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/processor.h>
35 #include <asm/system.h>
36 #include <asm/uaccess.h>
37 #include <asm/pgtable.h>
39 #include <asm/fixmap.h>
44 #include <asm/tlbflush.h>
45 #include <asm/pgalloc.h>
46 #include <asm/sections.h>
47 #include <asm/paravirt.h>
48 #include <asm/setup.h>
49 #include <asm/cacheflush.h>
51 unsigned int __VMALLOC_RESERVE = 128 << 20;
53 unsigned long max_pfn_mapped;
55 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
56 unsigned long highstart_pfn, highend_pfn;
58 static noinline int do_test_wp_bit(void);
61 static unsigned long __initdata table_start;
62 static unsigned long __meminitdata table_end;
63 static unsigned long __meminitdata table_top;
65 static int __initdata after_init_bootmem;
67 static __init void *alloc_low_page(unsigned long *phys)
69 unsigned long pfn = table_end++;
73 panic("alloc_low_page: ran out of memory");
75 adr = __va(pfn * PAGE_SIZE);
76 memset(adr, 0, PAGE_SIZE);
77 *phys = pfn * 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)
93 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
94 if (after_init_bootmem)
95 pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
97 pmd_table = (pmd_t *)alloc_low_page(&phys);
98 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
99 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
100 pud = pud_offset(pgd, 0);
101 BUG_ON(pmd_table != pmd_offset(pud, 0));
104 pud = pud_offset(pgd, 0);
105 pmd_table = pmd_offset(pud, 0);
111 * Create a page table and place a pointer to it in a middle page
114 static pte_t * __init one_page_table_init(pmd_t *pmd)
116 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
117 pte_t *page_table = NULL;
119 if (after_init_bootmem) {
120 #ifdef CONFIG_DEBUG_PAGEALLOC
121 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
125 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
128 page_table = (pte_t *)alloc_low_page(&phys);
131 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
132 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
133 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
136 return pte_offset_kernel(pmd, 0);
140 * This function initializes a certain range of kernel virtual memory
141 * with new bootmem page tables, everywhere page tables are missing in
144 * NOTE: The pagetables are allocated contiguous on the physical space
145 * so we can cache the place of the first one and move around without
146 * checking the pgd every time.
149 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
151 int pgd_idx, pmd_idx;
157 pgd_idx = pgd_index(vaddr);
158 pmd_idx = pmd_index(vaddr);
159 pgd = pgd_base + pgd_idx;
161 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
162 pmd = one_md_table_init(pgd);
163 pmd = pmd + pmd_index(vaddr);
164 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
166 one_page_table_init(pmd);
174 static inline int is_kernel_text(unsigned long addr)
176 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
182 * This maps the physical memory to kernel virtual address space, a total
183 * of max_low_pfn pages, by creating page tables starting from address
186 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
187 unsigned long start_pfn,
188 unsigned long end_pfn,
191 int pgd_idx, pmd_idx, pte_ofs;
196 unsigned pages_2m = 0, pages_4k = 0;
202 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
203 pgd = pgd_base + pgd_idx;
204 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
205 pmd = one_md_table_init(pgd);
209 #ifdef CONFIG_X86_PAE
210 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
215 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
217 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
220 * Map with big pages if possible, otherwise
221 * create normal page tables:
225 pgprot_t prot = PAGE_KERNEL_LARGE;
227 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
228 PAGE_OFFSET + PAGE_SIZE-1;
230 if (is_kernel_text(addr) ||
231 is_kernel_text(addr2))
232 prot = PAGE_KERNEL_LARGE_EXEC;
235 set_pmd(pmd, pfn_pmd(pfn, prot));
240 pte = one_page_table_init(pmd);
242 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
244 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
245 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
246 pgprot_t prot = PAGE_KERNEL;
248 if (is_kernel_text(addr))
249 prot = PAGE_KERNEL_EXEC;
252 set_pte(pte, pfn_pte(pfn, prot));
256 update_page_count(PG_LEVEL_2M, pages_2m);
257 update_page_count(PG_LEVEL_4K, pages_4k);
261 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
262 * is valid. The argument is a physical page number.
265 * On x86, access has to be given to the first megabyte of ram because that area
266 * contains bios code and data regions used by X and dosemu and similar apps.
267 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
268 * mmio resources as well as potential bios/acpi data regions.
270 int devmem_is_allowed(unsigned long pagenr)
274 if (!page_is_ram(pagenr))
279 #ifdef CONFIG_HIGHMEM
283 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
285 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
286 vaddr), vaddr), vaddr);
289 static void __init kmap_init(void)
291 unsigned long kmap_vstart;
294 * Cache the first kmap pte:
296 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
297 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
299 kmap_prot = PAGE_KERNEL;
302 static void __init permanent_kmaps_init(pgd_t *pgd_base)
311 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
313 pgd = swapper_pg_dir + pgd_index(vaddr);
314 pud = pud_offset(pgd, vaddr);
315 pmd = pmd_offset(pud, vaddr);
316 pte = pte_offset_kernel(pmd, vaddr);
317 pkmap_page_table = pte;
320 static void __init add_one_highpage_init(struct page *page, int pfn)
322 ClearPageReserved(page);
323 init_page_count(page);
328 struct add_highpages_data {
329 unsigned long start_pfn;
330 unsigned long end_pfn;
333 static int __init add_highpages_work_fn(unsigned long start_pfn,
334 unsigned long end_pfn, void *datax)
338 unsigned long final_start_pfn, final_end_pfn;
339 struct add_highpages_data *data;
341 data = (struct add_highpages_data *)datax;
343 final_start_pfn = max(start_pfn, data->start_pfn);
344 final_end_pfn = min(end_pfn, data->end_pfn);
345 if (final_start_pfn >= final_end_pfn)
348 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
350 if (!pfn_valid(node_pfn))
352 page = pfn_to_page(node_pfn);
353 add_one_highpage_init(page, node_pfn);
360 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
361 unsigned long end_pfn)
363 struct add_highpages_data data;
365 data.start_pfn = start_pfn;
366 data.end_pfn = end_pfn;
368 work_with_active_regions(nid, add_highpages_work_fn, &data);
372 static void __init set_highmem_pages_init(void)
374 add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
376 totalram_pages += totalhigh_pages;
378 #endif /* !CONFIG_NUMA */
381 # define kmap_init() do { } while (0)
382 # define permanent_kmaps_init(pgd_base) do { } while (0)
383 # define set_highmem_pages_init() do { } while (0)
384 #endif /* CONFIG_HIGHMEM */
386 void __init native_pagetable_setup_start(pgd_t *base)
388 unsigned long pfn, va;
395 * Remove any mappings which extend past the end of physical
396 * memory from the boot time page table:
398 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
399 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
400 pgd = base + pgd_index(va);
401 if (!pgd_present(*pgd))
404 pud = pud_offset(pgd, va);
405 pmd = pmd_offset(pud, va);
406 if (!pmd_present(*pmd))
409 pte = pte_offset_kernel(pmd, va);
410 if (!pte_present(*pte))
413 pte_clear(NULL, va, pte);
415 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
418 void __init native_pagetable_setup_done(pgd_t *base)
423 * Build a proper pagetable for the kernel mappings. Up until this
424 * point, we've been running on some set of pagetables constructed by
427 * If we're booting on native hardware, this will be a pagetable
428 * constructed in arch/x86/kernel/head_32.S. The root of the
429 * pagetable will be swapper_pg_dir.
431 * If we're booting paravirtualized under a hypervisor, then there are
432 * more options: we may already be running PAE, and the pagetable may
433 * or may not be based in swapper_pg_dir. In any case,
434 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
435 * appropriately for the rest of the initialization to work.
437 * In general, pagetable_init() assumes that the pagetable may already
438 * be partially populated, and so it avoids stomping on any existing
441 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
443 unsigned long vaddr, end;
446 * Fixed mappings, only the page table structure has to be
447 * created - mappings will be set by set_fixmap():
449 early_ioremap_clear();
450 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
451 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
452 page_table_range_init(vaddr, end, pgd_base);
453 early_ioremap_reset();
456 static void __init pagetable_init(void)
458 pgd_t *pgd_base = swapper_pg_dir;
460 paravirt_pagetable_setup_start(pgd_base);
462 permanent_kmaps_init(pgd_base);
464 paravirt_pagetable_setup_done(pgd_base);
467 #ifdef CONFIG_ACPI_SLEEP
469 * ACPI suspend needs this for resume, because things like the intel-agp
470 * driver might have split up a kernel 4MB mapping.
472 char swsusp_pg_dir[PAGE_SIZE]
473 __attribute__ ((aligned(PAGE_SIZE)));
475 static inline void save_pg_dir(void)
477 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
479 #else /* !CONFIG_ACPI_SLEEP */
480 static inline void save_pg_dir(void)
483 #endif /* !CONFIG_ACPI_SLEEP */
485 void zap_low_mappings(void)
490 * Zap initial low-memory mappings.
492 * Note that "pgd_clear()" doesn't do it for
493 * us, because pgd_clear() is a no-op on i386.
495 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
496 #ifdef CONFIG_X86_PAE
497 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
499 set_pgd(swapper_pg_dir+i, __pgd(0));
507 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL);
508 EXPORT_SYMBOL_GPL(__supported_pte_mask);
510 #ifdef CONFIG_X86_PAE
512 static int disable_nx __initdata;
517 * Control non executable mappings.
522 static int __init noexec_setup(char *str)
524 if (!str || !strcmp(str, "on")) {
526 __supported_pte_mask |= _PAGE_NX;
530 if (!strcmp(str, "off")) {
532 __supported_pte_mask &= ~_PAGE_NX;
540 early_param("noexec", noexec_setup);
542 static void __init set_nx(void)
544 unsigned int v[4], l, h;
546 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
547 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
549 if ((v[3] & (1 << 20)) && !disable_nx) {
550 rdmsr(MSR_EFER, l, h);
552 wrmsr(MSR_EFER, l, h);
554 __supported_pte_mask |= _PAGE_NX;
560 /* user-defined highmem size */
561 static unsigned int highmem_pages = -1;
564 * highmem=size forces highmem to be exactly 'size' bytes.
565 * This works even on boxes that have no highmem otherwise.
566 * This also works to reduce highmem size on bigger boxes.
568 static int __init parse_highmem(char *arg)
573 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
576 early_param("highmem", parse_highmem);
579 * Determine low and high memory ranges:
581 void __init find_low_pfn_range(void)
583 /* it could update max_pfn */
585 /* max_low_pfn is 0, we already have early_res support */
587 max_low_pfn = max_pfn;
588 if (max_low_pfn > MAXMEM_PFN) {
589 if (highmem_pages == -1)
590 highmem_pages = max_pfn - MAXMEM_PFN;
591 if (highmem_pages + MAXMEM_PFN < max_pfn)
592 max_pfn = MAXMEM_PFN + highmem_pages;
593 if (highmem_pages + MAXMEM_PFN > max_pfn) {
594 printk(KERN_WARNING "only %luMB highmem pages "
595 "available, ignoring highmem size of %uMB.\n",
596 pages_to_mb(max_pfn - MAXMEM_PFN),
597 pages_to_mb(highmem_pages));
600 max_low_pfn = MAXMEM_PFN;
601 #ifndef CONFIG_HIGHMEM
602 /* Maximum memory usable is what is directly addressable */
603 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
605 if (max_pfn > MAX_NONPAE_PFN)
607 "Use a HIGHMEM64G enabled kernel.\n");
609 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
610 max_pfn = MAXMEM_PFN;
611 #else /* !CONFIG_HIGHMEM */
612 #ifndef CONFIG_HIGHMEM64G
613 if (max_pfn > MAX_NONPAE_PFN) {
614 max_pfn = MAX_NONPAE_PFN;
615 printk(KERN_WARNING "Warning only 4GB will be used."
616 "Use a HIGHMEM64G enabled kernel.\n");
618 #endif /* !CONFIG_HIGHMEM64G */
619 #endif /* !CONFIG_HIGHMEM */
621 if (highmem_pages == -1)
623 #ifdef CONFIG_HIGHMEM
624 if (highmem_pages >= max_pfn) {
625 printk(KERN_ERR "highmem size specified (%uMB) is "
626 "bigger than pages available (%luMB)!.\n",
627 pages_to_mb(highmem_pages),
628 pages_to_mb(max_pfn));
632 if (max_low_pfn - highmem_pages <
633 64*1024*1024/PAGE_SIZE){
634 printk(KERN_ERR "highmem size %uMB results in "
635 "smaller than 64MB lowmem, ignoring it.\n"
636 , pages_to_mb(highmem_pages));
639 max_low_pfn -= highmem_pages;
643 printk(KERN_ERR "ignoring highmem size on non-highmem"
649 #ifndef CONFIG_NEED_MULTIPLE_NODES
650 void __init initmem_init(unsigned long start_pfn,
651 unsigned long end_pfn)
653 #ifdef CONFIG_HIGHMEM
654 highstart_pfn = highend_pfn = max_pfn;
655 if (max_pfn > max_low_pfn)
656 highstart_pfn = max_low_pfn;
657 memory_present(0, 0, highend_pfn);
658 e820_register_active_regions(0, 0, highend_pfn);
659 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
660 pages_to_mb(highend_pfn - highstart_pfn));
661 num_physpages = highend_pfn;
662 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
664 memory_present(0, 0, max_low_pfn);
665 e820_register_active_regions(0, 0, max_low_pfn);
666 num_physpages = max_low_pfn;
667 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
669 #ifdef CONFIG_FLATMEM
670 max_mapnr = num_physpages;
672 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
673 pages_to_mb(max_low_pfn));
675 setup_bootmem_allocator();
677 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
679 static void __init zone_sizes_init(void)
681 unsigned long max_zone_pfns[MAX_NR_ZONES];
682 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
683 max_zone_pfns[ZONE_DMA] =
684 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
685 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
686 #ifdef CONFIG_HIGHMEM
687 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
690 free_area_init_nodes(max_zone_pfns);
693 void __init setup_bootmem_allocator(void)
696 unsigned long bootmap_size, bootmap;
698 * Initialize the boot-time allocator (with low memory only):
700 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
701 bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
702 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
705 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
706 reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
708 /* don't touch min_low_pfn */
709 bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
710 min_low_pfn, max_low_pfn);
711 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
712 max_pfn_mapped<<PAGE_SHIFT);
713 printk(KERN_INFO " low ram: %08lx - %08lx\n",
714 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
715 printk(KERN_INFO " bootmap %08lx - %08lx\n",
716 bootmap, bootmap + bootmap_size);
717 for_each_online_node(i)
718 free_bootmem_with_active_regions(i, max_low_pfn);
719 early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
721 after_init_bootmem = 1;
724 static void __init find_early_table_space(unsigned long end)
726 unsigned long puds, pmds, ptes, tables, start;
728 puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
729 tables = PAGE_ALIGN(puds * sizeof(pud_t));
731 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
732 tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
737 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
739 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
741 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
743 tables += PAGE_ALIGN(ptes * sizeof(pte_t));
746 tables += PAGE_SIZE * 2;
749 * RED-PEN putting page tables only on node 0 could
750 * cause a hotspot and fill up ZONE_DMA. The page tables
751 * need roughly 0.5KB per GB.
754 table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
756 if (table_start == -1UL)
757 panic("Cannot find space for the kernel page tables");
759 table_start >>= PAGE_SHIFT;
760 table_end = table_start;
761 table_top = table_start + (tables>>PAGE_SHIFT);
763 printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
764 end, table_start << PAGE_SHIFT,
765 (table_start << PAGE_SHIFT) + tables);
768 unsigned long __init_refok init_memory_mapping(unsigned long start,
771 pgd_t *pgd_base = swapper_pg_dir;
772 unsigned long start_pfn, end_pfn;
773 unsigned long big_page_start;
776 * Find space for the kernel direct mapping tables.
778 if (!after_init_bootmem)
779 find_early_table_space(end);
781 #ifdef CONFIG_X86_PAE
784 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
787 /* Enable PSE if available */
789 set_in_cr4(X86_CR4_PSE);
791 /* Enable PGE if available */
793 set_in_cr4(X86_CR4_PGE);
794 __supported_pte_mask |= _PAGE_GLOBAL;
798 * Don't use a large page for the first 2/4MB of memory
799 * because there are often fixed size MTRRs in there
800 * and overlapping MTRRs into large pages can cause
803 big_page_start = PMD_SIZE;
805 if (start < big_page_start) {
806 start_pfn = start >> PAGE_SHIFT;
807 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
809 /* head is not big page alignment ? */
810 start_pfn = start >> PAGE_SHIFT;
811 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
812 << (PMD_SHIFT - PAGE_SHIFT);
814 if (start_pfn < end_pfn)
815 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
818 start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
819 << (PMD_SHIFT - PAGE_SHIFT);
820 if (start_pfn < (big_page_start >> PAGE_SHIFT))
821 start_pfn = big_page_start >> PAGE_SHIFT;
822 end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
823 if (start_pfn < end_pfn)
824 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
827 /* tail is not big page alignment ? */
829 if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
830 end_pfn = end >> PAGE_SHIFT;
831 if (start_pfn < end_pfn)
832 kernel_physical_mapping_init(pgd_base, start_pfn,
836 early_ioremap_page_table_range_init(pgd_base);
838 load_cr3(swapper_pg_dir);
842 if (!after_init_bootmem)
843 reserve_early(table_start << PAGE_SHIFT,
844 table_end << PAGE_SHIFT, "PGTABLE");
846 return end >> PAGE_SHIFT;
851 * paging_init() sets up the page tables - note that the first 8MB are
852 * already mapped by head.S.
854 * This routines also unmaps the page at virtual kernel address 0, so
855 * that we can trap those pesky NULL-reference errors in the kernel.
857 void __init paging_init(void)
866 * NOTE: at this point the bootmem allocator is fully available.
871 paravirt_post_allocator_init();
875 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
876 * and also on some strange 486's. All 586+'s are OK. This used to involve
877 * black magic jumps to work around some nasty CPU bugs, but fortunately the
878 * switch to using exceptions got rid of all that.
880 static void __init test_wp_bit(void)
883 "Checking if this processor honours the WP bit even in supervisor mode...");
885 /* Any page-aligned address will do, the test is non-destructive */
886 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
887 boot_cpu_data.wp_works_ok = do_test_wp_bit();
888 clear_fixmap(FIX_WP_TEST);
890 if (!boot_cpu_data.wp_works_ok) {
891 printk(KERN_CONT "No.\n");
892 #ifdef CONFIG_X86_WP_WORKS_OK
894 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
897 printk(KERN_CONT "Ok.\n");
901 static struct kcore_list kcore_mem, kcore_vmalloc;
903 void __init mem_init(void)
905 int codesize, reservedpages, datasize, initsize;
908 #ifdef CONFIG_FLATMEM
911 /* this will put all low memory onto the freelists */
912 totalram_pages += free_all_bootmem();
915 for (tmp = 0; tmp < max_low_pfn; tmp++)
917 * Only count reserved RAM pages:
919 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
922 set_highmem_pages_init();
924 codesize = (unsigned long) &_etext - (unsigned long) &_text;
925 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
926 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
928 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
929 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
930 VMALLOC_END-VMALLOC_START);
932 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
933 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
934 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
935 num_physpages << (PAGE_SHIFT-10),
937 reservedpages << (PAGE_SHIFT-10),
940 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
943 printk(KERN_INFO "virtual kernel memory layout:\n"
944 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
945 #ifdef CONFIG_HIGHMEM
946 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
948 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
949 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
950 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
951 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
952 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
953 FIXADDR_START, FIXADDR_TOP,
954 (FIXADDR_TOP - FIXADDR_START) >> 10,
956 #ifdef CONFIG_HIGHMEM
957 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
958 (LAST_PKMAP*PAGE_SIZE) >> 10,
961 VMALLOC_START, VMALLOC_END,
962 (VMALLOC_END - VMALLOC_START) >> 20,
964 (unsigned long)__va(0), (unsigned long)high_memory,
965 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
967 (unsigned long)&__init_begin, (unsigned long)&__init_end,
968 ((unsigned long)&__init_end -
969 (unsigned long)&__init_begin) >> 10,
971 (unsigned long)&_etext, (unsigned long)&_edata,
972 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
974 (unsigned long)&_text, (unsigned long)&_etext,
975 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
977 #ifdef CONFIG_HIGHMEM
978 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
979 BUG_ON(VMALLOC_END > PKMAP_BASE);
981 BUG_ON(VMALLOC_START > VMALLOC_END);
982 BUG_ON((unsigned long)high_memory > VMALLOC_START);
984 if (boot_cpu_data.wp_works_ok < 0)
992 #ifdef CONFIG_MEMORY_HOTPLUG
993 int arch_add_memory(int nid, u64 start, u64 size)
995 struct pglist_data *pgdata = NODE_DATA(nid);
996 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
997 unsigned long start_pfn = start >> PAGE_SHIFT;
998 unsigned long nr_pages = size >> PAGE_SHIFT;
1000 return __add_pages(zone, start_pfn, nr_pages);
1005 * This function cannot be __init, since exceptions don't work in that
1006 * section. Put this after the callers, so that it cannot be inlined.
1008 static noinline int do_test_wp_bit(void)
1013 __asm__ __volatile__(
1019 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1028 #ifdef CONFIG_DEBUG_RODATA
1029 const int rodata_test_data = 0xC3;
1030 EXPORT_SYMBOL_GPL(rodata_test_data);
1032 void mark_rodata_ro(void)
1034 unsigned long start = PFN_ALIGN(_text);
1035 unsigned long size = PFN_ALIGN(_etext) - start;
1037 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1038 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1041 #ifdef CONFIG_CPA_DEBUG
1042 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1044 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1046 printk(KERN_INFO "Testing CPA: write protecting again\n");
1047 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1050 size = (unsigned long)__end_rodata - start;
1051 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1052 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1056 #ifdef CONFIG_CPA_DEBUG
1057 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1058 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1060 printk(KERN_INFO "Testing CPA: write protecting again\n");
1061 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1066 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1068 #ifdef CONFIG_DEBUG_PAGEALLOC
1070 * If debugging page accesses then do not free this memory but
1071 * mark them not present - any buggy init-section access will
1072 * create a kernel page fault:
1074 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1075 begin, PAGE_ALIGN(end));
1076 set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1081 * We just marked the kernel text read only above, now that
1082 * we are going to free part of that, we need to make that
1085 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1087 for (addr = begin; addr < end; addr += PAGE_SIZE) {
1088 ClearPageReserved(virt_to_page(addr));
1089 init_page_count(virt_to_page(addr));
1090 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1094 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1098 void free_initmem(void)
1100 free_init_pages("unused kernel memory",
1101 (unsigned long)(&__init_begin),
1102 (unsigned long)(&__init_end));
1105 #ifdef CONFIG_BLK_DEV_INITRD
1106 void free_initrd_mem(unsigned long start, unsigned long end)
1108 free_init_pages("initrd memory", start, end);
1112 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1115 return reserve_bootmem(phys, len, flags);