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>
31 #include <linux/initrd.h>
32 #include <linux/dma-mapping.h>
33 #include <linux/scatterlist.h>
35 #include <asm/processor.h>
36 #include <asm/system.h>
37 #include <asm/uaccess.h>
38 #include <asm/pgtable.h>
40 #include <asm/fixmap.h>
44 #include <asm/tlbflush.h>
45 #include <asm/sections.h>
46 #include <asm/hypervisor.h>
47 #include <asm/swiotlb.h>
49 extern unsigned long *contiguous_bitmap;
51 unsigned int __VMALLOC_RESERVE = 128 << 20;
53 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
54 unsigned long highstart_pfn, highend_pfn;
56 static int noinline do_test_wp_bit(void);
59 * Creates a middle page table and puts a pointer to it in the
60 * given global directory entry. This only returns the gd entry
61 * in non-PAE compilation mode, since the middle layer is folded.
63 static pmd_t * __init one_md_table_init(pgd_t *pgd)
69 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
70 make_lowmem_page_readonly(pmd_table, XENFEAT_writable_page_tables);
71 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
72 pud = pud_offset(pgd, 0);
73 if (pmd_table != pmd_offset(pud, 0))
76 pud = pud_offset(pgd, 0);
77 pmd_table = pmd_offset(pud, 0);
84 * Create a page table and place a pointer to it in a middle page
87 static pte_t * __init one_page_table_init(pmd_t *pmd)
90 pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
91 make_lowmem_page_readonly(page_table,
92 XENFEAT_writable_page_tables);
93 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
94 if (page_table != pte_offset_kernel(pmd, 0))
100 return pte_offset_kernel(pmd, 0);
104 * This function initializes a certain range of kernel virtual memory
105 * with new bootmem page tables, everywhere page tables are missing in
110 * NOTE: The pagetables are allocated contiguous on the physical space
111 * so we can cache the place of the first one and move around without
112 * checking the pgd every time.
114 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
119 int pgd_idx, pmd_idx;
123 pgd_idx = pgd_index(vaddr);
124 pmd_idx = pmd_index(vaddr);
125 pgd = pgd_base + pgd_idx;
127 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
129 one_md_table_init(pgd);
130 pud = pud_offset(pgd, vaddr);
131 pmd = pmd_offset(pud, vaddr);
132 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
133 if (vaddr < HYPERVISOR_VIRT_START && pmd_none(*pmd))
134 one_page_table_init(pmd);
142 static inline int is_kernel_text(unsigned long addr)
144 if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
150 * This maps the physical memory to kernel virtual address space, a total
151 * of max_low_pfn pages, by creating page tables starting from address
154 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
160 int pgd_idx, pmd_idx, pte_ofs;
162 unsigned long max_ram_pfn = xen_start_info->nr_pages;
163 if (max_ram_pfn > max_low_pfn)
164 max_ram_pfn = max_low_pfn;
166 pgd_idx = pgd_index(PAGE_OFFSET);
167 pgd = pgd_base + pgd_idx;
169 pmd_idx = pmd_index(PAGE_OFFSET);
170 pte_ofs = pte_index(PAGE_OFFSET);
172 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
175 * Native linux hasn't PAE-paging enabled yet at this
176 * point. When running as xen domain we are in PAE
177 * mode already, thus we can't simply hook a empty
178 * pmd. That would kill the mappings we are currently
181 pmd = pmd_offset(pud_offset(pgd, PAGE_OFFSET), PAGE_OFFSET);
183 pmd = one_md_table_init(pgd);
185 if (pfn >= max_low_pfn)
188 for (; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
189 unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
190 if (address >= HYPERVISOR_VIRT_START)
193 /* Map with big pages if possible, otherwise create normal page tables. */
195 unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
197 if (is_kernel_text(address) || is_kernel_text(address2))
198 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
200 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
203 pte = one_page_table_init(pmd);
206 for (; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
207 /* XEN: Only map initial RAM allocation. */
208 if ((pfn >= max_ram_pfn) || pte_present(*pte))
210 if (is_kernel_text(address))
211 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
213 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
224 static inline int page_kills_ppro(unsigned long pagenr)
226 if (pagenr >= 0x70000 && pagenr <= 0x7003F)
233 #define page_kills_ppro(p) 0
237 extern int is_available_memory(efi_memory_desc_t *);
239 int page_is_ram(unsigned long pagenr)
242 unsigned long addr, end;
245 efi_memory_desc_t *md;
248 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
250 if (!is_available_memory(md))
252 addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
253 end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
255 if ((pagenr >= addr) && (pagenr < end))
261 for (i = 0; i < e820.nr_map; i++) {
263 if (e820.map[i].type != E820_RAM) /* not usable memory */
266 * !!!FIXME!!! Some BIOSen report areas as RAM that
267 * are not. Notably the 640->1Mb area. We need a sanity
270 addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
271 end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
272 if ((pagenr >= addr) && (pagenr < end))
278 int devmem_is_allowed(unsigned long pagenr)
282 if (!page_is_ram(pagenr))
287 EXPORT_SYMBOL_GPL(page_is_ram);
289 #ifdef CONFIG_HIGHMEM
293 #define kmap_get_fixmap_pte(vaddr) \
294 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
296 static void __init kmap_init(void)
298 unsigned long kmap_vstart;
300 /* cache the first kmap pte */
301 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
302 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
304 kmap_prot = PAGE_KERNEL;
307 static void __init permanent_kmaps_init(pgd_t *pgd_base)
316 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
318 pgd = swapper_pg_dir + pgd_index(vaddr);
319 pud = pud_offset(pgd, vaddr);
320 pmd = pmd_offset(pud, vaddr);
321 pte = pte_offset_kernel(pmd, vaddr);
322 pkmap_page_table = pte;
325 static void __meminit free_new_highpage(struct page *page, int pfn)
327 init_page_count(page);
328 if (pfn < xen_start_info->nr_pages)
333 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
335 if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
336 ClearPageReserved(page);
337 free_new_highpage(page, pfn);
339 SetPageReserved(page);
342 static int add_one_highpage_hotplug(struct page *page, unsigned long pfn)
344 free_new_highpage(page, pfn);
346 #ifdef CONFIG_FLATMEM
347 max_mapnr = max(pfn, max_mapnr);
354 * Not currently handling the NUMA case.
355 * Assuming single node and all memory that
356 * has been added dynamically that would be
357 * onlined here is in HIGHMEM
359 void online_page(struct page *page)
361 ClearPageReserved(page);
362 add_one_highpage_hotplug(page, page_to_pfn(page));
367 extern void set_highmem_pages_init(int);
369 static void __init set_highmem_pages_init(int bad_ppro)
372 for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
373 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
374 totalram_pages += totalhigh_pages;
376 #endif /* CONFIG_FLATMEM */
379 #define kmap_init() do { } while (0)
380 #define permanent_kmaps_init(pgd_base) do { } while (0)
381 #define set_highmem_pages_init(bad_ppro) do { } while (0)
382 #endif /* CONFIG_HIGHMEM */
384 unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
385 EXPORT_SYMBOL(__PAGE_KERNEL);
386 unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
389 extern void __init remap_numa_kva(void);
391 #define remap_numa_kva() do {} while (0)
394 pgd_t *swapper_pg_dir;
396 static void __init pagetable_init (void)
399 pgd_t *pgd_base = (pgd_t *)xen_start_info->pt_base;
401 swapper_pg_dir = pgd_base;
402 init_mm.pgd = pgd_base;
404 /* Enable PSE if available */
406 set_in_cr4(X86_CR4_PSE);
409 /* Enable PGE if available */
411 set_in_cr4(X86_CR4_PGE);
412 __PAGE_KERNEL |= _PAGE_GLOBAL;
413 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
416 kernel_physical_mapping_init(pgd_base);
420 * Fixed mappings, only the page table structure has to be
421 * created - mappings will be set by set_fixmap():
423 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
424 page_table_range_init(vaddr, 0, pgd_base);
426 permanent_kmaps_init(pgd_base);
429 #ifdef CONFIG_SOFTWARE_SUSPEND
431 * Swap suspend & friends need this for resume because things like the intel-agp
432 * driver might have split up a kernel 4MB mapping.
434 char __nosavedata swsusp_pg_dir[PAGE_SIZE]
435 __attribute__ ((aligned (PAGE_SIZE)));
437 static inline void save_pg_dir(void)
439 memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
442 static inline void save_pg_dir(void)
447 void zap_low_mappings (void)
454 * Zap initial low-memory mappings.
456 * Note that "pgd_clear()" doesn't do it for
457 * us, because pgd_clear() is a no-op on i386.
459 for (i = 0; i < USER_PTRS_PER_PGD; i++)
460 #if defined(CONFIG_X86_PAE) && !defined(CONFIG_XEN)
461 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
463 set_pgd(swapper_pg_dir+i, __pgd(0));
468 static int disable_nx __initdata = 0;
469 u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
470 EXPORT_SYMBOL(__supported_pte_mask);
475 * Control non executable mappings.
478 * off Disable (disables exec-shield too)
480 void __init noexec_setup(const char *str)
482 if (!strncmp(str, "on",2) && cpu_has_nx) {
483 __supported_pte_mask |= _PAGE_NX;
485 } else if (!strncmp(str,"off",3)) {
487 __supported_pte_mask &= ~_PAGE_NX;
493 #ifdef CONFIG_X86_PAE
495 static void __init set_nx(void)
497 unsigned int v[4], l, h;
499 if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
500 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
501 if ((v[3] & (1 << 20)) && !disable_nx) {
502 rdmsr(MSR_EFER, l, h);
504 wrmsr(MSR_EFER, l, h);
506 __supported_pte_mask |= _PAGE_NX;
512 * Enables/disables executability of a given kernel page and
513 * returns the previous setting.
515 int __init set_kernel_exec(unsigned long vaddr, int enable)
523 pte = lookup_address(vaddr);
526 if (!pte_exec_kernel(*pte))
530 pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
532 pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
541 * paging_init() sets up the page tables - note that the first 8MB are
542 * already mapped by head.S.
544 * This routines also unmaps the page at virtual kernel address 0, so
545 * that we can trap those pesky NULL-reference errors in the kernel.
547 void __init paging_init(void)
551 #ifdef CONFIG_X86_PAE
554 printk("NX (Execute Disable) protection: active\n");
558 printk("Using x86 segment limits to approximate NX protection\n");
562 #if defined(CONFIG_X86_PAE) && !defined(CONFIG_XEN)
564 * We will bail out later - printk doesn't work right now so
565 * the user would just see a hanging kernel.
566 * when running as xen domain we are already in PAE mode at
570 set_in_cr4(X86_CR4_PAE);
576 /* Switch to the real shared_info page, and clear the
578 set_fixmap(FIX_SHARED_INFO, xen_start_info->shared_info);
579 HYPERVISOR_shared_info = (shared_info_t *)fix_to_virt(FIX_SHARED_INFO);
580 memset(empty_zero_page, 0, sizeof(empty_zero_page));
582 /* Setup mapping of lower 1st MB */
583 for (i = 0; i < NR_FIX_ISAMAPS; i++)
584 if (xen_start_info->flags & SIF_PRIVILEGED)
585 set_fixmap(FIX_ISAMAP_BEGIN - i, i * PAGE_SIZE);
587 __set_fixmap(FIX_ISAMAP_BEGIN - i,
588 virt_to_machine(empty_zero_page),
593 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
594 * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
595 * used to involve black magic jumps to work around some nasty CPU bugs,
596 * but fortunately the switch to using exceptions got rid of all that.
599 static void __init test_wp_bit(void)
601 printk("Checking if this processor honours the WP bit even in supervisor mode... ");
603 /* Any page-aligned address will do, the test is non-destructive */
604 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
605 boot_cpu_data.wp_works_ok = do_test_wp_bit();
606 clear_fixmap(FIX_WP_TEST);
608 if (!boot_cpu_data.wp_works_ok) {
610 #ifdef CONFIG_X86_WP_WORKS_OK
611 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
618 static void __init set_max_mapnr_init(void)
620 #ifdef CONFIG_HIGHMEM
621 num_physpages = highend_pfn;
623 num_physpages = max_low_pfn;
625 #ifdef CONFIG_FLATMEM
626 max_mapnr = num_physpages;
630 static struct kcore_list kcore_mem, kcore_vmalloc;
632 void __init mem_init(void)
634 extern int ppro_with_ram_bug(void);
635 int codesize, reservedpages, datasize, initsize;
640 contiguous_bitmap = alloc_bootmem_low_pages(
641 (max_low_pfn + 2*BITS_PER_LONG) >> 3);
642 BUG_ON(!contiguous_bitmap);
643 memset(contiguous_bitmap, 0, (max_low_pfn + 2*BITS_PER_LONG) >> 3);
645 #if defined(CONFIG_SWIOTLB)
649 #ifdef CONFIG_FLATMEM
654 bad_ppro = ppro_with_ram_bug();
656 #ifdef CONFIG_HIGHMEM
657 /* check that fixmap and pkmap do not overlap */
658 if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
659 printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
660 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
661 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
666 set_max_mapnr_init();
668 #ifdef CONFIG_HIGHMEM
669 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
671 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
673 printk("vmalloc area: %lx-%lx, maxmem %lx\n",
674 VMALLOC_START,VMALLOC_END,MAXMEM);
675 BUG_ON(VMALLOC_START > VMALLOC_END);
677 /* this will put all low memory onto the freelists */
678 totalram_pages += free_all_bootmem();
679 /* XEN: init and count low-mem pages outside initial allocation. */
680 for (pfn = xen_start_info->nr_pages; pfn < max_low_pfn; pfn++) {
681 ClearPageReserved(&mem_map[pfn]);
682 init_page_count(&mem_map[pfn]);
687 for (tmp = 0; tmp < max_low_pfn; tmp++)
689 * Only count reserved RAM pages
691 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
694 set_highmem_pages_init(bad_ppro);
696 codesize = (unsigned long) &_etext - (unsigned long) &_text;
697 datasize = (unsigned long) &_edata - (unsigned long) &_etext;
698 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
700 kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
701 kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
702 VMALLOC_END-VMALLOC_START);
704 printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
705 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
706 num_physpages << (PAGE_SHIFT-10),
708 reservedpages << (PAGE_SHIFT-10),
711 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
714 #ifdef CONFIG_X86_PAE
716 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
718 if (boot_cpu_data.wp_works_ok < 0)
722 * Subtle. SMP is doing it's boot stuff late (because it has to
723 * fork idle threads) - but it also needs low mappings for the
724 * protected-mode entry to work. We zap these entries only after
725 * the WP-bit has been tested.
731 set_bit(PG_pinned, &virt_to_page(init_mm.pgd)->flags);
735 * this is for the non-NUMA, single node SMP system case.
736 * Specifically, in the case of x86, we will always add
737 * memory to the highmem for now.
739 #ifdef CONFIG_MEMORY_HOTPLUG
740 #ifndef CONFIG_NEED_MULTIPLE_NODES
741 int add_memory(u64 start, u64 size)
743 struct pglist_data *pgdata = &contig_page_data;
744 struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
745 unsigned long start_pfn = start >> PAGE_SHIFT;
746 unsigned long nr_pages = size >> PAGE_SHIFT;
748 return __add_pages(zone, start_pfn, nr_pages);
751 int remove_memory(u64 start, u64 size)
758 kmem_cache_t *pgd_cache;
759 kmem_cache_t *pmd_cache;
761 void __init pgtable_cache_init(void)
763 if (PTRS_PER_PMD > 1) {
764 pmd_cache = kmem_cache_create("pmd",
765 PTRS_PER_PMD*sizeof(pmd_t),
766 PTRS_PER_PMD*sizeof(pmd_t),
771 panic("pgtable_cache_init(): cannot create pmd cache");
773 pgd_cache = kmem_cache_create("pgd",
775 PTRS_PER_PGD*sizeof(pgd_t),
776 PTRS_PER_PGD*sizeof(pgd_t),
783 PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
785 panic("pgtable_cache_init(): Cannot create pgd cache");
789 * This function cannot be __init, since exceptions don't work in that
790 * section. Put this after the callers, so that it cannot be inlined.
792 static int noinline do_test_wp_bit(void)
797 __asm__ __volatile__(
802 ".section __ex_table,\"a\"\n"
806 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
815 #ifdef CONFIG_DEBUG_RODATA
817 extern char __start_rodata, __end_rodata;
818 void mark_rodata_ro(void)
820 unsigned long addr = (unsigned long)&__start_rodata;
822 for (; addr < (unsigned long)&__end_rodata; addr += PAGE_SIZE)
823 change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
825 printk ("Write protecting the kernel read-only data: %luk\n",
826 (unsigned long)(&__end_rodata - &__start_rodata) >> 10);
829 * change_page_attr() requires a global_flush_tlb() call after it.
830 * We do this after the printk so that if something went wrong in the
831 * change, the printk gets out at least to give a better debug hint
832 * of who is the culprit.
838 void free_init_pages(char *what, unsigned long begin, unsigned long end)
842 for (addr = begin; addr < end; addr += PAGE_SIZE) {
843 ClearPageReserved(virt_to_page(addr));
844 init_page_count(virt_to_page(addr));
845 memset((void *)addr, 0xcc, PAGE_SIZE);
849 printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
852 void free_initmem(void)
854 free_init_pages("unused kernel memory",
855 (unsigned long)(&__init_begin),
856 (unsigned long)(&__init_end));
859 #ifdef CONFIG_BLK_DEV_INITRD
860 void free_initrd_mem(unsigned long start, unsigned long end)
862 free_init_pages("initrd memory", start, end);