3 * Copyright (C) 1995 Linus Torvalds
5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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>
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/pfn.h>
25 #include <linux/poison.h>
26 #include <linux/bootmem.h>
27 #include <linux/slab.h>
28 #include <linux/proc_fs.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/initrd.h>
31 #include <linux/cpumask.h>
34 #include <asm/bios_ebda.h>
35 #include <asm/processor.h>
36 #include <asm/system.h>
37 #include <asm/uaccess.h>
38 #include <asm/pgtable.h>
40 #include <asm/fixmap.h>
45 #include <asm/tlbflush.h>
46 #include <asm/pgalloc.h>
47 #include <asm/sections.h>
48 #include <asm/paravirt.h>
49 #include <asm/setup.h>
50 #include <asm/cacheflush.h>
53 unsigned int __VMALLOC_RESERVE = 128 << 20;
55 unsigned long max_low_pfn_mapped;
56 unsigned long max_pfn_mapped;
58 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
59 unsigned long highstart_pfn, highend_pfn;
61 static noinline int do_test_wp_bit(void);
64 static unsigned long __initdata table_start;
65 static unsigned long __meminitdata table_end;
66 static unsigned long __meminitdata table_top;
68 static int __initdata after_init_bootmem;
70 static __init void *alloc_low_page(void)
72 unsigned long pfn = table_end++;
76 panic("alloc_low_page: ran out of memory");
78 adr = __va(pfn * PAGE_SIZE);
79 memset(adr, 0, PAGE_SIZE);
84 * Creates a middle page table and puts a pointer to it in the
85 * given global directory entry. This only returns the gd entry
86 * in non-PAE compilation mode, since the middle layer is folded.
88 static pmd_t * __init one_md_table_init(pgd_t *pgd)
94 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
95 if (after_init_bootmem)
96 pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
98 pmd_table = (pmd_t *)alloc_low_page();
99 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
100 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
101 pud = pud_offset(pgd, 0);
102 BUG_ON(pmd_table != pmd_offset(pud, 0));
107 pud = pud_offset(pgd, 0);
108 pmd_table = pmd_offset(pud, 0);
114 * Create a page table and place a pointer to it in a middle page
117 static pte_t * __init one_page_table_init(pmd_t *pmd)
119 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
120 pte_t *page_table = NULL;
122 if (after_init_bootmem) {
123 #ifdef CONFIG_DEBUG_PAGEALLOC
124 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
128 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
130 page_table = (pte_t *)alloc_low_page();
132 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
133 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
134 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
137 return pte_offset_kernel(pmd, 0);
141 * This function initializes a certain range of kernel virtual memory
142 * with new bootmem page tables, everywhere page tables are missing in
145 * NOTE: The pagetables are allocated contiguous on the physical space
146 * so we can cache the place of the first one and move around without
147 * checking the pgd every time.
150 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
152 int pgd_idx, pmd_idx;
158 pgd_idx = pgd_index(vaddr);
159 pmd_idx = pmd_index(vaddr);
160 pgd = pgd_base + pgd_idx;
162 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
163 pmd = one_md_table_init(pgd);
164 pmd = pmd + pmd_index(vaddr);
165 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
167 one_page_table_init(pmd);
175 static inline int is_kernel_text(unsigned long addr)
177 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
183 * This maps the physical memory to kernel virtual address space, a total
184 * of max_low_pfn pages, by creating page tables starting from address
187 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
188 unsigned long start_pfn,
189 unsigned long end_pfn,
192 int pgd_idx, pmd_idx, pte_ofs;
197 unsigned pages_2m, pages_4k;
201 * First iteration will setup identity mapping using large/small pages
202 * based on use_pse, with other attributes same as set by
203 * the early code in head_32.S
205 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
206 * as desired for the kernel identity mapping.
208 * This two pass mechanism conforms to the TLB app note which says:
210 * "Software should not write to a paging-structure entry in a way
211 * that would change, for any linear address, both the page size
212 * and either the page frame or attributes."
220 pages_2m = pages_4k = 0;
222 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
223 pgd = pgd_base + pgd_idx;
224 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
225 pmd = one_md_table_init(pgd);
229 #ifdef CONFIG_X86_PAE
230 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
235 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
237 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
240 * Map with big pages if possible, otherwise
241 * create normal page tables:
245 pgprot_t prot = PAGE_KERNEL_LARGE;
247 * first pass will use the same initial
248 * identity mapping attribute + _PAGE_PSE.
251 __pgprot(PTE_IDENT_ATTR |
254 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
255 PAGE_OFFSET + PAGE_SIZE-1;
257 if (is_kernel_text(addr) ||
258 is_kernel_text(addr2))
259 prot = PAGE_KERNEL_LARGE_EXEC;
262 if (mapping_iter == 1)
263 set_pmd(pmd, pfn_pmd(pfn, init_prot));
265 set_pmd(pmd, pfn_pmd(pfn, prot));
270 pte = one_page_table_init(pmd);
272 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
274 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
275 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
276 pgprot_t prot = PAGE_KERNEL;
278 * first pass will use the same initial
279 * identity mapping attribute.
281 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
283 if (is_kernel_text(addr))
284 prot = PAGE_KERNEL_EXEC;
287 if (mapping_iter == 1)
288 set_pte(pte, pfn_pte(pfn, init_prot));
290 set_pte(pte, pfn_pte(pfn, prot));
294 if (mapping_iter == 1) {
296 * update direct mapping page count only in the first
299 update_page_count(PG_LEVEL_2M, pages_2m);
300 update_page_count(PG_LEVEL_4K, pages_4k);
303 * local global flush tlb, which will flush the previous
304 * mappings present in both small and large page TLB's.
309 * Second iteration will set the actual desired PTE attributes.
317 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
318 * is valid. The argument is a physical page number.
321 * On x86, access has to be given to the first megabyte of ram because that area
322 * contains bios code and data regions used by X and dosemu and similar apps.
323 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
324 * mmio resources as well as potential bios/acpi data regions.
326 int devmem_is_allowed(unsigned long pagenr)
330 if (!page_is_ram(pagenr))
338 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
340 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
341 vaddr), vaddr), vaddr);
344 static void __init kmap_init(void)
346 unsigned long kmap_vstart;
349 * Cache the first kmap pte:
351 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
352 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
354 kmap_prot = PAGE_KERNEL;
357 #ifdef CONFIG_HIGHMEM
358 static void __init permanent_kmaps_init(pgd_t *pgd_base)
367 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
369 pgd = swapper_pg_dir + pgd_index(vaddr);
370 pud = pud_offset(pgd, vaddr);
371 pmd = pmd_offset(pud, vaddr);
372 pte = pte_offset_kernel(pmd, vaddr);
373 pkmap_page_table = pte;
376 static void __init add_one_highpage_init(struct page *page, int pfn)
378 ClearPageReserved(page);
379 init_page_count(page);
384 struct add_highpages_data {
385 unsigned long start_pfn;
386 unsigned long end_pfn;
389 static int __init add_highpages_work_fn(unsigned long start_pfn,
390 unsigned long end_pfn, void *datax)
394 unsigned long final_start_pfn, final_end_pfn;
395 struct add_highpages_data *data;
397 data = (struct add_highpages_data *)datax;
399 final_start_pfn = max(start_pfn, data->start_pfn);
400 final_end_pfn = min(end_pfn, data->end_pfn);
401 if (final_start_pfn >= final_end_pfn)
404 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
406 if (!pfn_valid(node_pfn))
408 page = pfn_to_page(node_pfn);
409 add_one_highpage_init(page, node_pfn);
416 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
417 unsigned long end_pfn)
419 struct add_highpages_data data;
421 data.start_pfn = start_pfn;
422 data.end_pfn = end_pfn;
424 work_with_active_regions(nid, add_highpages_work_fn, &data);
428 static void __init set_highmem_pages_init(void)
430 add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
432 totalram_pages += totalhigh_pages;
434 #endif /* !CONFIG_NUMA */
437 # define permanent_kmaps_init(pgd_base) do { } while (0)
438 # define set_highmem_pages_init() do { } while (0)
439 #endif /* CONFIG_HIGHMEM */
441 void __init native_pagetable_setup_start(pgd_t *base)
443 unsigned long pfn, va;
450 * Remove any mappings which extend past the end of physical
451 * memory from the boot time page table:
453 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
454 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
455 pgd = base + pgd_index(va);
456 if (!pgd_present(*pgd))
459 pud = pud_offset(pgd, va);
460 pmd = pmd_offset(pud, va);
461 if (!pmd_present(*pmd))
464 pte = pte_offset_kernel(pmd, va);
465 if (!pte_present(*pte))
468 pte_clear(NULL, va, pte);
470 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
473 void __init native_pagetable_setup_done(pgd_t *base)
478 * Build a proper pagetable for the kernel mappings. Up until this
479 * point, we've been running on some set of pagetables constructed by
482 * If we're booting on native hardware, this will be a pagetable
483 * constructed in arch/x86/kernel/head_32.S. The root of the
484 * pagetable will be swapper_pg_dir.
486 * If we're booting paravirtualized under a hypervisor, then there are
487 * more options: we may already be running PAE, and the pagetable may
488 * or may not be based in swapper_pg_dir. In any case,
489 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
490 * appropriately for the rest of the initialization to work.
492 * In general, pagetable_init() assumes that the pagetable may already
493 * be partially populated, and so it avoids stomping on any existing
496 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
498 unsigned long vaddr, end;
501 * Fixed mappings, only the page table structure has to be
502 * created - mappings will be set by set_fixmap():
504 early_ioremap_clear();
505 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
506 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
507 page_table_range_init(vaddr, end, pgd_base);
508 early_ioremap_reset();
511 static void __init pagetable_init(void)
513 pgd_t *pgd_base = swapper_pg_dir;
515 permanent_kmaps_init(pgd_base);
518 #ifdef CONFIG_ACPI_SLEEP
520 * ACPI suspend needs this for resume, because things like the intel-agp
521 * driver might have split up a kernel 4MB mapping.
523 char swsusp_pg_dir[PAGE_SIZE]
524 __attribute__ ((aligned(PAGE_SIZE)));
526 static inline void save_pg_dir(void)
528 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
530 #else /* !CONFIG_ACPI_SLEEP */
531 static inline void save_pg_dir(void)
534 #endif /* !CONFIG_ACPI_SLEEP */
536 void zap_low_mappings(void)
541 * Zap initial low-memory mappings.
543 * Note that "pgd_clear()" doesn't do it for
544 * us, because pgd_clear() is a no-op on i386.
546 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
547 #ifdef CONFIG_X86_PAE
548 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
550 set_pgd(swapper_pg_dir+i, __pgd(0));
558 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
559 EXPORT_SYMBOL_GPL(__supported_pte_mask);
561 #ifdef CONFIG_X86_PAE
563 static int disable_nx __initdata;
568 * Control non executable mappings.
573 static int __init noexec_setup(char *str)
575 if (!str || !strcmp(str, "on")) {
577 __supported_pte_mask |= _PAGE_NX;
581 if (!strcmp(str, "off")) {
583 __supported_pte_mask &= ~_PAGE_NX;
591 early_param("noexec", noexec_setup);
593 static void __init set_nx(void)
595 unsigned int v[4], l, h;
597 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
598 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
600 if ((v[3] & (1 << 20)) && !disable_nx) {
601 rdmsr(MSR_EFER, l, h);
603 wrmsr(MSR_EFER, l, h);
605 __supported_pte_mask |= _PAGE_NX;
611 /* user-defined highmem size */
612 static unsigned int highmem_pages = -1;
615 * highmem=size forces highmem to be exactly 'size' bytes.
616 * This works even on boxes that have no highmem otherwise.
617 * This also works to reduce highmem size on bigger boxes.
619 static int __init parse_highmem(char *arg)
624 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
627 early_param("highmem", parse_highmem);
630 * Determine low and high memory ranges:
632 void __init find_low_pfn_range(void)
634 /* it could update max_pfn */
636 /* max_low_pfn is 0, we already have early_res support */
638 max_low_pfn = max_pfn;
639 if (max_low_pfn > MAXMEM_PFN) {
640 if (highmem_pages == -1)
641 highmem_pages = max_pfn - MAXMEM_PFN;
642 if (highmem_pages + MAXMEM_PFN < max_pfn)
643 max_pfn = MAXMEM_PFN + highmem_pages;
644 if (highmem_pages + MAXMEM_PFN > max_pfn) {
645 printk(KERN_WARNING "only %luMB highmem pages "
646 "available, ignoring highmem size of %uMB.\n",
647 pages_to_mb(max_pfn - MAXMEM_PFN),
648 pages_to_mb(highmem_pages));
651 max_low_pfn = MAXMEM_PFN;
652 #ifndef CONFIG_HIGHMEM
653 /* Maximum memory usable is what is directly addressable */
654 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
656 if (max_pfn > MAX_NONPAE_PFN)
658 "Use a HIGHMEM64G enabled kernel.\n");
660 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
661 max_pfn = MAXMEM_PFN;
662 #else /* !CONFIG_HIGHMEM */
663 #ifndef CONFIG_HIGHMEM64G
664 if (max_pfn > MAX_NONPAE_PFN) {
665 max_pfn = MAX_NONPAE_PFN;
666 printk(KERN_WARNING "Warning only 4GB will be used."
667 "Use a HIGHMEM64G enabled kernel.\n");
669 #endif /* !CONFIG_HIGHMEM64G */
670 #endif /* !CONFIG_HIGHMEM */
672 if (highmem_pages == -1)
674 #ifdef CONFIG_HIGHMEM
675 if (highmem_pages >= max_pfn) {
676 printk(KERN_ERR "highmem size specified (%uMB) is "
677 "bigger than pages available (%luMB)!.\n",
678 pages_to_mb(highmem_pages),
679 pages_to_mb(max_pfn));
683 if (max_low_pfn - highmem_pages <
684 64*1024*1024/PAGE_SIZE){
685 printk(KERN_ERR "highmem size %uMB results in "
686 "smaller than 64MB lowmem, ignoring it.\n"
687 , pages_to_mb(highmem_pages));
690 max_low_pfn -= highmem_pages;
694 printk(KERN_ERR "ignoring highmem size on non-highmem"
700 #ifndef CONFIG_NEED_MULTIPLE_NODES
701 void __init initmem_init(unsigned long start_pfn,
702 unsigned long end_pfn)
704 #ifdef CONFIG_HIGHMEM
705 highstart_pfn = highend_pfn = max_pfn;
706 if (max_pfn > max_low_pfn)
707 highstart_pfn = max_low_pfn;
708 memory_present(0, 0, highend_pfn);
709 e820_register_active_regions(0, 0, highend_pfn);
710 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
711 pages_to_mb(highend_pfn - highstart_pfn));
712 num_physpages = highend_pfn;
713 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
715 memory_present(0, 0, max_low_pfn);
716 e820_register_active_regions(0, 0, max_low_pfn);
717 num_physpages = max_low_pfn;
718 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
720 #ifdef CONFIG_FLATMEM
721 max_mapnr = num_physpages;
723 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
724 pages_to_mb(max_low_pfn));
726 setup_bootmem_allocator();
728 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
730 static void __init zone_sizes_init(void)
732 unsigned long max_zone_pfns[MAX_NR_ZONES];
733 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
734 max_zone_pfns[ZONE_DMA] =
735 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
736 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
737 #ifdef CONFIG_HIGHMEM
738 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
741 free_area_init_nodes(max_zone_pfns);
744 void __init setup_bootmem_allocator(void)
747 unsigned long bootmap_size, bootmap;
749 * Initialize the boot-time allocator (with low memory only):
751 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
752 bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
753 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
756 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
757 reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
759 /* don't touch min_low_pfn */
760 bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
761 min_low_pfn, max_low_pfn);
762 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
763 max_pfn_mapped<<PAGE_SHIFT);
764 printk(KERN_INFO " low ram: %08lx - %08lx\n",
765 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
766 printk(KERN_INFO " bootmap %08lx - %08lx\n",
767 bootmap, bootmap + bootmap_size);
768 for_each_online_node(i)
769 free_bootmem_with_active_regions(i, max_low_pfn);
770 early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
772 after_init_bootmem = 1;
775 static void __init find_early_table_space(unsigned long end, int use_pse)
777 unsigned long puds, pmds, ptes, tables, start;
779 puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
780 tables = PAGE_ALIGN(puds * sizeof(pud_t));
782 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
783 tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
788 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
790 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
792 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
794 tables += PAGE_ALIGN(ptes * sizeof(pte_t));
797 tables += PAGE_SIZE * 2;
800 * RED-PEN putting page tables only on node 0 could
801 * cause a hotspot and fill up ZONE_DMA. The page tables
802 * need roughly 0.5KB per GB.
805 table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
807 if (table_start == -1UL)
808 panic("Cannot find space for the kernel page tables");
810 table_start >>= PAGE_SHIFT;
811 table_end = table_start;
812 table_top = table_start + (tables>>PAGE_SHIFT);
814 printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
815 end, table_start << PAGE_SHIFT,
816 (table_start << PAGE_SHIFT) + tables);
819 unsigned long __init_refok init_memory_mapping(unsigned long start,
822 pgd_t *pgd_base = swapper_pg_dir;
823 unsigned long start_pfn, end_pfn;
824 unsigned long big_page_start;
825 #ifdef CONFIG_DEBUG_PAGEALLOC
827 * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
828 * This will simplify cpa(), which otherwise needs to support splitting
829 * large pages into small in interrupt context, etc.
833 int use_pse = cpu_has_pse;
837 * Find space for the kernel direct mapping tables.
839 if (!after_init_bootmem)
840 find_early_table_space(end, use_pse);
842 #ifdef CONFIG_X86_PAE
845 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
848 /* Enable PSE if available */
850 set_in_cr4(X86_CR4_PSE);
852 /* Enable PGE if available */
854 set_in_cr4(X86_CR4_PGE);
855 __supported_pte_mask |= _PAGE_GLOBAL;
859 * Don't use a large page for the first 2/4MB of memory
860 * because there are often fixed size MTRRs in there
861 * and overlapping MTRRs into large pages can cause
864 big_page_start = PMD_SIZE;
866 if (start < big_page_start) {
867 start_pfn = start >> PAGE_SHIFT;
868 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
870 /* head is not big page alignment ? */
871 start_pfn = start >> PAGE_SHIFT;
872 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
873 << (PMD_SHIFT - PAGE_SHIFT);
875 if (start_pfn < end_pfn)
876 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
879 start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
880 << (PMD_SHIFT - PAGE_SHIFT);
881 if (start_pfn < (big_page_start >> PAGE_SHIFT))
882 start_pfn = big_page_start >> PAGE_SHIFT;
883 end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
884 if (start_pfn < end_pfn)
885 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
888 /* tail is not big page alignment ? */
890 if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
891 end_pfn = end >> PAGE_SHIFT;
892 if (start_pfn < end_pfn)
893 kernel_physical_mapping_init(pgd_base, start_pfn,
897 early_ioremap_page_table_range_init(pgd_base);
899 load_cr3(swapper_pg_dir);
903 if (!after_init_bootmem)
904 reserve_early(table_start << PAGE_SHIFT,
905 table_end << PAGE_SHIFT, "PGTABLE");
907 if (!after_init_bootmem)
908 early_memtest(start, end);
910 return end >> PAGE_SHIFT;
915 * paging_init() sets up the page tables - note that the first 8MB are
916 * already mapped by head.S.
918 * This routines also unmaps the page at virtual kernel address 0, so
919 * that we can trap those pesky NULL-reference errors in the kernel.
921 void __init paging_init(void)
930 * NOTE: at this point the bootmem allocator is fully available.
937 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
938 * and also on some strange 486's. All 586+'s are OK. This used to involve
939 * black magic jumps to work around some nasty CPU bugs, but fortunately the
940 * switch to using exceptions got rid of all that.
942 static void __init test_wp_bit(void)
945 "Checking if this processor honours the WP bit even in supervisor mode...");
947 /* Any page-aligned address will do, the test is non-destructive */
948 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
949 boot_cpu_data.wp_works_ok = do_test_wp_bit();
950 clear_fixmap(FIX_WP_TEST);
952 if (!boot_cpu_data.wp_works_ok) {
953 printk(KERN_CONT "No.\n");
954 #ifdef CONFIG_X86_WP_WORKS_OK
956 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
959 printk(KERN_CONT "Ok.\n");
963 static struct kcore_list kcore_mem, kcore_vmalloc;
965 void __init mem_init(void)
967 int codesize, reservedpages, datasize, initsize;
970 #ifdef CONFIG_FLATMEM
973 /* this will put all low memory onto the freelists */
974 totalram_pages += free_all_bootmem();
977 for (tmp = 0; tmp < max_low_pfn; tmp++)
979 * Only count reserved RAM pages:
981 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
984 set_highmem_pages_init();
986 codesize = (unsigned long) &_etext - (unsigned long) &_text;
987 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
988 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
990 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
991 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
992 VMALLOC_END-VMALLOC_START);
994 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
995 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
996 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
997 num_physpages << (PAGE_SHIFT-10),
999 reservedpages << (PAGE_SHIFT-10),
1002 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1005 printk(KERN_INFO "virtual kernel memory layout:\n"
1006 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1007 #ifdef CONFIG_HIGHMEM
1008 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1010 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
1011 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
1012 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
1013 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
1014 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
1015 FIXADDR_START, FIXADDR_TOP,
1016 (FIXADDR_TOP - FIXADDR_START) >> 10,
1018 #ifdef CONFIG_HIGHMEM
1019 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1020 (LAST_PKMAP*PAGE_SIZE) >> 10,
1023 VMALLOC_START, VMALLOC_END,
1024 (VMALLOC_END - VMALLOC_START) >> 20,
1026 (unsigned long)__va(0), (unsigned long)high_memory,
1027 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1029 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1030 ((unsigned long)&__init_end -
1031 (unsigned long)&__init_begin) >> 10,
1033 (unsigned long)&_etext, (unsigned long)&_edata,
1034 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1036 (unsigned long)&_text, (unsigned long)&_etext,
1037 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1040 * Check boundaries twice: Some fundamental inconsistencies can
1041 * be detected at build time already.
1043 #define __FIXADDR_TOP (-PAGE_SIZE)
1044 #ifdef CONFIG_HIGHMEM
1045 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
1046 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
1048 #define high_memory (-128UL << 20)
1049 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
1051 #undef __FIXADDR_TOP
1053 #ifdef CONFIG_HIGHMEM
1054 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
1055 BUG_ON(VMALLOC_END > PKMAP_BASE);
1057 BUG_ON(VMALLOC_START >= VMALLOC_END);
1058 BUG_ON((unsigned long)high_memory > VMALLOC_START);
1060 if (boot_cpu_data.wp_works_ok < 0)
1067 #ifdef CONFIG_MEMORY_HOTPLUG
1068 int arch_add_memory(int nid, u64 start, u64 size)
1070 struct pglist_data *pgdata = NODE_DATA(nid);
1071 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1072 unsigned long start_pfn = start >> PAGE_SHIFT;
1073 unsigned long nr_pages = size >> PAGE_SHIFT;
1075 return __add_pages(zone, start_pfn, nr_pages);
1080 * This function cannot be __init, since exceptions don't work in that
1081 * section. Put this after the callers, so that it cannot be inlined.
1083 static noinline int do_test_wp_bit(void)
1088 __asm__ __volatile__(
1094 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1103 #ifdef CONFIG_DEBUG_RODATA
1104 const int rodata_test_data = 0xC3;
1105 EXPORT_SYMBOL_GPL(rodata_test_data);
1107 void mark_rodata_ro(void)
1109 unsigned long start = PFN_ALIGN(_text);
1110 unsigned long size = PFN_ALIGN(_etext) - start;
1112 #ifndef CONFIG_DYNAMIC_FTRACE
1113 /* Dynamic tracing modifies the kernel text section */
1114 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1115 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1118 #ifdef CONFIG_CPA_DEBUG
1119 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1121 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1123 printk(KERN_INFO "Testing CPA: write protecting again\n");
1124 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1126 #endif /* CONFIG_DYNAMIC_FTRACE */
1129 size = (unsigned long)__end_rodata - start;
1130 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1131 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1135 #ifdef CONFIG_CPA_DEBUG
1136 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1137 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1139 printk(KERN_INFO "Testing CPA: write protecting again\n");
1140 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1145 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1147 #ifdef CONFIG_DEBUG_PAGEALLOC
1149 * If debugging page accesses then do not free this memory but
1150 * mark them not present - any buggy init-section access will
1151 * create a kernel page fault:
1153 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1154 begin, PAGE_ALIGN(end));
1155 set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1160 * We just marked the kernel text read only above, now that
1161 * we are going to free part of that, we need to make that
1164 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1166 for (addr = begin; addr < end; addr += PAGE_SIZE) {
1167 ClearPageReserved(virt_to_page(addr));
1168 init_page_count(virt_to_page(addr));
1169 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1173 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1177 void free_initmem(void)
1179 free_init_pages("unused kernel memory",
1180 (unsigned long)(&__init_begin),
1181 (unsigned long)(&__init_end));
1184 #ifdef CONFIG_BLK_DEV_INITRD
1185 void free_initrd_mem(unsigned long start, unsigned long end)
1187 free_init_pages("initrd memory", start, end);
1191 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1194 return reserve_bootmem(phys, len, flags);