/* * linux/arch/i386/mm/init.c * * Copyright (C) 1995 Linus Torvalds * * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include unsigned int __VMALLOC_RESERVE = 128 << 20; DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); unsigned long highstart_pfn, highend_pfn; static int noinline do_test_wp_bit(void); /* * Creates a middle page table and puts a pointer to it in the * given global directory entry. This only returns the gd entry * in non-PAE compilation mode, since the middle layer is folded. */ static pmd_t * __init one_md_table_init(pgd_t *pgd) { pud_t *pud; pmd_t *pmd_table; #ifdef CONFIG_X86_PAE pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE); set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); pud = pud_offset(pgd, 0); if (pmd_table != pmd_offset(pud, 0)) BUG(); #else pud = pud_offset(pgd, 0); pmd_table = pmd_offset(pud, 0); #endif return pmd_table; } /* * Create a page table and place a pointer to it in a middle page * directory entry. */ static pte_t * __init one_page_table_init(pmd_t *pmd) { if (pmd_none(*pmd)) { pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); if (page_table != pte_offset_kernel(pmd, 0)) BUG(); return page_table; } return pte_offset_kernel(pmd, 0); } /* * This function initializes a certain range of kernel virtual memory * with new bootmem page tables, everywhere page tables are missing in * the given range. */ /* * NOTE: The pagetables are allocated contiguous on the physical space * so we can cache the place of the first one and move around without * checking the pgd every time. */ static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; int pgd_idx, pmd_idx; unsigned long vaddr; vaddr = start; pgd_idx = pgd_index(vaddr); pmd_idx = pmd_index(vaddr); pgd = pgd_base + pgd_idx; for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { if (pgd_none(*pgd)) one_md_table_init(pgd); pud = pud_offset(pgd, vaddr); pmd = pmd_offset(pud, vaddr); for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) { if (pmd_none(*pmd)) one_page_table_init(pmd); vaddr += PMD_SIZE; } pmd_idx = 0; } } static inline int is_kernel_text(unsigned long addr) { if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end) return 1; return 0; } /* * This maps the physical memory to kernel virtual address space, a total * of max_low_pfn pages, by creating page tables starting from address * PAGE_OFFSET. */ static void __init kernel_physical_mapping_init(pgd_t *pgd_base) { unsigned long pfn; pgd_t *pgd; pmd_t *pmd; pte_t *pte; int pgd_idx, pmd_idx, pte_ofs; pgd_idx = pgd_index(PAGE_OFFSET); pgd = pgd_base + pgd_idx; pfn = 0; for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { pmd = one_md_table_init(pgd); if (pfn >= max_low_pfn) continue; for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) { unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET; /* Map with big pages if possible, otherwise create normal page tables. */ if (cpu_has_pse) { unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1; if (is_kernel_text(address) || is_kernel_text(address2)) set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC)); else set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE)); pfn += PTRS_PER_PTE; } else { pte = one_page_table_init(pmd); for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) { if (is_kernel_text(address)) set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); else set_pte(pte, pfn_pte(pfn, PAGE_KERNEL)); } } } } } static inline int page_kills_ppro(unsigned long pagenr) { if (pagenr >= 0x70000 && pagenr <= 0x7003F) return 1; return 0; } int page_is_ram(unsigned long pagenr) { int i; unsigned long addr, end; if (efi_enabled) { efi_memory_desc_t *md; void *p; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if (!is_available_memory(md)) continue; addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT; end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT; if ((pagenr >= addr) && (pagenr < end)) return 1; } return 0; } for (i = 0; i < e820.nr_map; i++) { if (e820.map[i].type != E820_RAM) /* not usable memory */ continue; /* * !!!FIXME!!! Some BIOSen report areas as RAM that * are not. Notably the 640->1Mb area. We need a sanity * check here. */ addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT; end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT; if ((pagenr >= addr) && (pagenr < end)) return 1; } return 0; } #ifdef CONFIG_HIGHMEM pte_t *kmap_pte; pgprot_t kmap_prot; #define kmap_get_fixmap_pte(vaddr) \ pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr)) static void __init kmap_init(void) { unsigned long kmap_vstart; /* cache the first kmap pte */ kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); kmap_pte = kmap_get_fixmap_pte(kmap_vstart); kmap_prot = PAGE_KERNEL; } static void __init permanent_kmaps_init(pgd_t *pgd_base) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; unsigned long vaddr; vaddr = PKMAP_BASE; page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); pgd = swapper_pg_dir + pgd_index(vaddr); pud = pud_offset(pgd, vaddr); pmd = pmd_offset(pud, vaddr); pte = pte_offset_kernel(pmd, vaddr); pkmap_page_table = pte; } static void __meminit free_new_highpage(struct page *page) { init_page_count(page); __free_page(page); totalhigh_pages++; } void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro) { if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) { ClearPageReserved(page); free_new_highpage(page); } else SetPageReserved(page); } static int add_one_highpage_hotplug(struct page *page, unsigned long pfn) { free_new_highpage(page); totalram_pages++; #ifdef CONFIG_FLATMEM max_mapnr = max(pfn, max_mapnr); #endif num_physpages++; return 0; } /* * Not currently handling the NUMA case. * Assuming single node and all memory that * has been added dynamically that would be * onlined here is in HIGHMEM */ void online_page(struct page *page) { ClearPageReserved(page); add_one_highpage_hotplug(page, page_to_pfn(page)); } #ifdef CONFIG_NUMA extern void set_highmem_pages_init(int); #else static void __init set_highmem_pages_init(int bad_ppro) { int pfn; for (pfn = highstart_pfn; pfn < highend_pfn; pfn++) add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro); totalram_pages += totalhigh_pages; } #endif /* CONFIG_FLATMEM */ #else #define kmap_init() do { } while (0) #define permanent_kmaps_init(pgd_base) do { } while (0) #define set_highmem_pages_init(bad_ppro) do { } while (0) #endif /* CONFIG_HIGHMEM */ unsigned long long __PAGE_KERNEL = _PAGE_KERNEL; EXPORT_SYMBOL(__PAGE_KERNEL); unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC; #ifdef CONFIG_NUMA extern void __init remap_numa_kva(void); #else #define remap_numa_kva() do {} while (0) #endif static void __init pagetable_init (void) { unsigned long vaddr; pgd_t *pgd_base = swapper_pg_dir; #ifdef CONFIG_X86_PAE int i; /* Init entries of the first-level page table to the zero page */ for (i = 0; i < PTRS_PER_PGD; i++) set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT)); #endif /* Enable PSE if available */ if (cpu_has_pse) { set_in_cr4(X86_CR4_PSE); } /* Enable PGE if available */ if (cpu_has_pge) { set_in_cr4(X86_CR4_PGE); __PAGE_KERNEL |= _PAGE_GLOBAL; __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL; } kernel_physical_mapping_init(pgd_base); remap_numa_kva(); /* * Fixed mappings, only the page table structure has to be * created - mappings will be set by set_fixmap(): */ vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; page_table_range_init(vaddr, 0, pgd_base); permanent_kmaps_init(pgd_base); #ifdef CONFIG_X86_PAE /* * Add low memory identity-mappings - SMP needs it when * starting up on an AP from real-mode. In the non-PAE * case we already have these mappings through head.S. * All user-space mappings are explicitly cleared after * SMP startup. */ set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]); #endif } #if defined(CONFIG_SOFTWARE_SUSPEND) || defined(CONFIG_ACPI_SLEEP) /* * Swap suspend & friends need this for resume because things like the intel-agp * driver might have split up a kernel 4MB mapping. */ char __nosavedata swsusp_pg_dir[PAGE_SIZE] __attribute__ ((aligned (PAGE_SIZE))); static inline void save_pg_dir(void) { memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE); } #else static inline void save_pg_dir(void) { } #endif void zap_low_mappings (void) { int i; save_pg_dir(); /* * Zap initial low-memory mappings. * * Note that "pgd_clear()" doesn't do it for * us, because pgd_clear() is a no-op on i386. */ for (i = 0; i < USER_PTRS_PER_PGD; i++) #ifdef CONFIG_X86_PAE set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page))); #else set_pgd(swapper_pg_dir+i, __pgd(0)); #endif flush_tlb_all(); } static int disable_nx __initdata = 0; u64 __supported_pte_mask __read_mostly = ~_PAGE_NX; /* * noexec = on|off * * Control non executable mappings. * * on Enable * off Disable */ static int __init noexec_setup(char *str) { if (!str || !strcmp(str, "on")) { if (cpu_has_nx) { __supported_pte_mask |= _PAGE_NX; disable_nx = 0; } } else if (!strcmp(str,"off")) { disable_nx = 1; __supported_pte_mask &= ~_PAGE_NX; } else return -EINVAL; return 0; } early_param("noexec", noexec_setup); int nx_enabled = 0; #ifdef CONFIG_X86_PAE static void __init set_nx(void) { unsigned int v[4], l, h; if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) { cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]); if ((v[3] & (1 << 20)) && !disable_nx) { rdmsr(MSR_EFER, l, h); l |= EFER_NX; wrmsr(MSR_EFER, l, h); nx_enabled = 1; __supported_pte_mask |= _PAGE_NX; } } } /* * Enables/disables executability of a given kernel page and * returns the previous setting. */ int __init set_kernel_exec(unsigned long vaddr, int enable) { pte_t *pte; int ret = 1; if (!nx_enabled) goto out; pte = lookup_address(vaddr); BUG_ON(!pte); if (!pte_exec_kernel(*pte)) ret = 0; if (enable) pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32)); else pte->pte_high |= 1 << (_PAGE_BIT_NX - 32); pte_update_defer(&init_mm, vaddr, pte); __flush_tlb_all(); out: return ret; } #endif /* * paging_init() sets up the page tables - note that the first 8MB are * already mapped by head.S. * * This routines also unmaps the page at virtual kernel address 0, so * that we can trap those pesky NULL-reference errors in the kernel. */ void __init paging_init(void) { #ifdef CONFIG_X86_PAE set_nx(); if (nx_enabled) printk("NX (Execute Disable) protection: active\n"); #endif pagetable_init(); load_cr3(swapper_pg_dir); #ifdef CONFIG_X86_PAE /* * We will bail out later - printk doesn't work right now so * the user would just see a hanging kernel. */ if (cpu_has_pae) set_in_cr4(X86_CR4_PAE); #endif __flush_tlb_all(); kmap_init(); } /* * Test if the WP bit works in supervisor mode. It isn't supported on 386's * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This * used to involve black magic jumps to work around some nasty CPU bugs, * but fortunately the switch to using exceptions got rid of all that. */ static void __init test_wp_bit(void) { printk("Checking if this processor honours the WP bit even in supervisor mode... "); /* Any page-aligned address will do, the test is non-destructive */ __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY); boot_cpu_data.wp_works_ok = do_test_wp_bit(); clear_fixmap(FIX_WP_TEST); if (!boot_cpu_data.wp_works_ok) { printk("No.\n"); #ifdef CONFIG_X86_WP_WORKS_OK panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!"); #endif } else { printk("Ok.\n"); } } static struct kcore_list kcore_mem, kcore_vmalloc; void __init mem_init(void) { extern int ppro_with_ram_bug(void); int codesize, reservedpages, datasize, initsize; int tmp; int bad_ppro; #ifdef CONFIG_FLATMEM BUG_ON(!mem_map); #endif bad_ppro = ppro_with_ram_bug(); #ifdef CONFIG_HIGHMEM /* check that fixmap and pkmap do not overlap */ if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) { printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n"); printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n", PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START); BUG(); } #endif /* this will put all low memory onto the freelists */ totalram_pages += free_all_bootmem(); reservedpages = 0; for (tmp = 0; tmp < max_low_pfn; tmp++) /* * Only count reserved RAM pages */ if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp))) reservedpages++; set_highmem_pages_init(bad_ppro); codesize = (unsigned long) &_etext - (unsigned long) &_text; datasize = (unsigned long) &_edata - (unsigned long) &_etext; initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT); kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, VMALLOC_END-VMALLOC_START); printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n", (unsigned long) nr_free_pages() << (PAGE_SHIFT-10), num_physpages << (PAGE_SHIFT-10), codesize >> 10, reservedpages << (PAGE_SHIFT-10), datasize >> 10, initsize >> 10, (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)) ); #if 1 /* double-sanity-check paranoia */ printk("virtual kernel memory layout:\n" " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" #ifdef CONFIG_HIGHMEM " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" #endif " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", FIXADDR_START, FIXADDR_TOP, (FIXADDR_TOP - FIXADDR_START) >> 10, #ifdef CONFIG_HIGHMEM PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, (LAST_PKMAP*PAGE_SIZE) >> 10, #endif VMALLOC_START, VMALLOC_END, (VMALLOC_END - VMALLOC_START) >> 20, (unsigned long)__va(0), (unsigned long)high_memory, ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, (unsigned long)&__init_begin, (unsigned long)&__init_end, ((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10, (unsigned long)&_etext, (unsigned long)&_edata, ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, (unsigned long)&_text, (unsigned long)&_etext, ((unsigned long)&_etext - (unsigned long)&_text) >> 10); #ifdef CONFIG_HIGHMEM BUG_ON(PKMAP_BASE+LAST_PKMAP*PAGE_SIZE > FIXADDR_START); BUG_ON(VMALLOC_END > PKMAP_BASE); #endif BUG_ON(VMALLOC_START > VMALLOC_END); BUG_ON((unsigned long)high_memory > VMALLOC_START); #endif /* double-sanity-check paranoia */ #ifdef CONFIG_X86_PAE if (!cpu_has_pae) panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!"); #endif if (boot_cpu_data.wp_works_ok < 0) test_wp_bit(); /* * Subtle. SMP is doing it's boot stuff late (because it has to * fork idle threads) - but it also needs low mappings for the * protected-mode entry to work. We zap these entries only after * the WP-bit has been tested. */ #ifndef CONFIG_SMP zap_low_mappings(); #endif } /* * this is for the non-NUMA, single node SMP system case. * Specifically, in the case of x86, we will always add * memory to the highmem for now. */ #ifdef CONFIG_MEMORY_HOTPLUG #ifndef CONFIG_NEED_MULTIPLE_NODES int arch_add_memory(int nid, u64 start, u64 size) { struct pglist_data *pgdata = &contig_page_data; struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; return __add_pages(zone, start_pfn, nr_pages); } int remove_memory(u64 start, u64 size) { return -EINVAL; } #endif #endif kmem_cache_t *pgd_cache; kmem_cache_t *pmd_cache; void __init pgtable_cache_init(void) { if (PTRS_PER_PMD > 1) { pmd_cache = kmem_cache_create("pmd", PTRS_PER_PMD*sizeof(pmd_t), PTRS_PER_PMD*sizeof(pmd_t), 0, pmd_ctor, NULL); if (!pmd_cache) panic("pgtable_cache_init(): cannot create pmd cache"); } pgd_cache = kmem_cache_create("pgd", PTRS_PER_PGD*sizeof(pgd_t), PTRS_PER_PGD*sizeof(pgd_t), 0, pgd_ctor, PTRS_PER_PMD == 1 ? pgd_dtor : NULL); if (!pgd_cache) panic("pgtable_cache_init(): Cannot create pgd cache"); } /* * This function cannot be __init, since exceptions don't work in that * section. Put this after the callers, so that it cannot be inlined. */ static int noinline do_test_wp_bit(void) { char tmp_reg; int flag; __asm__ __volatile__( " movb %0,%1 \n" "1: movb %1,%0 \n" " xorl %2,%2 \n" "2: \n" ".section __ex_table,\"a\"\n" " .align 4 \n" " .long 1b,2b \n" ".previous \n" :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), "=q" (tmp_reg), "=r" (flag) :"2" (1) :"memory"); return flag; } #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void) { unsigned long addr = (unsigned long)__start_rodata; for (; addr < (unsigned long)__end_rodata; addr += PAGE_SIZE) change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO); printk("Write protecting the kernel read-only data: %uk\n", (__end_rodata - __start_rodata) >> 10); /* * change_page_attr() requires a global_flush_tlb() call after it. * We do this after the printk so that if something went wrong in the * change, the printk gets out at least to give a better debug hint * of who is the culprit. */ global_flush_tlb(); } #endif void free_init_pages(char *what, unsigned long begin, unsigned long end) { unsigned long addr; for (addr = begin; addr < end; addr += PAGE_SIZE) { ClearPageReserved(virt_to_page(addr)); init_page_count(virt_to_page(addr)); memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); free_page(addr); totalram_pages++; } printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10); } void free_initmem(void) { free_init_pages("unused kernel memory", (unsigned long)(&__init_begin), (unsigned long)(&__init_end)); } #ifdef CONFIG_BLK_DEV_INITRD void free_initrd_mem(unsigned long start, unsigned long end) { free_init_pages("initrd memory", start, end); } #endif