator *iter = m->private;
2811        void *p = NULL;
2812        loff_t l;
2813
2814        if (!(iter->flags & FTRACE_ITER_DO_HASH))
2815                return NULL;
2816
2817        if (iter->func_pos > *pos)
2818                return NULL;
2819
2820        iter->hidx = 0;
2821        for (l = 0; l <= (*pos - iter->func_pos); ) {
2822                p = t_hash_next(m, &l);
2823                if (!p)
2824                        break;
2825        }
2826        if (!p)
2827                return NULL;
2828
2829        /* Only set this if we have an item */
2830        iter->flags |= FTRACE_ITER_HASH;
2831
2832        return iter;
2833}
2834
2835static int
2836t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2837{
2838        struct ftrace_func_probe *rec;
2839
2840        rec = iter->probe;
2841        if (WARN_ON_ONCE(!rec))
2842                return -EIO;
2843
2844        if (rec->ops->print)
2845                return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2846
2847        seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
2848
2849        if (rec->data)
2850                seq_printf(m, ":%p", rec->data);
2851        seq_putc(m, '\n');
2852
2853        return 0;
2854}
2855
2856static void *
2857t_next(struct seq_file *m, void *v, loff_t *pos)
2858{
2859        struct ftrace_iterator *iter = m->private;
2860        struct ftrace_ops *ops = iter->ops;
2861        struct dyn_ftrace *rec = NULL;
2862
2863        if (unlikely(ftrace_disabled))
2864                return NULL;
2865
2866        if (iter->flags & FTRACE_ITER_HASH)
2867                return t_hash_next(m, pos);
2868
2869        (*pos)++;
2870        iter->pos = iter->func_pos = *pos;
2871
2872        if (iter->flags & FTRACE_ITER_PRINTALL)
2873                return t_hash_start(m, pos);
2874
2875 retry:
2876        if (iter->idx >= iter->pg->index) {
2877                if (iter->pg->next) {
2878                        iter->pg = iter->pg->next;
2879                        iter->idx = 0;
2880                        goto retry;
2881                }
2882        } else {
2883                rec = &iter->pg->records[iter->idx++];
2884                if (((iter->flags & FTRACE_ITER_FILTER) &&
2885                     !(ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))) ||
2886
2887                    ((iter->flags & FTRACE_ITER_NOTRACE) &&
2888                     !ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) ||
2889
2890                    ((iter->flags & FTRACE_ITER_ENABLED) &&
2891                     !(rec->flags & FTRACE_FL_ENABLED))) {
2892
2893                        rec = NULL;
2894                        goto retry;
2895                }
2896        }
2897
2898        if (!rec)
2899                return t_hash_start(m, pos);
2900
2901        iter->func = rec;
2902
2903        return iter;
2904}
2905
2906static void reset_iter_read(struct ftrace_iterator *iter)
2907{
2908        iter->pos = 0;
2909        iter->func_pos = 0;
2910        iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_HASH);
2911}
2912
2913static void *t_start(struct seq_file *m, loff_t *pos)
2914{
2915        struct ftrace_iterator *iter = m->private;
2916        struct ftrace_ops *ops = iter->ops;
2917        void *p = NULL;
2918        loff_t l;
2919
2920        mutex_lock(&ftrace_lock);
2921
2922        if (unlikely(ftrace_disabled))
2923                return NULL;
2924
2925        /*
2926         * If an lseek was done, then reset and start from beginning.
2927         */
2928        if (*pos < iter->pos)
2929                reset_iter_read(iter);
2930
2931        /*
2932         * For set_ftrace_filter reading, if we have the filter
2933         * off, we can short cut and just print out that all
2934         * functions are enabled.
2935         */
2936        if ((iter->flags & FTRACE_ITER_FILTER &&
2937             ftrace_hash_empty(ops->func_hash->filter_hash)) ||
2938            (iter->flags & FTRACE_ITER_NOTRACE &&
2939             ftrace_hash_empty(ops->func_hash->notrace_hash))) {
2940                if (*pos > 0)
2941                        return t_hash_start(m, pos);
2942                iter->flags |= FTRACE_ITER_PRINTALL;
2943                /* reset in case of seek/pread */
2944                iter->flags &= ~FTRACE_ITER_HASH;
2945                return iter;
2946        }
2947
2948        if (iter->flags & FTRACE_ITER_HASH)
2949                return t_hash_start(m, pos);
2950
2951        /*
2952         * Unfortunately, we need to restart at ftrace_pages_start
2953         * every time we let go of the ftrace_mutex. This is because
2954         * those pointers can change without the lock.
2955         */
2956        iter->pg = ftrace_pages_start;
2957        iter->idx = 0;
2958        for (l = 0; l <= *pos; ) {
2959                p = t_next(m, p, &l);
2960                if (!p)
2961                        break;
2962        }
2963
2964        if (!p)
2965                return t_hash_start(m, pos);
2966
2967        return iter;
2968}
2969
2970static void t_stop(struct seq_file *m, void *p)
2971{
2972        mutex_unlock(&ftrace_lock);
2973}
2974
2975static int t_show(struct seq_file *m, void *v)
2976{
2977        struct ftrace_iterator *iter = m->private;
2978        struct dyn_ftrace *rec;
2979
2980        if (iter->flags & FTRACE_ITER_HASH)
2981                return t_hash_show(m, iter);
2982
2983        if (iter->flags & FTRACE_ITER_PRINTALL) {
2984                if (iter->flags & FTRACE_ITER_NOTRACE)
2985                        seq_printf(m, "#### no functions disabled ####\n");
2986                else
2987                        seq_printf(m, "#### all functions enabled ####\n");
2988                return 0;
2989        }
2990
2991        rec = iter->func;
2992
2993        if (!rec)
2994                return 0;
2995
2996        seq_printf(m, "%ps", (void *)rec->ip);
2997        if (iter->flags & FTRACE_ITER_ENABLED) {
2998                seq_printf(m, " (%ld)%s",
2999                           ftrace_rec_count(rec),
3000                           rec->flags & FTRACE_FL_REGS ? " R" : "  ");
3001                if (rec->flags & FTRACE_FL_TRAMP_EN) {
3002                        struct ftrace_ops *ops;
3003
3004                        ops = ftrace_find_tramp_ops_any(rec);
3005                        if (ops)
3006                                seq_printf(m, "\ttramp: %pS",
3007                                           (void *)ops->trampoline);
3008                        else
3009                                seq_printf(m, "\ttramp: ERROR!");
3010                }
3011        }       
3012
3013        seq_printf(m, "\n");
3014
3015        return 0;
3016}
3017
3018static const struct seq_operations show_ftrace_seq_ops = {
3019        .start = t_start,
3020        .next = t_next,
3021        .stop = t_stop,
3022        .show = t_show,
3023};
3024
3025static int
3026ftrace_avail_open(struct inode *inode, struct file *file)
3027{
3028        struct ftrace_iterator *iter;
3029
3030        if (unlikely(ftrace_disabled))
3031                return -ENODEV;
3032
3033        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3034        if (iter) {
3035                iter->pg = ftrace_pages_start;
3036                iter->ops = &global_ops;
3037        }
3038
3039        return iter ? 0 : -ENOMEM;
3040}
3041
3042static int
3043ftrace_enabled_open(struct inode *inode, struct file *file)
3044{
3045        struct ftrace_iterator *iter;
3046
3047        if (unlikely(ftrace_disabled))
3048                return -ENODEV;
3049
3050        iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3051        if (iter) {
3052                iter->pg = ftrace_pages_start;
3053                iter->flags = FTRACE_ITER_ENABLED;
3054                iter->ops = &global_ops;
3055        }
3056
3057        return iter ? 0 : -ENOMEM;
3058}
3059
3060/**
3061 * ftrace_regex_open - initialize function tracer filter files
3062 * @ops: The ftrace_ops that hold the hash filters
3063 * @flag: The type of filter to process
3064 * @inode: The inode, usually passed in to your open routine
3065 * @file: The file, usually passed in to your open routine
3066 *
3067 * ftrace_regex_open() initializes the filter files for the
3068 * @ops. Depending on @flag it may process the filter hash or
3069 * the notrace hash of @ops. With this called from the open
3070 * routine, you can use ftrace_filter_write() for the write
3071 * routine if @flag has FTRACE_ITER_FILTER set, or
3072 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3073 * tracing_lseek() should be used as the lseek routine, and
3074 * release must call ftrace_regex_release().
3075 */
3076int
3077ftrace_regex_open(struct ftrace_ops *ops, int flag,
3078                  struct inode *inode, struct file *file)
3079{
3080        struct ftrace_iterator *iter;
3081        struct ftrace_hash *hash;
3082        int ret = 0;
3083
3084        ftrace_ops_init(ops);
3085
3086        if (unlikely(ftrace_disabled))
3087                return -ENODEV;
3088
3089        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3090        if (!iter)
3091                return -ENOMEM;
3092
3093        if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
3094                kfree(iter);
3095                return -ENOMEM;
3096        }
3097
3098        iter->ops = ops;
3099        iter->flags = flag;
3100
3101        mutex_lock(&ops->func_hash->regex_lock);
3102
3103        if (flag & FTRACE_ITER_NOTRACE)
3104                hash = ops->func_hash->notrace_hash;
3105        else
3106                hash = ops->func_hash->filter_hash;
3107
3108        if (file->f_mode & FMODE_WRITE) {
3109                const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3110
3111                if (file->f_flags & O_TRUNC)
3112                        iter->hash = alloc_ftrace_hash(size_bits);
3113                else
3114                        iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3115
3116                if (!iter->hash) {
3117                        trace_parser_put(&iter->parser);
3118                        kfree(iter);
3119                        ret = -ENOMEM;
3120                        goto out_unlock;
3121                }
3122        }
3123
3124        if (file->f_mode & FMODE_READ) {
3125                iter->pg = ftrace_pages_start;
3126
3127                ret = seq_open(file, &show_ftrace_seq_ops);
3128                if (!ret) {
3129                        struct seq_file *m = file->private_data;
3130                        m->private = iter;
3131                } else {
3132                        /* Failed */
3133                        free_ftrace_hash(iter->hash);
3134                        trace_parser_put(&iter->parser);
3135                        kfree(iter);
3136                }
3137        } else
3138                file->private_data = iter;
3139
3140 out_unlock:
3141        mutex_unlock(&ops->func_hash->regex_lock);
3142
3143        return ret;
3144}
3145
3146static int
3147ftrace_filter_open(struct inode *inode, struct file *file)
3148{
3149        struct ftrace_ops *ops = inode->i_private;
3150
3151        return ftrace_regex_open(ops,
3152                        FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
3153                        inode, file);
3154}
3155
3156static int
3157ftrace_notrace_open(struct inode *inode, struct file *file)
3158{
3159        struct ftrace_ops *ops = inode->i_private;
3160
3161        return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3162                                 inode, file);
3163}
3164
3165static int ftrace_match(char *str, char *regex, int len, int type)
3166{
3167        int matched = 0;
3168        int slen;
3169
3170        switch (type) {
3171        case MATCH_FULL:
3172                if (strcmp(str, regex) == 0)
3173                        matched = 1;
3174                break;
3175        case MATCH_FRONT_ONLY:
3176                if (strncmp(str, regex, len) == 0)
3177                        matched = 1;
3178                break;
3179        case MATCH_MIDDLE_ONLY:
3180                if (strstr(str, regex))
3181                        matched = 1;
3182                break;
3183        case MATCH_END_ONLY:
3184                slen = strlen(str);
3185                if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
3186                        matched = 1;
3187                break;
3188        }
3189
3190        return matched;
3191}
3192
3193static int
3194enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
3195{
3196        struct ftrace_func_entry *entry;
3197        int ret = 0;
3198
3199        entry = ftrace_lookup_ip(hash, rec->ip);
3200        if (not) {
3201                /* Do nothing if it doesn't exist */
3202                if (!entry)
3203                        return 0;
3204
3205                free_hash_entry(hash, entry);
3206        } else {
3207                /* Do nothing if it exists */
3208                if (entry)
3209                        return 0;
3210
3211                ret = add_hash_entry(hash, rec->ip);
3212        }
3213        return ret;
3214}
3215
3216static int
3217ftrace_match_record(struct dyn_ftrace *rec, char *mod,
3218                    char *regex, int len, int type)
3219{
3220        char str[KSYM_SYMBOL_LEN];
3221        char *modname;
3222
3223        kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3224
3225        if (mod) {
3226                /* module lookup requires matching the module */
3227                if (!modname || strcmp(modname, mod))
3228                        return 0;
3229
3230                /* blank search means to match all funcs in the mod */
3231                if (!len)
3232                        return 1;
3233        }
3234
3235        return ftrace_match(str, regex, len, type);
3236}
3237
3238static int
3239match_records(struct ftrace_hash *hash, char *buff,
3240              int len, char *mod, int not)
3241{
3242        unsigned search_len = 0;
3243        struct ftrace_page *pg;
3244        struct dyn_ftrace *rec;
3245        int type = MATCH_FULL;
3246        char *search = buff;
3247        int found = 0;
3248        int ret;
3249
3250        if (len) {
3251                type = filter_parse_regex(buff, len, &search, &not);
3252                search_len = strlen(search);
3253        }
3254
3255        mutex_lock(&ftrace_lock);
3256
3257        if (unlikely(ftrace_disabled))
3258                goto out_unlock;
3259
3260        do_for_each_ftrace_rec(pg, rec) {
3261                if (ftrace_match_record(rec, mod, search, search_len, type)) {
3262                        ret = enter_record(hash, rec, not);
3263                        if (ret < 0) {
3264                                found = ret;
3265                                goto out_unlock;
3266                        }
3267                        found = 1;
3268                }
3269        } while_for_each_ftrace_rec();
3270 out_unlock:
3271        mutex_unlock(&ftrace_lock);
3272
3273        return found;
3274}
3275
3276static int
3277ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3278{
3279        return match_records(hash, buff, len, NULL, 0);
3280}
3281
3282static int
3283ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
3284{
3285        int not = 0;
3286
3287        /* blank or '*' mean the same */
3288        if (strcmp(buff, "*") == 0)
3289                buff[0] = 0;
3290
3291        /* handle the case of 'dont filter this module' */
3292        if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
3293                buff[0] = 0;
3294                not = 1;
3295        }
3296
3297        return match_records(hash, buff, strlen(buff), mod, not);
3298}
3299
3300/*
3301 * We register the module command as a template to show others how
3302 * to register the a command as well.
3303 */
3304
3305static int
3306ftrace_mod_callback(struct ftrace_hash *hash,
3307                    char *func, char *cmd, char *param, int enable)
3308{
3309        char *mod;
3310        int ret = -EINVAL;
3311
3312        /*
3313         * cmd == 'mod' because we only registered this func
3314         * for the 'mod' ftrace_func_command.
3315         * But if you register one func with multiple commands,
3316         * you can tell which command was used by the cmd
3317         * parameter.
3318         */
3319
3320        /* we must have a module name */
3321        if (!param)
3322                return ret;
3323
3324        mod = strsep(&param, ":");
3325        if (!strlen(mod))
3326                return ret;
3327
3328        ret = ftrace_match_module_records(hash, func, mod);
3329        if (!ret)
3330                ret = -EINVAL;
3331        if (ret < 0)
3332                return ret;
3333
3334        return 0;
3335}
3336
3337static struct ftrace_func_command ftrace_mod_cmd = {
3338        .name                   = "mod",
3339        .func                   = ftrace_mod_callback,
3340};
3341
3342static int __init ftrace_mod_cmd_init(void)
3343{
3344        return register_ftrace_command(&ftrace_mod_cmd);
3345}
3346core_initcall(ftrace_mod_cmd_init);
3347
3348static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
3349                                      struct ftrace_ops *op, struct pt_regs *pt_regs)
3350{
3351        struct ftrace_func_probe *entry;
3352        struct hlist_head *hhd;
3353        unsigned long key;
3354
3355        key = hash_long(ip, FTRACE_HASH_BITS);
3356
3357        hhd = &ftrace_func_hash[key];
3358
3359        if (hlist_empty(hhd))
3360                return;
3361
3362        /*
3363         * Disable preemption for these calls to prevent a RCU grace
3364         * period. This syncs the hash iteration and freeing of items
3365         * on the hash. rcu_read_lock is too dangerous here.
3366         */
3367        preempt_disable_notrace();
3368        hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
3369                if (entry->ip == ip)
3370                        entry->ops->func(ip, parent_ip, &entry->data);
3371        }
3372        preempt_enable_notrace();
3373}
3374
3375static struct ftrace_ops trace_probe_ops __read_mostly =
3376{
3377        .func           = function_trace_probe_call,
3378        .flags          = FTRACE_OPS_FL_INITIALIZED,
3379        INIT_OPS_HASH(trace_probe_ops)
3380};
3381
3382static int ftrace_probe_registered;
3383
3384static void __enable_ftrace_function_probe(struct ftrace_ops_hash *old_hash)
3385{
3386        int ret;
3387        int i;
3388
3389        if (ftrace_probe_registered) {
3390                /* still need to update the function call sites */
3391                if (ftrace_enabled)
3392                        ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3393                                               old_hash);
3394                return;
3395        }
3396
3397        for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3398                struct hlist_head *hhd = &ftrace_func_hash[i];
3399                if (hhd->first)
3400                        break;
3401        }
3402        /* Nothing registered? */
3403        if (i == FTRACE_FUNC_HASHSIZE)
3404                return;
3405
3406        ret = ftrace_startup(&trace_probe_ops, 0);
3407
3408        ftrace_probe_registered = 1;
3409}
3410
3411static bool __disable_ftrace_function_probe(void)
3412{
3413        int i;
3414
3415        if (!ftrace_probe_registered)
3416                return false;
3417
3418        for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3419                struct hlist_head *hhd = &ftrace_func_hash[i];
3420                if (hhd->first)
3421                        return false;
3422        }
3423
3424        /* no more funcs left */
3425        ftrace_shutdown(&trace_probe_ops, 0);
3426
3427        ftrace_probe_registered = 0;
3428        return true;
3429}
3430
3431
3432static void ftrace_free_entry(struct ftrace_func_probe *entry)
3433{
3434        if (entry->ops->free)
3435                entry->ops->free(entry->ops, entry->ip, &entry->data);
3436        kfree(entry);
3437}
3438
3439int
3440register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3441                              void *data)
3442{
3443        struct ftrace_ops_hash old_hash_ops;
3444        struct ftrace_func_probe *entry;
3445        struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3446        struct ftrace_hash *old_hash = *orig_hash;
3447        struct ftrace_hash *hash;
3448        struct ftrace_page *pg;
3449        struct dyn_ftrace *rec;
3450        int type, len, not;
3451        unsigned long key;
3452        int count = 0;
3453        char *search;
3454        int ret;
3455
3456        type = filter_parse_regex(glob, strlen(glob), &search, &not);
3457        len = strlen(search);
3458
3459        /* we do not support '!' for function probes */
3460        if (WARN_ON(not))
3461                return -EINVAL;
3462
3463        mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3464
3465        old_hash_ops.filter_hash = old_hash;
3466        /* Probes only have filters */
3467        old_hash_ops.notrace_hash = NULL;
3468
3469        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
3470        if (!hash) {
3471                count = -ENOMEM;
3472                goto out;
3473        }
3474
3475        if (unlikely(ftrace_disabled)) {
3476                count = -ENODEV;
3477                goto out;
3478        }
3479
3480        mutex_lock(&ftrace_lock);
3481
3482        do_for_each_ftrace_rec(pg, rec) {
3483
3484                if (!ftrace_match_record(rec, NULL, search, len, type))
3485                        continue;
3486
3487                entry = kmalloc(sizeof(*entry), GFP_KERNEL);
3488                if (!entry) {
3489                        /* If we did not process any, then return error */
3490                        if (!count)
3491                                count = -ENOMEM;
3492                        goto out_unlock;
3493                }
3494
3495                count++;
3496
3497                entry->data = data;
3498
3499                /*
3500                 * The caller might want to do something special
3501                 * for each function we find. We call the callback
3502                 * to give the caller an opportunity to do so.
3503                 */
3504                if (ops->init) {
3505                        if (ops->init(ops, rec->ip, &entry->data) < 0) {
3506                                /* caller does not like this func */
3507                                kfree(entry);
3508                                continue;
3509                        }
3510                }
3511
3512                ret = enter_record(hash, rec, 0);
3513                if (ret < 0) {
3514                        kfree(entry);
3515                        count = ret;
3516                        goto out_unlock;
3517                }
3518
3519                entry->ops = ops;
3520                entry->ip = rec->ip;
3521
3522                key = hash_long(entry->ip, FTRACE_HASH_BITS);
3523                hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
3524
3525        } while_for_each_ftrace_rec();
3526
3527        ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3528
3529        __enable_ftrace_function_probe(&old_hash_ops);
3530
3531        if (!ret)
3532                free_ftrace_hash_rcu(old_hash);
3533        else
3534                count = ret;
3535
3536 out_unlock:
3537        mutex_unlock(&ftrace_lock);
3538 out:
3539        mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3540        free_ftrace_hash(hash);
3541
3542        return count;
3543}
3544
3545enum {
3546        PROBE_TEST_FUNC         = 1,
3547        PROBE_TEST_DATA         = 2
3548};
3549
3550static void
3551__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3552                                  void *data, int flags)
3553{
3554        struct ftrace_ops_hash old_hash_ops;
3555        struct ftrace_func_entry *rec_entry;
3556        struct ftrace_func_probe *entry;
3557        struct ftrace_func_probe *p;
3558        struct ftrace_hash **orig_hash = &trace_probe_ops.func_hash->filter_hash;
3559        struct ftrace_hash *old_hash = *orig_hash;
3560        struct list_head free_list;
3561        struct ftrace_hash *hash;
3562        struct hlist_node *tmp;
3563        char str[KSYM_SYMBOL_LEN];
3564        int type = MATCH_FULL;
3565        int i, len = 0;
3566        char *search;
3567        int ret;
3568        bool disabled;
3569
3570        if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
3571                glob = NULL;
3572        else if (glob) {
3573                int not;
3574
3575                type = filter_parse_regex(glob, strlen(glob), &search, &not);
3576                len = strlen(search);
3577
3578                /* we do not support '!' for function probes */
3579                if (WARN_ON(not))
3580                        return;
3581        }
3582
3583        mutex_lock(&trace_probe_ops.func_hash->regex_lock);
3584
3585        old_hash_ops.filter_hash = old_hash;
3586        /* Probes only have filters */
3587        old_hash_ops.notrace_hash = NULL;
3588
3589        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3590        if (!hash)
3591                /* Hmm, should report this somehow */
3592                goto out_unlock;
3593
3594        INIT_LIST_HEAD(&free_list);
3595
3596        for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
3597                struct hlist_head *hhd = &ftrace_func_hash[i];
3598
3599                hlist_for_each_entry_safe(entry, tmp, hhd, node) {
3600
3601                        /* break up if statements for readability */
3602                        if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
3603                                continue;
3604
3605                        if ((flags & PROBE_TEST_DATA) && entry->data != data)
3606                                continue;
3607
3608                        /* do this last, since it is the most expensive */
3609                        if (glob) {
3610                                kallsyms_lookup(entry->ip, NULL, NULL,
3611                                                NULL, str);
3612                                if (!ftrace_match(str, glob, len, type))
3613                                        continue;
3614                        }
3615
3616                        rec_entry = ftrace_lookup_ip(hash, entry->ip);
3617                        /* It is possible more than one entry had this ip */
3618                        if (rec_entry)
3619                                free_hash_entry(hash, rec_entry);
3620
3621                        hlist_del_rcu(&entry->node);
3622                        list_add(&entry->free_list, &free_list);
3623                }
3624        }
3625        mutex_lock(&ftrace_lock);
3626        disabled = __disable_ftrace_function_probe();
3627        /*
3628         * Remove after the disable is called. Otherwise, if the last
3629         * probe is removed, a null hash means *all enabled*.
3630         */
3631        ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
3632
3633        /* still need to update the function call sites */
3634        if (ftrace_enabled && !disabled)
3635                ftrace_run_modify_code(&trace_probe_ops, FTRACE_UPDATE_CALLS,
3636                                       &old_hash_ops);
3637        synchronize_sched();
3638        if (!ret)
3639                free_ftrace_hash_rcu(old_hash);
3640
3641        list_for_each_entry_safe(entry, p, &free_list, free_list) {
3642                list_del(&entry->free_list);
3643                ftrace_free_entry(entry);
3644        }
3645        mutex_unlock(&ftrace_lock);
3646               
3647 out_unlock:
3648        mutex_unlock(&trace_probe_ops.func_hash->regex_lock);
3649        free_ftrace_hash(hash);
3650}
3651
3652void
3653unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3654                                void *data)
3655{
3656        __unregister_ftrace_function_probe(glob, ops, data,
3657                                          PROBE_TEST_FUNC | PROBE_TEST_DATA);
3658}
3659
3660void
3661unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3662{
3663        __unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
3664}
3665
3666void unregister_ftrace_function_probe_all(char *glob)
3667{
3668        __unregister_ftrace_function_probe(glob, NULL, NULL, 0);
3669}
3670
3671static LIST_HEAD(ftrace_commands);
3672static DEFINE_MUTEX(ftrace_cmd_mutex);
3673
3674/*
3675 * Currently we only register ftrace commands from __init, so mark this
3676 * __init too.
3677 */
3678__init int register_ftrace_command(struct ftrace_func_command *cmd)
3679{
3680        struct ftrace_func_command *p;
3681        int ret = 0;
3682
3683        mutex_lock(&ftrace_cmd_mutex);
3684        list_for_each_entry(p, &ftrace_commands, list) {
3685                if (strcmp(cmd->name, p->name) == 0) {
3686                        ret = -EBUSY;
3687                        goto out_unlock;
3688                }
3689        }
3690        list_add(&cmd->list, &ftrace_commands);
3691 out_unlock:
3692        mutex_unlock(&ftrace_cmd_mutex);
3693
3694        return ret;
3695}
3696
3697/*
3698 * Currently we only unregister ftrace commands from __init, so mark
3699 * this __init too.
3700 */
3701__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
3702{
3703        struct ftrace_func_command *p, *n;
3704        int ret = -ENODEV;
3705
3706        mutex_lock(&ftrace_cmd_mutex);
3707        list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3708                if (strcmp(cmd->name, p->name) == 0) {
3709                        ret = 0;
3710                        list_del_init(&p->list);
3711                        goto out_unlock;
3712                }
3713        }
3714 out_unlock:
3715        mutex_unlock(&ftrace_cmd_mutex);
3716
3717        return ret;
3718}
3719
3720static int ftrace_process_regex(struct ftrace_hash *hash,
3721                                char *buff, int len, int enable)
3722{
3723        char *func, *command, *next = buff;
3724        struct ftrace_func_command *p;
3725        int ret = -EINVAL;
3726
3727        func = strsep(&next, ":");
3728
3729        if (!next) {
3730                ret = ftrace_match_records(hash, func, len);
3731                if (!ret)
3732                        ret = -EINVAL;
3733                if (ret < 0)
3734                        return ret;
3735                return 0;
3736        }
3737
3738        /* command found */
3739
3740        command = strsep(&next, ":");
3741
3742        mutex_lock(&ftrace_cmd_mutex);
3743        list_for_each_entry(p, &ftrace_commands, list) {
3744                if (strcmp(p->name, command) == 0) {
3745                        ret = p->func(hash, func, command, next, enable);
3746                        goto out_unlock;
3747                }
3748        }
3749 out_unlock:
3750        mutex_unlock(&ftrace_cmd_mutex);
3751
3752        return ret;
3753}
3754
3755static ssize_t
3756ftrace_regex_write(struct file *file, const char __user *ubuf,
3757                   size_t cnt, loff_t *ppos, int enable)
3758{
3759        struct ftrace_iterator *iter;
3760        struct trace_parser *parser;
3761        ssize_t ret, read;
3762
3763        if (!cnt)
3764                return 0;
3765
3766        if (file->f_mode & FMODE_READ) {
3767                struct seq_file *m = file->private_data;
3768                iter = m->private;
3769        } else
3770                iter = file->private_data;
3771
3772        if (unlikely(ftrace_disabled))
3773                return -ENODEV;
3774
3775        /* iter->hash is a local copy, so we don't need regex_lock */
3776
3777        parser = &iter->parser;
3778        read = trace_get_user(parser, ubuf, cnt, ppos);
3779
3780        if (read >= 0 && trace_parser_loaded(parser) &&
3781            !trace_parser_cont(parser)) {
3782                ret = ftrace_process_regex(iter->hash, parser->buffer,
3783                                           parser->idx, enable);
3784                trace_parser_clear(parser);
3785                if (ret < 0)
3786                        goto out;
3787        }
3788
3789        ret = read;
3790 out:
3791        return ret;
3792}
3793
3794ssize_t
3795ftrace_filter_write(struct file *file, const char __user *ubuf,
3796                    size_t cnt, loff_t *ppos)
3797{
3798        return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3799}
3800
3801ssize_t
3802ftrace_notrace_write(struct file *file, const char __user *ubuf,
3803                     size_t cnt, loff_t *ppos)
3804{
3805        return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3806}
3807
3808static int
3809ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
3810{
3811        struct ftrace_func_entry *entry;
3812
3813        if (!ftrace_location(ip))
3814                return -EINVAL;
3815
3816        if (remove) {
3817                entry = ftrace_lookup_ip(hash, ip);
3818                if (!entry)
3819                        return -ENOENT;
3820                free_hash_entry(hash, entry);
3821                return 0;
3822        }
3823
3824        return add_hash_entry(hash, ip);
3825}
3826
3827static void ftrace_ops_update_code(struct ftrace_ops *ops,
3828                                   struct ftrace_ops_hash *old_hash)
3829{
3830        struct ftrace_ops *op;
3831
3832        if (!ftrace_enabled)
3833                return;
3834
3835        if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3836                ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3837                return;
3838        }
3839
3840        /*
3841         * If this is the shared global_ops filter, then we need to
3842         * check if there is another ops that shares it, is enabled.
3843         * If so, we still need to run the modify code.
3844         */
3845        if (ops->func_hash != &global_ops.local_hash)
3846                return;
3847
3848        do_for_each_ftrace_op(op, ftrace_ops_list) {
3849                if (op->func_hash == &global_ops.local_hash &&
3850                    op->flags & FTRACE_OPS_FL_ENABLED) {
3851                        ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3852                        /* Only need to do this once */
3853                        return;
3854                }
3855        } while_for_each_ftrace_op(op);
3856}
3857
3858static int
3859ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
3860                unsigned long ip, int remove, int reset, int enable)
3861{
3862        struct ftrace_hash **orig_hash;
3863        struct ftrace_ops_hash old_hash_ops;
3864        struct ftrace_hash *old_hash;
3865        struct ftrace_hash *hash;
3866        int ret;
3867
3868        if (unlikely(ftrace_disabled))
3869                return -ENODEV;
3870
3871        mutex_lock(&ops->func_hash->regex_lock);
3872
3873        if (enable)
3874                orig_hash = &ops->func_hash->filter_hash;
3875        else
3876                orig_hash = &ops->func_hash->notrace_hash;
3877
3878        if (reset)
3879                hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
3880        else
3881                hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3882
3883        if (!hash) {
3884                ret = -ENOMEM;
3885                goto out_regex_unlock;
3886        }
3887
3888        if (buf && !ftrace_match_records(hash, buf, len)) {
3889                ret = -EINVAL;
3890                goto out_regex_unlock;
3891        }
3892        if (ip) {
3893                ret = ftrace_match_addr(hash, ip, remove);
3894                if (ret < 0)
3895                        goto out_regex_unlock;
3896        }
3897
3898        mutex_lock(&ftrace_lock);
3899        old_hash = *orig_hash;
3900        old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3901        old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3902        ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3903        if (!ret) {
3904                ftrace_ops_update_code(ops, &old_hash_ops);
3905                free_ftrace_hash_rcu(old_hash);
3906        }
3907        mutex_unlock(&ftrace_lock);
3908
3909 out_regex_unlock:
3910        mutex_unlock(&ops->func_hash->regex_lock);
3911
3912        free_ftrace_hash(hash);
3913        return ret;
3914}
3915
3916static int
3917ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
3918                int reset, int enable)
3919{
3920        return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
3921}
3922
3923/**
3924 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
3925 * @ops - the ops to set the filter with
3926 * @ip - the address to add to or remove from the filter.
3927 * @remove - non zero to remove the ip from the filter
3928 * @reset - non zero to reset all filters before applying this filter.
3929 *
3930 * Filters denote which functions should be enabled when tracing is enabled
3931 * If @ip is NULL, it failes to update filter.
3932 */
3933int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
3934                         int remove, int reset)
3935{
3936        ftrace_ops_init(ops);
3937        return ftrace_set_addr(ops, ip, remove, reset, 1);
3938}
3939EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
3940
3941static int
3942ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3943                 int reset, int enable)
3944{
3945        return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
3946}
3947
3948/**
3949 * ftrace_set_filter - set a function to filter on in ftrace
3950 * @ops - the ops to set the filter with
3951 * @buf - the string that holds the function filter text.
3952 * @len - the length of the string.
3953 * @reset - non zero to reset all filters before applying this filter.
3954 *
3955 * Filters denote which functions should be enabled when tracing is enabled.
3956 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3957 */
3958int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3959                       int len, int reset)
3960{
3961        ftrace_ops_init(ops);
3962        return ftrace_set_regex(ops, buf, len, reset, 1);
3963}
3964EXPORT_SYMBOL_GPL(ftrace_set_filter);
3965
3966/**
3967 * ftrace_set_notrace - set a function to not trace in ftrace
3968 * @ops - the ops to set the notrace filter with
3969 * @buf - the string that holds the function notrace text.
3970 * @len - the length of the string.
3971 * @reset - non zero to reset all filters before applying this filter.
3972 *
3973 * Notrace Filters denote which functions should not be enabled when tracing
3974 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3975 * for tracing.
3976 */
3977int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3978                        int len, int reset)
3979{
3980        ftrace_ops_init(ops);
3981        return ftrace_set_regex(ops, buf, len, reset, 0);
3982}
3983EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3984/**
3985 * ftrace_set_global_filter - set a function to filter on with global tracers
3986 * @buf - the string that holds the function filter text.
3987 * @len - the length of the string.
3988 * @reset - non zero to reset all filters before applying this filter.
3989 *
3990 * Filters denote which functions should be enabled when tracing is enabled.
3991 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3992 */
3993void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3994{
3995        ftrace_set_regex(&global_ops, buf, len, reset, 1);
3996}
3997EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3998
3999/**
4000 * ftrace_set_global_notrace - set a function to not trace with global tracers
4001 * @buf - the string that holds the function notrace text.
4002 * @len - the length of the string.
4003 * @reset - non zero to reset all filters before applying this filter.
4004 *
4005 * Notrace Filters denote which functions should not be enabled when tracing
4006 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4007 * for tracing.
4008 */
4009void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4010{
4011        ftrace_set_regex(&global_ops, buf, len, reset, 0);
4012}
4013EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4014
4015/*
4016 * command line interface to allow users to set filters on boot up.
4017 */
4018#define FTRACE_FILTER_SIZE              COMMAND_LINE_SIZE
4019static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4020static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4021
4022/* Used by function selftest to not test if filter is set */
4023bool ftrace_filter_param __initdata;
4024
4025static int __init set_ftrace_notrace(char *str)
4026{
4027        ftrace_filter_param = true;
4028        strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4029        return 1;
4030}
4031__setup("ftrace_notrace=", set_ftrace_notrace);
4032
4033static int __init set_ftrace_filter(char *str)
4034{
4035        ftrace_filter_param = true;
4036        strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4037        return 1;
4038}
4039__setup("ftrace_filter=", set_ftrace_filter);
4040
4041#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4042static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4043static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4044static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
4045
4046static int __init set_graph_function(char *str)
4047{
4048        strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4049        return 1;
4050}
4051__setup("ftrace_graph_filter=", set_graph_function);
4052
4053static int __init set_graph_notrace_function(char *str)
4054{
4055        strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4056        return 1;
4057}
4058__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4059
4060static void __init set_ftrace_early_graph(char *buf, int enable)
4061{
4062        int ret;
4063        char *func;
4064        unsigned long *table = ftrace_graph_funcs;
4065        int *count = &ftrace_graph_count;
4066
4067        if (!enable) {
4068                table = ftrace_graph_notrace_funcs;
4069                count = &ftrace_graph_notrace_count;
4070        }
4071
4072        while (buf) {
4073                func = strsep(&buf, ",");
4074                /* we allow only one expression at a time */
4075                ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
4076                if (ret)
4077                        printk(KERN_DEBUG "ftrace: function %s not "
4078                                          "traceable\n", func);
4079        }
4080}
4081#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4082
4083void __init
4084ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4085{
4086        char *func;
4087
4088        ftrace_ops_init(ops);
4089
4090        while (buf) {
4091                func = strsep(&buf, ",");
4092                ftrace_set_regex(ops, func, strlen(func), 0, enable);
4093        }
4094}
4095
4096static void __init set_ftrace_early_filters(void)
4097{
4098        if (ftrace_filter_buf[0])
4099                ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
4100        if (ftrace_notrace_buf[0])
4101                ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
4102#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4103        if (ftrace_graph_buf[0])
4104                set_ftrace_early_graph(ftrace_graph_buf, 1);
4105        if (ftrace_graph_notrace_buf[0])
4106                set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
4107#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4108}
4109
4110int ftrace_regex_release(struct inode *inode, struct file *file)
4111{
4112        struct seq_file *m = (struct seq_file *)file->private_data;
4113        struct ftrace_ops_hash old_hash_ops;
4114        struct ftrace_iterator *iter;
4115        struct ftrace_hash **orig_hash;
4116        struct ftrace_hash *old_hash;
4117        struct trace_parser *parser;
4118        int filter_hash;
4119        int ret;
4120
4121        if (file->f_mode & FMODE_READ) {
4122                iter = m->private;
4123                seq_release(inode, file);
4124        } else
4125                iter = file->private_data;
4126
4127        parser = &iter->parser;
4128        if (trace_parser_loaded(parser)) {
4129                parser->buffer[parser->idx] = 0;
4130                ftrace_match_records(iter->hash, parser->buffer, parser->idx);
4131        }
4132
4133        trace_parser_put(parser);
4134
4135        mutex_lock(&iter->ops->func_hash->regex_lock);
4136
4137        if (file->f_mode & FMODE_WRITE) {
4138                filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
4139
4140                if (filter_hash)
4141                        orig_hash = &iter->ops->func_hash->filter_hash;
4142                else
4143                        orig_hash = &iter->ops->func_hash->notrace_hash;
4144
4145                mutex_lock(&ftrace_lock);
4146                old_hash = *orig_hash;
4147                old_hash_ops.filter_hash = iter->ops->func_hash->filter_hash;
4148                old_hash_ops.notrace_hash = iter->ops->func_hash->notrace_hash;
4149                ret = ftrace_hash_move(iter->ops, filter_hash,
4150                                       orig_hash, iter->hash);
4151                if (!ret) {
4152                        ftrace_ops_update_code(iter->ops, &old_hash_ops);
4153                        free_ftrace_hash_rcu(old_hash);
4154                }
4155                mutex_unlock(&ftrace_lock);
4156        }
4157
4158        mutex_unlock(&iter->ops->func_hash->regex_lock);
4159        free_ftrace_hash(iter->hash);
4160        kfree(iter);
4161
4162        return 0;
4163}
4164
4165static const struct file_operations ftrace_avail_fops = {
4166        .open = ftrace_avail_open,
4167        .read = seq_read,
4168        .llseek = seq_lseek,
4169        .release = seq_release_private,
4170};
4171
4172static const struct file_operations ftrace_enabled_fops = {
4173        .open = ftrace_enabled_open,
4174        .read = seq_read,
4175        .llseek = seq_lseek,
4176        .release = seq_release_private,
4177};
4178
4179static const struct file_operations ftrace_filter_fops = {
4180        .open = ftrace_filter_open,
4181        .read = seq_read,
4182        .write = ftrace_filter_write,
4183        .llseek = tracing_lseek,
4184        .release = ftrace_regex_release,
4185};
4186
4187static const struct file_operations ftrace_notrace_fops = {
4188        .open = ftrace_notrace_open,
4189        .read = seq_read,
4190        .write = ftrace_notrace_write,
4191        .llseek = tracing_lseek,
4192        .release = ftrace_regex_release,
4193};
4194
4195#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4196
4197static DEFINE_MUTEX(graph_lock);
4198
4199int ftrace_graph_count;
4200int ftrace_graph_notrace_count;
4201unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4202unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
4203
4204struct ftrace_graph_data {
4205        unsigned long *table;
4206        size_t size;
4207        int *count;
4208        const struct seq_operations *seq_ops;
4209};
4210
4211static void *
4212__g_next(struct seq_file *m, loff_t *pos)
4213{
4214        struct ftrace_graph_data *fgd = m->private;
4215
4216        if (*pos >= *fgd->count)
4217                return NULL;
4218        return &fgd->table[*pos];
4219}
4220
4221static void *
4222g_next(struct seq_file *m, void *v, loff_t *pos)
4223{
4224        (*pos)++;
4225        return __g_next(m, pos);
4226}
4227
4228static void *g_start(struct seq_file *m, loff_t *pos)
4229{
4230        struct ftrace_graph_data *fgd = m->private;
4231
4232        mutex_lock(&graph_lock);
4233
4234        /* Nothing, tell g_show to print all functions are enabled */
4235        if (!*fgd->count && !*pos)
4236                return (void *)1;
4237
4238        return __g_next(m, pos);
4239}
4240
4241static void g_stop(struct seq_file *m, void *p)
4242{
4243        mutex_unlock(&graph_lock);
4244}
4245
4246static int g_show(struct seq_file *m, void *v)
4247{
4248        unsigned long *ptr = v;
4249
4250        if (!ptr)
4251                return 0;
4252
4253        if (ptr == (unsigned long *)1) {
4254                struct ftrace_graph_data *fgd = m->private;
4255
4256                if (fgd->table == ftrace_graph_funcs)
4257                        seq_printf(m, "#### all functions enabled ####\n");
4258                else
4259                        seq_printf(m, "#### no functions disabled ####\n");
4260                return 0;
4261        }
4262
4263        seq_printf(m, "%ps\n", (void *)*ptr);
4264
4265        return 0;
4266}
4267
4268static const struct seq_operations ftrace_graph_seq_ops = {
4269        .start = g_start,
4270        .next = g_next,
4271        .stop = g_stop,
4272        .show = g_show,
4273};
4274
4275static int
4276__ftrace_graph_open(struct inode *inode, struct file *file,
4277                    struct ftrace_graph_data *fgd)
4278{
4279        int ret = 0;
4280
4281        mutex_lock(&graph_lock);
4282        if ((file->f_mode & FMODE_WRITE) &&
4283            (file->f_flags & O_TRUNC)) {
4284                *fgd->count = 0;
4285                memset(fgd->table, 0, fgd->size * sizeof(*fgd->table));
4286        }
4287        mutex_unlock(&graph_lock);
4288
4289        if (file->f_mode & FMODE_READ) {
4290                ret = seq_open(file, fgd->seq_ops);
4291                if (!ret) {
4292                        struct seq_file *m = file->private_data;
4293                        m->private = fgd;
4294                }
4295        } else
4296                file->private_data = fgd;
4297
4298        return ret;
4299}
4300
4301static int
4302ftrace_graph_open(struct inode *inode, struct file *file)
4303{
4304        struct ftrace_graph_data *fgd;
4305
4306        if (unlikely(ftrace_disabled))
4307                return -ENODEV;
4308
4309        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4310        if (fgd == NULL)
4311                return -ENOMEM;
4312
4313        fgd->table = ftrace_graph_funcs;
4314        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4315        fgd->count = &ftrace_graph_count;
4316        fgd->seq_ops = &ftrace_graph_seq_ops;
4317
4318        return __ftrace_graph_open(inode, file, fgd);
4319}
4320
4321static int
4322ftrace_graph_notrace_open(struct inode *inode, struct file *file)
4323{
4324        struct ftrace_graph_data *fgd;
4325
4326        if (unlikely(ftrace_disabled))
4327                return -ENODEV;
4328
4329        fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
4330        if (fgd == NULL)
4331                return -ENOMEM;
4332
4333        fgd->table = ftrace_graph_notrace_funcs;
4334        fgd->size = FTRACE_GRAPH_MAX_FUNCS;
4335        fgd->count = &ftrace_graph_notrace_count;
4336        fgd->seq_ops = &ftrace_graph_seq_ops;
4337
4338        return __ftrace_graph_open(inode, file, fgd);
4339}
4340
4341static int
4342ftrace_graph_release(struct inode *inode, struct file *file)
4343{
4344        if (file->f_mode & FMODE_READ) {
4345                struct seq_file *m = file->private_data;
4346
4347                kfree(m->private);
4348                seq_release(inode, file);
4349        } else {
4350                kfree(file->private_data);
4351        }
4352
4353        return 0;
4354}
4355
4356static int
4357ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
4358{
4359        struct dyn_ftrace *rec;
4360        struct ftrace_page *pg;
4361        int search_len;
4362        int fail = 1;
4363        int type, not;
4364        char *search;
4365        bool exists;
4366        int i;
4367
4368        /* decode regex */
4369        type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
4370        if (!not && *idx >= size)
4371                return -EBUSY;
4372
4373        search_len = strlen(search);
4374
4375        mutex_lock(&ftrace_lock);
4376
4377        if (unlikely(ftrace_disabled)) {
4378                mutex_unlock(&ftrace_lock);
4379                return -ENODEV;
4380        }
4381
4382        do_for_each_ftrace_rec(pg, rec) {
4383
4384                if (ftrace_match_record(rec, NULL, search, search_len, type)) {
4385                        /* if it is in the array */
4386                        exists = false;
4387                        for (i = 0; i < *idx; i++) {
4388                                if (array[i] == rec->ip) {
4389                                        exists = true;
4390                                        break;
4391                                }
4392                        }
4393
4394                        if (!not) {
4395                                fail = 0;
4396                                if (!exists) {
4397                                        array[(*idx)++] = rec->ip;
4398                                        if (*idx >= size)
4399                                                goto out;
4400                                }
4401                        } else {
4402                                if (exists) {
4403                                        array[i] = array[--(*idx)];
4404                                        array[*idx] = 0;
4405                                        fail = 0;
4406                                }
4407                        }
4408                }
4409        } while_for_each_ftrace_rec();
4410out:
4411        mutex_unlock(&ftrace_lock);
4412
4413        if (fail)
4414                return -EINVAL;
4415
4416        return 0;
4417}
4418
4419static ssize_t
4420ftrace_graph_write(struct file *file, const char __user *ubuf,
4421                   size_t cnt, loff_t *ppos)
4422{
4423        struct trace_parser parser;
4424        ssize_t read, ret = 0;
4425        struct ftrace_graph_data *fgd = file->private_data;
4426
4427        if (!cnt)
4428                return 0;
4429
4430        if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX))
4431                return -ENOMEM;
4432
4433        read = trace_get_user(&parser, ubuf, cnt, ppos);
4434
4435        if (read >= 0 && trace_parser_loaded((&parser))) {
4436                parser.buffer[parser.idx] = 0;
4437
4438                mutex_lock(&graph_lock);
4439
4440                /* we allow only one expression at a time */
4441                ret = ftrace_set_func(fgd->table, fgd->count, fgd->size,
4442                                      parser.buffer);
4443
4444                mutex_unlock(&graph_lock);
4445        }
4446
4447        if (!ret)
4448                ret = read;
4449
4450        trace_parser_put(&parser);
4451
4452        return ret;
4453}
4454
4455static const struct file_operations ftrace_graph_fops = {
4456        .open           = ftrace_graph_open,
4457        .read           = seq_read,
4458        .write          = ftrace_graph_write,
4459        .llseek         = tracing_lseek,
4460        .release        = ftrace_graph_release,
4461};
4462
4463static const struct file_operations ftrace_graph_notrace_fops = {
4464        .open           = ftrace_graph_notrace_open,
4465        .read           = seq_read,
4466        .write          = ftrace_graph_write,
4467        .llseek         = tracing_lseek,
4468        .release        = ftrace_graph_release,
4469};
4470#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4471
4472void ftrace_create_filter_files(struct ftrace_ops *ops,
4473                                struct dentry *parent)
4474{
4475
4476        trace_create_file("set_ftrace_filter", 0644, parent,
4477                          ops, &ftrace_filter_fops);
4478
4479        trace_create_file("set_ftrace_notrace", 0644, parent,
4480                          ops, &ftrace_notrace_fops);
4481}
4482
4483/*
4484 * The name "destroy_filter_files" is really a misnomer. Although
4485 * in the future, it may actualy delete the files, but this is
4486 * really intended to make sure the ops passed in are disabled
4487 * and that when this function returns, the caller is free to
4488 * free the ops.
4489 *
4490 * The "destroy" name is only to match the "create" name that this
4491 * should be paired with.
4492 */
4493void ftrace_destroy_filter_files(struct ftrace_ops *ops)
4494{
4495        mutex_lock(&ftrace_lock);
4496        if (ops->flags & FTRACE_OPS_FL_ENABLED)
4497                ftrace_shutdown(ops, 0);
4498        ops->flags |= FTRACE_OPS_FL_DELETED;
4499        mutex_unlock(&ftrace_lock);
4500}
4501
4502static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
4503{
4504
4505        trace_create_file("available_filter_functions", 0444,
4506                        d_tracer, NULL, &ftrace_avail_fops);
4507
4508        trace_create_file("enabled_functions", 0444,
4509                        d_tracer, NULL, &ftrace_enabled_fops);
4510
4511        ftrace_create_filter_files(&global_ops, d_tracer);
4512
4513#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4514        trace_create_file("set_graph_function", 0444, d_tracer,
4515                                    NULL,
4516                                    &ftrace_graph_fops);
4517        trace_create_file("set_graph_notrace", 0444, d_tracer,
4518                                    NULL,
4519                                    &ftrace_graph_notrace_fops);
4520#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4521
4522        return 0;
4523}
4524
4525static int ftrace_cmp_ips(const void *a, const void *b)
4526{
4527        const unsigned long *ipa = a;
4528        const unsigned long *ipb = b;
4529
4530        if (*ipa > *ipb)
4531                return 1;
4532        if (*ipa < *ipb)
4533                return -1;
4534        return 0;
4535}
4536
4537static void ftrace_swap_ips(void *a, void *b, int size)
4538{
4539        unsigned long *ipa = a;
4540        unsigned long *ipb = b;
4541        unsigned long t;
4542
4543        t = *ipa;
4544        *ipa = *ipb;
4545        *ipb = t;
4546}
4547
4548static int ftrace_process_locs(struct module *mod,
4549                               unsigned long *start,
4550                               unsigned long *end)
4551{
4552        struct ftrace_page *start_pg;
4553        struct ftrace_page *pg;
4554        struct dyn_ftrace *rec;
4555        unsigned long count;
4556        unsigned long *p;
4557        unsigned long addr;
4558        unsigned long flags = 0; /* Shut up gcc */
4559        int ret = -ENOMEM;
4560
4561        count = end - start;
4562
4563        if (!count)
4564                return 0;
4565
4566        sort(start, count, sizeof(*start),
4567             ftrace_cmp_ips, ftrace_swap_ips);
4568
4569        start_pg = ftrace_allocate_pages(count);
4570        if (!start_pg)
4571                return -ENOMEM;
4572
4573        mutex_lock(&ftrace_lock);
4574
4575        /*
4576         * Core and each module needs their own pages, as
4577         * modules will free them when they are removed.
4578         * Force a new page to be allocated for modules.
4579         */
4580        if (!mod) {
4581                WARN_ON(ftrace_pages || ftrace_pages_start);
4582                /* First initialization */
4583                ftrace_pages = ftrace_pages_start = start_pg;
4584        } else {
4585                if (!ftrace_pages)
4586                        goto out;
4587
4588                if (WARN_ON(ftrace_pages->next)) {
4589                        /* Hmm, we have free pages? */
4590                        while (ftrace_pages->next)
4591                                ftrace_pages = ftrace_pages->next;
4592                }
4593
4594                ftrace_pages->next = start_pg;
4595        }
4596
4597        p = start;
4598        pg = start_pg;
4599        while (p < end) {
4600                addr = ftrace_call_adjust(*p++);
4601                /*
4602                 * Some architecture linkers will pad between
4603                 * the different mcount_loc sections of different
4604                 * object files to satisfy alignments.
4605                 * Skip any NULL pointers.
4606                 */
4607                if (!addr)
4608                        continue;
4609
4610                if (pg->index == pg->size) {
4611                        /* We should have allocated enough */
4612                        if (WARN_ON(!pg->next))
4613                                break;
4614                        pg = pg->next;
4615                }
4616
4617                rec = &pg->records[pg->index++];
4618                rec->ip = addr;
4619        }
4620
4621        /* We should have used all pages */
4622        WARN_ON(pg->next);
4623
4624        /* Assign the last page to ftrace_pages */
4625        ftrace_pages = pg;
4626
4627        /*
4628         * We only need to disable interrupts on start up
4629         * because we are modifying code that an interrupt
4630         * may execute, and the modification is not atomic.
4631         * But for modules, nothing runs the code we modify
4632         * until we are finished with it, and there's no
4633         * reason to cause large interrupt latencies while we do it.
4634         */
4635        if (!mod)
4636                local_irq_save(flags);
4637        ftrace_update_code(mod, start_pg);
4638        if (!mod)
4639                local_irq_restore(flags);
4640        ret = 0;
4641 out:
4642        mutex_unlock(&ftrace_lock);
4643
4644        return ret;
4645}
4646
4647#ifdef CONFIG_MODULES
4648
4649#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
4650
4651void ftrace_release_mod(struct module *mod)
4652{
4653        struct dyn_ftrace *rec;
4654        struct ftrace_page **last_pg;
4655        struct ftrace_page *pg;
4656        int order;
4657
4658        mutex_lock(&ftrace_lock);
4659
4660        if (ftrace_disabled)
4661                goto out_unlock;
4662
4663        /*
4664         * Each module has its own ftrace_pages, remove
4665         * them from the list.
4666         */
4667        last_pg = &ftrace_pages_start;
4668        for (pg = ftrace_pages_start; pg; pg = *last_pg) {
4669                rec = &pg->records[0];
4670                if (within_module_core(rec->ip, mod)) {
4671                        /*
4672                         * As core pages are first, the first
4673                         * page should never be a module page.
4674                         */
4675                        if (WARN_ON(pg == ftrace_pages_start))
4676                                goto out_unlock;
4677
4678                        /* Check if we are deleting the last page */
4679                        if (pg == ftrace_pages)
4680                                ftrace_pages = next_to_ftrace_page(last_pg);
4681
4682                        *last_pg = pg->next;
4683                        order = get_count_order(pg->size / ENTRIES_PER_PAGE);
4684                        free_pages((unsigned long)pg->records, order);
4685                        kfree(pg);
4686                } else
4687                        last_pg = &pg->next;
4688        }
4689 out_unlock:
4690        mutex_unlock(&ftrace_lock);
4691}
4692
4693static void ftrace_init_module(struct module *mod,
4694                               unsigned long *start, unsigned long *end)
4695{
4696        if (ftrace_disabled || start == end)
4697                return;
4698        ftrace_process_locs(mod, start, end);
4699}
4700
4701void ftrace_module_init(struct module *mod)
4702{
4703        ftrace_init_module(mod, mod->ftrace_callsites,
4704                           mod->ftrace_callsites +
4705                           mod->num_ftrace_callsites);
4706}
4707
4708static int ftrace_module_notify_exit(struct notifier_block *self,
4709                                     unsigned long val, void *data)
4710{
4711        struct module *mod = data;
4712
4713        if (val == MODULE_STATE_GOING)
4714                ftrace_release_mod(mod);
4715
4716        return 0;
4717}
4718#else
4719static int ftrace_module_notify_exit(struct notifier_block *self,
4720                                     unsigned long val, void *data)
4721{
4722        return 0;
4723}
4724#endif /* CONFIG_MODULES */
4725
4726struct notifier_block ftrace_module_exit_nb = {
4727        .notifier_call = ftrace_module_notify_exit,
4728        .priority = INT_MIN,    /* Run after anything that can remove kprobes */
4729};
4730
4731void __init ftrace_init(void)
4732{
4733        extern unsigned long __start_mcount_loc[];
4734        extern unsigned long __stop_mcount_loc[];
4735        unsigned long count, flags;
4736        int ret;
4737
4738        local_irq_save(flags);
4739        ret = ftrace_dyn_arch_init();
4740        local_irq_restore(flags);
4741        if (ret)
4742                goto failed;
4743
4744        count = __stop_mcount_loc - __start_mcount_loc;
4745        if (!count) {
4746                pr_info("ftrace: No functions to be traced?\n");
4747                goto failed;
4748        }
4749
4750        pr_info("ftrace: allocating %ld entries in %ld pages\n",
4751                count, count / ENTRIES_PER_PAGE + 1);
4752
4753        last_ftrace_enabled = ftrace_enabled = 1;
4754
4755        ret = ftrace_process_locs(NULL,
4756                                  __start_mcount_loc,
4757                                  __stop_mcount_loc);
4758
4759        ret = register_module_notifier(&ftrace_module_exit_nb);
4760        if (ret)
4761                pr_warning("Failed to register trace ftrace module exit notifier\n");
4762
4763        set_ftrace_early_filters();
4764
4765        return;
4766 failed:
4767        ftrace_disabled = 1;
4768}
4769
4770#else
4771
4772static struct ftrace_ops global_ops = {
4773        .func                   = ftrace_stub,
4774        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4775};
4776
4777static int __init ftrace_nodyn_init(void)
4778{
4779        ftrace_enabled = 1;
4780        return 0;
4781}
4782core_initcall(ftrace_nodyn_init);
4783
4784static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
4785static inline void ftrace_startup_enable(int command) { }
4786static inline void ftrace_startup_all(int command) { }
4787/* Keep as macros so we do not need to define the commands */
4788# define ftrace_startup(ops, command)                                   \
4789        ({                                                              \
4790                int ___ret = __register_ftrace_function(ops);           \
4791                if (!___ret)                                            \
4792                        (ops)->flags |= FTRACE_OPS_FL_ENABLED;          \
4793                ___ret;                                                 \
4794        })
4795# define ftrace_shutdown(ops, command)                                  \
4796        ({                                                              \
4797                int ___ret = __unregister_ftrace_function(ops);         \
4798                if (!___ret)                                            \
4799                        (ops)->flags &= ~FTRACE_OPS_FL_ENABLED;         \
4800                ___ret;                                                 \
4801        })
4802
4803# define ftrace_startup_sysctl()        do { } while (0)
4804# define ftrace_shutdown_sysctl()       do { } while (0)
4805
4806static inline int
4807ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
4808{
4809        return 1;
4810}
4811
4812#endif /* CONFIG_DYNAMIC_FTRACE */
4813
4814__init void ftrace_init_global_array_ops(struct trace_array *tr)
4815{
4816        tr->ops = &global_ops;
4817        tr->ops->private = tr;
4818}
4819
4820void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
4821{
4822        /* If we filter on pids, update to use the pid function */
4823        if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
4824                if (WARN_ON(tr->ops->func != ftrace_stub))
4825                        printk("ftrace ops had %pS for function\n",
4826                               tr->ops->func);
4827                /* Only the top level instance does pid tracing */
4828                if (!list_empty(&ftrace_pids)) {
4829                        set_ftrace_pid_function(func);
4830                        func = ftrace_pid_func;
4831                }
4832        }
4833        tr->ops->func = func;
4834        tr->ops->private = tr;
4835}
4836
4837void ftrace_reset_array_ops(struct trace_array *tr)
4838{
4839        tr->ops->func = ftrace_stub;
4840}
4841
4842static void
4843ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
4844                        struct ftrace_ops *op, struct pt_regs *regs)
4845{
4846        if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
4847                return;
4848
4849        /*
4850         * Some of the ops may be dynamically allocated,
4851         * they must be freed after a synchronize_sched().
4852         */
4853        preempt_disable_notrace();
4854        trace_recursion_set(TRACE_CONTROL_BIT);
4855
4856        /*
4857         * Control funcs (perf) uses RCU. Only trace if
4858         * RCU is currently active.
4859         */
4860        if (!rcu_is_watching())
4861                goto out;
4862
4863        do_for_each_ftrace_op(op, ftrace_control_list) {
4864                if (!(op->flags & FTRACE_OPS_FL_STUB) &&
4865                    !ftrace_function_local_disabled(op) &&
4866                    ftrace_ops_test(op, ip, regs))
4867                        op->func(ip, parent_ip, op, regs);
4868        } while_for_each_ftrace_op(op);
4869 out:
4870        trace_recursion_clear(TRACE_CONTROL_BIT);
4871        preempt_enable_notrace();
4872}
4873
4874static struct ftrace_ops control_ops = {
4875        .func   = ftrace_ops_control_func,
4876        .flags  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
4877        INIT_OPS_HASH(control_ops)
4878};
4879
4880static inline void
4881__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4882                       struct ftrace_ops *ignored, struct pt_regs *regs)
4883{
4884        struct ftrace_ops *op;
4885        int bit;
4886
4887        bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4888        if (bit < 0)
4889                return;
4890
4891        /*
4892         * Some of the ops may be dynamically allocated,
4893         * they must be freed after a synchronize_sched().
4894         */
4895        preempt_disable_notrace();
4896        do_for_each_ftrace_op(op, ftrace_ops_list) {
4897                if (ftrace_ops_test(op, ip, regs)) {
4898                        if (FTRACE_WARN_ON(!op->func)) {
4899                                pr_warn("op=%p %pS\n", op, op);
4900                                goto out;
4901                        }
4902                        op->func(ip, parent_ip, op, regs);
4903                }
4904        } while_for_each_ftrace_op(op);
4905out:
4906        preempt_enable_notrace();
4907        trace_clear_recursion(bit);
4908}
4909
4910/*
4911 * Some archs only support passing ip and parent_ip. Even though
4912 * the list function ignores the op parameter, we do not want any
4913 * C side effects, where a function is called without the caller
4914 * sending a third parameter.
4915 * Archs are to support both the regs and ftrace_ops at the same time.
4916 * If they support ftrace_ops, it is assumed they support regs.
4917 * If call backs want to use regs, they must either check for regs
4918 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
4919 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
4920 * An architecture can pass partial regs with ftrace_ops and still
4921 * set the ARCH_SUPPORT_FTARCE_OPS.
4922 */
4923#if ARCH_SUPPORTS_FTRACE_OPS
4924static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
4925                                 struct ftrace_ops *op, struct pt_regs *regs)
4926{
4927        __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
4928}
4929#else
4930static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
4931{
4932        __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
4933}
4934#endif
4935
4936/*
4937 * If there's only one function registered but it does not support
4938 * recursion, this function will be called by the mcount trampoline.
4939 * This function will handle recursion protection.
4940 */
4941static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
4942                                   struct ftrace_ops *op, struct pt_regs *regs)
4943{
4944        int bit;
4945
4946        bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
4947        if (bit < 0)
4948                return;
4949
4950        op->func(ip, parent_ip, op, regs);
4951
4952        trace_clear_recursion(bit);
4953}
4954
4955/**
4956 * ftrace_ops_get_func - get the function a trampoline should call
4957 * @ops: the ops to get the function for
4958 *
4959 * Normally the mcount trampoline will call the ops->func, but there
4960 * are times that it should not. For example, if the ops does not
4961 * have its own recursion protection, then it should call the
4962 * ftrace_ops_recurs_func() instead.
4963 *
4964 * Returns the function that the trampoline should call for @ops.
4965 */
4966ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
4967{
4968        /*
4969         * If this is a dynamic ops or we force list func,
4970         * then it needs to call the list anyway.
4971         */
4972        if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
4973                return ftrace_ops_list_func;
4974
4975        /*
4976         * If the func handles its own recursion, call it directly.
4977         * Otherwise call the recursion protected function that
4978         * will call the ftrace ops function.
4979         */
4980        if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
4981                return ftrace_ops_recurs_func;
4982
4983        return ops->func;
4984}
4985
4986static void clear_ftrace_swapper(void)
4987{
4988        struct task_struct *p;
4989        int cpu;
4990
4991        get_online_cpus();
4992        for_each_online_cpu(cpu) {
4993                p = idle_task(cpu);
4994                clear_tsk_trace_trace(p);
4995        }
4996        put_online_cpus();
4997}
4998
4999static void set_ftrace_swapper(void)
5000{
5001        struct task_struct *p;
5002        int cpu;
5003
5004        get_online_cpus();
5005        for_each_online_cpu(cpu) {
5006                p = idle_task(cpu);
5007                set_tsk_trace_trace(p);
5008        }
5009        put_online_cpus();
5010}
5011
5012static void clear_ftrace_pid(struct pid *pid)
5013{
5014        struct task_struct *p;
5015
5016        rcu_read_lock();
5017        do_each_pid_task(pid, PIDTYPE_PID, p) {
5018                clear_tsk_trace_trace(p);
5019        } while_each_pid_task(pid, PIDTYPE_PID, p);
5020        rcu_read_unlock();
5021
5022        put_pid(pid);
5023}
5024
5025static void set_ftrace_pid(struct pid *pid)
5026{
5027        struct task_struct *p;
5028
5029        rcu_read_lock();
5030        do_each_pid_task(pid, PIDTYPE_PID, p) {
5031                set_tsk_trace_trace(p);
5032        } while_each_pid_task(pid, PIDTYPE_PID, p);
5033        rcu_read_unlock();
5034}
5035
5036static void clear_ftrace_pid_task(struct pid *pid)
5037{
5038        if (pid == ftrace_swapper_pid)
5039                clear_ftrace_swapper();
5040        else
5041                clear_ftrace_pid(pid);
5042}
5043
5044static void set_ftrace_pid_task(struct pid *pid)
5045{
5046        if (pid == ftrace_swapper_pid)
5047                set_ftrace_swapper();
5048        else
5049                set_ftrace_pid(pid);
5050}
5051
5052static int ftrace_pid_add(int p)
5053{
5054        struct pid *pid;
5055        struct ftrace_pid *fpid;
5056        int ret = -EINVAL;
5057
5058        mutex_lock(&ftrace_lock);
5059
5060        if (!p)
5061                pid = ftrace_swapper_pid;
5062        else
5063                pid = find_get_pid(p);
5064
5065        if (!pid)
5066                goto out;
5067
5068        ret = 0;
5069
5070        list_for_each_entry(fpid, &ftrace_pids, list)
5071                if (fpid->pid == pid)
5072                        goto out_put;
5073
5074        ret = -ENOMEM;
5075
5076        fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
5077        if (!fpid)
5078                goto out_put;
5079
5080        list_add(&fpid->list, &ftrace_pids);
5081        fpid->pid = pid;
5082
5083        set_ftrace_pid_task(pid);
5084
5085        ftrace_update_pid_func();
5086
5087        ftrace_startup_all(0);
5088
5089        mutex_unlock(&ftrace_lock);
5090        return 0;
5091
5092out_put:
5093        if (pid != ftrace_swapper_pid)
5094                put_pid(pid);
5095
5096out:
5097        mutex_unlock(&ftrace_lock);
5098        return ret;
5099}
5100
5101static void ftrace_pid_reset(void)
5102{
5103        struct ftrace_pid *fpid, *safe;
5104
5105        mutex_lock(&ftrace_lock);
5106        list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
5107                struct pid *pid = fpid->pid;
5108
5109                clear_ftrace_pid_task(pid);
5110
5111                list_del(&fpid->list);
5112                kfree(fpid);
5113        }
5114
5115        ftrace_update_pid_func();
5116        ftrace_startup_all(0);
5117
5118        mutex_unlock(&ftrace_lock);
5119}
5120
5121static void *fpid_start(struct seq_file *m, loff_t *pos)
5122{
5123        mutex_lock(&ftrace_lock);
5124
5125        if (list_empty(&ftrace_pids) && (!*pos))
5126                return (void *) 1;
5127
5128        return seq_list_start(&ftrace_pids, *pos);
5129}
5130
5131static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
5132{
5133        if (v == (void *)1)
5134                return NULL;
5135
5136        return seq_list_next(v, &ftrace_pids, pos);
5137}
5138
5139static void fpid_stop(struct seq_file *m, void *p)
5140{
5141        mutex_unlock(&ftrace_lock);
5142}
5143
5144static int fpid_show(struct seq_file *m, void *v)
5145{
5146        const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
5147
5148        if (v == (void *)1) {
5149                seq_printf(m, "no pid\n");
5150                return 0;
5151        }
5152
5153        if (fpid->pid == ftrace_swapper_pid)
5154                seq_printf(m, "swapper tasks\n");
5155        else
5156                seq_printf(m, "%u\n", pid_vnr(fpid->pid));
5157
5158        return 0;
5159}
5160
5161static const struct seq_operations ftrace_pid_sops = {
5162        .start = fpid_start,
5163        .next = fpid_next,
5164        .stop = fpid_stop,
5165        .show = fpid_show,
5166};
5167
5168static int
5169ftrace_pid_open(struct inode *inode, struct file *file)
5170{
5171        int ret = 0;
5172
5173        if ((file->f_mode & FMODE_WRITE) &&
5174            (file->f_flags & O_TRUNC))
5175                ftrace_pid_reset();
5176
5177        if (file->f_mode & FMODE_READ)
5178                ret = seq_open(file, &ftrace_pid_sops);
5179
5180        return ret;
5181}
5182
5183static ssize_t
5184ftrace_pid_write(struct file *filp, const char __user *ubuf,
5185                   size_t cnt, loff_t *ppos)
5186{
5187        char buf[64], *tmp;
5188        long val;
5189        int ret;
5190
5191        if (cnt >= sizeof(buf))
5192                return -EINVAL;
5193
5194        if (copy_from_user(&buf, ubuf, cnt))
5195                return -EFAULT;
5196
5197        buf[cnt] = 0;
5198
5199        /*
5200         * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
5201         * to clean the filter quietly.
5202         */
5203        tmp = strstrip(buf);
5204        if (strlen(tmp) == 0)
5205                return 1;
5206
5207        ret = kstrtol(tmp, 10, &val);
5208        if (ret < 0)
5209                return ret;
5210
5211        ret = ftrace_pid_add(val);
5212
5213        return ret ? ret : cnt;
5214}
5215
5216static int
5217ftrace_pid_release(struct inode *inode, struct file *file)
5218{
5219        if (file->f_mode & FMODE_READ)
5220                seq_release(inode, file);
5221
5222        return 0;
5223}
5224
5225static const struct file_operations ftrace_pid_fops = {
5226        .open           = ftrace_pid_open,
5227        .write          = ftrace_pid_write,
5228        .read           = seq_read,
5229        .llseek         = tracing_lseek,
5230        .release        = ftrace_pid_release,
5231};
5232
5233static __init int ftrace_init_debugfs(void)
5234{
5235        struct dentry *d_tracer;
5236
5237        d_tracer = tracing_init_dentry();
5238        if (!d_tracer)
5239                return 0;
5240
5241        ftrace_init_dyn_debugfs(d_tracer);
5242
5243        trace_create_file("set_ftrace_pid", 0644, d_tracer,
5244                            NULL, &ftrace_pid_fops);
5245
5246        ftrace_profile_debugfs(d_tracer);
5247
5248        return 0;
5249}
5250fs_initcall(ftrace_init_debugfs);
5251
5252/**
5253 * ftrace_kill - kill ftrace
5254 *
5255 * This function should be used by panic code. It stops ftrace
5256 * but in a not so nice way. If you need to simply kill ftrace
5257 * from a non-atomic section, use ftrace_kill.
5258 */
5259void ftrace_kill(void)
5260{
5261        ftrace_disabled = 1;
5262        ftrace_enabled = 0;
5263        clear_ftrace_function();
5264}
5265
5266/**
5267 * Test if ftrace is dead or not.
5268 */
5269int ftrace_is_dead(void)
5270{
5271        return ftrace_disabled;
5272}
5273
5274/**
5275 * register_ftrace_function - register a function for profiling
5276 * @ops - ops structure that holds the function for profiling.
5277 *
5278 * Register a function to be called by all functions in the
5279 * kernel.
5280 *
5281 * Note: @ops->func and all the functions it calls must be labeled
5282 *       with "notrace", otherwise it will go into a
5283 *       recursive loop.
5284 */
5285int register_ftrace_function(struct ftrace_ops *ops)
5286{
5287        int ret = -1;
5288
5289        ftrace_ops_init(ops);
5290
5291        mutex_lock(&ftrace_lock);
5292
5293        ret = ftrace_startup(ops, 0);
5294
5295        mutex_unlock(&ftrace_lock);
5296
5297        return ret;
5298}
5299EXPORT_SYMBOL_GPL(register_ftrace_function);
5300
5301/**
5302 * unregister_ftrace_function - unregister a function for profiling.
5303 * @ops - ops structure that holds the function to unregister
5304 *
5305 * Unregister a function that was added to be called by ftrace profiling.
5306 */
5307int unregister_ftrace_function(struct ftrace_ops *ops)
5308{
5309        int ret;
5310
5311        mutex_lock(&ftrace_lock);
5312        ret = ftrace_shutdown(ops, 0);
5313        mutex_unlock(&ftrace_lock);
5314
5315        return ret;
5316}
5317EXPORT_SYMBOL_GPL(unregister_ftrace_function);
5318
5319int
5320ftrace_enable_sysctl(struct ctl_table *table, int write,
5321                     void __user *buffer, size_t *lenp,
5322                     loff_t *ppos)
5323{
5324        int ret = -ENODEV;
5325
5326        mutex_lock(&ftrace_lock);
5327
5328        if (unlikely(ftrace_disabled))
5329                goto out;
5330
5331        ret = proc_dointvec(table, write, buffer, lenp, ppos);
5332
5333        if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
5334                goto out;
5335
5336        last_ftrace_enabled = !!ftrace_enabled;
5337
5338        if (ftrace_enabled) {
5339
5340                /* we are starting ftrace again */
5341                if (ftrace_ops_list != &ftrace_list_end)
5342                        update_ftrace_function();
5343
5344                ftrace_startup_sysctl();
5345
5346        } else {
5347                /* stopping ftrace calls (just send to ftrace_stub) */
5348                ftrace_trace_function = ftrace_stub;
5349
5350                ftrace_shutdown_sysctl();
5351        }
5352
5353 out:
5354        mutex_unlock(&ftrace_lock);
5355        return ret;
5356}
5357
5358#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5359
5360static struct ftrace_ops graph_ops = {
5361        .func                   = ftrace_stub,
5362        .flags                  = FTRACE_OPS_FL_RECURSION_SAFE |
5363                                   FTRACE_OPS_FL_INITIALIZED |
5364                                   FTRACE_OPS_FL_STUB,
5365#ifdef FTRACE_GRAPH_TRAMP_ADDR
5366        .trampoline             = FTRACE_GRAPH_TRAMP_ADDR,
5367#endif
5368        ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
5369};
5370
5371int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
5372{
5373        return 0;
5374}
5375
5376/* The callbacks that hook a function */
5377trace_func_graph_ret_t ftrace_graph_return =
5378                        (trace_func_graph_ret_t)ftrace_stub;
5379trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
5380static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
5381
5382/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
5383static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
5384{
5385        int i;
5386        int ret = 0;
5387        unsigned long flags;
5388        int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
5389        struct task_struct *g, *t;
5390
5391        for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
5392                ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
5393                                        * sizeof(struct ftrace_ret_stack),
5394                                        GFP_KERNEL);
5395                if (!ret_stack_list[i]) {
5396                        start = 0;
5397                        end = i;
5398                        ret = -ENOMEM;
5399                        goto free;
5400                }
5401        }
5402
5403        read_lock_irqsave(&tasklist_lock, flags);
5404        do_each_thread(g, t) {
5405                if (start == end) {
5406                        ret = -EAGAIN;
5407                        goto unlock;
5408                }
5409
5410                if (t->ret_stack == NULL) {
5411                        atomic_set(&t->tracing_graph_pause, 0);
5412                        atomic_set(&t->trace_overrun, 0);
5413                        t->curr_ret_stack = -1;
5414                        /* Make sure the tasks see the -1 first: */
5415                        smp_wmb();
5416                        t->ret_stack = ret_stack_list[start++];
5417                }
5418        } while_each_thread(g, t);
5419
5420unlock:
5421        read_unlock_irqrestore(&tasklist_lock, flags);
5422free:
5423        for (i = start; i < end; i++)
5424                kfree(ret_stack_list[i]);
5425        return ret;
5426}
5427
5428static void
5429ftrace_graph_probe_sched_switch(void *ignore,
5430                        struct task_struct *prev, struct task_struct *next)
5431{
5432        unsigned long long timestamp;
5433        int index;
5434
5435        /*
5436         * Does the user want to count the time a function was asleep.
5437         * If so, do not update the time stamps.
5438         */
5439        if (trace_flags & TRACE_ITER_SLEEP_TIME)
5440                return;
5441
5442        timestamp = trace_clock_local();
5443
5444        prev->ftrace_timestamp = timestamp;
5445
5446        /* only process tasks that we timestamped */
5447        if (!next->ftrace_timestamp)
5448                return;
5449
5450        /*
5451         * Update all the counters in next to make up for the
5452         * time next was sleeping.
5453         */
5454        timestamp -= next->ftrace_timestamp;
5455
5456        for (index = next->curr_ret_stack; index >= 0; index--)
5457                next->ret_stack[index].calltime += timestamp;
5458}
5459
5460/* Allocate a return stack for each task */
5461static int start_graph_tracing(void)
5462{
5463        struct ftrace_ret_stack **ret_stack_list;
5464        int ret, cpu;
5465
5466        ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
5467                                sizeof(struct ftrace_ret_stack *),
5468                                GFP_KERNEL);
5469
5470        if (!ret_stack_list)
5471                return -ENOMEM;
5472
5473        /* The cpu_boot init_task->ret_stack will never be freed */
5474        for_each_online_cpu(cpu) {
5475                if (!idle_task(cpu)->ret_stack)
5476                        ftrace_graph_init_idle_task(idle_task(cpu), cpu);
5477        }
5478
5479        do {
5480                ret = alloc_retstack_tasklist(ret_stack_list);
5481        } while (ret == -EAGAIN);
5482
5483        if (!ret) {
5484                ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5485                if (ret)
5486                        pr_info("ftrace_graph: Couldn't activate tracepoint"
5487                                " probe to kernel_sched_switch\n");
5488        }
5489
5490        kfree(ret_stack_list);
5491        return ret;
5492}
5493
5494/*
5495 * Hibernation protection.
5496 * The state of the current task is too much unstable during
5497 * suspend/restore to disk. We want to protect against that.
5498 */
5499static int
5500ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
5501                                                        void *unused)
5502{
5503        switch (state) {
5504        case PM_HIBERNATION_PREPARE:
5505                pause_graph_tracing();
5506                break;
5507
5508        case PM_POST_HIBERNATION:
5509                unpause_graph_tracing();
5510                break;
5511        }
5512        return NOTIFY_DONE;
5513}
5514
5515static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
5516{
5517        if (!ftrace_ops_test(&global_ops, trace->func, NULL))
5518                return 0;
5519        return __ftrace_graph_entry(trace);
5520}
5521
5522/*
5523 * The function graph tracer should only trace the functions defined
5524 * by set_ftrace_filter and set_ftrace_notrace. If another function
5525 * tracer ops is registered, the graph tracer requires testing the
5526 * function against the global ops, and not just trace any function
5527 * that any ftrace_ops registered.
5528 */
5529static void update_function_graph_func(void)
5530{
5531        struct ftrace_ops *op;
5532        bool do_test = false;
5533
5534        /*
5535         * The graph and global ops share the same set of functions
5536         * to test. If any other ops is on the list, then
5537         * the graph tracing needs to test if its the function
5538         * it should call.
5539         */
5540        do_for_each_ftrace_op(op, ftrace_ops_list) {
5541                if (op != &global_ops && op != &graph_ops &&
5542                    op != &ftrace_list_end) {
5543                        do_test = true;
5544                        /* in double loop, break out with goto */
5545                        goto out;
5546                }
5547        } while_for_each_ftrace_op(op);
5548 out:
5549        if (do_test)
5550                ftrace_graph_entry = ftrace_graph_entry_test;
5551        else
5552                ftrace_graph_entry = __ftrace_graph_entry;
5553}
5554
5555static struct notifier_block ftrace_suspend_notifier = {
5556        .notifier_call = ftrace_suspend_notifier_call,
5557};
5558
5559int register_ftrace_graph(trace_func_graph_ret_t retfunc,
5560                        trace_func_graph_ent_t entryfunc)
5561{
5562        int ret = 0;
5563
5564        mutex_lock(&ftrace_lock);
5565
5566        /* we currently allow only one tracer registered at a time */
5567        if (ftrace_graph_active) {
5568                ret = -EBUSY;
5569                goto out;
5570        }
5571
5572        register_pm_notifier(&ftrace_suspend_notifier);
5573
5574        ftrace_graph_active++;
5575        ret = start_graph_tracing();
5576        if (ret) {
5577                ftrace_graph_active--;
5578                goto out;
5579        }
5580
5581        ftrace_graph_return = retfunc;
5582
5583        /*
5584         * Update the indirect function to the entryfunc, and the
5585         * function that gets called to the entry_test first. Then
5586         * call the update fgraph entry function to determine if
5587         * the entryfunc should be called directly or not.
5588         */
5589        __ftrace_graph_entry = entryfunc;
5590        ftrace_graph_entry = ftrace_graph_entry_test;
5591        update_function_graph_func();
5592
5593        ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
5594
5595out:
5596        mutex_unlock(&ftrace_lock);
5597        return ret;
5598}
5599
5600void unregister_ftrace_graph(void)
5601{
5602        mutex_lock(&ftrace_lock);
5603
5604        if (unlikely(!ftrace_graph_active))
5605                goto out;
5606
5607        ftrace_graph_active--;
5608        ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
5609        ftrace_graph_entry = ftrace_graph_entry_stub;
5610        __ftrace_graph_entry = ftrace_graph_entry_stub;
5611        ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
5612        unregister_pm_notifier(&ftrace_suspend_notifier);
5613        unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
5614
5615 out:
5616        mutex_unlock(&ftrace_lock);
5617}
5618
5619static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
5620
5621static void
5622graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
5623{
5624        atomic_set(&t->tracing_graph_pause, 0);
5625        atomic_set(&t->trace_overrun, 0);
5626        t->ftrace_timestamp = 0;
5627        /* make curr_ret_stack visible before we add the ret_stack */
5628        smp_wmb();
5629        t->ret_stack = ret_stack;
5630}
5631
5632/*
5633 * Allocate a return stack for the idle task. May be the first
5634 * time through, or it may be done by CPU hotplug online.
5635 */
5636void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
5637{
5638        t->curr_ret_stack = -1;
5639        /*
5640         * The idle task has no parent, it either has its own
5641         * stack or no stack at all.
5642         */
5643        if (t->ret_stack)
5644                WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
5645
5646        if (ftrace_graph_active) {
5647                struct ftrace_ret_stack *ret_stack;
5648
5649                ret_stack = per_cpu(idle_ret_stack, cpu);
5650                if (!ret_stack) {
5651                        ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5652                                            * sizeof(struct ftrace_ret_stack),
5653                                            GFP_KERNEL);
5654                        if (!ret_stack)
5655                                return;
5656                        per_cpu(idle_ret_stack, cpu) = ret_stack;
5657                }
5658                graph_init_task(t, ret_stack);
5659        }
5660}
5661
5662/* Allocate a return stack for newly created task */
5663void ftrace_graph_init_task(struct task_struct *t)
5664{
5665        /* Make sure we do not use the parent ret_stack */
5666        t->ret_stack = NULL;
5667        t->curr_ret_stack = -1;
5668
5669        if (ftrace_graph_active) {
5670                struct ftrace_ret_stack *ret_stack;
5671
5672                ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
5673                                * sizeof(struct ftrace_ret_stack),
5674                                GFP_KERNEL);
5675                if (!ret_stack)
5676                        return;
5677                graph_init_task(t, ret_stack);
5678        }
5679}
5680
5681void ftrace_graph_exit_task(struct task_struct *t)
5682{
5683        struct ftrace_ret_stack *ret_stack = t->ret_stack;
5684
5685        t->ret_stack = NULL;
5686        /* NULL must become visible to IRQs before we free it: */
5687        barrier();
5688
5689        kfree(ret_stack);
5690}
5691#endif
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