source: src/linux/universal/linux-4.4/arch/x86/mm/init.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 2 months 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
21/*
22 * We need to define the tracepoints somewhere, and tlb.c
23 * is only compied when SMP=y.
24 */
25#define CREATE_TRACE_POINTS
26#include <trace/events/tlb.h>
27
28#include "mm_internal.h"
29
30/*
31 * Tables translating between page_cache_type_t and pte encoding.
32 *
33 * The default values are defined statically as minimal supported mode;
34 * WC and WT fall back to UC-.  pat_init() updates these values to support
35 * more cache modes, WC and WT, when it is safe to do so.  See pat_init()
36 * for the details.  Note, __early_ioremap() used during early boot-time
37 * takes pgprot_t (pte encoding) and does not use these tables.
38 *
39 *   Index into __cachemode2pte_tbl[] is the cachemode.
40 *
41 *   Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
42 *   (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
43 */
44uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
45        [_PAGE_CACHE_MODE_WB      ]     = 0         | 0        ,
46        [_PAGE_CACHE_MODE_WC      ]     = 0         | _PAGE_PCD,
47        [_PAGE_CACHE_MODE_UC_MINUS]     = 0         | _PAGE_PCD,
48        [_PAGE_CACHE_MODE_UC      ]     = _PAGE_PWT | _PAGE_PCD,
49        [_PAGE_CACHE_MODE_WT      ]     = 0         | _PAGE_PCD,
50        [_PAGE_CACHE_MODE_WP      ]     = 0         | _PAGE_PCD,
51};
52EXPORT_SYMBOL(__cachemode2pte_tbl);
53
54uint8_t __pte2cachemode_tbl[8] = {
55        [__pte2cm_idx( 0        | 0         | 0        )] = _PAGE_CACHE_MODE_WB,
56        [__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
57        [__pte2cm_idx( 0        | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,
58        [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC,
59        [__pte2cm_idx( 0        | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
60        [__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
61        [__pte2cm_idx(0         | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
62        [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
63};
64EXPORT_SYMBOL(__pte2cachemode_tbl);
65
66static unsigned long __initdata pgt_buf_start;
67static unsigned long __initdata pgt_buf_end;
68static unsigned long __initdata pgt_buf_top;
69
70static unsigned long min_pfn_mapped;
71
72static bool __initdata can_use_brk_pgt = true;
73
74/*
75 * Pages returned are already directly mapped.
76 *
77 * Changing that is likely to break Xen, see commit:
78 *
79 *    279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
80 *
81 * for detailed information.
82 */
83__ref void *alloc_low_pages(unsigned int num)
84{
85        unsigned long pfn;
86        int i;
87
88        if (after_bootmem) {
89                unsigned int order;
90
91                order = get_order((unsigned long)num << PAGE_SHIFT);
92                return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK |
93                                                __GFP_ZERO, order);
94        }
95
96        if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
97                unsigned long ret;
98                if (min_pfn_mapped >= max_pfn_mapped)
99                        panic("alloc_low_pages: ran out of memory");
100                ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
101                                        max_pfn_mapped << PAGE_SHIFT,
102                                        PAGE_SIZE * num , PAGE_SIZE);
103                if (!ret)
104                        panic("alloc_low_pages: can not alloc memory");
105                memblock_reserve(ret, PAGE_SIZE * num);
106                pfn = ret >> PAGE_SHIFT;
107        } else {
108                pfn = pgt_buf_end;
109                pgt_buf_end += num;
110                printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
111                        pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
112        }
113
114        for (i = 0; i < num; i++) {
115                void *adr;
116
117                adr = __va((pfn + i) << PAGE_SHIFT);
118                clear_page(adr);
119        }
120
121        return __va(pfn << PAGE_SHIFT);
122}
123
124/* need 3 4k for initial PMD_SIZE,  3 4k for 0-ISA_END_ADDRESS */
125#define INIT_PGT_BUF_SIZE       (6 * PAGE_SIZE)
126RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
127void  __init early_alloc_pgt_buf(void)
128{
129        unsigned long tables = INIT_PGT_BUF_SIZE;
130        phys_addr_t base;
131
132        base = __pa(extend_brk(tables, PAGE_SIZE));
133
134        pgt_buf_start = base >> PAGE_SHIFT;
135        pgt_buf_end = pgt_buf_start;
136        pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
137}
138
139int after_bootmem;
140
141early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
142
143struct map_range {
144        unsigned long start;
145        unsigned long end;
146        unsigned page_size_mask;
147};
148
149static int page_size_mask;
150
151static void __init probe_page_size_mask(void)
152{
153#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
154        /*
155         * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
156         * This will simplify cpa(), which otherwise needs to support splitting
157         * large pages into small in interrupt context, etc.
158         */
159        if (cpu_has_pse)
160                page_size_mask |= 1 << PG_LEVEL_2M;
161#endif
162
163        /* Enable PSE if available */
164        if (cpu_has_pse)
165                cr4_set_bits_and_update_boot(X86_CR4_PSE);
166
167        /* Enable PGE if available */
168        if (cpu_has_pge) {
169                cr4_set_bits_and_update_boot(X86_CR4_PGE);
170                __supported_pte_mask |= _PAGE_GLOBAL;
171        } else
172                __supported_pte_mask &= ~_PAGE_GLOBAL;
173
174        /* Enable 1 GB linear kernel mappings if available: */
175        if (direct_gbpages && cpu_has_gbpages) {
176                printk(KERN_INFO "Using GB pages for direct mapping\n");
177                page_size_mask |= 1 << PG_LEVEL_1G;
178        } else {
179                direct_gbpages = 0;
180        }
181}
182
183#ifdef CONFIG_X86_32
184#define NR_RANGE_MR 3
185#else /* CONFIG_X86_64 */
186#define NR_RANGE_MR 5
187#endif
188
189static int __meminit save_mr(struct map_range *mr, int nr_range,
190                             unsigned long start_pfn, unsigned long end_pfn,
191                             unsigned long page_size_mask)
192{
193        if (start_pfn < end_pfn) {
194                if (nr_range >= NR_RANGE_MR)
195                        panic("run out of range for init_memory_mapping\n");
196                mr[nr_range].start = start_pfn<<PAGE_SHIFT;
197                mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
198                mr[nr_range].page_size_mask = page_size_mask;
199                nr_range++;
200        }
201
202        return nr_range;
203}
204
205/*
206 * adjust the page_size_mask for small range to go with
207 *      big page size instead small one if nearby are ram too.
208 */
209static void __init_refok adjust_range_page_size_mask(struct map_range *mr,
210                                                         int nr_range)
211{
212        int i;
213
214        for (i = 0; i < nr_range; i++) {
215                if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
216                    !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
217                        unsigned long start = round_down(mr[i].start, PMD_SIZE);
218                        unsigned long end = round_up(mr[i].end, PMD_SIZE);
219
220#ifdef CONFIG_X86_32
221                        if ((end >> PAGE_SHIFT) > max_low_pfn)
222                                continue;
223#endif
224
225                        if (memblock_is_region_memory(start, end - start))
226                                mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
227                }
228                if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
229                    !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
230                        unsigned long start = round_down(mr[i].start, PUD_SIZE);
231                        unsigned long end = round_up(mr[i].end, PUD_SIZE);
232
233                        if (memblock_is_region_memory(start, end - start))
234                                mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
235                }
236        }
237}
238
239static const char *page_size_string(struct map_range *mr)
240{
241        static const char str_1g[] = "1G";
242        static const char str_2m[] = "2M";
243        static const char str_4m[] = "4M";
244        static const char str_4k[] = "4k";
245
246        if (mr->page_size_mask & (1<<PG_LEVEL_1G))
247                return str_1g;
248        /*
249         * 32-bit without PAE has a 4M large page size.
250         * PG_LEVEL_2M is misnamed, but we can at least
251         * print out the right size in the string.
252         */
253        if (IS_ENABLED(CONFIG_X86_32) &&
254            !IS_ENABLED(CONFIG_X86_PAE) &&
255            mr->page_size_mask & (1<<PG_LEVEL_2M))
256                return str_4m;
257
258        if (mr->page_size_mask & (1<<PG_LEVEL_2M))
259                return str_2m;
260
261        return str_4k;
262}
263
264static int __meminit split_mem_range(struct map_range *mr, int nr_range,
265                                     unsigned long start,
266                                     unsigned long end)
267{
268        unsigned long start_pfn, end_pfn, limit_pfn;
269        unsigned long pfn;
270        int i;
271
272        limit_pfn = PFN_DOWN(end);
273
274        /* head if not big page alignment ? */
275        pfn = start_pfn = PFN_DOWN(start);
276#ifdef CONFIG_X86_32
277        /*
278         * Don't use a large page for the first 2/4MB of memory
279         * because there are often fixed size MTRRs in there
280         * and overlapping MTRRs into large pages can cause
281         * slowdowns.
282         */
283        if (pfn == 0)
284                end_pfn = PFN_DOWN(PMD_SIZE);
285        else
286                end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
287#else /* CONFIG_X86_64 */
288        end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
289#endif
290        if (end_pfn > limit_pfn)
291                end_pfn = limit_pfn;
292        if (start_pfn < end_pfn) {
293                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
294                pfn = end_pfn;
295        }
296
297        /* big page (2M) range */
298        start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
299#ifdef CONFIG_X86_32
300        end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
301#else /* CONFIG_X86_64 */
302        end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
303        if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
304                end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
305#endif
306
307        if (start_pfn < end_pfn) {
308                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
309                                page_size_mask & (1<<PG_LEVEL_2M));
310                pfn = end_pfn;
311        }
312
313#ifdef CONFIG_X86_64
314        /* big page (1G) range */
315        start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
316        end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
317        if (start_pfn < end_pfn) {
318                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
319                                page_size_mask &
320                                 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
321                pfn = end_pfn;
322        }
323
324        /* tail is not big page (1G) alignment */
325        start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
326        end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
327        if (start_pfn < end_pfn) {
328                nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
329                                page_size_mask & (1<<PG_LEVEL_2M));
330                pfn = end_pfn;
331        }
332#endif
333
334        /* tail is not big page (2M) alignment */
335        start_pfn = pfn;
336        end_pfn = limit_pfn;
337        nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
338
339        if (!after_bootmem)
340                adjust_range_page_size_mask(mr, nr_range);
341
342        /* try to merge same page size and continuous */
343        for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
344                unsigned long old_start;
345                if (mr[i].end != mr[i+1].start ||
346                    mr[i].page_size_mask != mr[i+1].page_size_mask)
347                        continue;
348                /* move it */
349                old_start = mr[i].start;
350                memmove(&mr[i], &mr[i+1],
351                        (nr_range - 1 - i) * sizeof(struct map_range));
352                mr[i--].start = old_start;
353                nr_range--;
354        }
355
356        for (i = 0; i < nr_range; i++)
357                pr_debug(" [mem %#010lx-%#010lx] page %s\n",
358                                mr[i].start, mr[i].end - 1,
359                                page_size_string(&mr[i]));
360
361        return nr_range;
362}
363
364struct range pfn_mapped[E820_X_MAX];
365int nr_pfn_mapped;
366
367static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
368{
369        nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_X_MAX,
370                                             nr_pfn_mapped, start_pfn, end_pfn);
371        nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);
372
373        max_pfn_mapped = max(max_pfn_mapped, end_pfn);
374
375        if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
376                max_low_pfn_mapped = max(max_low_pfn_mapped,
377                                         min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
378}
379
380bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
381{
382        int i;
383
384        for (i = 0; i < nr_pfn_mapped; i++)
385                if ((start_pfn >= pfn_mapped[i].start) &&
386                    (end_pfn <= pfn_mapped[i].end))
387                        return true;
388
389        return false;
390}
391
392/*
393 * Setup the direct mapping of the physical memory at PAGE_OFFSET.
394 * This runs before bootmem is initialized and gets pages directly from
395 * the physical memory. To access them they are temporarily mapped.
396 */
397unsigned long __init_refok init_memory_mapping(unsigned long start,
398                                               unsigned long end)
399{
400        struct map_range mr[NR_RANGE_MR];
401        unsigned long ret = 0;
402        int nr_range, i;
403
404        pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
405               start, end - 1);
406
407        memset(mr, 0, sizeof(mr));
408        nr_range = split_mem_range(mr, 0, start, end);
409
410        for (i = 0; i < nr_range; i++)
411                ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
412                                                   mr[i].page_size_mask);
413
414        add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
415
416        return ret >> PAGE_SHIFT;
417}
418
419/*
420 * We need to iterate through the E820 memory map and create direct mappings
421 * for only E820_RAM and E820_KERN_RESERVED regions. We cannot simply
422 * create direct mappings for all pfns from [0 to max_low_pfn) and
423 * [4GB to max_pfn) because of possible memory holes in high addresses
424 * that cannot be marked as UC by fixed/variable range MTRRs.
425 * Depending on the alignment of E820 ranges, this may possibly result
426 * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
427 *
428 * init_mem_mapping() calls init_range_memory_mapping() with big range.
429 * That range would have hole in the middle or ends, and only ram parts
430 * will be mapped in init_range_memory_mapping().
431 */
432static unsigned long __init init_range_memory_mapping(
433                                           unsigned long r_start,
434                                           unsigned long r_end)
435{
436        unsigned long start_pfn, end_pfn;
437        unsigned long mapped_ram_size = 0;
438        int i;
439
440        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
441                u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
442                u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
443                if (start >= end)
444                        continue;
445
446                /*
447                 * if it is overlapping with brk pgt, we need to
448                 * alloc pgt buf from memblock instead.
449                 */
450                can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
451                                    min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
452                init_memory_mapping(start, end);
453                mapped_ram_size += end - start;
454                can_use_brk_pgt = true;
455        }
456
457        return mapped_ram_size;
458}
459
460static unsigned long __init get_new_step_size(unsigned long step_size)
461{
462        /*
463         * Initial mapped size is PMD_SIZE (2M).
464         * We can not set step_size to be PUD_SIZE (1G) yet.
465         * In worse case, when we cross the 1G boundary, and
466         * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
467         * to map 1G range with PTE. Hence we use one less than the
468         * difference of page table level shifts.
469         *
470         * Don't need to worry about overflow in the top-down case, on 32bit,
471         * when step_size is 0, round_down() returns 0 for start, and that
472         * turns it into 0x100000000ULL.
473         * In the bottom-up case, round_up(x, 0) returns 0 though too, which
474         * needs to be taken into consideration by the code below.
475         */
476        return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
477}
478
479/**
480 * memory_map_top_down - Map [map_start, map_end) top down
481 * @map_start: start address of the target memory range
482 * @map_end: end address of the target memory range
483 *
484 * This function will setup direct mapping for memory range
485 * [map_start, map_end) in top-down. That said, the page tables
486 * will be allocated at the end of the memory, and we map the
487 * memory in top-down.
488 */
489static void __init memory_map_top_down(unsigned long map_start,
490                                       unsigned long map_end)
491{
492        unsigned long real_end, start, last_start;
493        unsigned long step_size;
494        unsigned long addr;
495        unsigned long mapped_ram_size = 0;
496
497        /* xen has big range in reserved near end of ram, skip it at first.*/
498        addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
499        real_end = addr + PMD_SIZE;
500
501        /* step_size need to be small so pgt_buf from BRK could cover it */
502        step_size = PMD_SIZE;
503        max_pfn_mapped = 0; /* will get exact value next */
504        min_pfn_mapped = real_end >> PAGE_SHIFT;
505        last_start = start = real_end;
506
507        /*
508         * We start from the top (end of memory) and go to the bottom.
509         * The memblock_find_in_range() gets us a block of RAM from the
510         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
511         * for page table.
512         */
513        while (last_start > map_start) {
514                if (last_start > step_size) {
515                        start = round_down(last_start - 1, step_size);
516                        if (start < map_start)
517                                start = map_start;
518                } else
519                        start = map_start;
520                mapped_ram_size += init_range_memory_mapping(start,
521                                                        last_start);
522                last_start = start;
523                min_pfn_mapped = last_start >> PAGE_SHIFT;
524                if (mapped_ram_size >= step_size)
525                        step_size = get_new_step_size(step_size);
526        }
527
528        if (real_end < map_end)
529                init_range_memory_mapping(real_end, map_end);
530}
531
532/**
533 * memory_map_bottom_up - Map [map_start, map_end) bottom up
534 * @map_start: start address of the target memory range
535 * @map_end: end address of the target memory range
536 *
537 * This function will setup direct mapping for memory range
538 * [map_start, map_end) in bottom-up. Since we have limited the
539 * bottom-up allocation above the kernel, the page tables will
540 * be allocated just above the kernel and we map the memory
541 * in [map_start, map_end) in bottom-up.
542 */
543static void __init memory_map_bottom_up(unsigned long map_start,
544                                        unsigned long map_end)
545{
546        unsigned long next, start;
547        unsigned long mapped_ram_size = 0;
548        /* step_size need to be small so pgt_buf from BRK could cover it */
549        unsigned long step_size = PMD_SIZE;
550
551        start = map_start;
552        min_pfn_mapped = start >> PAGE_SHIFT;
553
554        /*
555         * We start from the bottom (@map_start) and go to the top (@map_end).
556         * The memblock_find_in_range() gets us a block of RAM from the
557         * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
558         * for page table.
559         */
560        while (start < map_end) {
561                if (step_size && map_end - start > step_size) {
562                        next = round_up(start + 1, step_size);
563                        if (next > map_end)
564                                next = map_end;
565                } else {
566                        next = map_end;
567                }
568
569                mapped_ram_size += init_range_memory_mapping(start, next);
570                start = next;
571
572                if (mapped_ram_size >= step_size)
573                        step_size = get_new_step_size(step_size);
574        }
575}
576
577void __init init_mem_mapping(void)
578{
579        unsigned long end;
580
581        probe_page_size_mask();
582
583#ifdef CONFIG_X86_64
584        end = max_pfn << PAGE_SHIFT;
585#else
586        end = max_low_pfn << PAGE_SHIFT;
587#endif
588
589        /* the ISA range is always mapped regardless of memory holes */
590        init_memory_mapping(0, ISA_END_ADDRESS);
591
592        /*
593         * If the allocation is in bottom-up direction, we setup direct mapping
594         * in bottom-up, otherwise we setup direct mapping in top-down.
595         */
596        if (memblock_bottom_up()) {
597                unsigned long kernel_end = __pa_symbol(_end);
598
599                /*
600                 * we need two separate calls here. This is because we want to
601                 * allocate page tables above the kernel. So we first map
602                 * [kernel_end, end) to make memory above the kernel be mapped
603                 * as soon as possible. And then use page tables allocated above
604                 * the kernel to map [ISA_END_ADDRESS, kernel_end).
605                 */
606                memory_map_bottom_up(kernel_end, end);
607                memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
608        } else {
609                memory_map_top_down(ISA_END_ADDRESS, end);
610        }
611
612#ifdef CONFIG_X86_64
613        if (max_pfn > max_low_pfn) {
614                /* can we preseve max_low_pfn ?*/
615                max_low_pfn = max_pfn;
616        }
617#else
618        early_ioremap_page_table_range_init();
619#endif
620
621        load_cr3(swapper_pg_dir);
622        __flush_tlb_all();
623
624        early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
625}
626
627/*
628 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
629 * is valid. The argument is a physical page number.
630 *
631 * On x86, access has to be given to the first megabyte of RAM because that
632 * area traditionally contains BIOS code and data regions used by X, dosemu,
633 * and similar apps. Since they map the entire memory range, the whole range
634 * must be allowed (for mapping), but any areas that would otherwise be
635 * disallowed are flagged as being "zero filled" instead of rejected.
636 * Access has to be given to non-kernel-ram areas as well, these contain the
637 * PCI mmio resources as well as potential bios/acpi data regions.
638 */
639int devmem_is_allowed(unsigned long pagenr)
640{
641        if (page_is_ram(pagenr)) {
642                /*
643                 * For disallowed memory regions in the low 1MB range,
644                 * request that the page be shown as all zeros.
645                 */
646                if (pagenr < 256)
647                        return 2;
648
649                return 0;
650        }
651
652        /*
653         * This must follow RAM test, since System RAM is considered a
654         * restricted resource under CONFIG_STRICT_IOMEM.
655         */
656        if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
657                /* Low 1MB bypasses iomem restrictions. */
658                if (pagenr < 256)
659                        return 1;
660
661                return 0;
662        }
663
664        return 1;
665}
666
667void free_init_pages(char *what, unsigned long begin, unsigned long end)
668{
669        unsigned long begin_aligned, end_aligned;
670
671        /* Make sure boundaries are page aligned */
672        begin_aligned = PAGE_ALIGN(begin);
673        end_aligned   = end & PAGE_MASK;
674
675        if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
676                begin = begin_aligned;
677                end   = end_aligned;
678        }
679
680        if (begin >= end)
681                return;
682
683        /*
684         * If debugging page accesses then do not free this memory but
685         * mark them not present - any buggy init-section access will
686         * create a kernel page fault:
687         */
688#ifdef CONFIG_DEBUG_PAGEALLOC
689        printk(KERN_INFO "debug: unmapping init [mem %#010lx-%#010lx]\n",
690                begin, end - 1);
691        set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
692#else
693        /*
694         * We just marked the kernel text read only above, now that
695         * we are going to free part of that, we need to make that
696         * writeable and non-executable first.
697         */
698        set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
699        set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
700
701        free_reserved_area((void *)begin, (void *)end, POISON_FREE_INITMEM, what);
702#endif
703}
704
705void free_initmem(void)
706{
707        free_init_pages("unused kernel",
708                        (unsigned long)(&__init_begin),
709                        (unsigned long)(&__init_end));
710}
711
712#ifdef CONFIG_BLK_DEV_INITRD
713void __init free_initrd_mem(unsigned long start, unsigned long end)
714{
715        /*
716         * Remember, initrd memory may contain microcode or other useful things.
717         * Before we lose initrd mem, we need to find a place to hold them
718         * now that normal virtual memory is enabled.
719         */
720        save_microcode_in_initrd();
721
722        /*
723         * end could be not aligned, and We can not align that,
724         * decompresser could be confused by aligned initrd_end
725         * We already reserve the end partial page before in
726         *   - i386_start_kernel()
727         *   - x86_64_start_kernel()
728         *   - relocate_initrd()
729         * So here We can do PAGE_ALIGN() safely to get partial page to be freed
730         */
731        free_init_pages("initrd", start, PAGE_ALIGN(end));
732}
733#endif
734
735void __init zone_sizes_init(void)
736{
737        unsigned long max_zone_pfns[MAX_NR_ZONES];
738
739        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
740
741#ifdef CONFIG_ZONE_DMA
742        max_zone_pfns[ZONE_DMA]         = min(MAX_DMA_PFN, max_low_pfn);
743#endif
744#ifdef CONFIG_ZONE_DMA32
745        max_zone_pfns[ZONE_DMA32]       = min(MAX_DMA32_PFN, max_low_pfn);
746#endif
747        max_zone_pfns[ZONE_NORMAL]      = max_low_pfn;
748#ifdef CONFIG_HIGHMEM
749        max_zone_pfns[ZONE_HIGHMEM]     = max_pfn;
750#endif
751
752        free_area_init_nodes(max_zone_pfns);
753}
754
755DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
756#ifdef CONFIG_SMP
757        .active_mm = &init_mm,
758        .state = 0,
759#endif
760        .cr4 = ~0UL,    /* fail hard if we screw up cr4 shadow initialization */
761};
762EXPORT_SYMBOL_GPL(cpu_tlbstate);
763
764void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
765{
766        /* entry 0 MUST be WB (hardwired to speed up translations) */
767        BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
768
769        __cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
770        __pte2cachemode_tbl[entry] = cache;
771}
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