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1 /*
2  *
3  *  Copyright (C) 1995  Linus Torvalds
4  *
5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
6  */
7
8 #include <linux/module.h>
9 #include <linux/signal.h>
10 #include <linux/sched.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
15 #include <linux/ptrace.h>
16 #include <linux/mman.h>
17 #include <linux/mm.h>
18 #include <linux/hugetlb.h>
19 #include <linux/swap.h>
20 #include <linux/smp.h>
21 #include <linux/init.h>
22 #include <linux/highmem.h>
23 #include <linux/pagemap.h>
24 #include <linux/pci.h>
25 #include <linux/pfn.h>
26 #include <linux/poison.h>
27 #include <linux/bootmem.h>
28 #include <linux/proc_fs.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/initrd.h>
31 #include <linux/cpumask.h>
32 #include <linux/gfp.h>
33
34 #include <asm/asm.h>
35 #include <asm/bios_ebda.h>
36 #include <asm/processor.h>
37 #include <asm/system.h>
38 #include <asm/uaccess.h>
39 #include <asm/pgtable.h>
40 #include <asm/dma.h>
41 #include <asm/fixmap.h>
42 #include <asm/e820.h>
43 #include <asm/apic.h>
44 #include <asm/bugs.h>
45 #include <asm/tlb.h>
46 #include <asm/tlbflush.h>
47 #include <asm/pgalloc.h>
48 #include <asm/sections.h>
49 #include <asm/paravirt.h>
50 #include <asm/setup.h>
51 #include <asm/cacheflush.h>
52 #include <asm/page_types.h>
53 #include <asm/init.h>
54
55 unsigned long highstart_pfn, highend_pfn;
56
57 static noinline int do_test_wp_bit(void);
58
59 bool __read_mostly __vmalloc_start_set = false;
60
61 static __init void *alloc_low_page(void)
62 {
63         unsigned long pfn = e820_table_end++;
64         void *adr;
65
66         if (pfn >= e820_table_top)
67                 panic("alloc_low_page: ran out of memory");
68
69         adr = __va(pfn * PAGE_SIZE);
70         clear_page(adr);
71         return adr;
72 }
73
74 /*
75  * Creates a middle page table and puts a pointer to it in the
76  * given global directory entry. This only returns the gd entry
77  * in non-PAE compilation mode, since the middle layer is folded.
78  */
79 static pmd_t * __init one_md_table_init(pgd_t *pgd)
80 {
81         pud_t *pud;
82         pmd_t *pmd_table;
83
84 #ifdef CONFIG_X86_PAE
85         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
86                 if (after_bootmem)
87                         pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
88                 else
89                         pmd_table = (pmd_t *)alloc_low_page();
90                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
91                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
92                 pud = pud_offset(pgd, 0);
93                 BUG_ON(pmd_table != pmd_offset(pud, 0));
94
95                 return pmd_table;
96         }
97 #endif
98         pud = pud_offset(pgd, 0);
99         pmd_table = pmd_offset(pud, 0);
100
101         return pmd_table;
102 }
103
104 /*
105  * Create a page table and place a pointer to it in a middle page
106  * directory entry:
107  */
108 static pte_t * __init one_page_table_init(pmd_t *pmd)
109 {
110         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
111                 pte_t *page_table = NULL;
112
113                 if (after_bootmem) {
114 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
115                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
116 #endif
117                         if (!page_table)
118                                 page_table =
119                                 (pte_t *)alloc_bootmem_pages(PAGE_SIZE);
120                 } else
121                         page_table = (pte_t *)alloc_low_page();
122
123                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
124                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
125                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
126         }
127
128         return pte_offset_kernel(pmd, 0);
129 }
130
131 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
132 {
133         int pgd_idx = pgd_index(vaddr);
134         int pmd_idx = pmd_index(vaddr);
135
136         return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
137 }
138
139 pte_t * __init populate_extra_pte(unsigned long vaddr)
140 {
141         int pte_idx = pte_index(vaddr);
142         pmd_t *pmd;
143
144         pmd = populate_extra_pmd(vaddr);
145         return one_page_table_init(pmd) + pte_idx;
146 }
147
148 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
149                                            unsigned long vaddr, pte_t *lastpte)
150 {
151 #ifdef CONFIG_HIGHMEM
152         /*
153          * Something (early fixmap) may already have put a pte
154          * page here, which causes the page table allocation
155          * to become nonlinear. Attempt to fix it, and if it
156          * is still nonlinear then we have to bug.
157          */
158         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
159         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
160
161         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
162             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
163             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
164             && ((__pa(pte) >> PAGE_SHIFT) < e820_table_start
165                 || (__pa(pte) >> PAGE_SHIFT) >= e820_table_end)) {
166                 pte_t *newpte;
167                 int i;
168
169                 BUG_ON(after_bootmem);
170                 newpte = alloc_low_page();
171                 for (i = 0; i < PTRS_PER_PTE; i++)
172                         set_pte(newpte + i, pte[i]);
173
174                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
175                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
176                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
177                 __flush_tlb_all();
178
179                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
180                 pte = newpte;
181         }
182         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
183                && vaddr > fix_to_virt(FIX_KMAP_END)
184                && lastpte && lastpte + PTRS_PER_PTE != pte);
185 #endif
186         return pte;
187 }
188
189 /*
190  * This function initializes a certain range of kernel virtual memory
191  * with new bootmem page tables, everywhere page tables are missing in
192  * the given range.
193  *
194  * NOTE: The pagetables are allocated contiguous on the physical space
195  * so we can cache the place of the first one and move around without
196  * checking the pgd every time.
197  */
198 static void __init
199 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
200 {
201         int pgd_idx, pmd_idx;
202         unsigned long vaddr;
203         pgd_t *pgd;
204         pmd_t *pmd;
205         pte_t *pte = NULL;
206
207         vaddr = start;
208         pgd_idx = pgd_index(vaddr);
209         pmd_idx = pmd_index(vaddr);
210         pgd = pgd_base + pgd_idx;
211
212         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
213                 pmd = one_md_table_init(pgd);
214                 pmd = pmd + pmd_index(vaddr);
215                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
216                                                         pmd++, pmd_idx++) {
217                         pte = page_table_kmap_check(one_page_table_init(pmd),
218                                                     pmd, vaddr, pte);
219
220                         vaddr += PMD_SIZE;
221                 }
222                 pmd_idx = 0;
223         }
224 }
225
226 static inline int is_kernel_text(unsigned long addr)
227 {
228         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
229                 return 1;
230         return 0;
231 }
232
233 /*
234  * This maps the physical memory to kernel virtual address space, a total
235  * of max_low_pfn pages, by creating page tables starting from address
236  * PAGE_OFFSET:
237  */
238 unsigned long __init
239 kernel_physical_mapping_init(unsigned long start,
240                              unsigned long end,
241                              unsigned long page_size_mask)
242 {
243         int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
244         unsigned long last_map_addr = end;
245         unsigned long start_pfn, end_pfn;
246         pgd_t *pgd_base = swapper_pg_dir;
247         int pgd_idx, pmd_idx, pte_ofs;
248         unsigned long pfn;
249         pgd_t *pgd;
250         pmd_t *pmd;
251         pte_t *pte;
252         unsigned pages_2m, pages_4k;
253         int mapping_iter;
254
255         start_pfn = start >> PAGE_SHIFT;
256         end_pfn = end >> PAGE_SHIFT;
257
258         /*
259          * First iteration will setup identity mapping using large/small pages
260          * based on use_pse, with other attributes same as set by
261          * the early code in head_32.S
262          *
263          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
264          * as desired for the kernel identity mapping.
265          *
266          * This two pass mechanism conforms to the TLB app note which says:
267          *
268          *     "Software should not write to a paging-structure entry in a way
269          *      that would change, for any linear address, both the page size
270          *      and either the page frame or attributes."
271          */
272         mapping_iter = 1;
273
274         if (!cpu_has_pse)
275                 use_pse = 0;
276
277 repeat:
278         pages_2m = pages_4k = 0;
279         pfn = start_pfn;
280         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
281         pgd = pgd_base + pgd_idx;
282         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
283                 pmd = one_md_table_init(pgd);
284
285                 if (pfn >= end_pfn)
286                         continue;
287 #ifdef CONFIG_X86_PAE
288                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
289                 pmd += pmd_idx;
290 #else
291                 pmd_idx = 0;
292 #endif
293                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
294                      pmd++, pmd_idx++) {
295                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
296
297                         /*
298                          * Map with big pages if possible, otherwise
299                          * create normal page tables:
300                          */
301                         if (use_pse) {
302                                 unsigned int addr2;
303                                 pgprot_t prot = PAGE_KERNEL_LARGE;
304                                 /*
305                                  * first pass will use the same initial
306                                  * identity mapping attribute + _PAGE_PSE.
307                                  */
308                                 pgprot_t init_prot =
309                                         __pgprot(PTE_IDENT_ATTR |
310                                                  _PAGE_PSE);
311
312                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
313                                         PAGE_OFFSET + PAGE_SIZE-1;
314
315                                 if (is_kernel_text(addr) ||
316                                     is_kernel_text(addr2))
317                                         prot = PAGE_KERNEL_LARGE_EXEC;
318
319                                 pages_2m++;
320                                 if (mapping_iter == 1)
321                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
322                                 else
323                                         set_pmd(pmd, pfn_pmd(pfn, prot));
324
325                                 pfn += PTRS_PER_PTE;
326                                 continue;
327                         }
328                         pte = one_page_table_init(pmd);
329
330                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
331                         pte += pte_ofs;
332                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
333                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
334                                 pgprot_t prot = PAGE_KERNEL;
335                                 /*
336                                  * first pass will use the same initial
337                                  * identity mapping attribute.
338                                  */
339                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
340
341                                 if (is_kernel_text(addr))
342                                         prot = PAGE_KERNEL_EXEC;
343
344                                 pages_4k++;
345                                 if (mapping_iter == 1) {
346                                         set_pte(pte, pfn_pte(pfn, init_prot));
347                                         last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
348                                 } else
349                                         set_pte(pte, pfn_pte(pfn, prot));
350                         }
351                 }
352         }
353         if (mapping_iter == 1) {
354                 /*
355                  * update direct mapping page count only in the first
356                  * iteration.
357                  */
358                 update_page_count(PG_LEVEL_2M, pages_2m);
359                 update_page_count(PG_LEVEL_4K, pages_4k);
360
361                 /*
362                  * local global flush tlb, which will flush the previous
363                  * mappings present in both small and large page TLB's.
364                  */
365                 __flush_tlb_all();
366
367                 /*
368                  * Second iteration will set the actual desired PTE attributes.
369                  */
370                 mapping_iter = 2;
371                 goto repeat;
372         }
373         return last_map_addr;
374 }
375
376 pte_t *kmap_pte;
377 pgprot_t kmap_prot;
378
379 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
380 {
381         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
382                         vaddr), vaddr), vaddr);
383 }
384
385 static void __init kmap_init(void)
386 {
387         unsigned long kmap_vstart;
388
389         /*
390          * Cache the first kmap pte:
391          */
392         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
393         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
394
395         kmap_prot = PAGE_KERNEL;
396 }
397
398 #ifdef CONFIG_HIGHMEM
399 static void __init permanent_kmaps_init(pgd_t *pgd_base)
400 {
401         unsigned long vaddr;
402         pgd_t *pgd;
403         pud_t *pud;
404         pmd_t *pmd;
405         pte_t *pte;
406
407         vaddr = PKMAP_BASE;
408         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
409
410         pgd = swapper_pg_dir + pgd_index(vaddr);
411         pud = pud_offset(pgd, vaddr);
412         pmd = pmd_offset(pud, vaddr);
413         pte = pte_offset_kernel(pmd, vaddr);
414         pkmap_page_table = pte;
415 }
416
417 static void __init add_one_highpage_init(struct page *page)
418 {
419         ClearPageReserved(page);
420         init_page_count(page);
421         __free_page(page);
422         totalhigh_pages++;
423 }
424
425 struct add_highpages_data {
426         unsigned long start_pfn;
427         unsigned long end_pfn;
428 };
429
430 static int __init add_highpages_work_fn(unsigned long start_pfn,
431                                          unsigned long end_pfn, void *datax)
432 {
433         int node_pfn;
434         struct page *page;
435         unsigned long final_start_pfn, final_end_pfn;
436         struct add_highpages_data *data;
437
438         data = (struct add_highpages_data *)datax;
439
440         final_start_pfn = max(start_pfn, data->start_pfn);
441         final_end_pfn = min(end_pfn, data->end_pfn);
442         if (final_start_pfn >= final_end_pfn)
443                 return 0;
444
445         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
446              node_pfn++) {
447                 if (!pfn_valid(node_pfn))
448                         continue;
449                 page = pfn_to_page(node_pfn);
450                 add_one_highpage_init(page);
451         }
452
453         return 0;
454
455 }
456
457 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
458                                               unsigned long end_pfn)
459 {
460         struct add_highpages_data data;
461
462         data.start_pfn = start_pfn;
463         data.end_pfn = end_pfn;
464
465         work_with_active_regions(nid, add_highpages_work_fn, &data);
466 }
467
468 #else
469 static inline void permanent_kmaps_init(pgd_t *pgd_base)
470 {
471 }
472 #endif /* CONFIG_HIGHMEM */
473
474 void __init native_pagetable_setup_start(pgd_t *base)
475 {
476         unsigned long pfn, va;
477         pgd_t *pgd;
478         pud_t *pud;
479         pmd_t *pmd;
480         pte_t *pte;
481
482         /*
483          * Remove any mappings which extend past the end of physical
484          * memory from the boot time page table:
485          */
486         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
487                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
488                 pgd = base + pgd_index(va);
489                 if (!pgd_present(*pgd))
490                         break;
491
492                 pud = pud_offset(pgd, va);
493                 pmd = pmd_offset(pud, va);
494                 if (!pmd_present(*pmd))
495                         break;
496
497                 pte = pte_offset_kernel(pmd, va);
498                 if (!pte_present(*pte))
499                         break;
500
501                 pte_clear(NULL, va, pte);
502         }
503         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
504 }
505
506 void __init native_pagetable_setup_done(pgd_t *base)
507 {
508 }
509
510 /*
511  * Build a proper pagetable for the kernel mappings.  Up until this
512  * point, we've been running on some set of pagetables constructed by
513  * the boot process.
514  *
515  * If we're booting on native hardware, this will be a pagetable
516  * constructed in arch/x86/kernel/head_32.S.  The root of the
517  * pagetable will be swapper_pg_dir.
518  *
519  * If we're booting paravirtualized under a hypervisor, then there are
520  * more options: we may already be running PAE, and the pagetable may
521  * or may not be based in swapper_pg_dir.  In any case,
522  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
523  * appropriately for the rest of the initialization to work.
524  *
525  * In general, pagetable_init() assumes that the pagetable may already
526  * be partially populated, and so it avoids stomping on any existing
527  * mappings.
528  */
529 void __init early_ioremap_page_table_range_init(void)
530 {
531         pgd_t *pgd_base = swapper_pg_dir;
532         unsigned long vaddr, end;
533
534         /*
535          * Fixed mappings, only the page table structure has to be
536          * created - mappings will be set by set_fixmap():
537          */
538         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
539         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
540         page_table_range_init(vaddr, end, pgd_base);
541         early_ioremap_reset();
542 }
543
544 static void __init pagetable_init(void)
545 {
546         pgd_t *pgd_base = swapper_pg_dir;
547
548         permanent_kmaps_init(pgd_base);
549 }
550
551 #ifdef CONFIG_ACPI_SLEEP
552 /*
553  * ACPI suspend needs this for resume, because things like the intel-agp
554  * driver might have split up a kernel 4MB mapping.
555  */
556 char swsusp_pg_dir[PAGE_SIZE]
557         __attribute__ ((aligned(PAGE_SIZE)));
558
559 static inline void save_pg_dir(void)
560 {
561         copy_page(swsusp_pg_dir, swapper_pg_dir);
562 }
563 #else /* !CONFIG_ACPI_SLEEP */
564 static inline void save_pg_dir(void)
565 {
566 }
567 #endif /* !CONFIG_ACPI_SLEEP */
568
569 void zap_low_mappings(bool early)
570 {
571         int i;
572
573         /*
574          * Zap initial low-memory mappings.
575          *
576          * Note that "pgd_clear()" doesn't do it for
577          * us, because pgd_clear() is a no-op on i386.
578          */
579         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
580 #ifdef CONFIG_X86_PAE
581                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
582 #else
583                 set_pgd(swapper_pg_dir+i, __pgd(0));
584 #endif
585         }
586
587         if (early)
588                 __flush_tlb();
589         else
590                 flush_tlb_all();
591 }
592
593 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
594 EXPORT_SYMBOL_GPL(__supported_pte_mask);
595
596 /* user-defined highmem size */
597 static unsigned int highmem_pages = -1;
598
599 /*
600  * highmem=size forces highmem to be exactly 'size' bytes.
601  * This works even on boxes that have no highmem otherwise.
602  * This also works to reduce highmem size on bigger boxes.
603  */
604 static int __init parse_highmem(char *arg)
605 {
606         if (!arg)
607                 return -EINVAL;
608
609         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
610         return 0;
611 }
612 early_param("highmem", parse_highmem);
613
614 #define MSG_HIGHMEM_TOO_BIG \
615         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
616
617 #define MSG_LOWMEM_TOO_SMALL \
618         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
619 /*
620  * All of RAM fits into lowmem - but if user wants highmem
621  * artificially via the highmem=x boot parameter then create
622  * it:
623  */
624 void __init lowmem_pfn_init(void)
625 {
626         /* max_low_pfn is 0, we already have early_res support */
627         max_low_pfn = max_pfn;
628
629         if (highmem_pages == -1)
630                 highmem_pages = 0;
631 #ifdef CONFIG_HIGHMEM
632         if (highmem_pages >= max_pfn) {
633                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
634                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
635                 highmem_pages = 0;
636         }
637         if (highmem_pages) {
638                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
639                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
640                                 pages_to_mb(highmem_pages));
641                         highmem_pages = 0;
642                 }
643                 max_low_pfn -= highmem_pages;
644         }
645 #else
646         if (highmem_pages)
647                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
648 #endif
649 }
650
651 #define MSG_HIGHMEM_TOO_SMALL \
652         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
653
654 #define MSG_HIGHMEM_TRIMMED \
655         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
656 /*
657  * We have more RAM than fits into lowmem - we try to put it into
658  * highmem, also taking the highmem=x boot parameter into account:
659  */
660 void __init highmem_pfn_init(void)
661 {
662         max_low_pfn = MAXMEM_PFN;
663
664         if (highmem_pages == -1)
665                 highmem_pages = max_pfn - MAXMEM_PFN;
666
667         if (highmem_pages + MAXMEM_PFN < max_pfn)
668                 max_pfn = MAXMEM_PFN + highmem_pages;
669
670         if (highmem_pages + MAXMEM_PFN > max_pfn) {
671                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
672                         pages_to_mb(max_pfn - MAXMEM_PFN),
673                         pages_to_mb(highmem_pages));
674                 highmem_pages = 0;
675         }
676 #ifndef CONFIG_HIGHMEM
677         /* Maximum memory usable is what is directly addressable */
678         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
679         if (max_pfn > MAX_NONPAE_PFN)
680                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
681         else
682                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
683         max_pfn = MAXMEM_PFN;
684 #else /* !CONFIG_HIGHMEM */
685 #ifndef CONFIG_HIGHMEM64G
686         if (max_pfn > MAX_NONPAE_PFN) {
687                 max_pfn = MAX_NONPAE_PFN;
688                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
689         }
690 #endif /* !CONFIG_HIGHMEM64G */
691 #endif /* !CONFIG_HIGHMEM */
692 }
693
694 /*
695  * Determine low and high memory ranges:
696  */
697 void __init find_low_pfn_range(void)
698 {
699         /* it could update max_pfn */
700
701         if (max_pfn <= MAXMEM_PFN)
702                 lowmem_pfn_init();
703         else
704                 highmem_pfn_init();
705 }
706
707 #ifndef CONFIG_NEED_MULTIPLE_NODES
708 void __init initmem_init(unsigned long start_pfn, unsigned long end_pfn,
709                                 int acpi, int k8)
710 {
711 #ifdef CONFIG_HIGHMEM
712         highstart_pfn = highend_pfn = max_pfn;
713         if (max_pfn > max_low_pfn)
714                 highstart_pfn = max_low_pfn;
715         e820_register_active_regions(0, 0, highend_pfn);
716         sparse_memory_present_with_active_regions(0);
717         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
718                 pages_to_mb(highend_pfn - highstart_pfn));
719         num_physpages = highend_pfn;
720         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
721 #else
722         e820_register_active_regions(0, 0, max_low_pfn);
723         sparse_memory_present_with_active_regions(0);
724         num_physpages = max_low_pfn;
725         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
726 #endif
727 #ifdef CONFIG_FLATMEM
728         max_mapnr = num_physpages;
729 #endif
730         __vmalloc_start_set = true;
731
732         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
733                         pages_to_mb(max_low_pfn));
734
735         setup_bootmem_allocator();
736 }
737 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
738
739 static void __init zone_sizes_init(void)
740 {
741         unsigned long max_zone_pfns[MAX_NR_ZONES];
742         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
743         max_zone_pfns[ZONE_DMA] =
744                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
745         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
746 #ifdef CONFIG_HIGHMEM
747         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
748 #endif
749
750         free_area_init_nodes(max_zone_pfns);
751 }
752
753 #ifndef CONFIG_NO_BOOTMEM
754 static unsigned long __init setup_node_bootmem(int nodeid,
755                                  unsigned long start_pfn,
756                                  unsigned long end_pfn,
757                                  unsigned long bootmap)
758 {
759         unsigned long bootmap_size;
760
761         /* don't touch min_low_pfn */
762         bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
763                                          bootmap >> PAGE_SHIFT,
764                                          start_pfn, end_pfn);
765         printk(KERN_INFO "  node %d low ram: %08lx - %08lx\n",
766                 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
767         printk(KERN_INFO "  node %d bootmap %08lx - %08lx\n",
768                  nodeid, bootmap, bootmap + bootmap_size);
769         free_bootmem_with_active_regions(nodeid, end_pfn);
770
771         return bootmap + bootmap_size;
772 }
773 #endif
774
775 void __init setup_bootmem_allocator(void)
776 {
777 #ifndef CONFIG_NO_BOOTMEM
778         int nodeid;
779         unsigned long bootmap_size, bootmap;
780         /*
781          * Initialize the boot-time allocator (with low memory only):
782          */
783         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
784         bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
785                                  PAGE_SIZE);
786         if (bootmap == -1L)
787                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
788         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
789 #endif
790
791         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
792                  max_pfn_mapped<<PAGE_SHIFT);
793         printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
794
795 #ifndef CONFIG_NO_BOOTMEM
796         for_each_online_node(nodeid) {
797                  unsigned long start_pfn, end_pfn;
798
799 #ifdef CONFIG_NEED_MULTIPLE_NODES
800                 start_pfn = node_start_pfn[nodeid];
801                 end_pfn = node_end_pfn[nodeid];
802                 if (start_pfn > max_low_pfn)
803                         continue;
804                 if (end_pfn > max_low_pfn)
805                         end_pfn = max_low_pfn;
806 #else
807                 start_pfn = 0;
808                 end_pfn = max_low_pfn;
809 #endif
810                 bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
811                                                  bootmap);
812         }
813 #endif
814
815         after_bootmem = 1;
816 }
817
818 /*
819  * paging_init() sets up the page tables - note that the first 8MB are
820  * already mapped by head.S.
821  *
822  * This routines also unmaps the page at virtual kernel address 0, so
823  * that we can trap those pesky NULL-reference errors in the kernel.
824  */
825 void __init paging_init(void)
826 {
827         pagetable_init();
828
829         __flush_tlb_all();
830
831         kmap_init();
832
833         /*
834          * NOTE: at this point the bootmem allocator is fully available.
835          */
836         sparse_init();
837         zone_sizes_init();
838 }
839
840 /*
841  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
842  * and also on some strange 486's. All 586+'s are OK. This used to involve
843  * black magic jumps to work around some nasty CPU bugs, but fortunately the
844  * switch to using exceptions got rid of all that.
845  */
846 static void __init test_wp_bit(void)
847 {
848         printk(KERN_INFO
849   "Checking if this processor honours the WP bit even in supervisor mode...");
850
851         /* Any page-aligned address will do, the test is non-destructive */
852         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
853         boot_cpu_data.wp_works_ok = do_test_wp_bit();
854         clear_fixmap(FIX_WP_TEST);
855
856         if (!boot_cpu_data.wp_works_ok) {
857                 printk(KERN_CONT "No.\n");
858 #ifdef CONFIG_X86_WP_WORKS_OK
859                 panic(
860   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
861 #endif
862         } else {
863                 printk(KERN_CONT "Ok.\n");
864         }
865 }
866
867 void __init mem_init(void)
868 {
869         int codesize, reservedpages, datasize, initsize;
870         int tmp;
871
872         pci_iommu_alloc();
873
874 #ifdef CONFIG_FLATMEM
875         BUG_ON(!mem_map);
876 #endif
877         /* this will put all low memory onto the freelists */
878         totalram_pages += free_all_bootmem();
879
880         reservedpages = 0;
881         for (tmp = 0; tmp < max_low_pfn; tmp++)
882                 /*
883                  * Only count reserved RAM pages:
884                  */
885                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
886                         reservedpages++;
887
888         set_highmem_pages_init();
889
890         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
891         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
892         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
893
894         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
895                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
896                 nr_free_pages() << (PAGE_SHIFT-10),
897                 num_physpages << (PAGE_SHIFT-10),
898                 codesize >> 10,
899                 reservedpages << (PAGE_SHIFT-10),
900                 datasize >> 10,
901                 initsize >> 10,
902                 totalhigh_pages << (PAGE_SHIFT-10));
903
904         printk(KERN_INFO "virtual kernel memory layout:\n"
905                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
906 #ifdef CONFIG_HIGHMEM
907                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
908 #endif
909                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
910                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
911                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
912                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
913                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
914                 FIXADDR_START, FIXADDR_TOP,
915                 (FIXADDR_TOP - FIXADDR_START) >> 10,
916
917 #ifdef CONFIG_HIGHMEM
918                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
919                 (LAST_PKMAP*PAGE_SIZE) >> 10,
920 #endif
921
922                 VMALLOC_START, VMALLOC_END,
923                 (VMALLOC_END - VMALLOC_START) >> 20,
924
925                 (unsigned long)__va(0), (unsigned long)high_memory,
926                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
927
928                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
929                 ((unsigned long)&__init_end -
930                  (unsigned long)&__init_begin) >> 10,
931
932                 (unsigned long)&_etext, (unsigned long)&_edata,
933                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
934
935                 (unsigned long)&_text, (unsigned long)&_etext,
936                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
937
938         /*
939          * Check boundaries twice: Some fundamental inconsistencies can
940          * be detected at build time already.
941          */
942 #define __FIXADDR_TOP (-PAGE_SIZE)
943 #ifdef CONFIG_HIGHMEM
944         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
945         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
946 #endif
947 #define high_memory (-128UL << 20)
948         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
949 #undef high_memory
950 #undef __FIXADDR_TOP
951
952 #ifdef CONFIG_HIGHMEM
953         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
954         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
955 #endif
956         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
957         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
958
959         if (boot_cpu_data.wp_works_ok < 0)
960                 test_wp_bit();
961
962         save_pg_dir();
963         zap_low_mappings(true);
964 }
965
966 #ifdef CONFIG_MEMORY_HOTPLUG
967 int arch_add_memory(int nid, u64 start, u64 size)
968 {
969         struct pglist_data *pgdata = NODE_DATA(nid);
970         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
971         unsigned long start_pfn = start >> PAGE_SHIFT;
972         unsigned long nr_pages = size >> PAGE_SHIFT;
973
974         return __add_pages(nid, zone, start_pfn, nr_pages);
975 }
976 #endif
977
978 /*
979  * This function cannot be __init, since exceptions don't work in that
980  * section.  Put this after the callers, so that it cannot be inlined.
981  */
982 static noinline int do_test_wp_bit(void)
983 {
984         char tmp_reg;
985         int flag;
986
987         __asm__ __volatile__(
988                 "       movb %0, %1     \n"
989                 "1:     movb %1, %0     \n"
990                 "       xorl %2, %2     \n"
991                 "2:                     \n"
992                 _ASM_EXTABLE(1b,2b)
993                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
994                  "=q" (tmp_reg),
995                  "=r" (flag)
996                 :"2" (1)
997                 :"memory");
998
999         return flag;
1000 }
1001
1002 #ifdef CONFIG_DEBUG_RODATA
1003 const int rodata_test_data = 0xC3;
1004 EXPORT_SYMBOL_GPL(rodata_test_data);
1005
1006 int kernel_set_to_readonly __read_mostly;
1007
1008 void set_kernel_text_rw(void)
1009 {
1010         unsigned long start = PFN_ALIGN(_text);
1011         unsigned long size = PFN_ALIGN(_etext) - start;
1012
1013         if (!kernel_set_to_readonly)
1014                 return;
1015
1016         pr_debug("Set kernel text: %lx - %lx for read write\n",
1017                  start, start+size);
1018
1019         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1020 }
1021
1022 void set_kernel_text_ro(void)
1023 {
1024         unsigned long start = PFN_ALIGN(_text);
1025         unsigned long size = PFN_ALIGN(_etext) - start;
1026
1027         if (!kernel_set_to_readonly)
1028                 return;
1029
1030         pr_debug("Set kernel text: %lx - %lx for read only\n",
1031                  start, start+size);
1032
1033         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1034 }
1035
1036 void mark_rodata_ro(void)
1037 {
1038         unsigned long start = PFN_ALIGN(_text);
1039         unsigned long size = PFN_ALIGN(_etext) - start;
1040
1041         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1042         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1043                 size >> 10);
1044
1045         kernel_set_to_readonly = 1;
1046
1047 #ifdef CONFIG_CPA_DEBUG
1048         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1049                 start, start+size);
1050         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1051
1052         printk(KERN_INFO "Testing CPA: write protecting again\n");
1053         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1054 #endif
1055
1056         start += size;
1057         size = (unsigned long)__end_rodata - start;
1058         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1059         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1060                 size >> 10);
1061         rodata_test();
1062
1063 #ifdef CONFIG_CPA_DEBUG
1064         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1065         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1066
1067         printk(KERN_INFO "Testing CPA: write protecting again\n");
1068         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1069 #endif
1070 }
1071 #endif
1072
1073 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1074                                    int flags)
1075 {
1076         return reserve_bootmem(phys, len, flags);
1077 }