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>
52 unsigned int __VMALLOC_RESERVE = 128 << 20;
54 unsigned long max_low_pfn_mapped;
55 unsigned long max_pfn_mapped;
57 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
58 unsigned long highstart_pfn, highend_pfn;
60 static noinline int do_test_wp_bit(void);
63 static unsigned long __initdata table_start;
64 static unsigned long __meminitdata table_end;
65 static unsigned long __meminitdata table_top;
67 static int __initdata after_init_bootmem;
69 static __init void *alloc_low_page(unsigned long *phys)
71 unsigned long pfn = table_end++;
75 panic("alloc_low_page: ran out of memory");
77 adr = __va(pfn * PAGE_SIZE);
78 memset(adr, 0, PAGE_SIZE);
79 *phys = pfn * 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)
95 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
96 if (after_init_bootmem)
97 pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
99 pmd_table = (pmd_t *)alloc_low_page(&phys);
100 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
101 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
102 pud = pud_offset(pgd, 0);
103 BUG_ON(pmd_table != pmd_offset(pud, 0));
106 pud = pud_offset(pgd, 0);
107 pmd_table = pmd_offset(pud, 0);
113 * Create a page table and place a pointer to it in a middle page
116 static pte_t * __init one_page_table_init(pmd_t *pmd)
118 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
119 pte_t *page_table = NULL;
121 if (after_init_bootmem) {
122 #ifdef CONFIG_DEBUG_PAGEALLOC
123 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
127 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
130 page_table = (pte_t *)alloc_low_page(&phys);
133 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
134 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
135 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
138 return pte_offset_kernel(pmd, 0);
142 * This function initializes a certain range of kernel virtual memory
143 * with new bootmem page tables, everywhere page tables are missing in
146 * NOTE: The pagetables are allocated contiguous on the physical space
147 * so we can cache the place of the first one and move around without
148 * checking the pgd every time.
151 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
153 int pgd_idx, pmd_idx;
159 pgd_idx = pgd_index(vaddr);
160 pmd_idx = pmd_index(vaddr);
161 pgd = pgd_base + pgd_idx;
163 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
164 pmd = one_md_table_init(pgd);
165 pmd = pmd + pmd_index(vaddr);
166 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
168 one_page_table_init(pmd);
176 static inline int is_kernel_text(unsigned long addr)
178 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
184 * This maps the physical memory to kernel virtual address space, a total
185 * of max_low_pfn pages, by creating page tables starting from address
188 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
189 unsigned long start_pfn,
190 unsigned long end_pfn,
193 int pgd_idx, pmd_idx, pte_ofs;
198 unsigned pages_2m = 0, pages_4k = 0;
204 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
205 pgd = pgd_base + pgd_idx;
206 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
207 pmd = one_md_table_init(pgd);
211 #ifdef CONFIG_X86_PAE
212 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
217 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
219 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
222 * Map with big pages if possible, otherwise
223 * create normal page tables:
227 pgprot_t prot = PAGE_KERNEL_LARGE;
229 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
230 PAGE_OFFSET + PAGE_SIZE-1;
232 if (is_kernel_text(addr) ||
233 is_kernel_text(addr2))
234 prot = PAGE_KERNEL_LARGE_EXEC;
237 set_pmd(pmd, pfn_pmd(pfn, prot));
242 pte = one_page_table_init(pmd);
244 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
246 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
247 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
248 pgprot_t prot = PAGE_KERNEL;
250 if (is_kernel_text(addr))
251 prot = PAGE_KERNEL_EXEC;
254 set_pte(pte, pfn_pte(pfn, prot));
258 update_page_count(PG_LEVEL_2M, pages_2m);
259 update_page_count(PG_LEVEL_4K, pages_4k);
263 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
264 * is valid. The argument is a physical page number.
267 * On x86, access has to be given to the first megabyte of ram because that area
268 * contains bios code and data regions used by X and dosemu and similar apps.
269 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
270 * mmio resources as well as potential bios/acpi data regions.
272 int devmem_is_allowed(unsigned long pagenr)
276 if (!page_is_ram(pagenr))
281 #ifdef CONFIG_HIGHMEM
285 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
287 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
288 vaddr), vaddr), vaddr);
291 static void __init kmap_init(void)
293 unsigned long kmap_vstart;
296 * Cache the first kmap pte:
298 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
299 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
301 kmap_prot = PAGE_KERNEL;
304 static void __init permanent_kmaps_init(pgd_t *pgd_base)
313 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
315 pgd = swapper_pg_dir + pgd_index(vaddr);
316 pud = pud_offset(pgd, vaddr);
317 pmd = pmd_offset(pud, vaddr);
318 pte = pte_offset_kernel(pmd, vaddr);
319 pkmap_page_table = pte;
322 static void __init add_one_highpage_init(struct page *page, int pfn)
324 ClearPageReserved(page);
325 init_page_count(page);
330 struct add_highpages_data {
331 unsigned long start_pfn;
332 unsigned long end_pfn;
335 static int __init add_highpages_work_fn(unsigned long start_pfn,
336 unsigned long end_pfn, void *datax)
340 unsigned long final_start_pfn, final_end_pfn;
341 struct add_highpages_data *data;
343 data = (struct add_highpages_data *)datax;
345 final_start_pfn = max(start_pfn, data->start_pfn);
346 final_end_pfn = min(end_pfn, data->end_pfn);
347 if (final_start_pfn >= final_end_pfn)
350 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
352 if (!pfn_valid(node_pfn))
354 page = pfn_to_page(node_pfn);
355 add_one_highpage_init(page, node_pfn);
362 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
363 unsigned long end_pfn)
365 struct add_highpages_data data;
367 data.start_pfn = start_pfn;
368 data.end_pfn = end_pfn;
370 work_with_active_regions(nid, add_highpages_work_fn, &data);
374 static void __init set_highmem_pages_init(void)
376 add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
378 totalram_pages += totalhigh_pages;
380 #endif /* !CONFIG_NUMA */
383 # define kmap_init() do { } while (0)
384 # define permanent_kmaps_init(pgd_base) do { } while (0)
385 # define set_highmem_pages_init() do { } while (0)
386 #endif /* CONFIG_HIGHMEM */
388 void __init native_pagetable_setup_start(pgd_t *base)
390 unsigned long pfn, va;
397 * Remove any mappings which extend past the end of physical
398 * memory from the boot time page table:
400 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
401 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
402 pgd = base + pgd_index(va);
403 if (!pgd_present(*pgd))
406 pud = pud_offset(pgd, va);
407 pmd = pmd_offset(pud, va);
408 if (!pmd_present(*pmd))
411 pte = pte_offset_kernel(pmd, va);
412 if (!pte_present(*pte))
415 pte_clear(NULL, va, pte);
417 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
420 void __init native_pagetable_setup_done(pgd_t *base)
425 * Build a proper pagetable for the kernel mappings. Up until this
426 * point, we've been running on some set of pagetables constructed by
429 * If we're booting on native hardware, this will be a pagetable
430 * constructed in arch/x86/kernel/head_32.S. The root of the
431 * pagetable will be swapper_pg_dir.
433 * If we're booting paravirtualized under a hypervisor, then there are
434 * more options: we may already be running PAE, and the pagetable may
435 * or may not be based in swapper_pg_dir. In any case,
436 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
437 * appropriately for the rest of the initialization to work.
439 * In general, pagetable_init() assumes that the pagetable may already
440 * be partially populated, and so it avoids stomping on any existing
443 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
445 unsigned long vaddr, end;
448 * Fixed mappings, only the page table structure has to be
449 * created - mappings will be set by set_fixmap():
451 early_ioremap_clear();
452 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
453 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
454 page_table_range_init(vaddr, end, pgd_base);
455 early_ioremap_reset();
458 static void __init pagetable_init(void)
460 pgd_t *pgd_base = swapper_pg_dir;
462 paravirt_pagetable_setup_start(pgd_base);
464 permanent_kmaps_init(pgd_base);
466 paravirt_pagetable_setup_done(pgd_base);
469 #ifdef CONFIG_ACPI_SLEEP
471 * ACPI suspend needs this for resume, because things like the intel-agp
472 * driver might have split up a kernel 4MB mapping.
474 char swsusp_pg_dir[PAGE_SIZE]
475 __attribute__ ((aligned(PAGE_SIZE)));
477 static inline void save_pg_dir(void)
479 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
481 #else /* !CONFIG_ACPI_SLEEP */
482 static inline void save_pg_dir(void)
485 #endif /* !CONFIG_ACPI_SLEEP */
487 void zap_low_mappings(void)
492 * Zap initial low-memory mappings.
494 * Note that "pgd_clear()" doesn't do it for
495 * us, because pgd_clear() is a no-op on i386.
497 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
498 #ifdef CONFIG_X86_PAE
499 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
501 set_pgd(swapper_pg_dir+i, __pgd(0));
509 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL);
510 EXPORT_SYMBOL_GPL(__supported_pte_mask);
512 #ifdef CONFIG_X86_PAE
514 static int disable_nx __initdata;
519 * Control non executable mappings.
524 static int __init noexec_setup(char *str)
526 if (!str || !strcmp(str, "on")) {
528 __supported_pte_mask |= _PAGE_NX;
532 if (!strcmp(str, "off")) {
534 __supported_pte_mask &= ~_PAGE_NX;
542 early_param("noexec", noexec_setup);
544 static void __init set_nx(void)
546 unsigned int v[4], l, h;
548 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
549 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
551 if ((v[3] & (1 << 20)) && !disable_nx) {
552 rdmsr(MSR_EFER, l, h);
554 wrmsr(MSR_EFER, l, h);
556 __supported_pte_mask |= _PAGE_NX;
562 /* user-defined highmem size */
563 static unsigned int highmem_pages = -1;
566 * highmem=size forces highmem to be exactly 'size' bytes.
567 * This works even on boxes that have no highmem otherwise.
568 * This also works to reduce highmem size on bigger boxes.
570 static int __init parse_highmem(char *arg)
575 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
578 early_param("highmem", parse_highmem);
581 * Determine low and high memory ranges:
583 void __init find_low_pfn_range(void)
585 /* it could update max_pfn */
587 /* max_low_pfn is 0, we already have early_res support */
589 max_low_pfn = max_pfn;
590 if (max_low_pfn > MAXMEM_PFN) {
591 if (highmem_pages == -1)
592 highmem_pages = max_pfn - MAXMEM_PFN;
593 if (highmem_pages + MAXMEM_PFN < max_pfn)
594 max_pfn = MAXMEM_PFN + highmem_pages;
595 if (highmem_pages + MAXMEM_PFN > max_pfn) {
596 printk(KERN_WARNING "only %luMB highmem pages "
597 "available, ignoring highmem size of %uMB.\n",
598 pages_to_mb(max_pfn - MAXMEM_PFN),
599 pages_to_mb(highmem_pages));
602 max_low_pfn = MAXMEM_PFN;
603 #ifndef CONFIG_HIGHMEM
604 /* Maximum memory usable is what is directly addressable */
605 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
607 if (max_pfn > MAX_NONPAE_PFN)
609 "Use a HIGHMEM64G enabled kernel.\n");
611 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
612 max_pfn = MAXMEM_PFN;
613 #else /* !CONFIG_HIGHMEM */
614 #ifndef CONFIG_HIGHMEM64G
615 if (max_pfn > MAX_NONPAE_PFN) {
616 max_pfn = MAX_NONPAE_PFN;
617 printk(KERN_WARNING "Warning only 4GB will be used."
618 "Use a HIGHMEM64G enabled kernel.\n");
620 #endif /* !CONFIG_HIGHMEM64G */
621 #endif /* !CONFIG_HIGHMEM */
623 if (highmem_pages == -1)
625 #ifdef CONFIG_HIGHMEM
626 if (highmem_pages >= max_pfn) {
627 printk(KERN_ERR "highmem size specified (%uMB) is "
628 "bigger than pages available (%luMB)!.\n",
629 pages_to_mb(highmem_pages),
630 pages_to_mb(max_pfn));
634 if (max_low_pfn - highmem_pages <
635 64*1024*1024/PAGE_SIZE){
636 printk(KERN_ERR "highmem size %uMB results in "
637 "smaller than 64MB lowmem, ignoring it.\n"
638 , pages_to_mb(highmem_pages));
641 max_low_pfn -= highmem_pages;
645 printk(KERN_ERR "ignoring highmem size on non-highmem"
651 #ifndef CONFIG_NEED_MULTIPLE_NODES
652 void __init initmem_init(unsigned long start_pfn,
653 unsigned long end_pfn)
655 #ifdef CONFIG_HIGHMEM
656 highstart_pfn = highend_pfn = max_pfn;
657 if (max_pfn > max_low_pfn)
658 highstart_pfn = max_low_pfn;
659 memory_present(0, 0, highend_pfn);
660 e820_register_active_regions(0, 0, highend_pfn);
661 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
662 pages_to_mb(highend_pfn - highstart_pfn));
663 num_physpages = highend_pfn;
664 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
666 memory_present(0, 0, max_low_pfn);
667 e820_register_active_regions(0, 0, max_low_pfn);
668 num_physpages = max_low_pfn;
669 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
671 #ifdef CONFIG_FLATMEM
672 max_mapnr = num_physpages;
674 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
675 pages_to_mb(max_low_pfn));
677 setup_bootmem_allocator();
679 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
681 static void __init zone_sizes_init(void)
683 unsigned long max_zone_pfns[MAX_NR_ZONES];
684 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
685 max_zone_pfns[ZONE_DMA] =
686 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
687 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
688 #ifdef CONFIG_HIGHMEM
689 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
692 free_area_init_nodes(max_zone_pfns);
695 void __init setup_bootmem_allocator(void)
698 unsigned long bootmap_size, bootmap;
700 * Initialize the boot-time allocator (with low memory only):
702 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
703 bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
704 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
707 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
708 reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
710 /* don't touch min_low_pfn */
711 bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
712 min_low_pfn, max_low_pfn);
713 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
714 max_pfn_mapped<<PAGE_SHIFT);
715 printk(KERN_INFO " low ram: %08lx - %08lx\n",
716 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
717 printk(KERN_INFO " bootmap %08lx - %08lx\n",
718 bootmap, bootmap + bootmap_size);
719 for_each_online_node(i)
720 free_bootmem_with_active_regions(i, max_low_pfn);
721 early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
723 after_init_bootmem = 1;
726 static void __init find_early_table_space(unsigned long end)
728 unsigned long puds, pmds, ptes, tables, start;
730 puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
731 tables = PAGE_ALIGN(puds * sizeof(pud_t));
733 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
734 tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
739 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
741 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
743 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
745 tables += PAGE_ALIGN(ptes * sizeof(pte_t));
748 tables += PAGE_SIZE * 2;
751 * RED-PEN putting page tables only on node 0 could
752 * cause a hotspot and fill up ZONE_DMA. The page tables
753 * need roughly 0.5KB per GB.
756 table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
758 if (table_start == -1UL)
759 panic("Cannot find space for the kernel page tables");
761 table_start >>= PAGE_SHIFT;
762 table_end = table_start;
763 table_top = table_start + (tables>>PAGE_SHIFT);
765 printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
766 end, table_start << PAGE_SHIFT,
767 (table_start << PAGE_SHIFT) + tables);
770 unsigned long __init_refok init_memory_mapping(unsigned long start,
773 pgd_t *pgd_base = swapper_pg_dir;
774 unsigned long start_pfn, end_pfn;
775 unsigned long big_page_start;
778 * Find space for the kernel direct mapping tables.
780 if (!after_init_bootmem)
781 find_early_table_space(end);
783 #ifdef CONFIG_X86_PAE
786 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
789 /* Enable PSE if available */
791 set_in_cr4(X86_CR4_PSE);
793 /* Enable PGE if available */
795 set_in_cr4(X86_CR4_PGE);
796 __supported_pte_mask |= _PAGE_GLOBAL;
800 * Don't use a large page for the first 2/4MB of memory
801 * because there are often fixed size MTRRs in there
802 * and overlapping MTRRs into large pages can cause
805 big_page_start = PMD_SIZE;
807 if (start < big_page_start) {
808 start_pfn = start >> PAGE_SHIFT;
809 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
811 /* head is not big page alignment ? */
812 start_pfn = start >> PAGE_SHIFT;
813 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
814 << (PMD_SHIFT - PAGE_SHIFT);
816 if (start_pfn < end_pfn)
817 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
820 start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
821 << (PMD_SHIFT - PAGE_SHIFT);
822 if (start_pfn < (big_page_start >> PAGE_SHIFT))
823 start_pfn = big_page_start >> PAGE_SHIFT;
824 end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
825 if (start_pfn < end_pfn)
826 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
829 /* tail is not big page alignment ? */
831 if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
832 end_pfn = end >> PAGE_SHIFT;
833 if (start_pfn < end_pfn)
834 kernel_physical_mapping_init(pgd_base, start_pfn,
838 early_ioremap_page_table_range_init(pgd_base);
840 load_cr3(swapper_pg_dir);
844 if (!after_init_bootmem)
845 reserve_early(table_start << PAGE_SHIFT,
846 table_end << PAGE_SHIFT, "PGTABLE");
848 if (!after_init_bootmem)
849 early_memtest(start, end);
851 return end >> PAGE_SHIFT;
856 * paging_init() sets up the page tables - note that the first 8MB are
857 * already mapped by head.S.
859 * This routines also unmaps the page at virtual kernel address 0, so
860 * that we can trap those pesky NULL-reference errors in the kernel.
862 void __init paging_init(void)
871 * NOTE: at this point the bootmem allocator is fully available.
878 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
879 * and also on some strange 486's. All 586+'s are OK. This used to involve
880 * black magic jumps to work around some nasty CPU bugs, but fortunately the
881 * switch to using exceptions got rid of all that.
883 static void __init test_wp_bit(void)
886 "Checking if this processor honours the WP bit even in supervisor mode...");
888 /* Any page-aligned address will do, the test is non-destructive */
889 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
890 boot_cpu_data.wp_works_ok = do_test_wp_bit();
891 clear_fixmap(FIX_WP_TEST);
893 if (!boot_cpu_data.wp_works_ok) {
894 printk(KERN_CONT "No.\n");
895 #ifdef CONFIG_X86_WP_WORKS_OK
897 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
900 printk(KERN_CONT "Ok.\n");
904 static struct kcore_list kcore_mem, kcore_vmalloc;
906 void __init mem_init(void)
908 int codesize, reservedpages, datasize, initsize;
911 #ifdef CONFIG_FLATMEM
914 /* this will put all low memory onto the freelists */
915 totalram_pages += free_all_bootmem();
918 for (tmp = 0; tmp < max_low_pfn; tmp++)
920 * Only count reserved RAM pages:
922 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
925 set_highmem_pages_init();
927 codesize = (unsigned long) &_etext - (unsigned long) &_text;
928 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
929 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
931 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
932 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
933 VMALLOC_END-VMALLOC_START);
935 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
936 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
937 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
938 num_physpages << (PAGE_SHIFT-10),
940 reservedpages << (PAGE_SHIFT-10),
943 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
946 printk(KERN_INFO "virtual kernel memory layout:\n"
947 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
948 #ifdef CONFIG_HIGHMEM
949 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
951 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
952 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
953 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
954 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
955 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
956 FIXADDR_START, FIXADDR_TOP,
957 (FIXADDR_TOP - FIXADDR_START) >> 10,
959 #ifdef CONFIG_HIGHMEM
960 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
961 (LAST_PKMAP*PAGE_SIZE) >> 10,
964 VMALLOC_START, VMALLOC_END,
965 (VMALLOC_END - VMALLOC_START) >> 20,
967 (unsigned long)__va(0), (unsigned long)high_memory,
968 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
970 (unsigned long)&__init_begin, (unsigned long)&__init_end,
971 ((unsigned long)&__init_end -
972 (unsigned long)&__init_begin) >> 10,
974 (unsigned long)&_etext, (unsigned long)&_edata,
975 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
977 (unsigned long)&_text, (unsigned long)&_etext,
978 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
980 #ifdef CONFIG_HIGHMEM
981 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
982 BUG_ON(VMALLOC_END > PKMAP_BASE);
984 BUG_ON(VMALLOC_START > VMALLOC_END);
985 BUG_ON((unsigned long)high_memory > VMALLOC_START);
987 if (boot_cpu_data.wp_works_ok < 0)
995 #ifdef CONFIG_MEMORY_HOTPLUG
996 int arch_add_memory(int nid, u64 start, u64 size)
998 struct pglist_data *pgdata = NODE_DATA(nid);
999 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1000 unsigned long start_pfn = start >> PAGE_SHIFT;
1001 unsigned long nr_pages = size >> PAGE_SHIFT;
1003 return __add_pages(zone, start_pfn, nr_pages);
1008 * This function cannot be __init, since exceptions don't work in that
1009 * section. Put this after the callers, so that it cannot be inlined.
1011 static noinline int do_test_wp_bit(void)
1016 __asm__ __volatile__(
1022 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1031 #ifdef CONFIG_DEBUG_RODATA
1032 const int rodata_test_data = 0xC3;
1033 EXPORT_SYMBOL_GPL(rodata_test_data);
1035 void mark_rodata_ro(void)
1037 unsigned long start = PFN_ALIGN(_text);
1038 unsigned long size = PFN_ALIGN(_etext) - start;
1040 #ifndef CONFIG_DYNAMIC_FTRACE
1041 /* Dynamic tracing modifies the kernel text section */
1042 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1043 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1046 #ifdef CONFIG_CPA_DEBUG
1047 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1049 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1051 printk(KERN_INFO "Testing CPA: write protecting again\n");
1052 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1054 #endif /* CONFIG_DYNAMIC_FTRACE */
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",
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);
1067 printk(KERN_INFO "Testing CPA: write protecting again\n");
1068 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1073 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1075 #ifdef CONFIG_DEBUG_PAGEALLOC
1077 * If debugging page accesses then do not free this memory but
1078 * mark them not present - any buggy init-section access will
1079 * create a kernel page fault:
1081 printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1082 begin, PAGE_ALIGN(end));
1083 set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1088 * We just marked the kernel text read only above, now that
1089 * we are going to free part of that, we need to make that
1092 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1094 for (addr = begin; addr < end; addr += PAGE_SIZE) {
1095 ClearPageReserved(virt_to_page(addr));
1096 init_page_count(virt_to_page(addr));
1097 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1101 printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1105 void free_initmem(void)
1107 free_init_pages("unused kernel memory",
1108 (unsigned long)(&__init_begin),
1109 (unsigned long)(&__init_end));
1112 #ifdef CONFIG_BLK_DEV_INITRD
1113 void free_initrd_mem(unsigned long start, unsigned long end)
1115 free_init_pages("initrd memory", start, end);
1119 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1122 return reserve_bootmem(phys, len, flags);