/* * * 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 #include #include #include #include #include #include unsigned int __VMALLOC_RESERVE = 128 << 20; unsigned long max_pfn_mapped; DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); unsigned long highstart_pfn, highend_pfn; static noinline int 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 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE); paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); pud = pud_offset(pgd, 0); BUG_ON(pmd_table != pmd_offset(pud, 0)); } #endif pud = pud_offset(pgd, 0); pmd_table = pmd_offset(pud, 0); 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_val(*pmd) & _PAGE_PRESENT)) { pte_t *page_table = NULL; #ifdef CONFIG_DEBUG_PAGEALLOC page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE); #endif if (!page_table) { page_table = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE); } paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); BUG_ON(page_table != pte_offset_kernel(pmd, 0)); } 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) { int pgd_idx, pmd_idx; unsigned long vaddr; pgd_t *pgd; pmd_t *pmd; 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++) { pmd = one_md_table_init(pgd); pmd = pmd + pmd_index(vaddr); for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) { 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) { int pgd_idx, pmd_idx, pte_ofs; unsigned long pfn; pgd_t *pgd; pmd_t *pmd; pte_t *pte; 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 addr = pfn * PAGE_SIZE + PAGE_OFFSET; /* * Map with big pages if possible, otherwise * create normal page tables: * * Don't use a large page for the first 2/4MB of memory * because there are often fixed size MTRRs in there * and overlapping MTRRs into large pages can cause * slowdowns. */ if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) { unsigned int addr2; pgprot_t prot = PAGE_KERNEL_LARGE; addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1; if (is_kernel_text(addr) || is_kernel_text(addr2)) prot = PAGE_KERNEL_LARGE_EXEC; set_pmd(pmd, pfn_pmd(pfn, prot)); pfn += PTRS_PER_PTE; max_pfn_mapped = pfn; continue; } pte = one_page_table_init(pmd); for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { pgprot_t prot = PAGE_KERNEL; if (is_kernel_text(addr)) prot = PAGE_KERNEL_EXEC; set_pte(pte, pfn_pte(pfn, prot)); } max_pfn_mapped = pfn; } } } static inline int page_kills_ppro(unsigned long pagenr) { if (pagenr >= 0x70000 && pagenr <= 0x7003F) return 1; return 0; } /* * devmem_is_allowed() checks to see if /dev/mem access to a certain address * is valid. The argument is a physical page number. * * * On x86, access has to be given to the first megabyte of ram because that area * contains bios code and data regions used by X and dosemu and similar apps. * Access has to be given to non-kernel-ram areas as well, these contain the PCI * mmio resources as well as potential bios/acpi data regions. */ int devmem_is_allowed(unsigned long pagenr) { if (pagenr <= 256) return 1; if (!page_is_ram(pagenr)) return 1; return 0; } #ifdef CONFIG_HIGHMEM pte_t *kmap_pte; pgprot_t kmap_prot; static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) { return 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) { unsigned long vaddr; pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; 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; } 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)) && !page_is_reserved_early(pfn)) { ClearPageReserved(page); init_page_count(page); __free_page(page); totalhigh_pages++; } else SetPageReserved(page); } #ifndef CONFIG_NUMA static void __init set_highmem_pages_init(int bad_ppro) { int pfn; for (pfn = highstart_pfn; pfn < highend_pfn; pfn++) { /* * Holes under sparsemem might not have no mem_map[]: */ if (pfn_valid(pfn)) add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro); } totalram_pages += totalhigh_pages; } #endif /* !CONFIG_NUMA */ #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 */ pteval_t __PAGE_KERNEL = _PAGE_KERNEL; EXPORT_SYMBOL(__PAGE_KERNEL); pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC; void __init native_pagetable_setup_start(pgd_t *base) { unsigned long pfn, va; pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; /* * Remove any mappings which extend past the end of physical * memory from the boot time page table: */ for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) { va = PAGE_OFFSET + (pfn<> PAGE_SHIFT); } void __init native_pagetable_setup_done(pgd_t *base) { } /* * Build a proper pagetable for the kernel mappings. Up until this * point, we've been running on some set of pagetables constructed by * the boot process. * * If we're booting on native hardware, this will be a pagetable * constructed in arch/x86/kernel/head_32.S. The root of the * pagetable will be swapper_pg_dir. * * If we're booting paravirtualized under a hypervisor, then there are * more options: we may already be running PAE, and the pagetable may * or may not be based in swapper_pg_dir. In any case, * paravirt_pagetable_setup_start() will set up swapper_pg_dir * appropriately for the rest of the initialization to work. * * In general, pagetable_init() assumes that the pagetable may already * be partially populated, and so it avoids stomping on any existing * mappings. */ static void __init pagetable_init(void) { pgd_t *pgd_base = swapper_pg_dir; unsigned long vaddr, end; paravirt_pagetable_setup_start(pgd_base); /* 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(): */ early_ioremap_clear(); vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; page_table_range_init(vaddr, end, pgd_base); early_ioremap_reset(); permanent_kmaps_init(pgd_base); paravirt_pagetable_setup_done(pgd_base); } #ifdef CONFIG_ACPI_SLEEP /* * ACPI suspend needs this for resume, because things like the intel-agp * driver might have split up a kernel 4MB mapping. */ char 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 /* !CONFIG_ACPI_SLEEP */ static inline void save_pg_dir(void) { } #endif /* !CONFIG_ACPI_SLEEP */ void zap_low_mappings(void) { int i; /* * 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 < KERNEL_PGD_BOUNDARY; 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(); } int nx_enabled; pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX; EXPORT_SYMBOL_GPL(__supported_pte_mask); #ifdef CONFIG_X86_PAE static int disable_nx __initdata; /* * 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); 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; } } } #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(KERN_INFO "NX (Execute Disable) protection: active\n"); #endif pagetable_init(); load_cr3(swapper_pg_dir); __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. 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(KERN_INFO "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(KERN_CONT "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(KERN_CONT "Ok.\n"); } } static struct kcore_list kcore_mem, kcore_vmalloc; void __init mem_init(void) { int codesize, reservedpages, datasize, initsize; int tmp, 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(KERN_INFO "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 */ if (boot_cpu_data.wp_works_ok < 0) test_wp_bit(); cpa_init(); save_pg_dir(); zap_low_mappings(); } #ifdef CONFIG_MEMORY_HOTPLUG int arch_add_memory(int nid, u64 start, u64 size) { struct pglist_data *pgdata = NODE_DATA(nid); 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); } #endif /* * 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 noinline int 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" _ASM_EXTABLE(1b,2b) :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), "=q" (tmp_reg), "=r" (flag) :"2" (1) :"memory"); return flag; } #ifdef CONFIG_DEBUG_RODATA const int rodata_test_data = 0xC3; EXPORT_SYMBOL_GPL(rodata_test_data); void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_text); unsigned long size = PFN_ALIGN(_etext) - start; set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); printk(KERN_INFO "Write protecting the kernel text: %luk\n", size >> 10); #ifdef CONFIG_CPA_DEBUG printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", start, start+size); set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); printk(KERN_INFO "Testing CPA: write protecting again\n"); set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); #endif start += size; size = (unsigned long)__end_rodata - start; set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", size >> 10); rodata_test(); #ifdef CONFIG_CPA_DEBUG printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); printk(KERN_INFO "Testing CPA: write protecting again\n"); set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); #endif } #endif void free_init_pages(char *what, unsigned long begin, unsigned long end) { #ifdef CONFIG_DEBUG_PAGEALLOC /* * If debugging page accesses then do not free this memory but * mark them not present - any buggy init-section access will * create a kernel page fault: */ printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n", begin, PAGE_ALIGN(end)); set_memory_np(begin, (end - begin) >> PAGE_SHIFT); #else unsigned long addr; /* * We just marked the kernel text read only above, now that * we are going to free part of that, we need to make that * writeable first. */ set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); 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: %luk freed\n", what, (end - begin) >> 10); #endif } 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 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len, int flags) { return reserve_bootmem(phys, len, flags); }