2 * linux/arch/i386/mm/init.c
4 * Copyright (C) 1995 Linus Torvalds
6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
9 #include <linux/module.h>
10 #include <linux/signal.h>
11 #include <linux/sched.h>
12 #include <linux/kernel.h>
13 #include <linux/errno.h>
14 #include <linux/string.h>
15 #include <linux/types.h>
16 #include <linux/ptrace.h>
17 #include <linux/mman.h>
19 #include <linux/hugetlb.h>
20 #include <linux/swap.h>
21 #include <linux/smp.h>
22 #include <linux/init.h>
23 #include <linux/highmem.h>
24 #include <linux/pagemap.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/efi.h>
30 #include <linux/memory_hotplug.h>
31 #include <linux/initrd.h>
32 #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>
43 #include <asm/tlbflush.h>
44 #include <asm/sections.h>
46 unsigned int __VMALLOC_RESERVE = 128 << 20;
48 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
49 unsigned long highstart_pfn, highend_pfn;
51 static int noinline do_test_wp_bit(void);
54 * Creates a middle page table and puts a pointer to it in the
55 * given global directory entry. This only returns the gd entry
56 * in non-PAE compilation mode, since the middle layer is folded.
58 static pmd_t * __init one_md_table_init(pgd_t *pgd)
64 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
65 paravirt_alloc_pd(__pa(pmd_table) >> PAGE_SHIFT);
66 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
67 pud = pud_offset(pgd, 0);
68 if (pmd_table != pmd_offset(pud, 0))
71 pud = pud_offset(pgd, 0);
72 pmd_table = pmd_offset(pud, 0);
79 * Create a page table and place a pointer to it in a middle page
82 static pte_t * __init one_page_table_init(pmd_t *pmd)
85 pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
86 paravirt_alloc_pt(__pa(page_table) >> PAGE_SHIFT);
87 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
88 if (page_table != pte_offset_kernel(pmd, 0))
94 return pte_offset_kernel(pmd, 0);
98 * This function initializes a certain range of kernel virtual memory
99 * with new bootmem page tables, everywhere page tables are missing in
104 * NOTE: The pagetables are allocated contiguous on the physical space
105 * so we can cache the place of the first one and move around without
106 * checking the pgd every time.
108 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
113 int pgd_idx, pmd_idx;
117 pgd_idx = pgd_index(vaddr);
118 pmd_idx = pmd_index(vaddr);
119 pgd = pgd_base + pgd_idx;
121 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
123 one_md_table_init(pgd);
124 pud = pud_offset(pgd, vaddr);
125 pmd = pmd_offset(pud, vaddr);
126 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
128 one_page_table_init(pmd);
136 static inline int is_kernel_text(unsigned long addr)
138 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
144 * This maps the physical memory to kernel virtual address space, a total
145 * of max_low_pfn pages, by creating page tables starting from address
148 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
154 int pgd_idx, pmd_idx, pte_ofs;
156 pgd_idx = pgd_index(PAGE_OFFSET);
157 pgd = pgd_base + pgd_idx;
160 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
161 pmd = one_md_table_init(pgd);
162 if (pfn >= max_low_pfn)
164 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
165 unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
167 /* Map with big pages if possible, otherwise create normal page tables. */
169 unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
171 if (is_kernel_text(address) || is_kernel_text(address2))
172 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
174 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
177 pte = one_page_table_init(pmd);
179 for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
180 if (is_kernel_text(address))
181 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
183 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
190 static inline int page_kills_ppro(unsigned long pagenr)
192 if (pagenr >= 0x70000 && pagenr <= 0x7003F)
197 int page_is_ram(unsigned long pagenr)
200 unsigned long addr, end;
203 efi_memory_desc_t *md;
206 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
208 if (!is_available_memory(md))
210 addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
211 end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
213 if ((pagenr >= addr) && (pagenr < end))
219 for (i = 0; i < e820.nr_map; i++) {
221 if (e820.map[i].type != E820_RAM) /* not usable memory */
224 * !!!FIXME!!! Some BIOSen report areas as RAM that
225 * are not. Notably the 640->1Mb area. We need a sanity
228 addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
229 end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
230 if ((pagenr >= addr) && (pagenr < end))
236 #ifdef CONFIG_HIGHMEM
240 #define kmap_get_fixmap_pte(vaddr) \
241 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
243 static void __init kmap_init(void)
245 unsigned long kmap_vstart;
247 /* cache the first kmap pte */
248 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
249 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
251 kmap_prot = PAGE_KERNEL;
254 static void __init permanent_kmaps_init(pgd_t *pgd_base)
263 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
265 pgd = swapper_pg_dir + pgd_index(vaddr);
266 pud = pud_offset(pgd, vaddr);
267 pmd = pmd_offset(pud, vaddr);
268 pte = pte_offset_kernel(pmd, vaddr);
269 pkmap_page_table = pte;
272 static void __meminit free_new_highpage(struct page *page)
274 init_page_count(page);
279 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
281 if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
282 ClearPageReserved(page);
283 free_new_highpage(page);
285 SetPageReserved(page);
288 static int __meminit add_one_highpage_hotplug(struct page *page, unsigned long pfn)
290 free_new_highpage(page);
292 #ifdef CONFIG_FLATMEM
293 max_mapnr = max(pfn, max_mapnr);
300 * Not currently handling the NUMA case.
301 * Assuming single node and all memory that
302 * has been added dynamically that would be
303 * onlined here is in HIGHMEM
305 void __meminit online_page(struct page *page)
307 ClearPageReserved(page);
308 add_one_highpage_hotplug(page, page_to_pfn(page));
313 extern void set_highmem_pages_init(int);
315 static void __init set_highmem_pages_init(int bad_ppro)
318 for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
319 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
320 totalram_pages += totalhigh_pages;
322 #endif /* CONFIG_FLATMEM */
325 #define kmap_init() do { } while (0)
326 #define permanent_kmaps_init(pgd_base) do { } while (0)
327 #define set_highmem_pages_init(bad_ppro) do { } while (0)
328 #endif /* CONFIG_HIGHMEM */
330 unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
331 EXPORT_SYMBOL(__PAGE_KERNEL);
332 unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
335 extern void __init remap_numa_kva(void);
337 #define remap_numa_kva() do {} while (0)
340 static void __init pagetable_init (void)
343 pgd_t *pgd_base = swapper_pg_dir;
345 #ifdef CONFIG_X86_PAE
347 /* Init entries of the first-level page table to the zero page */
348 for (i = 0; i < PTRS_PER_PGD; i++)
349 set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
351 paravirt_alloc_pd(__pa(swapper_pg_dir) >> PAGE_SHIFT);
354 /* Enable PSE if available */
356 set_in_cr4(X86_CR4_PSE);
359 /* Enable PGE if available */
361 set_in_cr4(X86_CR4_PGE);
362 __PAGE_KERNEL |= _PAGE_GLOBAL;
363 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
366 kernel_physical_mapping_init(pgd_base);
370 * Fixed mappings, only the page table structure has to be
371 * created - mappings will be set by set_fixmap():
373 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
374 page_table_range_init(vaddr, 0, pgd_base);
376 permanent_kmaps_init(pgd_base);
378 #ifdef CONFIG_X86_PAE
380 * Add low memory identity-mappings - SMP needs it when
381 * starting up on an AP from real-mode. In the non-PAE
382 * case we already have these mappings through head.S.
383 * All user-space mappings are explicitly cleared after
386 set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
390 #if defined(CONFIG_SOFTWARE_SUSPEND) || defined(CONFIG_ACPI_SLEEP)
392 * Swap suspend & friends need this for resume because things like the intel-agp
393 * driver might have split up a kernel 4MB mapping.
395 char __nosavedata swsusp_pg_dir[PAGE_SIZE]
396 __attribute__ ((aligned (PAGE_SIZE)));
398 static inline void save_pg_dir(void)
400 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
403 static inline void save_pg_dir(void)
408 void zap_low_mappings (void)
415 * Zap initial low-memory mappings.
417 * Note that "pgd_clear()" doesn't do it for
418 * us, because pgd_clear() is a no-op on i386.
420 for (i = 0; i < USER_PTRS_PER_PGD; i++)
421 #ifdef CONFIG_X86_PAE
422 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
424 set_pgd(swapper_pg_dir+i, __pgd(0));
429 static int disable_nx __initdata = 0;
430 u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
435 * Control non executable mappings.
440 static int __init noexec_setup(char *str)
442 if (!str || !strcmp(str, "on")) {
444 __supported_pte_mask |= _PAGE_NX;
447 } else if (!strcmp(str,"off")) {
449 __supported_pte_mask &= ~_PAGE_NX;
455 early_param("noexec", noexec_setup);
458 #ifdef CONFIG_X86_PAE
460 static void __init set_nx(void)
462 unsigned int v[4], l, h;
464 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
465 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
466 if ((v[3] & (1 << 20)) && !disable_nx) {
467 rdmsr(MSR_EFER, l, h);
469 wrmsr(MSR_EFER, l, h);
471 __supported_pte_mask |= _PAGE_NX;
477 * Enables/disables executability of a given kernel page and
478 * returns the previous setting.
480 int __init set_kernel_exec(unsigned long vaddr, int enable)
488 pte = lookup_address(vaddr);
491 if (!pte_exec_kernel(*pte))
495 pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
497 pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
498 pte_update_defer(&init_mm, vaddr, pte);
507 * paging_init() sets up the page tables - note that the first 8MB are
508 * already mapped by head.S.
510 * This routines also unmaps the page at virtual kernel address 0, so
511 * that we can trap those pesky NULL-reference errors in the kernel.
513 void __init paging_init(void)
515 #ifdef CONFIG_X86_PAE
518 printk("NX (Execute Disable) protection: active\n");
523 load_cr3(swapper_pg_dir);
525 #ifdef CONFIG_X86_PAE
527 * We will bail out later - printk doesn't work right now so
528 * the user would just see a hanging kernel.
531 set_in_cr4(X86_CR4_PAE);
539 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
540 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
541 * used to involve black magic jumps to work around some nasty CPU bugs,
542 * but fortunately the switch to using exceptions got rid of all that.
545 static void __init test_wp_bit(void)
547 printk("Checking if this processor honours the WP bit even in supervisor mode... ");
549 /* Any page-aligned address will do, the test is non-destructive */
550 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
551 boot_cpu_data.wp_works_ok = do_test_wp_bit();
552 clear_fixmap(FIX_WP_TEST);
554 if (!boot_cpu_data.wp_works_ok) {
556 #ifdef CONFIG_X86_WP_WORKS_OK
557 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
564 static struct kcore_list kcore_mem, kcore_vmalloc;
566 void __init mem_init(void)
568 extern int ppro_with_ram_bug(void);
569 int codesize, reservedpages, datasize, initsize;
573 #ifdef CONFIG_FLATMEM
577 bad_ppro = ppro_with_ram_bug();
579 #ifdef CONFIG_HIGHMEM
580 /* check that fixmap and pkmap do not overlap */
581 if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
582 printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
583 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
584 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
589 /* this will put all low memory onto the freelists */
590 totalram_pages += free_all_bootmem();
593 for (tmp = 0; tmp < max_low_pfn; tmp++)
595 * Only count reserved RAM pages
597 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
600 set_highmem_pages_init(bad_ppro);
602 codesize = (unsigned long) &_etext - (unsigned long) &_text;
603 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
604 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
606 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
607 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
608 VMALLOC_END-VMALLOC_START);
610 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
611 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
612 num_physpages << (PAGE_SHIFT-10),
614 reservedpages << (PAGE_SHIFT-10),
617 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
620 #if 1 /* double-sanity-check paranoia */
621 printk("virtual kernel memory layout:\n"
622 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
623 #ifdef CONFIG_HIGHMEM
624 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
626 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
627 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
628 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
629 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
630 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
631 FIXADDR_START, FIXADDR_TOP,
632 (FIXADDR_TOP - FIXADDR_START) >> 10,
634 #ifdef CONFIG_HIGHMEM
635 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
636 (LAST_PKMAP*PAGE_SIZE) >> 10,
639 VMALLOC_START, VMALLOC_END,
640 (VMALLOC_END - VMALLOC_START) >> 20,
642 (unsigned long)__va(0), (unsigned long)high_memory,
643 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
645 (unsigned long)&__init_begin, (unsigned long)&__init_end,
646 ((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10,
648 (unsigned long)&_etext, (unsigned long)&_edata,
649 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
651 (unsigned long)&_text, (unsigned long)&_etext,
652 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
654 #ifdef CONFIG_HIGHMEM
655 BUG_ON(PKMAP_BASE+LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
656 BUG_ON(VMALLOC_END > PKMAP_BASE);
658 BUG_ON(VMALLOC_START > VMALLOC_END);
659 BUG_ON((unsigned long)high_memory > VMALLOC_START);
660 #endif /* double-sanity-check paranoia */
662 #ifdef CONFIG_X86_PAE
664 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
666 if (boot_cpu_data.wp_works_ok < 0)
670 * Subtle. SMP is doing it's boot stuff late (because it has to
671 * fork idle threads) - but it also needs low mappings for the
672 * protected-mode entry to work. We zap these entries only after
673 * the WP-bit has been tested.
680 #ifdef CONFIG_MEMORY_HOTPLUG
681 int arch_add_memory(int nid, u64 start, u64 size)
683 struct pglist_data *pgdata = NODE_DATA(nid);
684 struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
685 unsigned long start_pfn = start >> PAGE_SHIFT;
686 unsigned long nr_pages = size >> PAGE_SHIFT;
688 return __add_pages(zone, start_pfn, nr_pages);
691 int remove_memory(u64 start, u64 size)
695 EXPORT_SYMBOL_GPL(remove_memory);
698 struct kmem_cache *pgd_cache;
699 struct kmem_cache *pmd_cache;
701 void __init pgtable_cache_init(void)
703 if (PTRS_PER_PMD > 1) {
704 pmd_cache = kmem_cache_create("pmd",
705 PTRS_PER_PMD*sizeof(pmd_t),
706 PTRS_PER_PMD*sizeof(pmd_t),
711 panic("pgtable_cache_init(): cannot create pmd cache");
713 pgd_cache = kmem_cache_create("pgd",
714 PTRS_PER_PGD*sizeof(pgd_t),
715 PTRS_PER_PGD*sizeof(pgd_t),
718 PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
720 panic("pgtable_cache_init(): Cannot create pgd cache");
724 * This function cannot be __init, since exceptions don't work in that
725 * section. Put this after the callers, so that it cannot be inlined.
727 static int noinline do_test_wp_bit(void)
732 __asm__ __volatile__(
737 ".section __ex_table,\"a\"\n"
741 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
750 #ifdef CONFIG_DEBUG_RODATA
752 void mark_rodata_ro(void)
754 unsigned long addr = (unsigned long)__start_rodata;
756 for (; addr < (unsigned long)__end_rodata; addr += PAGE_SIZE)
757 change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
759 printk("Write protecting the kernel read-only data: %uk\n",
760 (__end_rodata - __start_rodata) >> 10);
763 * change_page_attr() requires a global_flush_tlb() call after it.
764 * We do this after the printk so that if something went wrong in the
765 * change, the printk gets out at least to give a better debug hint
766 * of who is the culprit.
772 void free_init_pages(char *what, unsigned long begin, unsigned long end)
776 for (addr = begin; addr < end; addr += PAGE_SIZE) {
777 ClearPageReserved(virt_to_page(addr));
778 init_page_count(virt_to_page(addr));
779 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
783 printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
786 void free_initmem(void)
788 free_init_pages("unused kernel memory",
789 (unsigned long)(&__init_begin),
790 (unsigned long)(&__init_end));
793 #ifdef CONFIG_BLK_DEV_INITRD
794 void free_initrd_mem(unsigned long start, unsigned long end)
796 free_init_pages("initrd memory", start, end);