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/config.h>
10 #include <linux/module.h>
11 #include <linux/signal.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/string.h>
16 #include <linux/types.h>
17 #include <linux/ptrace.h>
18 #include <linux/mman.h>
20 #include <linux/hugetlb.h>
21 #include <linux/swap.h>
22 #include <linux/smp.h>
23 #include <linux/init.h>
24 #include <linux/highmem.h>
25 #include <linux/pagemap.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>
32 #include <asm/processor.h>
33 #include <asm/system.h>
34 #include <asm/uaccess.h>
35 #include <asm/pgtable.h>
37 #include <asm/fixmap.h>
41 #include <asm/tlbflush.h>
42 #include <asm/sections.h>
44 unsigned int __VMALLOC_RESERVE = 128 << 20;
46 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
47 unsigned long highstart_pfn, highend_pfn;
49 static int noinline do_test_wp_bit(void);
52 * Creates a middle page table and puts a pointer to it in the
53 * given global directory entry. This only returns the gd entry
54 * in non-PAE compilation mode, since the middle layer is folded.
56 static pmd_t * __init one_md_table_init(pgd_t *pgd)
62 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
63 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
64 pud = pud_offset(pgd, 0);
65 if (pmd_table != pmd_offset(pud, 0))
68 pud = pud_offset(pgd, 0);
69 pmd_table = pmd_offset(pud, 0);
76 * Create a page table and place a pointer to it in a middle page
79 static pte_t * __init one_page_table_init(pmd_t *pmd)
82 pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
83 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
84 if (page_table != pte_offset_kernel(pmd, 0))
90 return pte_offset_kernel(pmd, 0);
94 * This function initializes a certain range of kernel virtual memory
95 * with new bootmem page tables, everywhere page tables are missing in
100 * NOTE: The pagetables are allocated contiguous on the physical space
101 * so we can cache the place of the first one and move around without
102 * checking the pgd every time.
104 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
109 int pgd_idx, pmd_idx;
113 pgd_idx = pgd_index(vaddr);
114 pmd_idx = pmd_index(vaddr);
115 pgd = pgd_base + pgd_idx;
117 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
119 one_md_table_init(pgd);
120 pud = pud_offset(pgd, vaddr);
121 pmd = pmd_offset(pud, vaddr);
122 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
124 one_page_table_init(pmd);
132 static inline int is_kernel_text(unsigned long addr)
134 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
140 * This maps the physical memory to kernel virtual address space, a total
141 * of max_low_pfn pages, by creating page tables starting from address
144 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
150 int pgd_idx, pmd_idx, pte_ofs;
152 pgd_idx = pgd_index(PAGE_OFFSET);
153 pgd = pgd_base + pgd_idx;
156 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
157 pmd = one_md_table_init(pgd);
158 if (pfn >= max_low_pfn)
160 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
161 unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
163 /* Map with big pages if possible, otherwise create normal page tables. */
165 unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
167 if (is_kernel_text(address) || is_kernel_text(address2))
168 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
170 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
173 pte = one_page_table_init(pmd);
175 for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
176 if (is_kernel_text(address))
177 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
179 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
186 static inline int page_kills_ppro(unsigned long pagenr)
188 if (pagenr >= 0x70000 && pagenr <= 0x7003F)
193 extern int is_available_memory(efi_memory_desc_t *);
195 int page_is_ram(unsigned long pagenr)
198 unsigned long addr, end;
201 efi_memory_desc_t *md;
204 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
206 if (!is_available_memory(md))
208 addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
209 end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
211 if ((pagenr >= addr) && (pagenr < end))
217 for (i = 0; i < e820.nr_map; i++) {
219 if (e820.map[i].type != E820_RAM) /* not usable memory */
222 * !!!FIXME!!! Some BIOSen report areas as RAM that
223 * are not. Notably the 640->1Mb area. We need a sanity
226 addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
227 end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
228 if ((pagenr >= addr) && (pagenr < end))
234 #ifdef CONFIG_HIGHMEM
238 #define kmap_get_fixmap_pte(vaddr) \
239 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
241 static void __init kmap_init(void)
243 unsigned long kmap_vstart;
245 /* cache the first kmap pte */
246 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
247 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
249 kmap_prot = PAGE_KERNEL;
252 static void __init permanent_kmaps_init(pgd_t *pgd_base)
261 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
263 pgd = swapper_pg_dir + pgd_index(vaddr);
264 pud = pud_offset(pgd, vaddr);
265 pmd = pmd_offset(pud, vaddr);
266 pte = pte_offset_kernel(pmd, vaddr);
267 pkmap_page_table = pte;
270 void __devinit free_new_highpage(struct page *page)
272 set_page_count(page, 1);
277 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
279 if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
280 ClearPageReserved(page);
281 free_new_highpage(page);
283 SetPageReserved(page);
286 static int add_one_highpage_hotplug(struct page *page, unsigned long pfn)
288 free_new_highpage(page);
290 #ifdef CONFIG_FLATMEM
291 max_mapnr = max(pfn, max_mapnr);
298 * Not currently handling the NUMA case.
299 * Assuming single node and all memory that
300 * has been added dynamically that would be
301 * onlined here is in HIGHMEM
303 void online_page(struct page *page)
305 ClearPageReserved(page);
306 add_one_highpage_hotplug(page, page_to_pfn(page));
311 extern void set_highmem_pages_init(int);
313 static void __init set_highmem_pages_init(int bad_ppro)
316 for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
317 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
318 totalram_pages += totalhigh_pages;
320 #endif /* CONFIG_FLATMEM */
323 #define kmap_init() do { } while (0)
324 #define permanent_kmaps_init(pgd_base) do { } while (0)
325 #define set_highmem_pages_init(bad_ppro) do { } while (0)
326 #endif /* CONFIG_HIGHMEM */
328 unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
329 EXPORT_SYMBOL(__PAGE_KERNEL);
330 unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
333 extern void __init remap_numa_kva(void);
335 #define remap_numa_kva() do {} while (0)
338 static void __init pagetable_init (void)
341 pgd_t *pgd_base = swapper_pg_dir;
343 #ifdef CONFIG_X86_PAE
345 /* Init entries of the first-level page table to the zero page */
346 for (i = 0; i < PTRS_PER_PGD; i++)
347 set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
350 /* Enable PSE if available */
352 set_in_cr4(X86_CR4_PSE);
355 /* Enable PGE if available */
357 set_in_cr4(X86_CR4_PGE);
358 __PAGE_KERNEL |= _PAGE_GLOBAL;
359 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
362 kernel_physical_mapping_init(pgd_base);
366 * Fixed mappings, only the page table structure has to be
367 * created - mappings will be set by set_fixmap():
369 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
370 page_table_range_init(vaddr, 0, pgd_base);
372 permanent_kmaps_init(pgd_base);
374 #ifdef CONFIG_X86_PAE
376 * Add low memory identity-mappings - SMP needs it when
377 * starting up on an AP from real-mode. In the non-PAE
378 * case we already have these mappings through head.S.
379 * All user-space mappings are explicitly cleared after
382 set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
386 #ifdef CONFIG_SOFTWARE_SUSPEND
388 * Swap suspend & friends need this for resume because things like the intel-agp
389 * driver might have split up a kernel 4MB mapping.
391 char __nosavedata swsusp_pg_dir[PAGE_SIZE]
392 __attribute__ ((aligned (PAGE_SIZE)));
394 static inline void save_pg_dir(void)
396 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
399 static inline void save_pg_dir(void)
404 void zap_low_mappings (void)
411 * Zap initial low-memory mappings.
413 * Note that "pgd_clear()" doesn't do it for
414 * us, because pgd_clear() is a no-op on i386.
416 for (i = 0; i < USER_PTRS_PER_PGD; i++)
417 #ifdef CONFIG_X86_PAE
418 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
420 set_pgd(swapper_pg_dir+i, __pgd(0));
425 static int disable_nx __initdata = 0;
426 u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
431 * Control non executable mappings.
436 void __init noexec_setup(const char *str)
438 if (!strncmp(str, "on",2) && cpu_has_nx) {
439 __supported_pte_mask |= _PAGE_NX;
441 } else if (!strncmp(str,"off",3)) {
443 __supported_pte_mask &= ~_PAGE_NX;
448 #ifdef CONFIG_X86_PAE
450 static void __init set_nx(void)
452 unsigned int v[4], l, h;
454 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
455 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
456 if ((v[3] & (1 << 20)) && !disable_nx) {
457 rdmsr(MSR_EFER, l, h);
459 wrmsr(MSR_EFER, l, h);
461 __supported_pte_mask |= _PAGE_NX;
467 * Enables/disables executability of a given kernel page and
468 * returns the previous setting.
470 int __init set_kernel_exec(unsigned long vaddr, int enable)
478 pte = lookup_address(vaddr);
481 if (!pte_exec_kernel(*pte))
485 pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
487 pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
496 * paging_init() sets up the page tables - note that the first 8MB are
497 * already mapped by head.S.
499 * This routines also unmaps the page at virtual kernel address 0, so
500 * that we can trap those pesky NULL-reference errors in the kernel.
502 void __init paging_init(void)
504 #ifdef CONFIG_X86_PAE
507 printk("NX (Execute Disable) protection: active\n");
512 load_cr3(swapper_pg_dir);
514 #ifdef CONFIG_X86_PAE
516 * We will bail out later - printk doesn't work right now so
517 * the user would just see a hanging kernel.
520 set_in_cr4(X86_CR4_PAE);
528 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
529 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
530 * used to involve black magic jumps to work around some nasty CPU bugs,
531 * but fortunately the switch to using exceptions got rid of all that.
534 static void __init test_wp_bit(void)
536 printk("Checking if this processor honours the WP bit even in supervisor mode... ");
538 /* Any page-aligned address will do, the test is non-destructive */
539 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
540 boot_cpu_data.wp_works_ok = do_test_wp_bit();
541 clear_fixmap(FIX_WP_TEST);
543 if (!boot_cpu_data.wp_works_ok) {
545 #ifdef CONFIG_X86_WP_WORKS_OK
546 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
553 static void __init set_max_mapnr_init(void)
555 #ifdef CONFIG_HIGHMEM
556 num_physpages = highend_pfn;
558 num_physpages = max_low_pfn;
560 #ifdef CONFIG_FLATMEM
561 max_mapnr = num_physpages;
565 static struct kcore_list kcore_mem, kcore_vmalloc;
567 void __init mem_init(void)
569 extern int ppro_with_ram_bug(void);
570 int codesize, reservedpages, datasize, initsize;
574 #ifdef CONFIG_FLATMEM
579 bad_ppro = ppro_with_ram_bug();
581 #ifdef CONFIG_HIGHMEM
582 /* check that fixmap and pkmap do not overlap */
583 if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
584 printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
585 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
586 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
591 set_max_mapnr_init();
593 #ifdef CONFIG_HIGHMEM
594 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
596 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
599 /* this will put all low memory onto the freelists */
600 totalram_pages += free_all_bootmem();
603 for (tmp = 0; tmp < max_low_pfn; tmp++)
605 * Only count reserved RAM pages
607 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
610 set_highmem_pages_init(bad_ppro);
612 codesize = (unsigned long) &_etext - (unsigned long) &_text;
613 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
614 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
616 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
617 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
618 VMALLOC_END-VMALLOC_START);
620 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
621 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
622 num_physpages << (PAGE_SHIFT-10),
624 reservedpages << (PAGE_SHIFT-10),
627 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
630 #ifdef CONFIG_X86_PAE
632 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
634 if (boot_cpu_data.wp_works_ok < 0)
638 * Subtle. SMP is doing it's boot stuff late (because it has to
639 * fork idle threads) - but it also needs low mappings for the
640 * protected-mode entry to work. We zap these entries only after
641 * the WP-bit has been tested.
649 * this is for the non-NUMA, single node SMP system case.
650 * Specifically, in the case of x86, we will always add
651 * memory to the highmem for now.
653 #ifndef CONFIG_NEED_MULTIPLE_NODES
654 int add_memory(u64 start, u64 size)
656 struct pglist_data *pgdata = &contig_page_data;
657 struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
658 unsigned long start_pfn = start >> PAGE_SHIFT;
659 unsigned long nr_pages = size >> PAGE_SHIFT;
661 return __add_pages(zone, start_pfn, nr_pages);
664 int remove_memory(u64 start, u64 size)
670 kmem_cache_t *pgd_cache;
671 kmem_cache_t *pmd_cache;
673 void __init pgtable_cache_init(void)
675 if (PTRS_PER_PMD > 1) {
676 pmd_cache = kmem_cache_create("pmd",
677 PTRS_PER_PMD*sizeof(pmd_t),
678 PTRS_PER_PMD*sizeof(pmd_t),
683 panic("pgtable_cache_init(): cannot create pmd cache");
685 pgd_cache = kmem_cache_create("pgd",
686 PTRS_PER_PGD*sizeof(pgd_t),
687 PTRS_PER_PGD*sizeof(pgd_t),
690 PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
692 panic("pgtable_cache_init(): Cannot create pgd cache");
696 * This function cannot be __init, since exceptions don't work in that
697 * section. Put this after the callers, so that it cannot be inlined.
699 static int noinline do_test_wp_bit(void)
704 __asm__ __volatile__(
709 ".section __ex_table,\"a\"\n"
713 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
722 void free_initmem(void)
726 addr = (unsigned long)(&__init_begin);
727 for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
728 ClearPageReserved(virt_to_page(addr));
729 set_page_count(virt_to_page(addr), 1);
730 memset((void *)addr, 0xcc, PAGE_SIZE);
734 printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10);
737 #ifdef CONFIG_BLK_DEV_INITRD
738 void free_initrd_mem(unsigned long start, unsigned long end)
741 printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
742 for (; start < end; start += PAGE_SIZE) {
743 ClearPageReserved(virt_to_page(start));
744 set_page_count(virt_to_page(start), 1);