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/memblock.h>
29 #include <linux/proc_fs.h>
30 #include <linux/memory_hotplug.h>
31 #include <linux/initrd.h>
32 #include <linux/cpumask.h>
33 #include <linux/gfp.h>
36 #include <asm/bios_ebda.h>
37 #include <asm/processor.h>
38 #include <asm/system.h>
39 #include <asm/uaccess.h>
40 #include <asm/pgtable.h>
42 #include <asm/fixmap.h>
47 #include <asm/tlbflush.h>
48 #include <asm/pgalloc.h>
49 #include <asm/sections.h>
50 #include <asm/paravirt.h>
51 #include <asm/setup.h>
52 #include <asm/cacheflush.h>
53 #include <asm/page_types.h>
56 unsigned long highstart_pfn, highend_pfn;
58 static noinline int do_test_wp_bit(void);
60 bool __read_mostly __vmalloc_start_set = false;
62 static __init void *alloc_low_page(void)
64 unsigned long pfn = e820_table_end++;
67 if (pfn >= e820_table_top)
68 panic("alloc_low_page: ran out of memory");
70 adr = __va(pfn * PAGE_SIZE);
71 memset(adr, 0, PAGE_SIZE);
76 * Creates a middle page table and puts a pointer to it in the
77 * given global directory entry. This only returns the gd entry
78 * in non-PAE compilation mode, since the middle layer is folded.
80 static pmd_t * __init one_md_table_init(pgd_t *pgd)
86 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
88 pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
90 pmd_table = (pmd_t *)alloc_low_page();
91 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
92 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
93 pud = pud_offset(pgd, 0);
94 BUG_ON(pmd_table != pmd_offset(pud, 0));
99 pud = pud_offset(pgd, 0);
100 pmd_table = pmd_offset(pud, 0);
106 * Create a page table and place a pointer to it in a middle page
109 static pte_t * __init one_page_table_init(pmd_t *pmd)
111 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
112 pte_t *page_table = NULL;
115 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
116 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
120 (pte_t *)alloc_bootmem_pages(PAGE_SIZE);
122 page_table = (pte_t *)alloc_low_page();
124 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
125 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
126 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
129 return pte_offset_kernel(pmd, 0);
132 pmd_t * __init populate_extra_pmd(unsigned long vaddr)
134 int pgd_idx = pgd_index(vaddr);
135 int pmd_idx = pmd_index(vaddr);
137 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
140 pte_t * __init populate_extra_pte(unsigned long vaddr)
142 int pte_idx = pte_index(vaddr);
145 pmd = populate_extra_pmd(vaddr);
146 return one_page_table_init(pmd) + pte_idx;
149 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
150 unsigned long vaddr, pte_t *lastpte)
152 #ifdef CONFIG_HIGHMEM
154 * Something (early fixmap) may already have put a pte
155 * page here, which causes the page table allocation
156 * to become nonlinear. Attempt to fix it, and if it
157 * is still nonlinear then we have to bug.
159 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
160 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
162 if (pmd_idx_kmap_begin != pmd_idx_kmap_end
163 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
164 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
165 && ((__pa(pte) >> PAGE_SHIFT) < e820_table_start
166 || (__pa(pte) >> PAGE_SHIFT) >= e820_table_end)) {
170 BUG_ON(after_bootmem);
171 newpte = alloc_low_page();
172 for (i = 0; i < PTRS_PER_PTE; i++)
173 set_pte(newpte + i, pte[i]);
175 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
176 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
177 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
180 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
183 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
184 && vaddr > fix_to_virt(FIX_KMAP_END)
185 && lastpte && lastpte + PTRS_PER_PTE != pte);
191 * This function initializes a certain range of kernel virtual memory
192 * with new bootmem page tables, everywhere page tables are missing in
195 * NOTE: The pagetables are allocated contiguous on the physical space
196 * so we can cache the place of the first one and move around without
197 * checking the pgd every time.
200 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
202 int pgd_idx, pmd_idx;
209 pgd_idx = pgd_index(vaddr);
210 pmd_idx = pmd_index(vaddr);
211 pgd = pgd_base + pgd_idx;
213 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
214 pmd = one_md_table_init(pgd);
215 pmd = pmd + pmd_index(vaddr);
216 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
218 pte = page_table_kmap_check(one_page_table_init(pmd),
227 static inline int is_kernel_text(unsigned long addr)
229 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
235 * This maps the physical memory to kernel virtual address space, a total
236 * of max_low_pfn pages, by creating page tables starting from address
240 kernel_physical_mapping_init(unsigned long start,
242 unsigned long page_size_mask)
244 int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
245 unsigned long last_map_addr = end;
246 unsigned long start_pfn, end_pfn;
247 pgd_t *pgd_base = swapper_pg_dir;
248 int pgd_idx, pmd_idx, pte_ofs;
253 unsigned pages_2m, pages_4k;
256 start_pfn = start >> PAGE_SHIFT;
257 end_pfn = end >> PAGE_SHIFT;
260 * First iteration will setup identity mapping using large/small pages
261 * based on use_pse, with other attributes same as set by
262 * the early code in head_32.S
264 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
265 * as desired for the kernel identity mapping.
267 * This two pass mechanism conforms to the TLB app note which says:
269 * "Software should not write to a paging-structure entry in a way
270 * that would change, for any linear address, both the page size
271 * and either the page frame or attributes."
279 pages_2m = pages_4k = 0;
281 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
282 pgd = pgd_base + pgd_idx;
283 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
284 pmd = one_md_table_init(pgd);
288 #ifdef CONFIG_X86_PAE
289 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
294 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
296 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
299 * Map with big pages if possible, otherwise
300 * create normal page tables:
304 pgprot_t prot = PAGE_KERNEL_LARGE;
306 * first pass will use the same initial
307 * identity mapping attribute + _PAGE_PSE.
310 __pgprot(PTE_IDENT_ATTR |
313 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
314 PAGE_OFFSET + PAGE_SIZE-1;
316 if (is_kernel_text(addr) ||
317 is_kernel_text(addr2))
318 prot = PAGE_KERNEL_LARGE_EXEC;
321 if (mapping_iter == 1)
322 set_pmd(pmd, pfn_pmd(pfn, init_prot));
324 set_pmd(pmd, pfn_pmd(pfn, prot));
329 pte = one_page_table_init(pmd);
331 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
333 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
334 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
335 pgprot_t prot = PAGE_KERNEL;
337 * first pass will use the same initial
338 * identity mapping attribute.
340 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
342 if (is_kernel_text(addr))
343 prot = PAGE_KERNEL_EXEC;
346 if (mapping_iter == 1) {
347 set_pte(pte, pfn_pte(pfn, init_prot));
348 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
350 set_pte(pte, pfn_pte(pfn, prot));
354 if (mapping_iter == 1) {
356 * update direct mapping page count only in the first
359 update_page_count(PG_LEVEL_2M, pages_2m);
360 update_page_count(PG_LEVEL_4K, pages_4k);
363 * local global flush tlb, which will flush the previous
364 * mappings present in both small and large page TLB's.
369 * Second iteration will set the actual desired PTE attributes.
374 return last_map_addr;
380 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
382 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
383 vaddr), vaddr), vaddr);
386 static void __init kmap_init(void)
388 unsigned long kmap_vstart;
391 * Cache the first kmap pte:
393 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
394 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
396 kmap_prot = PAGE_KERNEL;
399 #ifdef CONFIG_HIGHMEM
400 static void __init permanent_kmaps_init(pgd_t *pgd_base)
409 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
411 pgd = swapper_pg_dir + pgd_index(vaddr);
412 pud = pud_offset(pgd, vaddr);
413 pmd = pmd_offset(pud, vaddr);
414 pte = pte_offset_kernel(pmd, vaddr);
415 pkmap_page_table = pte;
418 static void __init add_one_highpage_init(struct page *page)
420 ClearPageReserved(page);
421 init_page_count(page);
426 struct add_highpages_data {
427 unsigned long start_pfn;
428 unsigned long end_pfn;
431 static int __init add_highpages_work_fn(unsigned long start_pfn,
432 unsigned long end_pfn, void *datax)
436 unsigned long final_start_pfn, final_end_pfn;
437 struct add_highpages_data *data;
439 data = (struct add_highpages_data *)datax;
441 final_start_pfn = max(start_pfn, data->start_pfn);
442 final_end_pfn = min(end_pfn, data->end_pfn);
443 if (final_start_pfn >= final_end_pfn)
446 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
448 if (!pfn_valid(node_pfn))
450 page = pfn_to_page(node_pfn);
451 add_one_highpage_init(page);
458 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
459 unsigned long end_pfn)
461 struct add_highpages_data data;
463 data.start_pfn = start_pfn;
464 data.end_pfn = end_pfn;
466 work_with_active_regions(nid, add_highpages_work_fn, &data);
470 static inline void permanent_kmaps_init(pgd_t *pgd_base)
473 #endif /* CONFIG_HIGHMEM */
475 void __init native_pagetable_setup_start(pgd_t *base)
477 unsigned long pfn, va;
484 * Remove any mappings which extend past the end of physical
485 * memory from the boot time page table:
487 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
488 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
489 pgd = base + pgd_index(va);
490 if (!pgd_present(*pgd))
493 pud = pud_offset(pgd, va);
494 pmd = pmd_offset(pud, va);
495 if (!pmd_present(*pmd))
498 pte = pte_offset_kernel(pmd, va);
499 if (!pte_present(*pte))
502 pte_clear(NULL, va, pte);
504 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
507 void __init native_pagetable_setup_done(pgd_t *base)
512 * Build a proper pagetable for the kernel mappings. Up until this
513 * point, we've been running on some set of pagetables constructed by
516 * If we're booting on native hardware, this will be a pagetable
517 * constructed in arch/x86/kernel/head_32.S. The root of the
518 * pagetable will be swapper_pg_dir.
520 * If we're booting paravirtualized under a hypervisor, then there are
521 * more options: we may already be running PAE, and the pagetable may
522 * or may not be based in swapper_pg_dir. In any case,
523 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
524 * appropriately for the rest of the initialization to work.
526 * In general, pagetable_init() assumes that the pagetable may already
527 * be partially populated, and so it avoids stomping on any existing
530 void __init early_ioremap_page_table_range_init(void)
532 pgd_t *pgd_base = swapper_pg_dir;
533 unsigned long vaddr, end;
536 * Fixed mappings, only the page table structure has to be
537 * created - mappings will be set by set_fixmap():
539 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
540 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
541 page_table_range_init(vaddr, end, pgd_base);
542 early_ioremap_reset();
545 static void __init pagetable_init(void)
547 pgd_t *pgd_base = swapper_pg_dir;
549 permanent_kmaps_init(pgd_base);
552 #ifdef CONFIG_ACPI_SLEEP
554 * ACPI suspend needs this for resume, because things like the intel-agp
555 * driver might have split up a kernel 4MB mapping.
557 char swsusp_pg_dir[PAGE_SIZE]
558 __attribute__ ((aligned(PAGE_SIZE)));
560 static inline void save_pg_dir(void)
562 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
564 #else /* !CONFIG_ACPI_SLEEP */
565 static inline void save_pg_dir(void)
568 #endif /* !CONFIG_ACPI_SLEEP */
570 void zap_low_mappings(bool early)
575 * Zap initial low-memory mappings.
577 * Note that "pgd_clear()" doesn't do it for
578 * us, because pgd_clear() is a no-op on i386.
580 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
581 #ifdef CONFIG_X86_PAE
582 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
584 set_pgd(swapper_pg_dir+i, __pgd(0));
594 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
595 EXPORT_SYMBOL_GPL(__supported_pte_mask);
597 /* user-defined highmem size */
598 static unsigned int highmem_pages = -1;
601 * highmem=size forces highmem to be exactly 'size' bytes.
602 * This works even on boxes that have no highmem otherwise.
603 * This also works to reduce highmem size on bigger boxes.
605 static int __init parse_highmem(char *arg)
610 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
613 early_param("highmem", parse_highmem);
615 #define MSG_HIGHMEM_TOO_BIG \
616 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
618 #define MSG_LOWMEM_TOO_SMALL \
619 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
621 * All of RAM fits into lowmem - but if user wants highmem
622 * artificially via the highmem=x boot parameter then create
625 void __init lowmem_pfn_init(void)
627 /* max_low_pfn is 0, we already have early_res support */
628 max_low_pfn = max_pfn;
630 if (highmem_pages == -1)
632 #ifdef CONFIG_HIGHMEM
633 if (highmem_pages >= max_pfn) {
634 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
635 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
639 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
640 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
641 pages_to_mb(highmem_pages));
644 max_low_pfn -= highmem_pages;
648 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
652 #define MSG_HIGHMEM_TOO_SMALL \
653 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
655 #define MSG_HIGHMEM_TRIMMED \
656 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
658 * We have more RAM than fits into lowmem - we try to put it into
659 * highmem, also taking the highmem=x boot parameter into account:
661 void __init highmem_pfn_init(void)
663 max_low_pfn = MAXMEM_PFN;
665 if (highmem_pages == -1)
666 highmem_pages = max_pfn - MAXMEM_PFN;
668 if (highmem_pages + MAXMEM_PFN < max_pfn)
669 max_pfn = MAXMEM_PFN + highmem_pages;
671 if (highmem_pages + MAXMEM_PFN > max_pfn) {
672 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
673 pages_to_mb(max_pfn - MAXMEM_PFN),
674 pages_to_mb(highmem_pages));
677 #ifndef CONFIG_HIGHMEM
678 /* Maximum memory usable is what is directly addressable */
679 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
680 if (max_pfn > MAX_NONPAE_PFN)
681 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
683 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
684 max_pfn = MAXMEM_PFN;
685 #else /* !CONFIG_HIGHMEM */
686 #ifndef CONFIG_HIGHMEM64G
687 if (max_pfn > MAX_NONPAE_PFN) {
688 max_pfn = MAX_NONPAE_PFN;
689 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
691 #endif /* !CONFIG_HIGHMEM64G */
692 #endif /* !CONFIG_HIGHMEM */
696 * Determine low and high memory ranges:
698 void __init find_low_pfn_range(void)
700 /* it could update max_pfn */
702 if (max_pfn <= MAXMEM_PFN)
708 #ifndef CONFIG_NEED_MULTIPLE_NODES
709 void __init initmem_init(unsigned long start_pfn, unsigned long end_pfn,
712 #ifdef CONFIG_HIGHMEM
713 highstart_pfn = highend_pfn = max_pfn;
714 if (max_pfn > max_low_pfn)
715 highstart_pfn = max_low_pfn;
716 memblock_x86_register_active_regions(0, 0, highend_pfn);
717 sparse_memory_present_with_active_regions(0);
718 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
719 pages_to_mb(highend_pfn - highstart_pfn));
720 num_physpages = highend_pfn;
721 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
723 memblock_x86_register_active_regions(0, 0, max_low_pfn);
724 sparse_memory_present_with_active_regions(0);
725 num_physpages = max_low_pfn;
726 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
728 #ifdef CONFIG_FLATMEM
729 max_mapnr = num_physpages;
731 __vmalloc_start_set = true;
733 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
734 pages_to_mb(max_low_pfn));
736 setup_bootmem_allocator();
738 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
740 static void __init zone_sizes_init(void)
742 unsigned long max_zone_pfns[MAX_NR_ZONES];
743 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
744 max_zone_pfns[ZONE_DMA] =
745 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
746 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
747 #ifdef CONFIG_HIGHMEM
748 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
751 free_area_init_nodes(max_zone_pfns);
754 #ifndef CONFIG_NO_BOOTMEM
755 static unsigned long __init setup_node_bootmem(int nodeid,
756 unsigned long start_pfn,
757 unsigned long end_pfn,
758 unsigned long bootmap)
760 unsigned long bootmap_size;
762 /* don't touch min_low_pfn */
763 bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
764 bootmap >> PAGE_SHIFT,
766 printk(KERN_INFO " node %d low ram: %08lx - %08lx\n",
767 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
768 printk(KERN_INFO " node %d bootmap %08lx - %08lx\n",
769 nodeid, bootmap, bootmap + bootmap_size);
770 free_bootmem_with_active_regions(nodeid, end_pfn);
772 return bootmap + bootmap_size;
776 void __init setup_bootmem_allocator(void)
778 #ifndef CONFIG_NO_BOOTMEM
780 phys_addr_t bootmap_size, bootmap;
782 * Initialize the boot-time allocator (with low memory only):
784 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
785 bootmap = memblock_find_in_range(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
787 if (bootmap == MEMBLOCK_ERROR)
788 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
789 memblock_x86_reserve_range(bootmap, bootmap + bootmap_size, "BOOTMAP");
792 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
793 max_pfn_mapped<<PAGE_SHIFT);
794 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
796 #ifndef CONFIG_NO_BOOTMEM
797 for_each_online_node(nodeid) {
798 unsigned long start_pfn, end_pfn;
800 #ifdef CONFIG_NEED_MULTIPLE_NODES
801 start_pfn = node_start_pfn[nodeid];
802 end_pfn = node_end_pfn[nodeid];
803 if (start_pfn > max_low_pfn)
805 if (end_pfn > max_low_pfn)
806 end_pfn = max_low_pfn;
809 end_pfn = max_low_pfn;
811 bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
820 * paging_init() sets up the page tables - note that the first 8MB are
821 * already mapped by head.S.
823 * This routines also unmaps the page at virtual kernel address 0, so
824 * that we can trap those pesky NULL-reference errors in the kernel.
826 void __init paging_init(void)
835 * NOTE: at this point the bootmem allocator is fully available.
842 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
843 * and also on some strange 486's. All 586+'s are OK. This used to involve
844 * black magic jumps to work around some nasty CPU bugs, but fortunately the
845 * switch to using exceptions got rid of all that.
847 static void __init test_wp_bit(void)
850 "Checking if this processor honours the WP bit even in supervisor mode...");
852 /* Any page-aligned address will do, the test is non-destructive */
853 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
854 boot_cpu_data.wp_works_ok = do_test_wp_bit();
855 clear_fixmap(FIX_WP_TEST);
857 if (!boot_cpu_data.wp_works_ok) {
858 printk(KERN_CONT "No.\n");
859 #ifdef CONFIG_X86_WP_WORKS_OK
861 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
864 printk(KERN_CONT "Ok.\n");
868 void __init mem_init(void)
870 int codesize, reservedpages, datasize, initsize;
875 #ifdef CONFIG_FLATMEM
878 /* this will put all low memory onto the freelists */
879 totalram_pages += free_all_bootmem();
882 for (tmp = 0; tmp < max_low_pfn; tmp++)
884 * Only count reserved RAM pages:
886 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
889 set_highmem_pages_init();
891 codesize = (unsigned long) &_etext - (unsigned long) &_text;
892 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
893 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
895 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
896 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
897 nr_free_pages() << (PAGE_SHIFT-10),
898 num_physpages << (PAGE_SHIFT-10),
900 reservedpages << (PAGE_SHIFT-10),
903 totalhigh_pages << (PAGE_SHIFT-10));
905 printk(KERN_INFO "virtual kernel memory layout:\n"
906 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
907 #ifdef CONFIG_HIGHMEM
908 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
910 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
911 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
912 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
913 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
914 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
915 FIXADDR_START, FIXADDR_TOP,
916 (FIXADDR_TOP - FIXADDR_START) >> 10,
918 #ifdef CONFIG_HIGHMEM
919 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
920 (LAST_PKMAP*PAGE_SIZE) >> 10,
923 VMALLOC_START, VMALLOC_END,
924 (VMALLOC_END - VMALLOC_START) >> 20,
926 (unsigned long)__va(0), (unsigned long)high_memory,
927 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
929 (unsigned long)&__init_begin, (unsigned long)&__init_end,
930 ((unsigned long)&__init_end -
931 (unsigned long)&__init_begin) >> 10,
933 (unsigned long)&_etext, (unsigned long)&_edata,
934 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
936 (unsigned long)&_text, (unsigned long)&_etext,
937 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
940 * Check boundaries twice: Some fundamental inconsistencies can
941 * be detected at build time already.
943 #define __FIXADDR_TOP (-PAGE_SIZE)
944 #ifdef CONFIG_HIGHMEM
945 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
946 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
948 #define high_memory (-128UL << 20)
949 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
953 #ifdef CONFIG_HIGHMEM
954 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
955 BUG_ON(VMALLOC_END > PKMAP_BASE);
957 BUG_ON(VMALLOC_START >= VMALLOC_END);
958 BUG_ON((unsigned long)high_memory > VMALLOC_START);
960 if (boot_cpu_data.wp_works_ok < 0)
964 zap_low_mappings(true);
967 #ifdef CONFIG_MEMORY_HOTPLUG
968 int arch_add_memory(int nid, u64 start, u64 size)
970 struct pglist_data *pgdata = NODE_DATA(nid);
971 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
972 unsigned long start_pfn = start >> PAGE_SHIFT;
973 unsigned long nr_pages = size >> PAGE_SHIFT;
975 return __add_pages(nid, zone, start_pfn, nr_pages);
980 * This function cannot be __init, since exceptions don't work in that
981 * section. Put this after the callers, so that it cannot be inlined.
983 static noinline int do_test_wp_bit(void)
988 __asm__ __volatile__(
994 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1003 #ifdef CONFIG_DEBUG_RODATA
1004 const int rodata_test_data = 0xC3;
1005 EXPORT_SYMBOL_GPL(rodata_test_data);
1007 int kernel_set_to_readonly __read_mostly;
1009 void set_kernel_text_rw(void)
1011 unsigned long start = PFN_ALIGN(_text);
1012 unsigned long size = PFN_ALIGN(_etext) - start;
1014 if (!kernel_set_to_readonly)
1017 pr_debug("Set kernel text: %lx - %lx for read write\n",
1020 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1023 void set_kernel_text_ro(void)
1025 unsigned long start = PFN_ALIGN(_text);
1026 unsigned long size = PFN_ALIGN(_etext) - start;
1028 if (!kernel_set_to_readonly)
1031 pr_debug("Set kernel text: %lx - %lx for read only\n",
1034 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1037 void mark_rodata_ro(void)
1039 unsigned long start = PFN_ALIGN(_text);
1040 unsigned long size = PFN_ALIGN(_etext) - start;
1042 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1043 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1046 kernel_set_to_readonly = 1;
1048 #ifdef CONFIG_CPA_DEBUG
1049 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1051 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1053 printk(KERN_INFO "Testing CPA: write protecting again\n");
1054 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1058 size = (unsigned long)__end_rodata - start;
1059 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1060 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1064 #ifdef CONFIG_CPA_DEBUG
1065 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1066 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1068 printk(KERN_INFO "Testing CPA: write protecting again\n");
1069 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);