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>
52 #include <asm/page_types.h>
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);
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_low_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 #ifdef CONFIG_DEBUG_PAGEALLOC
116 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
120 (pte_t *)alloc_bootmem_low_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 start_pfn, end_pfn;
246 pgd_t *pgd_base = swapper_pg_dir;
247 int pgd_idx, pmd_idx, pte_ofs;
252 unsigned pages_2m, pages_4k;
255 start_pfn = start >> PAGE_SHIFT;
256 end_pfn = end >> PAGE_SHIFT;
259 * First iteration will setup identity mapping using large/small pages
260 * based on use_pse, with other attributes same as set by
261 * the early code in head_32.S
263 * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
264 * as desired for the kernel identity mapping.
266 * This two pass mechanism conforms to the TLB app note which says:
268 * "Software should not write to a paging-structure entry in a way
269 * that would change, for any linear address, both the page size
270 * and either the page frame or attributes."
278 pages_2m = pages_4k = 0;
280 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
281 pgd = pgd_base + pgd_idx;
282 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
283 pmd = one_md_table_init(pgd);
287 #ifdef CONFIG_X86_PAE
288 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
293 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
295 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
298 * Map with big pages if possible, otherwise
299 * create normal page tables:
303 pgprot_t prot = PAGE_KERNEL_LARGE;
305 * first pass will use the same initial
306 * identity mapping attribute + _PAGE_PSE.
309 __pgprot(PTE_IDENT_ATTR |
312 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
313 PAGE_OFFSET + PAGE_SIZE-1;
315 if (is_kernel_text(addr) ||
316 is_kernel_text(addr2))
317 prot = PAGE_KERNEL_LARGE_EXEC;
320 if (mapping_iter == 1)
321 set_pmd(pmd, pfn_pmd(pfn, init_prot));
323 set_pmd(pmd, pfn_pmd(pfn, prot));
328 pte = one_page_table_init(pmd);
330 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
332 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
333 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
334 pgprot_t prot = PAGE_KERNEL;
336 * first pass will use the same initial
337 * identity mapping attribute.
339 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
341 if (is_kernel_text(addr))
342 prot = PAGE_KERNEL_EXEC;
345 if (mapping_iter == 1)
346 set_pte(pte, pfn_pte(pfn, init_prot));
348 set_pte(pte, pfn_pte(pfn, prot));
352 if (mapping_iter == 1) {
354 * update direct mapping page count only in the first
357 update_page_count(PG_LEVEL_2M, pages_2m);
358 update_page_count(PG_LEVEL_4K, pages_4k);
361 * local global flush tlb, which will flush the previous
362 * mappings present in both small and large page TLB's.
367 * Second iteration will set the actual desired PTE attributes.
378 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
380 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
381 vaddr), vaddr), vaddr);
384 static void __init kmap_init(void)
386 unsigned long kmap_vstart;
389 * Cache the first kmap pte:
391 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
392 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
394 kmap_prot = PAGE_KERNEL;
397 #ifdef CONFIG_HIGHMEM
398 static void __init permanent_kmaps_init(pgd_t *pgd_base)
407 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
409 pgd = swapper_pg_dir + pgd_index(vaddr);
410 pud = pud_offset(pgd, vaddr);
411 pmd = pmd_offset(pud, vaddr);
412 pte = pte_offset_kernel(pmd, vaddr);
413 pkmap_page_table = pte;
416 static void __init add_one_highpage_init(struct page *page, int pfn)
418 ClearPageReserved(page);
419 init_page_count(page);
424 struct add_highpages_data {
425 unsigned long start_pfn;
426 unsigned long end_pfn;
429 static int __init add_highpages_work_fn(unsigned long start_pfn,
430 unsigned long end_pfn, void *datax)
434 unsigned long final_start_pfn, final_end_pfn;
435 struct add_highpages_data *data;
437 data = (struct add_highpages_data *)datax;
439 final_start_pfn = max(start_pfn, data->start_pfn);
440 final_end_pfn = min(end_pfn, data->end_pfn);
441 if (final_start_pfn >= final_end_pfn)
444 for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
446 if (!pfn_valid(node_pfn))
448 page = pfn_to_page(node_pfn);
449 add_one_highpage_init(page, node_pfn);
456 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
457 unsigned long end_pfn)
459 struct add_highpages_data data;
461 data.start_pfn = start_pfn;
462 data.end_pfn = end_pfn;
464 work_with_active_regions(nid, add_highpages_work_fn, &data);
468 static inline void permanent_kmaps_init(pgd_t *pgd_base)
471 #endif /* CONFIG_HIGHMEM */
473 void __init native_pagetable_setup_start(pgd_t *base)
475 unsigned long pfn, va;
482 * Remove any mappings which extend past the end of physical
483 * memory from the boot time page table:
485 for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
486 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
487 pgd = base + pgd_index(va);
488 if (!pgd_present(*pgd))
491 pud = pud_offset(pgd, va);
492 pmd = pmd_offset(pud, va);
493 if (!pmd_present(*pmd))
496 pte = pte_offset_kernel(pmd, va);
497 if (!pte_present(*pte))
500 pte_clear(NULL, va, pte);
502 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
505 void __init native_pagetable_setup_done(pgd_t *base)
510 * Build a proper pagetable for the kernel mappings. Up until this
511 * point, we've been running on some set of pagetables constructed by
514 * If we're booting on native hardware, this will be a pagetable
515 * constructed in arch/x86/kernel/head_32.S. The root of the
516 * pagetable will be swapper_pg_dir.
518 * If we're booting paravirtualized under a hypervisor, then there are
519 * more options: we may already be running PAE, and the pagetable may
520 * or may not be based in swapper_pg_dir. In any case,
521 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
522 * appropriately for the rest of the initialization to work.
524 * In general, pagetable_init() assumes that the pagetable may already
525 * be partially populated, and so it avoids stomping on any existing
528 void __init early_ioremap_page_table_range_init(void)
530 pgd_t *pgd_base = swapper_pg_dir;
531 unsigned long vaddr, end;
534 * Fixed mappings, only the page table structure has to be
535 * created - mappings will be set by set_fixmap():
537 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
538 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
539 page_table_range_init(vaddr, end, pgd_base);
540 early_ioremap_reset();
543 static void __init pagetable_init(void)
545 pgd_t *pgd_base = swapper_pg_dir;
547 permanent_kmaps_init(pgd_base);
550 #ifdef CONFIG_ACPI_SLEEP
552 * ACPI suspend needs this for resume, because things like the intel-agp
553 * driver might have split up a kernel 4MB mapping.
555 char swsusp_pg_dir[PAGE_SIZE]
556 __attribute__ ((aligned(PAGE_SIZE)));
558 static inline void save_pg_dir(void)
560 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
562 #else /* !CONFIG_ACPI_SLEEP */
563 static inline void save_pg_dir(void)
566 #endif /* !CONFIG_ACPI_SLEEP */
568 void zap_low_mappings(void)
573 * Zap initial low-memory mappings.
575 * Note that "pgd_clear()" doesn't do it for
576 * us, because pgd_clear() is a no-op on i386.
578 for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
579 #ifdef CONFIG_X86_PAE
580 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
582 set_pgd(swapper_pg_dir+i, __pgd(0));
588 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
589 EXPORT_SYMBOL_GPL(__supported_pte_mask);
591 /* user-defined highmem size */
592 static unsigned int highmem_pages = -1;
595 * highmem=size forces highmem to be exactly 'size' bytes.
596 * This works even on boxes that have no highmem otherwise.
597 * This also works to reduce highmem size on bigger boxes.
599 static int __init parse_highmem(char *arg)
604 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
607 early_param("highmem", parse_highmem);
609 #define MSG_HIGHMEM_TOO_BIG \
610 "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
612 #define MSG_LOWMEM_TOO_SMALL \
613 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
615 * All of RAM fits into lowmem - but if user wants highmem
616 * artificially via the highmem=x boot parameter then create
619 void __init lowmem_pfn_init(void)
621 /* max_low_pfn is 0, we already have early_res support */
622 max_low_pfn = max_pfn;
624 if (highmem_pages == -1)
626 #ifdef CONFIG_HIGHMEM
627 if (highmem_pages >= max_pfn) {
628 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
629 pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
633 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
634 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
635 pages_to_mb(highmem_pages));
638 max_low_pfn -= highmem_pages;
642 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
646 #define MSG_HIGHMEM_TOO_SMALL \
647 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
649 #define MSG_HIGHMEM_TRIMMED \
650 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
652 * We have more RAM than fits into lowmem - we try to put it into
653 * highmem, also taking the highmem=x boot parameter into account:
655 void __init highmem_pfn_init(void)
657 max_low_pfn = MAXMEM_PFN;
659 if (highmem_pages == -1)
660 highmem_pages = max_pfn - MAXMEM_PFN;
662 if (highmem_pages + MAXMEM_PFN < max_pfn)
663 max_pfn = MAXMEM_PFN + highmem_pages;
665 if (highmem_pages + MAXMEM_PFN > max_pfn) {
666 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
667 pages_to_mb(max_pfn - MAXMEM_PFN),
668 pages_to_mb(highmem_pages));
671 #ifndef CONFIG_HIGHMEM
672 /* Maximum memory usable is what is directly addressable */
673 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
674 if (max_pfn > MAX_NONPAE_PFN)
675 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
677 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
678 max_pfn = MAXMEM_PFN;
679 #else /* !CONFIG_HIGHMEM */
680 #ifndef CONFIG_HIGHMEM64G
681 if (max_pfn > MAX_NONPAE_PFN) {
682 max_pfn = MAX_NONPAE_PFN;
683 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
685 #endif /* !CONFIG_HIGHMEM64G */
686 #endif /* !CONFIG_HIGHMEM */
690 * Determine low and high memory ranges:
692 void __init find_low_pfn_range(void)
694 /* it could update max_pfn */
696 if (max_pfn <= MAXMEM_PFN)
702 #ifndef CONFIG_NEED_MULTIPLE_NODES
703 void __init initmem_init(unsigned long start_pfn,
704 unsigned long end_pfn)
706 #ifdef CONFIG_HIGHMEM
707 highstart_pfn = highend_pfn = max_pfn;
708 if (max_pfn > max_low_pfn)
709 highstart_pfn = max_low_pfn;
710 memory_present(0, 0, highend_pfn);
711 e820_register_active_regions(0, 0, highend_pfn);
712 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
713 pages_to_mb(highend_pfn - highstart_pfn));
714 num_physpages = highend_pfn;
715 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
717 memory_present(0, 0, max_low_pfn);
718 e820_register_active_regions(0, 0, max_low_pfn);
719 num_physpages = max_low_pfn;
720 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
722 #ifdef CONFIG_FLATMEM
723 max_mapnr = num_physpages;
725 __vmalloc_start_set = true;
727 printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
728 pages_to_mb(max_low_pfn));
730 setup_bootmem_allocator();
732 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
734 static void __init zone_sizes_init(void)
736 unsigned long max_zone_pfns[MAX_NR_ZONES];
737 memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
738 max_zone_pfns[ZONE_DMA] =
739 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
740 max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
741 #ifdef CONFIG_HIGHMEM
742 max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
745 free_area_init_nodes(max_zone_pfns);
748 static unsigned long __init setup_node_bootmem(int nodeid,
749 unsigned long start_pfn,
750 unsigned long end_pfn,
751 unsigned long bootmap)
753 unsigned long bootmap_size;
755 /* don't touch min_low_pfn */
756 bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
757 bootmap >> PAGE_SHIFT,
759 printk(KERN_INFO " node %d low ram: %08lx - %08lx\n",
760 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
761 printk(KERN_INFO " node %d bootmap %08lx - %08lx\n",
762 nodeid, bootmap, bootmap + bootmap_size);
763 free_bootmem_with_active_regions(nodeid, end_pfn);
764 early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
766 return bootmap + bootmap_size;
769 void __init setup_bootmem_allocator(void)
772 unsigned long bootmap_size, bootmap;
774 * Initialize the boot-time allocator (with low memory only):
776 bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
777 bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
780 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
781 reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
783 printk(KERN_INFO " mapped low ram: 0 - %08lx\n",
784 max_pfn_mapped<<PAGE_SHIFT);
785 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
787 for_each_online_node(nodeid) {
788 unsigned long start_pfn, end_pfn;
790 #ifdef CONFIG_NEED_MULTIPLE_NODES
791 start_pfn = node_start_pfn[nodeid];
792 end_pfn = node_end_pfn[nodeid];
793 if (start_pfn > max_low_pfn)
795 if (end_pfn > max_low_pfn)
796 end_pfn = max_low_pfn;
799 end_pfn = max_low_pfn;
801 bootmap = setup_node_bootmem(nodeid, start_pfn, end_pfn,
809 * paging_init() sets up the page tables - note that the first 8MB are
810 * already mapped by head.S.
812 * This routines also unmaps the page at virtual kernel address 0, so
813 * that we can trap those pesky NULL-reference errors in the kernel.
815 void __init paging_init(void)
824 * NOTE: at this point the bootmem allocator is fully available.
831 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
832 * and also on some strange 486's. All 586+'s are OK. This used to involve
833 * black magic jumps to work around some nasty CPU bugs, but fortunately the
834 * switch to using exceptions got rid of all that.
836 static void __init test_wp_bit(void)
839 "Checking if this processor honours the WP bit even in supervisor mode...");
841 /* Any page-aligned address will do, the test is non-destructive */
842 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
843 boot_cpu_data.wp_works_ok = do_test_wp_bit();
844 clear_fixmap(FIX_WP_TEST);
846 if (!boot_cpu_data.wp_works_ok) {
847 printk(KERN_CONT "No.\n");
848 #ifdef CONFIG_X86_WP_WORKS_OK
850 "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
853 printk(KERN_CONT "Ok.\n");
857 static struct kcore_list kcore_mem, kcore_vmalloc;
859 void __init mem_init(void)
861 int codesize, reservedpages, datasize, initsize;
866 #ifdef CONFIG_FLATMEM
869 /* this will put all low memory onto the freelists */
870 totalram_pages += free_all_bootmem();
873 for (tmp = 0; tmp < max_low_pfn; tmp++)
875 * Only count reserved RAM pages:
877 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
880 set_highmem_pages_init();
882 codesize = (unsigned long) &_etext - (unsigned long) &_text;
883 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
884 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
886 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
887 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
888 VMALLOC_END-VMALLOC_START);
890 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
891 "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
892 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
893 num_physpages << (PAGE_SHIFT-10),
895 reservedpages << (PAGE_SHIFT-10),
898 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
901 printk(KERN_INFO "virtual kernel memory layout:\n"
902 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
903 #ifdef CONFIG_HIGHMEM
904 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
906 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
907 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
908 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
909 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
910 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
911 FIXADDR_START, FIXADDR_TOP,
912 (FIXADDR_TOP - FIXADDR_START) >> 10,
914 #ifdef CONFIG_HIGHMEM
915 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
916 (LAST_PKMAP*PAGE_SIZE) >> 10,
919 VMALLOC_START, VMALLOC_END,
920 (VMALLOC_END - VMALLOC_START) >> 20,
922 (unsigned long)__va(0), (unsigned long)high_memory,
923 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
925 (unsigned long)&__init_begin, (unsigned long)&__init_end,
926 ((unsigned long)&__init_end -
927 (unsigned long)&__init_begin) >> 10,
929 (unsigned long)&_etext, (unsigned long)&_edata,
930 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
932 (unsigned long)&_text, (unsigned long)&_etext,
933 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
936 * Check boundaries twice: Some fundamental inconsistencies can
937 * be detected at build time already.
939 #define __FIXADDR_TOP (-PAGE_SIZE)
940 #ifdef CONFIG_HIGHMEM
941 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
942 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE);
944 #define high_memory (-128UL << 20)
945 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END);
949 #ifdef CONFIG_HIGHMEM
950 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
951 BUG_ON(VMALLOC_END > PKMAP_BASE);
953 BUG_ON(VMALLOC_START >= VMALLOC_END);
954 BUG_ON((unsigned long)high_memory > VMALLOC_START);
956 if (boot_cpu_data.wp_works_ok < 0)
963 #ifdef CONFIG_MEMORY_HOTPLUG
964 int arch_add_memory(int nid, u64 start, u64 size)
966 struct pglist_data *pgdata = NODE_DATA(nid);
967 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
968 unsigned long start_pfn = start >> PAGE_SHIFT;
969 unsigned long nr_pages = size >> PAGE_SHIFT;
971 return __add_pages(nid, zone, start_pfn, nr_pages);
976 * This function cannot be __init, since exceptions don't work in that
977 * section. Put this after the callers, so that it cannot be inlined.
979 static noinline int do_test_wp_bit(void)
984 __asm__ __volatile__(
990 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
999 #ifdef CONFIG_DEBUG_RODATA
1000 const int rodata_test_data = 0xC3;
1001 EXPORT_SYMBOL_GPL(rodata_test_data);
1003 static int kernel_set_to_readonly;
1005 void set_kernel_text_rw(void)
1007 unsigned long start = PFN_ALIGN(_text);
1008 unsigned long size = PFN_ALIGN(_etext) - start;
1010 if (!kernel_set_to_readonly)
1013 pr_debug("Set kernel text: %lx - %lx for read write\n",
1016 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1019 void set_kernel_text_ro(void)
1021 unsigned long start = PFN_ALIGN(_text);
1022 unsigned long size = PFN_ALIGN(_etext) - start;
1024 if (!kernel_set_to_readonly)
1027 pr_debug("Set kernel text: %lx - %lx for read only\n",
1030 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1033 void mark_rodata_ro(void)
1035 unsigned long start = PFN_ALIGN(_text);
1036 unsigned long size = PFN_ALIGN(_etext) - start;
1038 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1039 printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1042 kernel_set_to_readonly = 1;
1044 #ifdef CONFIG_CPA_DEBUG
1045 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1047 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1049 printk(KERN_INFO "Testing CPA: write protecting again\n");
1050 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1054 size = (unsigned long)__end_rodata - start;
1055 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1056 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1060 #ifdef CONFIG_CPA_DEBUG
1061 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1062 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1064 printk(KERN_INFO "Testing CPA: write protecting again\n");
1065 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1070 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1073 return reserve_bootmem(phys, len, flags);