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/pci.h>
25 #include <linux/pfn.h>
26 #include <linux/poison.h>
27 #include <linux/bootmem.h>
28 #include <linux/slab.h>
29 #include <linux/proc_fs.h>
30 #include <linux/memory_hotplug.h>
31 #include <linux/initrd.h>
32 #include <linux/cpumask.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>
41 #include <asm/fixmap.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>
53 unsigned long max_low_pfn_mapped;
54 unsigned long max_pfn_mapped;
56 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
57 unsigned long highstart_pfn, highend_pfn;
59 static noinline int do_test_wp_bit(void);
62 static unsigned long __initdata table_start;
63 static unsigned long __meminitdata table_end;
64 static unsigned long __meminitdata table_top;
66 static int __initdata after_init_bootmem;
68 static __init void *alloc_low_page(void)
70 unsigned long pfn = table_end++;
74 panic("alloc_low_page: ran out of memory");
76 adr = __va(pfn * PAGE_SIZE);
77 memset(adr, 0, PAGE_SIZE);
82 * Creates a middle page table and puts a pointer to it in the
83 * given global directory entry. This only returns the gd entry
84 * in non-PAE compilation mode, since the middle layer is folded.
86 static pmd_t * __init one_md_table_init(pgd_t *pgd)
92 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
93 if (after_init_bootmem)
94 pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
96 pmd_table = (pmd_t *)alloc_low_page();
97 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
98 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
99 pud = pud_offset(pgd, 0);
100 BUG_ON(pmd_table != pmd_offset(pud, 0));
105 pud = pud_offset(pgd, 0);
106 pmd_table = pmd_offset(pud, 0);
112 * Create a page table and place a pointer to it in a middle page
115 static pte_t * __init one_page_table_init(pmd_t *pmd)
117 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
118 pte_t *page_table = NULL;
120 if (after_init_bootmem) {
121 #ifdef CONFIG_DEBUG_PAGEALLOC
122 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
126 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
128 page_table = (pte_t *)alloc_low_page();
130 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
131 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
132 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
135 return pte_offset_kernel(pmd, 0);
138 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
139 unsigned long vaddr, pte_t *lastpte)
141 #ifdef CONFIG_HIGHMEM
143 * Something (early fixmap) may already have put a pte
144 * page here, which causes the page table allocation
145 * to become nonlinear. Attempt to fix it, and if it
146 * is still nonlinear then we have to bug.
148 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
149 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
151 if (pmd_idx_kmap_begin != pmd_idx_kmap_end
152 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
153 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
154 && ((__pa(pte) >> PAGE_SHIFT) < table_start
155 || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
159 BUG_ON(after_init_bootmem);
160 newpte = alloc_low_page();
161 for (i = 0; i < PTRS_PER_PTE; i++)
162 set_pte(newpte + i, pte[i]);
164 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
165 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
166 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
169 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
172 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
173 && vaddr > fix_to_virt(FIX_KMAP_END)
174 && lastpte && lastpte + PTRS_PER_PTE != pte);
180 * This function initializes a certain range of kernel virtual memory
181 * with new bootmem page tables, everywhere page tables are missing in
184 * NOTE: The pagetables are allocated contiguous on the physical space
185 * so we can cache the place of the first one and move around without
186 * checking the pgd every time.
189 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
191 int pgd_idx, pmd_idx;
198 pgd_idx = pgd_index(vaddr);
199 pmd_idx = pmd_index(vaddr);
200 pgd = pgd_base + pgd_idx;
202 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
203 pmd = one_md_table_init(pgd);
204 pmd = pmd + pmd_index(vaddr);
205 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
207 pte = page_table_kmap_check(one_page_table_init(pmd),
216 static inline int is_kernel_text(unsigned long addr)
218 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
224 * This maps the physical memory to kernel virtual address space, a total
225 * of max_low_pfn pages, by creating page tables starting from address
228 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
229 unsigned long start_pfn,
230 unsigned long end_pfn,
233 int pgd_idx, pmd_idx, pte_ofs;
238 unsigned pages_2m, pages_4k;
242 * First iteration will setup identity mapping using large/small pages
243 * based on use_pse, with other attributes same as set by
244 * the early code in head_32.S
246 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
247 * as desired for the kernel identity mapping.
249 * This two pass mechanism conforms to the TLB app note which says:
251 * "Software should not write to a paging-structure entry in a way
252 * that would change, for any linear address, both the page size
253 * and either the page frame or attributes."
261 pages_2m = pages_4k = 0;
263 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
264 pgd = pgd_base + pgd_idx;
265 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
266 pmd = one_md_table_init(pgd);
270 #ifdef CONFIG_X86_PAE
271 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
276 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
278 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
281 * Map with big pages if possible, otherwise
282 * create normal page tables:
286 pgprot_t prot = PAGE_KERNEL_LARGE;
288 * first pass will use the same initial
289 * identity mapping attribute + _PAGE_PSE.
292 __pgprot(PTE_IDENT_ATTR |
295 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
296 PAGE_OFFSET + PAGE_SIZE-1;
298 if (is_kernel_text(addr) ||
299 is_kernel_text(addr2))
300 prot = PAGE_KERNEL_LARGE_EXEC;
303 if (mapping_iter == 1)
304 set_pmd(pmd, pfn_pmd(pfn, init_prot));
306 set_pmd(pmd, pfn_pmd(pfn, prot));
311 pte = one_page_table_init(pmd);
313 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
315 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
316 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
317 pgprot_t prot = PAGE_KERNEL;
319 * first pass will use the same initial
320 * identity mapping attribute.
322 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
324 if (is_kernel_text(addr))
325 prot = PAGE_KERNEL_EXEC;
328 if (mapping_iter == 1)
329 set_pte(pte, pfn_pte(pfn, init_prot));
331 set_pte(pte, pfn_pte(pfn, prot));
335 if (mapping_iter == 1) {
337 * update direct mapping page count only in the first
340 update_page_count(PG_LEVEL_2M, pages_2m);
341 update_page_count(PG_LEVEL_4K, pages_4k);
344 * local global flush tlb, which will flush the previous
345 * mappings present in both small and large page TLB's.
350 * Second iteration will set the actual desired PTE attributes.
358 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
359 * is valid. The argument is a physical page number.
362 * On x86, access has to be given to the first megabyte of ram because that area
363 * contains bios code and data regions used by X and dosemu and similar apps.
364 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
365 * mmio resources as well as potential bios/acpi data regions.
367 int devmem_is_allowed(unsigned long pagenr)
371 if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
373 if (!page_is_ram(pagenr))
381 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
383 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
384 vaddr), vaddr), vaddr);
387 static void __init kmap_init(void)
389 unsigned long kmap_vstart;
392 * Cache the first kmap pte:
394 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
395 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
397 kmap_prot = PAGE_KERNEL;
400 #ifdef CONFIG_HIGHMEM
401 static void __init permanent_kmaps_init(pgd_t *pgd_base)
410 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
412 pgd = swapper_pg_dir + pgd_index(vaddr);
413 pud = pud_offset(pgd, vaddr);
414 pmd = pmd_offset(pud, vaddr);
415 pte = pte_offset_kernel(pmd, vaddr);
416 pkmap_page_table = pte;
419 static void __init add_one_highpage_init(struct page *page, int pfn)
421 ClearPageReserved(page);
422 init_page_count(page);
427 struct add_highpages_data {
428 unsigned long start_pfn;
429 unsigned long end_pfn;
432 static int __init add_highpages_work_fn(unsigned long start_pfn,
433 unsigned long end_pfn, void *datax)
437 unsigned long final_start_pfn, final_end_pfn;
438 struct add_highpages_data *data;
440 data = (struct add_highpages_data *)datax;
442 final_start_pfn = max(start_pfn, data->start_pfn);
443 final_end_pfn = min(end_pfn, data->end_pfn);
444 if (final_start_pfn >= final_end_pfn)
447 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
449 if (!pfn_valid(node_pfn))
451 page = pfn_to_page(node_pfn);
452 add_one_highpage_init(page, node_pfn);
459 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
460 unsigned long end_pfn)
462 struct add_highpages_data data;
464 data.start_pfn = start_pfn;
465 data.end_pfn = end_pfn;
467 work_with_active_regions(nid, add_highpages_work_fn, &data);
471 static void __init set_highmem_pages_init(void)
473 add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
475 totalram_pages += totalhigh_pages;
477 #endif /* !CONFIG_NUMA */
480 static inline void permanent_kmaps_init(pgd_t *pgd_base)
483 static inline void set_highmem_pages_init(void)
486 #endif /* CONFIG_HIGHMEM */
488 void __init native_pagetable_setup_start(pgd_t *base)
490 unsigned long pfn, va;
497 * Remove any mappings which extend past the end of physical
498 * memory from the boot time page table:
500 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
501 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
502 pgd = base + pgd_index(va);
503 if (!pgd_present(*pgd))
506 pud = pud_offset(pgd, va);
507 pmd = pmd_offset(pud, va);
508 if (!pmd_present(*pmd))
511 pte = pte_offset_kernel(pmd, va);
512 if (!pte_present(*pte))
515 pte_clear(NULL, va, pte);
517 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
520 void __init native_pagetable_setup_done(pgd_t *base)
525 * Build a proper pagetable for the kernel mappings. Up until this
526 * point, we've been running on some set of pagetables constructed by
529 * If we're booting on native hardware, this will be a pagetable
530 * constructed in arch/x86/kernel/head_32.S. The root of the
531 * pagetable will be swapper_pg_dir.
533 * If we're booting paravirtualized under a hypervisor, then there are
534 * more options: we may already be running PAE, and the pagetable may
535 * or may not be based in swapper_pg_dir. In any case,
536 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
537 * appropriately for the rest of the initialization to work.
539 * In general, pagetable_init() assumes that the pagetable may already
540 * be partially populated, and so it avoids stomping on any existing
543 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
545 unsigned long vaddr, end;
548 * Fixed mappings, only the page table structure has to be
549 * created - mappings will be set by set_fixmap():
551 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
552 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
553 page_table_range_init(vaddr, end, pgd_base);
554 early_ioremap_reset();
557 static void __init pagetable_init(void)
559 pgd_t *pgd_base = swapper_pg_dir;
561 permanent_kmaps_init(pgd_base);
564 #ifdef CONFIG_ACPI_SLEEP
566 * ACPI suspend needs this for resume, because things like the intel-agp
567 * driver might have split up a kernel 4MB mapping.
569 char swsusp_pg_dir[PAGE_SIZE]
570 __attribute__ ((aligned(PAGE_SIZE)));
572 static inline void save_pg_dir(void)
574 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
576 #else /* !CONFIG_ACPI_SLEEP */
577 static inline void save_pg_dir(void)
580 #endif /* !CONFIG_ACPI_SLEEP */
582 void zap_low_mappings(void)
587 * Zap initial low-memory mappings.
589 * Note that "pgd_clear()" doesn't do it for
590 * us, because pgd_clear() is a no-op on i386.
592 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
593 #ifdef CONFIG_X86_PAE
594 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
596 set_pgd(swapper_pg_dir+i, __pgd(0));
604 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
605 EXPORT_SYMBOL_GPL(__supported_pte_mask);
607 #ifdef CONFIG_X86_PAE
609 static int disable_nx __initdata;
614 * Control non executable mappings.
619 static int __init noexec_setup(char *str)
621 if (!str || !strcmp(str, "on")) {
623 __supported_pte_mask |= _PAGE_NX;
627 if (!strcmp(str, "off")) {
629 __supported_pte_mask &= ~_PAGE_NX;
637 early_param("noexec", noexec_setup);
639 static void __init set_nx(void)
641 unsigned int v[4], l, h;
643 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
644 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
646 if ((v[3] & (1 << 20)) && !disable_nx) {
647 rdmsr(MSR_EFER, l, h);
649 wrmsr(MSR_EFER, l, h);
651 __supported_pte_mask |= _PAGE_NX;
657 /* user-defined highmem size */
658 static unsigned int highmem_pages = -1;
661 * highmem=size forces highmem to be exactly 'size' bytes.
662 * This works even on boxes that have no highmem otherwise.
663 * This also works to reduce highmem size on bigger boxes.
665 static int __init parse_highmem(char *arg)
670 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
673 early_param("highmem", parse_highmem);
675 #define MSG_HIGHMEM_TOO_BIG \
676 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
678 #define MSG_LOWMEM_TOO_SMALL \
679 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
681 * All of RAM fits into lowmem - but if user wants highmem
682 * artificially via the highmem=x boot parameter then create
685 void __init lowmem_pfn_init(void)
687 /* max_low_pfn is 0, we already have early_res support */
688 max_low_pfn = max_pfn;
690 if (highmem_pages == -1)
692 #ifdef CONFIG_HIGHMEM
693 if (highmem_pages >= max_pfn) {
694 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
695 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
699 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
700 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
701 pages_to_mb(highmem_pages));
704 max_low_pfn -= highmem_pages;
708 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
712 #define MSG_HIGHMEM_TOO_SMALL \
713 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
715 #define MSG_HIGHMEM_TRIMMED \
716 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
718 * We have more RAM than fits into lowmem - we try to put it into
719 * highmem, also taking the highmem=x boot parameter into account:
721 void __init highmem_pfn_init(void)
723 max_low_pfn = MAXMEM_PFN;
725 if (highmem_pages == -1)
726 highmem_pages = max_pfn - MAXMEM_PFN;
728 if (highmem_pages + MAXMEM_PFN < max_pfn)
729 max_pfn = MAXMEM_PFN + highmem_pages;
731 if (highmem_pages + MAXMEM_PFN > max_pfn) {
732 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
733 pages_to_mb(max_pfn - MAXMEM_PFN),
734 pages_to_mb(highmem_pages));
737 #ifndef CONFIG_HIGHMEM
738 /* Maximum memory usable is what is directly addressable */
739 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
740 if (max_pfn > MAX_NONPAE_PFN)
741 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
743 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
744 max_pfn = MAXMEM_PFN;
745 #else /* !CONFIG_HIGHMEM */
746 #ifndef CONFIG_HIGHMEM64G
747 if (max_pfn > MAX_NONPAE_PFN) {
748 max_pfn = MAX_NONPAE_PFN;
749 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
751 #endif /* !CONFIG_HIGHMEM64G */
752 #endif /* !CONFIG_HIGHMEM */
756 * Determine low and high memory ranges:
758 void __init find_low_pfn_range(void)
760 /* it could update max_pfn */
762 if (max_pfn <= MAXMEM_PFN)
768 #ifndef CONFIG_NEED_MULTIPLE_NODES
769 void __init initmem_init(unsigned long start_pfn,
770 unsigned long end_pfn)
772 #ifdef CONFIG_HIGHMEM
773 highstart_pfn = highend_pfn = max_pfn;
774 if (max_pfn > max_low_pfn)
775 highstart_pfn = max_low_pfn;
776 memory_present(0, 0, highend_pfn);
777 e820_register_active_regions(0, 0, highend_pfn);
778 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
779 pages_to_mb(highend_pfn - highstart_pfn));
780 num_physpages = highend_pfn;
781 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
783 memory_present(0, 0, max_low_pfn);
784 e820_register_active_regions(0, 0, max_low_pfn);
785 num_physpages = max_low_pfn;
786 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
788 #ifdef CONFIG_FLATMEM
789 max_mapnr = num_physpages;
791 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
792 pages_to_mb(max_low_pfn));
794 setup_bootmem_allocator();
796 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
798 static void __init zone_sizes_init(void)
800 unsigned long max_zone_pfns[MAX_NR_ZONES];
801 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
802 max_zone_pfns[ZONE_DMA] =
803 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
804 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
805 #ifdef CONFIG_HIGHMEM
806 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
809 free_area_init_nodes(max_zone_pfns);
812 void __init setup_bootmem_allocator(void)
815 unsigned long bootmap_size, bootmap;
817 * Initialize the boot-time allocator (with low memory only):
819 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
820 bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
821 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
824 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
825 reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
827 /* don't touch min_low_pfn */
828 bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
829 min_low_pfn, max_low_pfn);
830 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
831 max_pfn_mapped<<PAGE_SHIFT);
832 printk(KERN_INFO " low ram: %08lx - %08lx\n",
833 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
834 printk(KERN_INFO " bootmap %08lx - %08lx\n",
835 bootmap, bootmap + bootmap_size);
836 for_each_online_node(i)
837 free_bootmem_with_active_regions(i, max_low_pfn);
838 early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
840 after_init_bootmem = 1;
843 static void __init find_early_table_space(unsigned long end, int use_pse)
845 unsigned long puds, pmds, ptes, tables, start;
847 puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
848 tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
850 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
851 tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
856 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
858 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
860 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
862 tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
865 tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
868 * RED-PEN putting page tables only on node 0 could
869 * cause a hotspot and fill up ZONE_DMA. The page tables
870 * need roughly 0.5KB per GB.
873 table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
875 if (table_start == -1UL)
876 panic("Cannot find space for the kernel page tables");
878 table_start >>= PAGE_SHIFT;
879 table_end = table_start;
880 table_top = table_start + (tables>>PAGE_SHIFT);
882 printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
883 end, table_start << PAGE_SHIFT,
884 (table_start << PAGE_SHIFT) + tables);
887 unsigned long __init_refok init_memory_mapping(unsigned long start,
890 pgd_t *pgd_base = swapper_pg_dir;
891 unsigned long start_pfn, end_pfn;
892 unsigned long big_page_start;
893 #ifdef CONFIG_DEBUG_PAGEALLOC
895 * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
896 * This will simplify cpa(), which otherwise needs to support splitting
897 * large pages into small in interrupt context, etc.
901 int use_pse = cpu_has_pse;
905 * Find space for the kernel direct mapping tables.
907 if (!after_init_bootmem)
908 find_early_table_space(end, use_pse);
910 #ifdef CONFIG_X86_PAE
913 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
916 /* Enable PSE if available */
918 set_in_cr4(X86_CR4_PSE);
920 /* Enable PGE if available */
922 set_in_cr4(X86_CR4_PGE);
923 __supported_pte_mask |= _PAGE_GLOBAL;
927 * Don't use a large page for the first 2/4MB of memory
928 * because there are often fixed size MTRRs in there
929 * and overlapping MTRRs into large pages can cause
932 big_page_start = PMD_SIZE;
934 if (start < big_page_start) {
935 start_pfn = start >> PAGE_SHIFT;
936 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
938 /* head is not big page alignment ? */
939 start_pfn = start >> PAGE_SHIFT;
940 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
941 << (PMD_SHIFT - PAGE_SHIFT);
943 if (start_pfn < end_pfn)
944 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
947 start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
948 << (PMD_SHIFT - PAGE_SHIFT);
949 if (start_pfn < (big_page_start >> PAGE_SHIFT))
950 start_pfn = big_page_start >> PAGE_SHIFT;
951 end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
952 if (start_pfn < end_pfn)
953 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
956 /* tail is not big page alignment ? */
958 if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
959 end_pfn = end >> PAGE_SHIFT;
960 if (start_pfn < end_pfn)
961 kernel_physical_mapping_init(pgd_base, start_pfn,
965 early_ioremap_page_table_range_init(pgd_base);
967 load_cr3(swapper_pg_dir);
971 if (!after_init_bootmem)
972 reserve_early(table_start << PAGE_SHIFT,
973 table_end << PAGE_SHIFT, "PGTABLE");
975 if (!after_init_bootmem)
976 early_memtest(start, end);
978 return end >> PAGE_SHIFT;
983 * paging_init() sets up the page tables - note that the first 8MB are
984 * already mapped by head.S.
986 * This routines also unmaps the page at virtual kernel address 0, so
987 * that we can trap those pesky NULL-reference errors in the kernel.
989 void __init paging_init(void)
998 * NOTE: at this point the bootmem allocator is fully available.
1005 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
1006 * and also on some strange 486's. All 586+'s are OK. This used to involve
1007 * black magic jumps to work around some nasty CPU bugs, but fortunately the
1008 * switch to using exceptions got rid of all that.
1010 static void __init test_wp_bit(void)
1013 "Checking if this processor honours the WP bit even in supervisor mode...");
1015 /* Any page-aligned address will do, the test is non-destructive */
1016 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
1017 boot_cpu_data.wp_works_ok = do_test_wp_bit();
1018 clear_fixmap(FIX_WP_TEST);
1020 if (!boot_cpu_data.wp_works_ok) {
1021 printk(KERN_CONT "No.\n");
1022 #ifdef CONFIG_X86_WP_WORKS_OK
1024 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
1027 printk(KERN_CONT "Ok.\n");
1031 static struct kcore_list kcore_mem, kcore_vmalloc;
1033 void __init mem_init(void)
1035 int codesize, reservedpages, datasize, initsize;
1040 #ifdef CONFIG_FLATMEM
1043 /* this will put all low memory onto the freelists */
1044 totalram_pages += free_all_bootmem();
1047 for (tmp = 0; tmp < max_low_pfn; tmp++)
1049 * Only count reserved RAM pages:
1051 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
1054 set_highmem_pages_init();
1056 codesize = (unsigned long) &_etext - (unsigned long) &_text;
1057 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
1058 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
1060 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
1061 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
1062 VMALLOC_END-VMALLOC_START);
1064 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
1065 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1066 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1067 num_physpages << (PAGE_SHIFT-10),
1069 reservedpages << (PAGE_SHIFT-10),
1072 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1075 printk(KERN_INFO "virtual kernel memory layout:\n"
1076 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1077 #ifdef CONFIG_HIGHMEM
1078 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
1080 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
1081 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
1082 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
1083 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
1084 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
1085 FIXADDR_START, FIXADDR_TOP,
1086 (FIXADDR_TOP - FIXADDR_START) >> 10,
1088 #ifdef CONFIG_HIGHMEM
1089 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1090 (LAST_PKMAP*PAGE_SIZE) >> 10,
1093 VMALLOC_START, VMALLOC_END,
1094 (VMALLOC_END - VMALLOC_START) >> 20,
1096 (unsigned long)__va(0), (unsigned long)high_memory,
1097 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1099 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1100 ((unsigned long)&__init_end -
1101 (unsigned long)&__init_begin) >> 10,
1103 (unsigned long)&_etext, (unsigned long)&_edata,
1104 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1106 (unsigned long)&_text, (unsigned long)&_etext,
1107 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1110 * Check boundaries twice: Some fundamental inconsistencies can
1111 * be detected at build time already.
1113 #define __FIXADDR_TOP (-PAGE_SIZE)
1114 #ifdef CONFIG_HIGHMEM
1115 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
1116 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
1118 #define high_memory (-128UL << 20)
1119 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
1121 #undef __FIXADDR_TOP
1123 #ifdef CONFIG_HIGHMEM
1124 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
1125 BUG_ON(VMALLOC_END > PKMAP_BASE);
1127 BUG_ON(VMALLOC_START >= VMALLOC_END);
1128 BUG_ON((unsigned long)high_memory > VMALLOC_START);
1130 if (boot_cpu_data.wp_works_ok < 0)
1137 #ifdef CONFIG_MEMORY_HOTPLUG
1138 int arch_add_memory(int nid, u64 start, u64 size)
1140 struct pglist_data *pgdata = NODE_DATA(nid);
1141 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1142 unsigned long start_pfn = start >> PAGE_SHIFT;
1143 unsigned long nr_pages = size >> PAGE_SHIFT;
1145 return __add_pages(nid, zone, start_pfn, nr_pages);
1150 * This function cannot be __init, since exceptions don't work in that
1151 * section. Put this after the callers, so that it cannot be inlined.
1153 static noinline int do_test_wp_bit(void)
1158 __asm__ __volatile__(
1164 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1173 #ifdef CONFIG_DEBUG_RODATA
1174 const int rodata_test_data = 0xC3;
1175 EXPORT_SYMBOL_GPL(rodata_test_data);
1177 void mark_rodata_ro(void)
1179 unsigned long start = PFN_ALIGN(_text);
1180 unsigned long size = PFN_ALIGN(_etext) - start;
1182 #ifndef CONFIG_DYNAMIC_FTRACE
1183 /* Dynamic tracing modifies the kernel text section */
1184 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1185 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1188 #ifdef CONFIG_CPA_DEBUG
1189 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1191 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1193 printk(KERN_INFO "Testing CPA: write protecting again\n");
1194 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1196 #endif /* CONFIG_DYNAMIC_FTRACE */
1199 size = (unsigned long)__end_rodata - start;
1200 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1201 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1205 #ifdef CONFIG_CPA_DEBUG
1206 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1207 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1209 printk(KERN_INFO "Testing CPA: write protecting again\n");
1210 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1215 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1217 unsigned long addr = begin;
1223 * If debugging page accesses then do not free this memory but
1224 * mark them not present - any buggy init-section access will
1225 * create a kernel page fault:
1227 #ifdef CONFIG_DEBUG_PAGEALLOC
1228 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1229 begin, PAGE_ALIGN(end));
1230 set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1233 * We just marked the kernel text read only above, now that
1234 * we are going to free part of that, we need to make that
1237 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1239 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1241 for (; addr < end; addr += PAGE_SIZE) {
1242 ClearPageReserved(virt_to_page(addr));
1243 init_page_count(virt_to_page(addr));
1244 memset((void *)(addr & ~(PAGE_SIZE-1)),
1245 POISON_FREE_INITMEM, PAGE_SIZE);
1252 void free_initmem(void)
1254 free_init_pages("unused kernel memory",
1255 (unsigned long)(&__init_begin),
1256 (unsigned long)(&__init_end));
1259 #ifdef CONFIG_BLK_DEV_INITRD
1260 void free_initrd_mem(unsigned long start, unsigned long end)
1262 free_init_pages("initrd memory", start, end);
1266 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1269 return reserve_bootmem(phys, len, flags);