source: src/linux/universal/linux-4.9/arch/x86/mm/init.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 5 weeks ago

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1#include <linux/gfp.h>
2#include <linux/initrd.h>
3#include <linux/ioport.h>
4#include <linux/swap.h>
5#include <linux/memblock.h>
6#include <linux/bootmem.h>      /* for max_low_pfn */
7
8#include <asm/cacheflush.h>
9#include <asm/e820.h>
10#include <asm/init.h>
11#include <asm/page.h>
12#include <asm/page_types.h>
13#include <asm/sections.h>
14#include <asm/setup.h>
15#include <asm/tlbflush.h>
16#include <asm/tlb.h>
17#include <asm/proto.h>
18#include <asm/dma.h>            /* for MAX_DMA_PFN */
19#include <asm/microcode.h>
20#include <asm/kaslr.h>
21
22/*
23 * We need to define the tracepoints somewhere, and tlb.c
24 * is only compied when SMP=y.
25 */
26#define CREATE_TRACE_POINTS
27#include <trace/events/tlb.h>
28
29#include "mm_internal.h"
30
31/*
32 * Tables translating between page_cache_type_t and pte encoding.
33 *
34 * The default values are defined statically as minimal supported mode;
35 * WC and WT fall back to UC-.  pat_init() updates these values to support
36 * more cache modes, WC and WT, when it is safe to do so.  See pat_init()
37 * for the details.  Note, __early_ioremap() used during early boot-time
38 * takes pgprot_t (pte encoding) and does not use these tables.
39 *
40 *   Index into __cachemode2pte_tbl[] is the cachemode.
41 *
42 *   Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
43 *   (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
44 */
45uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
46        [_PAGE_CACHE_MODE_WB      ]     = 0         | 0        ,
47        [_PAGE_CACHE_MODE_WC      ]     = 0         | _PAGE_PCD,
48        [_PAGE_CACHE_MODE_UC_MINUS]     = 0         | _PAGE_PCD,
49        [_PAGE_CACHE_MODE_UC      ]     = _PAGE_PWT | _PAGE_PCD,
50        [_PAGE_CACHE_MODE_WT      ]     = 0         | _PAGE_PCD,
51        [_PAGE_CACHE_MODE_WP      ]     = 0         | _PAGE_PCD,
52};
53EXPORT_SYMBOL(__cachemode2pte_tbl);
54
55uint8_t __pte2cachemode_tbl[8] = {
56        [__pte2cm_idx( 0        | 0         | 0        )] = _PAGE_CACHE_MODE_WB,
57        [__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
58        [__pte2cm_idx( 0        | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
59        [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC,
60        [__pte2cm_idx( 0        | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
61        [__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
62        [__pte2cm_idx(0         | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
63        [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
64};
65EXPORT_SYMBOL(__pte2cachemode_tbl);
66
67static unsigned long __initdata pgt_buf_start;
68static unsigned long __initdata pgt_buf_end;
69static unsigned long __initdata pgt_buf_top;
70
71static unsigned long min_pfn_mapped;
72
73static bool __initdata can_use_brk_pgt = true;
74
75/*
76 * Pages returned are already directly mapped.
77 *
78 * Changing that is likely to break Xen, see commit:
79 *
80 *    279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
81 *
82 * for detailed information.
83 */
84__ref void *alloc_low_pages(unsigned int num)
85{
86        unsigned long pfn;
87        int i;
88
89        if (after_bootmem) {
90                unsigned int order;
91
92                order = get_order((unsigned long)num << PAGE_SHIFT);
93                return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK |
94                                                __GFP_ZERO, order);
95        }
96
97        if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
98                unsigned long ret;
99                if (min_pfn_mapped >= max_pfn_mapped)
100                        panic("alloc_low_pages: ran out of memory");
101                ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
102                                        max_pfn_mapped << PAGE_SHIFT,
103                                        PAGE_SIZE * num , PAGE_SIZE);
104                if (!ret)
105                        panic("alloc_low_pages: can not alloc memory");
106                memblock_reserve(ret, PAGE_SIZE * num);
107                pfn = ret >> PAGE_SHIFT;
108        } else {
109                pfn = pgt_buf_end;
110                pgt_buf_end += num;
111                printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
112                        pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
113        }
114
115        for (i = 0; i < num; i++) {
116                void *adr;
117
118                adr = __va((pfn + i) << PAGE_SHIFT);
119                clear_page(adr);
120        }
121
122        return __va(pfn << PAGE_SHIFT);
123}
124
125/*
126 * By default need 3 4k for initial PMD_SIZE,  3 4k for 0-ISA_END_ADDRESS.
127 * With KASLR memory randomization, depending on the machine e820 memory
128 * and the PUD alignment. We may need twice more pages when KASLR memory
129 * randomization is enabled.
130 */
131#ifndef CONFIG_RANDOMIZE_MEMORY
132#define INIT_PGD_PAGE_COUNT      6
133#else
134#define INIT_PGD_PAGE_COUNT      12
135#endif
136#define INIT_PGT_BUF_SIZE       (INIT_PGD_PAGE_COUNT * PAGE_SIZE)
137RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
138void  __init early_alloc_pgt_buf(void)
139{
140        unsigned long tables = INIT_PGT_BUF_SIZE;
141        phys_addr_t base;
142
143        base = __pa(extend_brk(tables, PAGE_SIZE));
144
145        pgt_buf_start = base >> PAGE_SHIFT;
146        pgt_buf_end = pgt_buf_start;
147        pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
148}
149
150int after_bootmem;
151
152early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
153
154struct map_range {
155        unsigned long start;
156        unsigned long end;
157        unsigned page_size_mask;
158};
159
160static int page_size_mask;
161
162static void __init probe_page_size_mask(void)
163{
164#if !defined(CONFIG_KMEMCHECK)
165        /*
166         * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will
167         * use small pages.
168         * This will simplify cpa(), which otherwise needs to support splitting
169         * large pages into small in interrupt context, etc.
170         */
171        if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
172                page_size_mask |= 1 << PG_LEVEL_2M;
173#endif
174
175        /* Enable PSE if available */
176        if (boot_cpu_has(X86_FEATURE_PSE))
177                cr4_set_bits_and_update_boot(X86_CR4_PSE);
178
179        /* Enable PGE if available */
180        if (boot_cpu_has(X86_FEATURE_PGE)) {
181                cr4_set_bits_and_update_boot(X86_CR4_PGE);
182                __supported_pte_mask |= _PAGE_GLOBAL;
183        } else
184                __supported_pte_mask &= ~_PAGE_GLOBAL;
185
186        /* Enable 1 GB linear kernel mappings if available: */
187        if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
188                printk(KERN_INFO "Using GB pages for direct mapping\n");
189                page_size_mask |= 1 << PG_LEVEL_1G;
190        } else {
191                direct_gbpages = 0;
192        }
193}
194
195#ifdef CONFIG_X86_32
196#define NR_RANGE_MR 3
197#else /* CONFIG_X86_64 */
198#define NR_RANGE_MR 5
199#endif
200
201static int __meminit save_mr(struct map_range *mr, int nr_range,
202                             unsigned long start_pfn, unsigned long end_pfn,
203                             unsigned long page_size_mask)
204{
205        if (start_pfn < end_pfn) {
206                if (nr_range >= NR_RANGE_MR)
207                        panic("run out of range for init_memory_mapping\n");
208                mr[nr_range].start = start_pfn<<PAGE_SHIFT;
209                mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
210                mr[nr_range].page_size_mask = page_size_mask;
211                nr_range++;
212        }
213
214        return nr_range;
215}
216
217/*
218 * adjust the page_size_mask for small range to go with
219 *      big page size instead small one if nearby are ram too.
220 */
221static void __ref adjust_range_page_size_mask(struct map_range *mr,
222                                                         int nr_range)
223{
224        int i;
225
226        for (i = 0; i < nr_range; i++) {
227                if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
228                    !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
229                        unsigned long start = round_down(mr[i].start, PMD_SIZE);
230                        unsigned long end = round_up(mr[i].end, PMD_SIZE);
231
232#ifdef CONFIG_X86_32
233                        if ((end >> PAGE_SHIFT) > max_low_pfn)
234                                continue;
235#endif
236
237                        if (memblock_is_region_memory(start, end - start))
238                                mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
239                }
240                if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
241                    !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
242                        unsigned long start = round_down(mr[i].start, PUD_SIZE);
243                        unsigned long end = round_up(mr[i].end, PUD_SIZE);
244
245                        if (memblock_is_region_memory(start, end - start))
246                                mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
247                }
248        }
249}
250
251static const char *page_size_string(struct map_range *mr)
252{
253        static const char str_1g[] = "1G";
254        static const char str_2m[] = "2M";
255        static const char str_4m[] = "4M";
256        static const char str_4k[] = "4k";
257
258        if (mr->page_size_mask & (1<<PG_LEVEL_1G))
259                return str_1g;
260        /*
261         * 32-bit without PAE has a 4M large page size.
262         * PG_LEVEL_2M is misnamed, but we can at least
263         * print out the right size in the string.
264         */
265        if (IS_ENABLED(CONFIG_X86_32) &&
266            !IS_ENABLED(CONFIG_X86_PAE) &&
267            mr->page_size_mask & (1<<PG_LEVEL_2M))
268                return str_4m;
269
270        if (mr->page_size_mask & (1<<PG_LEVEL_2M))
271                return str_2m;
272
273        return str_4k;
274}
275
276static int __meminit split_mem_range(struct map_range *mr, int nr_range,
277                                     unsigned long start,
278                                     unsigned long end)
279{
280        unsigned long start_pfn, end_pfn, limit_pfn;
281        unsigned long pfn;
282        int i;
283
284        limit_pfn = PFN_DOWN(end);
285
286        /* head if not big page alignment ? */
287        pfn = start_pfn = PFN_DOWN(start);
288#ifdef CONFIG_X86_32
289        /*
290         * Don't use a large page for the first 2/4MB of memory
291         * because there are often fixed size MTRRs in there
292         * and overlapping MTRRs into large pages can cause
293         * slowdowns.
294         */
295        if (pfn == 0)
296                end_pfn = PFN_DOWN(PMD_SIZE);
297        else
298                end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
299#else /* CONFIG_X86_64 */
300        end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
301#endif
302        if (end_pfn > limit_pfn)
303                end_pfn = limit_pfn;
304        if (start_pfn < end_pfn) {
305                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
306                pfn = end_pfn;
307        }
308
309        /* big page (2M) range */
310        start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
311#ifdef CONFIG_X86_32
312        end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
313#else /* CONFIG_X86_64 */
314        end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
315        if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
316                end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
317#endif
318
319        if (start_pfn < end_pfn) {
320                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
321                                page_size_mask & (1<<PG_LEVEL_2M));
322                pfn = end_pfn;
323        }
324
325#ifdef CONFIG_X86_64
326        /* big page (1G) range */
327        start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
328        end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
329        if (start_pfn < end_pfn) {
330                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
331                                page_size_mask &
332                                 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
333                pfn = end_pfn;
334        }
335
336        /* tail is not big page (1G) alignment */
337        start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
338        end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
339        if (start_pfn < end_pfn) {
340                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
341                                page_size_mask & (1<<PG_LEVEL_2M));
342                pfn = end_pfn;
343        }
344#endif
345
346        /* tail is not big page (2M) alignment */
347        start_pfn = pfn;
348        end_pfn = limit_pfn;
349        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
350
351        if (!after_bootmem)
352                adjust_range_page_size_mask(mr, nr_range);
353
354        /* try to merge same page size and continuous */
355        for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
356                unsigned long old_start;
357                if (mr[i].end != mr[i+1].start ||
358                    mr[i].page_size_mask != mr[i+1].page_size_mask)
359                        continue;
360                /* move it */
361                old_start = mr[i].start;
362                memmove(&mr[i], &mr[i+1],
363                        (nr_range - 1 - i) * sizeof(struct map_range));
364                mr[i--].start = old_start;
365                nr_range--;
366        }
367
368        for (i = 0; i < nr_range; i++)
369                pr_debug(" [mem %#010lx-%#010lx] page %s\n",
370                                mr[i].start, mr[i].end - 1,
371                                page_size_string(&mr[i]));
372
373        return nr_range;
374}
375
376struct range pfn_mapped[E820_X_MAX];
377int nr_pfn_mapped;
378
379static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
380{
381        nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_X_MAX,
382                                             nr_pfn_mapped, start_pfn, end_pfn);
383        nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);
384
385        max_pfn_mapped = max(max_pfn_mapped, end_pfn);
386
387        if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
388                max_low_pfn_mapped = max(max_low_pfn_mapped,
389                                         min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
390}
391
392bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
393{
394        int i;
395
396        for (i = 0; i < nr_pfn_mapped; i++)
397                if ((start_pfn >= pfn_mapped[i].start) &&
398                    (end_pfn <= pfn_mapped[i].end))
399                        return true;
400
401        return false;
402}
403
404/*
405 * Setup the direct mapping of the physical memory at PAGE_OFFSET.
406 * This runs before bootmem is initialized and gets pages directly from
407 * the physical memory. To access them they are temporarily mapped.
408 */
409unsigned long __ref init_memory_mapping(unsigned long start,
410                                               unsigned long end)
411{
412        struct map_range mr[NR_RANGE_MR];
413        unsigned long ret = 0;
414        int nr_range, i;
415
416        pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
417               start, end - 1);
418
419        memset(mr, 0, sizeof(mr));
420        nr_range = split_mem_range(mr, 0, start, end);
421
422        for (i = 0; i < nr_range; i++)
423                ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
424                                                   mr[i].page_size_mask);
425
426        add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
427
428        return ret >> PAGE_SHIFT;
429}
430
431/*
432 * We need to iterate through the E820 memory map and create direct mappings
433 * for only E820_RAM and E820_KERN_RESERVED regions. We cannot simply
434 * create direct mappings for all pfns from [0 to max_low_pfn) and
435 * [4GB to max_pfn) because of possible memory holes in high addresses
436 * that cannot be marked as UC by fixed/variable range MTRRs.
437 * Depending on the alignment of E820 ranges, this may possibly result
438 * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
439 *
440 * init_mem_mapping() calls init_range_memory_mapping() with big range.
441 * That range would have hole in the middle or ends, and only ram parts
442 * will be mapped in init_range_memory_mapping().
443 */
444static unsigned long __init init_range_memory_mapping(
445                                           unsigned long r_start,
446                                           unsigned long r_end)
447{
448        unsigned long start_pfn, end_pfn;
449        unsigned long mapped_ram_size = 0;
450        int i;
451
452        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
453                u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
454                u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
455                if (start >= end)
456                        continue;
457
458                /*
459                 * if it is overlapping with brk pgt, we need to
460                 * alloc pgt buf from memblock instead.
461                 */
462                can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
463                                    min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
464                init_memory_mapping(start, end);
465                mapped_ram_size += end - start;
466                can_use_brk_pgt = true;
467        }
468
469        return mapped_ram_size;
470}
471
472static unsigned long __init get_new_step_size(unsigned long step_size)
473{
474        /*
475         * Initial mapped size is PMD_SIZE (2M).
476         * We can not set step_size to be PUD_SIZE (1G) yet.
477         * In worse case, when we cross the 1G boundary, and
478         * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
479         * to map 1G range with PTE. Hence we use one less than the
480         * difference of page table level shifts.
481         *
482         * Don't need to worry about overflow in the top-down case, on 32bit,
483         * when step_size is 0, round_down() returns 0 for start, and that
484         * turns it into 0x100000000ULL.
485         * In the bottom-up case, round_up(x, 0) returns 0 though too, which
486         * needs to be taken into consideration by the code below.
487         */
488        return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
489}
490
491/**
492 * memory_map_top_down - Map [map_start, map_end) top down
493 * @map_start: start address of the target memory range
494 * @map_end: end address of the target memory range
495 *
496 * This function will setup direct mapping for memory range
497 * [map_start, map_end) in top-down. That said, the page tables
498 * will be allocated at the end of the memory, and we map the
499 * memory in top-down.
500 */
501static void __init memory_map_top_down(unsigned long map_start,
502                                       unsigned long map_end)
503{
504        unsigned long real_end, start, last_start;
505        unsigned long step_size;
506        unsigned long addr;
507        unsigned long mapped_ram_size = 0;
508
509        /* xen has big range in reserved near end of ram, skip it at first.*/
510        addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
511        real_end = addr + PMD_SIZE;
512
513        /* step_size need to be small so pgt_buf from BRK could cover it */
514        step_size = PMD_SIZE;
515        max_pfn_mapped = 0; /* will get exact value next */
516        min_pfn_mapped = real_end >> PAGE_SHIFT;
517        last_start = start = real_end;
518
519        /*
520         * We start from the top (end of memory) and go to the bottom.
521         * The memblock_find_in_range() gets us a block of RAM from the
522         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
523         * for page table.
524         */
525        while (last_start > map_start) {
526                if (last_start > step_size) {
527                        start = round_down(last_start - 1, step_size);
528                        if (start < map_start)
529                                start = map_start;
530                } else
531                        start = map_start;
532                mapped_ram_size += init_range_memory_mapping(start,
533                                                        last_start);
534                last_start = start;
535                min_pfn_mapped = last_start >> PAGE_SHIFT;
536                if (mapped_ram_size >= step_size)
537                        step_size = get_new_step_size(step_size);
538        }
539
540        if (real_end < map_end)
541                init_range_memory_mapping(real_end, map_end);
542}
543
544/**
545 * memory_map_bottom_up - Map [map_start, map_end) bottom up
546 * @map_start: start address of the target memory range
547 * @map_end: end address of the target memory range
548 *
549 * This function will setup direct mapping for memory range
550 * [map_start, map_end) in bottom-up. Since we have limited the
551 * bottom-up allocation above the kernel, the page tables will
552 * be allocated just above the kernel and we map the memory
553 * in [map_start, map_end) in bottom-up.
554 */
555static void __init memory_map_bottom_up(unsigned long map_start,
556                                        unsigned long map_end)
557{
558        unsigned long next, start;
559        unsigned long mapped_ram_size = 0;
560        /* step_size need to be small so pgt_buf from BRK could cover it */
561        unsigned long step_size = PMD_SIZE;
562
563        start = map_start;
564        min_pfn_mapped = start >> PAGE_SHIFT;
565
566        /*
567         * We start from the bottom (@map_start) and go to the top (@map_end).
568         * The memblock_find_in_range() gets us a block of RAM from the
569         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
570         * for page table.
571         */
572        while (start < map_end) {
573                if (step_size && map_end - start > step_size) {
574                        next = round_up(start + 1, step_size);
575                        if (next > map_end)
576                                next = map_end;
577                } else {
578                        next = map_end;
579                }
580
581                mapped_ram_size += init_range_memory_mapping(start, next);
582                start = next;
583
584                if (mapped_ram_size >= step_size)
585                        step_size = get_new_step_size(step_size);
586        }
587}
588
589void __init init_mem_mapping(void)
590{
591        unsigned long end;
592
593        probe_page_size_mask();
594
595#ifdef CONFIG_X86_64
596        end = max_pfn << PAGE_SHIFT;
597#else
598        end = max_low_pfn << PAGE_SHIFT;
599#endif
600
601        /* the ISA range is always mapped regardless of memory holes */
602        init_memory_mapping(0, ISA_END_ADDRESS);
603
604        /* Init the trampoline, possibly with KASLR memory offset */
605        init_trampoline();
606
607        /*
608         * If the allocation is in bottom-up direction, we setup direct mapping
609         * in bottom-up, otherwise we setup direct mapping in top-down.
610         */
611        if (memblock_bottom_up()) {
612                unsigned long kernel_end = __pa_symbol(_end);
613
614                /*
615                 * we need two separate calls here. This is because we want to
616                 * allocate page tables above the kernel. So we first map
617                 * [kernel_end, end) to make memory above the kernel be mapped
618                 * as soon as possible. And then use page tables allocated above
619                 * the kernel to map [ISA_END_ADDRESS, kernel_end).
620                 */
621                memory_map_bottom_up(kernel_end, end);
622                memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
623        } else {
624                memory_map_top_down(ISA_END_ADDRESS, end);
625        }
626
627#ifdef CONFIG_X86_64
628        if (max_pfn > max_low_pfn) {
629                /* can we preseve max_low_pfn ?*/
630                max_low_pfn = max_pfn;
631        }
632#else
633        early_ioremap_page_table_range_init();
634#endif
635
636        load_cr3(swapper_pg_dir);
637        __flush_tlb_all();
638
639        early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
640}
641
642/*
643 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
644 * is valid. The argument is a physical page number.
645 *
646 * On x86, access has to be given to the first megabyte of RAM because that
647 * area traditionally contains BIOS code and data regions used by X, dosemu,
648 * and similar apps. Since they map the entire memory range, the whole range
649 * must be allowed (for mapping), but any areas that would otherwise be
650 * disallowed are flagged as being "zero filled" instead of rejected.
651 * Access has to be given to non-kernel-ram areas as well, these contain the
652 * PCI mmio resources as well as potential bios/acpi data regions.
653 */
654int devmem_is_allowed(unsigned long pagenr)
655{
656        if (page_is_ram(pagenr)) {
657                /*
658                 * For disallowed memory regions in the low 1MB range,
659                 * request that the page be shown as all zeros.
660                 */
661                if (pagenr < 256)
662                        return 2;
663
664                return 0;
665        }
666
667        /*
668         * This must follow RAM test, since System RAM is considered a
669         * restricted resource under CONFIG_STRICT_IOMEM.
670         */
671        if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
672                /* Low 1MB bypasses iomem restrictions. */
673                if (pagenr < 256)
674                        return 1;
675
676                return 0;
677        }
678
679        return 1;
680}
681
682void free_init_pages(char *what, unsigned long begin, unsigned long end)
683{
684        unsigned long begin_aligned, end_aligned;
685
686        /* Make sure boundaries are page aligned */
687        begin_aligned = PAGE_ALIGN(begin);
688        end_aligned   = end & PAGE_MASK;
689
690        if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
691                begin = begin_aligned;
692                end   = end_aligned;
693        }
694
695        if (begin >= end)
696                return;
697
698        /*
699         * If debugging page accesses then do not free this memory but
700         * mark them not present - any buggy init-section access will
701         * create a kernel page fault:
702         */
703        if (debug_pagealloc_enabled()) {
704                pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n",
705                        begin, end - 1);
706                set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
707        } else {
708                /*
709                 * We just marked the kernel text read only above, now that
710                 * we are going to free part of that, we need to make that
711                 * writeable and non-executable first.
712                 */
713                set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
714                set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
715
716                free_reserved_area((void *)begin, (void *)end,
717                                   POISON_FREE_INITMEM, what);
718        }
719}
720
721void __ref free_initmem(void)
722{
723        e820_reallocate_tables();
724
725        free_init_pages("unused kernel",
726                        (unsigned long)(&__init_begin),
727                        (unsigned long)(&__init_end));
728}
729
730#ifdef CONFIG_BLK_DEV_INITRD
731void __init free_initrd_mem(unsigned long start, unsigned long end)
732{
733        /*
734         * end could be not aligned, and We can not align that,
735         * decompresser could be confused by aligned initrd_end
736         * We already reserve the end partial page before in
737         *   - i386_start_kernel()
738         *   - x86_64_start_kernel()
739         *   - relocate_initrd()
740         * So here We can do PAGE_ALIGN() safely to get partial page to be freed
741         */
742        free_init_pages("initrd", start, PAGE_ALIGN(end));
743}
744#endif
745
746void __init zone_sizes_init(void)
747{
748        unsigned long max_zone_pfns[MAX_NR_ZONES];
749
750        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
751
752#ifdef CONFIG_ZONE_DMA
753        max_zone_pfns[ZONE_DMA]         = min(MAX_DMA_PFN, max_low_pfn);
754#endif
755#ifdef CONFIG_ZONE_DMA32
756        max_zone_pfns[ZONE_DMA32]       = min(MAX_DMA32_PFN, max_low_pfn);
757#endif
758        max_zone_pfns[ZONE_NORMAL]      = max_low_pfn;
759#ifdef CONFIG_HIGHMEM
760        max_zone_pfns[ZONE_HIGHMEM]     = max_pfn;
761#endif
762
763        free_area_init_nodes(max_zone_pfns);
764}
765
766DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
767#ifdef CONFIG_SMP
768        .active_mm = &init_mm,
769        .state = 0,
770#endif
771        .cr4 = ~0UL,    /* fail hard if we screw up cr4 shadow initialization */
772};
773EXPORT_SYMBOL_GPL(cpu_tlbstate);
774
775void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
776{
777        /* entry 0 MUST be WB (hardwired to speed up translations) */
778        BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
779
780        __cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
781        __pte2cachemode_tbl[entry] = cache;
782}
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