diff options
Diffstat (limited to 'arch/arm/mm/mmu.c')
| -rw-r--r-- | arch/arm/mm/mmu.c | 771 |
1 files changed, 771 insertions, 0 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c new file mode 100644 index 00000000000..e566cbe4b22 --- /dev/null +++ b/arch/arm/mm/mmu.c @@ -0,0 +1,771 @@ +/* + * linux/arch/arm/mm/mmu.c + * + * Copyright (C) 1995-2005 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/bootmem.h> +#include <linux/mman.h> +#include <linux/nodemask.h> + +#include <asm/mach-types.h> +#include <asm/setup.h> +#include <asm/sizes.h> +#include <asm/tlb.h> + +#include <asm/mach/arch.h> +#include <asm/mach/map.h> + +#include "mm.h" + +DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); + +extern void _stext, __data_start, _end; +extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; + +/* + * empty_zero_page is a special page that is used for + * zero-initialized data and COW. + */ +struct page *empty_zero_page; + +/* + * The pmd table for the upper-most set of pages. + */ +pmd_t *top_pmd; + +#define CPOLICY_UNCACHED 0 +#define CPOLICY_BUFFERED 1 +#define CPOLICY_WRITETHROUGH 2 +#define CPOLICY_WRITEBACK 3 +#define CPOLICY_WRITEALLOC 4 + +static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK; +static unsigned int ecc_mask __initdata = 0; +pgprot_t pgprot_kernel; + +EXPORT_SYMBOL(pgprot_kernel); + +struct cachepolicy { + const char policy[16]; + unsigned int cr_mask; + unsigned int pmd; + unsigned int pte; +}; + +static struct cachepolicy cache_policies[] __initdata = { + { + .policy = "uncached", + .cr_mask = CR_W|CR_C, + .pmd = PMD_SECT_UNCACHED, + .pte = 0, + }, { + .policy = "buffered", + .cr_mask = CR_C, + .pmd = PMD_SECT_BUFFERED, + .pte = PTE_BUFFERABLE, + }, { + .policy = "writethrough", + .cr_mask = 0, + .pmd = PMD_SECT_WT, + .pte = PTE_CACHEABLE, + }, { + .policy = "writeback", + .cr_mask = 0, + .pmd = PMD_SECT_WB, + .pte = PTE_BUFFERABLE|PTE_CACHEABLE, + }, { + .policy = "writealloc", + .cr_mask = 0, + .pmd = PMD_SECT_WBWA, + .pte = PTE_BUFFERABLE|PTE_CACHEABLE, + } +}; + +/* + * These are useful for identifing cache coherency + * problems by allowing the cache or the cache and + * writebuffer to be turned off. (Note: the write + * buffer should not be on and the cache off). + */ +static void __init early_cachepolicy(char **p) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cache_policies); i++) { + int len = strlen(cache_policies[i].policy); + + if (memcmp(*p, cache_policies[i].policy, len) == 0) { + cachepolicy = i; + cr_alignment &= ~cache_policies[i].cr_mask; + cr_no_alignment &= ~cache_policies[i].cr_mask; + *p += len; + break; + } + } + if (i == ARRAY_SIZE(cache_policies)) + printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n"); + flush_cache_all(); + set_cr(cr_alignment); +} +__early_param("cachepolicy=", early_cachepolicy); + +static void __init early_nocache(char **__unused) +{ + char *p = "buffered"; + printk(KERN_WARNING "nocache is deprecated; use cachepolicy=%s\n", p); + early_cachepolicy(&p); +} +__early_param("nocache", early_nocache); + +static void __init early_nowrite(char **__unused) +{ + char *p = "uncached"; + printk(KERN_WARNING "nowb is deprecated; use cachepolicy=%s\n", p); + early_cachepolicy(&p); +} +__early_param("nowb", early_nowrite); + +static void __init early_ecc(char **p) +{ + if (memcmp(*p, "on", 2) == 0) { + ecc_mask = PMD_PROTECTION; + *p += 2; + } else if (memcmp(*p, "off", 3) == 0) { + ecc_mask = 0; + *p += 3; + } +} +__early_param("ecc=", early_ecc); + +static int __init noalign_setup(char *__unused) +{ + cr_alignment &= ~CR_A; + cr_no_alignment &= ~CR_A; + set_cr(cr_alignment); + return 1; +} +__setup("noalign", noalign_setup); + +struct mem_types { + unsigned int prot_pte; + unsigned int prot_l1; + unsigned int prot_sect; + unsigned int domain; +}; + +static struct mem_types mem_types[] __initdata = { + [MT_DEVICE] = { + .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | + L_PTE_WRITE, + .prot_l1 = PMD_TYPE_TABLE, + .prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED | + PMD_SECT_AP_WRITE, + .domain = DOMAIN_IO, + }, + [MT_CACHECLEAN] = { + .prot_sect = PMD_TYPE_SECT | PMD_BIT4, + .domain = DOMAIN_KERNEL, + }, + [MT_MINICLEAN] = { + .prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_MINICACHE, + .domain = DOMAIN_KERNEL, + }, + [MT_LOW_VECTORS] = { + .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | + L_PTE_EXEC, + .prot_l1 = PMD_TYPE_TABLE, + .domain = DOMAIN_USER, + }, + [MT_HIGH_VECTORS] = { + .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | + L_PTE_USER | L_PTE_EXEC, + .prot_l1 = PMD_TYPE_TABLE, + .domain = DOMAIN_USER, + }, + [MT_MEMORY] = { + .prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_AP_WRITE, + .domain = DOMAIN_KERNEL, + }, + [MT_ROM] = { + .prot_sect = PMD_TYPE_SECT | PMD_BIT4, + .domain = DOMAIN_KERNEL, + }, + [MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */ + .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | + L_PTE_WRITE, + .prot_l1 = PMD_TYPE_TABLE, + .prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_UNCACHED | + PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE | + PMD_SECT_TEX(1), + .domain = DOMAIN_IO, + }, + [MT_NONSHARED_DEVICE] = { + .prot_l1 = PMD_TYPE_TABLE, + .prot_sect = PMD_TYPE_SECT | PMD_BIT4 | PMD_SECT_NONSHARED_DEV | + PMD_SECT_AP_WRITE, + .domain = DOMAIN_IO, + } +}; + +/* + * Adjust the PMD section entries according to the CPU in use. + */ +static void __init build_mem_type_table(void) +{ + struct cachepolicy *cp; + unsigned int cr = get_cr(); + unsigned int user_pgprot, kern_pgprot; + int cpu_arch = cpu_architecture(); + int i; + +#if defined(CONFIG_CPU_DCACHE_DISABLE) + if (cachepolicy > CPOLICY_BUFFERED) + cachepolicy = CPOLICY_BUFFERED; +#elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH) + if (cachepolicy > CPOLICY_WRITETHROUGH) + cachepolicy = CPOLICY_WRITETHROUGH; +#endif + if (cpu_arch < CPU_ARCH_ARMv5) { + if (cachepolicy >= CPOLICY_WRITEALLOC) + cachepolicy = CPOLICY_WRITEBACK; + ecc_mask = 0; + } + + /* + * Xscale must not have PMD bit 4 set for section mappings. + */ + if (cpu_is_xscale()) + for (i = 0; i < ARRAY_SIZE(mem_types); i++) + mem_types[i].prot_sect &= ~PMD_BIT4; + + /* + * ARMv5 and lower, excluding Xscale, bit 4 must be set for + * page tables. + */ + if (cpu_arch < CPU_ARCH_ARMv6 && !cpu_is_xscale()) + for (i = 0; i < ARRAY_SIZE(mem_types); i++) + if (mem_types[i].prot_l1) + mem_types[i].prot_l1 |= PMD_BIT4; + + cp = &cache_policies[cachepolicy]; + kern_pgprot = user_pgprot = cp->pte; + + /* + * Enable CPU-specific coherency if supported. + * (Only available on XSC3 at the moment.) + */ + if (arch_is_coherent()) { + if (cpu_is_xsc3()) { + mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S; + mem_types[MT_MEMORY].prot_pte |= L_PTE_COHERENT; + } + } + + /* + * ARMv6 and above have extended page tables. + */ + if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) { + /* + * bit 4 becomes XN which we must clear for the + * kernel memory mapping. + */ + mem_types[MT_MEMORY].prot_sect &= ~PMD_SECT_XN; + mem_types[MT_ROM].prot_sect &= ~PMD_SECT_XN; + + /* + * Mark cache clean areas and XIP ROM read only + * from SVC mode and no access from userspace. + */ + mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE; + mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE; + mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE; + + /* + * Mark the device area as "shared device" + */ + mem_types[MT_DEVICE].prot_pte |= L_PTE_BUFFERABLE; + mem_types[MT_DEVICE].prot_sect |= PMD_SECT_BUFFERED; + + /* + * User pages need to be mapped with the ASID + * (iow, non-global) + */ + user_pgprot |= L_PTE_ASID; + +#ifdef CONFIG_SMP + /* + * Mark memory with the "shared" attribute for SMP systems + */ + user_pgprot |= L_PTE_SHARED; + kern_pgprot |= L_PTE_SHARED; + mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S; +#endif + } + + for (i = 0; i < 16; i++) { + unsigned long v = pgprot_val(protection_map[i]); + v = (v & ~(L_PTE_BUFFERABLE|L_PTE_CACHEABLE)) | user_pgprot; + protection_map[i] = __pgprot(v); + } + + mem_types[MT_LOW_VECTORS].prot_pte |= kern_pgprot; + mem_types[MT_HIGH_VECTORS].prot_pte |= kern_pgprot; + + if (cpu_arch >= CPU_ARCH_ARMv5) { +#ifndef CONFIG_SMP + /* + * Only use write-through for non-SMP systems + */ + mem_types[MT_LOW_VECTORS].prot_pte &= ~L_PTE_BUFFERABLE; + mem_types[MT_HIGH_VECTORS].prot_pte &= ~L_PTE_BUFFERABLE; +#endif + } else { + mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1); + } + + pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | + L_PTE_DIRTY | L_PTE_WRITE | + L_PTE_EXEC | kern_pgprot); + + mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask; + mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask; + mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd; + mem_types[MT_ROM].prot_sect |= cp->pmd; + + switch (cp->pmd) { + case PMD_SECT_WT: + mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT; + break; + case PMD_SECT_WB: + case PMD_SECT_WBWA: + mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB; + break; + } + printk("Memory policy: ECC %sabled, Data cache %s\n", + ecc_mask ? "en" : "dis", cp->policy); +} + +#define vectors_base() (vectors_high() ? 0xffff0000 : 0) + +/* + * Create a SECTION PGD between VIRT and PHYS in domain + * DOMAIN with protection PROT. This operates on half- + * pgdir entry increments. + */ +static inline void +alloc_init_section(unsigned long virt, unsigned long phys, int prot) +{ + pmd_t *pmdp = pmd_off_k(virt); + + if (virt & (1 << 20)) + pmdp++; + + *pmdp = __pmd(phys | prot); + flush_pmd_entry(pmdp); +} + +/* + * Create a SUPER SECTION PGD between VIRT and PHYS with protection PROT + */ +static inline void +alloc_init_supersection(unsigned long virt, unsigned long phys, int prot) +{ + int i; + + for (i = 0; i < 16; i += 1) { + alloc_init_section(virt, phys, prot | PMD_SECT_SUPER); + + virt += (PGDIR_SIZE / 2); + } +} + +/* + * Add a PAGE mapping between VIRT and PHYS in domain + * DOMAIN with protection PROT. Note that due to the + * way we map the PTEs, we must allocate two PTE_SIZE'd + * blocks - one for the Linux pte table, and one for + * the hardware pte table. + */ +static inline void +alloc_init_page(unsigned long virt, unsigned long phys, unsigned int prot_l1, pgprot_t prot) +{ + pmd_t *pmdp = pmd_off_k(virt); + pte_t *ptep; + + if (pmd_none(*pmdp)) { + ptep = alloc_bootmem_low_pages(2 * PTRS_PER_PTE * + sizeof(pte_t)); + + __pmd_populate(pmdp, __pa(ptep) | prot_l1); + } + ptep = pte_offset_kernel(pmdp, virt); + + set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot)); +} + +/* + * Create the page directory entries and any necessary + * page tables for the mapping specified by `md'. We + * are able to cope here with varying sizes and address + * offsets, and we take full advantage of sections and + * supersections. + */ +void __init create_mapping(struct map_desc *md) +{ + unsigned long virt, length; + int prot_sect, prot_l1, domain; + pgprot_t prot_pte; + unsigned long off = (u32)__pfn_to_phys(md->pfn); + + if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) { + printk(KERN_WARNING "BUG: not creating mapping for " + "0x%08llx at 0x%08lx in user region\n", + __pfn_to_phys((u64)md->pfn), md->virtual); + return; + } + + if ((md->type == MT_DEVICE || md->type == MT_ROM) && + md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) { + printk(KERN_WARNING "BUG: mapping for 0x%08llx at 0x%08lx " + "overlaps vmalloc space\n", + __pfn_to_phys((u64)md->pfn), md->virtual); + } + + domain = mem_types[md->type].domain; + prot_pte = __pgprot(mem_types[md->type].prot_pte); + prot_l1 = mem_types[md->type].prot_l1 | PMD_DOMAIN(domain); + prot_sect = mem_types[md->type].prot_sect | PMD_DOMAIN(domain); + + /* + * Catch 36-bit addresses + */ + if(md->pfn >= 0x100000) { + if(domain) { + printk(KERN_ERR "MM: invalid domain in supersection " + "mapping for 0x%08llx at 0x%08lx\n", + __pfn_to_phys((u64)md->pfn), md->virtual); + return; + } + if((md->virtual | md->length | __pfn_to_phys(md->pfn)) + & ~SUPERSECTION_MASK) { + printk(KERN_ERR "MM: cannot create mapping for " + "0x%08llx at 0x%08lx invalid alignment\n", + __pfn_to_phys((u64)md->pfn), md->virtual); + return; + } + + /* + * Shift bits [35:32] of address into bits [23:20] of PMD + * (See ARMv6 spec). + */ + off |= (((md->pfn >> (32 - PAGE_SHIFT)) & 0xF) << 20); + } + + virt = md->virtual; + off -= virt; + length = md->length; + + if (mem_types[md->type].prot_l1 == 0 && + (virt & 0xfffff || (virt + off) & 0xfffff || (virt + length) & 0xfffff)) { + printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not " + "be mapped using pages, ignoring.\n", + __pfn_to_phys(md->pfn), md->virtual); + return; + } + + while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) { + alloc_init_page(virt, virt + off, prot_l1, prot_pte); + + virt += PAGE_SIZE; + length -= PAGE_SIZE; + } + + /* N.B. ARMv6 supersections are only defined to work with domain 0. + * Since domain assignments can in fact be arbitrary, the + * 'domain == 0' check below is required to insure that ARMv6 + * supersections are only allocated for domain 0 regardless + * of the actual domain assignments in use. + */ + if ((cpu_architecture() >= CPU_ARCH_ARMv6 || cpu_is_xsc3()) + && domain == 0) { + /* + * Align to supersection boundary if !high pages. + * High pages have already been checked for proper + * alignment above and they will fail the SUPSERSECTION_MASK + * check because of the way the address is encoded into + * offset. + */ + if (md->pfn <= 0x100000) { + while ((virt & ~SUPERSECTION_MASK || + (virt + off) & ~SUPERSECTION_MASK) && + length >= (PGDIR_SIZE / 2)) { + alloc_init_section(virt, virt + off, prot_sect); + + virt += (PGDIR_SIZE / 2); + length -= (PGDIR_SIZE / 2); + } + } + + while (length >= SUPERSECTION_SIZE) { + alloc_init_supersection(virt, virt + off, prot_sect); + + virt += SUPERSECTION_SIZE; + length -= SUPERSECTION_SIZE; + } + } + + /* + * A section mapping covers half a "pgdir" entry. + */ + while (length >= (PGDIR_SIZE / 2)) { + alloc_init_section(virt, virt + off, prot_sect); + + virt += (PGDIR_SIZE / 2); + length -= (PGDIR_SIZE / 2); + } + + while (length >= PAGE_SIZE) { + alloc_init_page(virt, virt + off, prot_l1, prot_pte); + + virt += PAGE_SIZE; + length -= PAGE_SIZE; + } +} + +/* + * Create the architecture specific mappings + */ +void __init iotable_init(struct map_desc *io_desc, int nr) +{ + int i; + + for (i = 0; i < nr; i++) + create_mapping(io_desc + i); +} + +static inline void prepare_page_table(struct meminfo *mi) +{ + unsigned long addr; + + /* + * Clear out all the mappings below the kernel image. + */ + for (addr = 0; addr < MODULE_START; addr += PGDIR_SIZE) + pmd_clear(pmd_off_k(addr)); + +#ifdef CONFIG_XIP_KERNEL + /* The XIP kernel is mapped in the module area -- skip over it */ + addr = ((unsigned long)&_etext + PGDIR_SIZE - 1) & PGDIR_MASK; +#endif + for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE) + pmd_clear(pmd_off_k(addr)); + + /* + * Clear out all the kernel space mappings, except for the first + * memory bank, up to the end of the vmalloc region. + */ + for (addr = __phys_to_virt(mi->bank[0].start + mi->bank[0].size); + addr < VMALLOC_END; addr += PGDIR_SIZE) + pmd_clear(pmd_off_k(addr)); +} + +/* + * Reserve the various regions of node 0 + */ +void __init reserve_node_zero(pg_data_t *pgdat) +{ + unsigned long res_size = 0; + + /* + * Register the kernel text and data with bootmem. + * Note that this can only be in node 0. + */ +#ifdef CONFIG_XIP_KERNEL + reserve_bootmem_node(pgdat, __pa(&__data_start), &_end - &__data_start); +#else + reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext); +#endif + + /* + * Reserve the page tables. These are already in use, + * and can only be in node 0. + */ + reserve_bootmem_node(pgdat, __pa(swapper_pg_dir), + PTRS_PER_PGD * sizeof(pgd_t)); + + /* + * Hmm... This should go elsewhere, but we really really need to + * stop things allocating the low memory; ideally we need a better + * implementation of GFP_DMA which does not assume that DMA-able + * memory starts at zero. + */ + if (machine_is_integrator() || machine_is_cintegrator()) + res_size = __pa(swapper_pg_dir) - PHYS_OFFSET; + + /* + * These should likewise go elsewhere. They pre-reserve the + * screen memory region at the start of main system memory. + */ + if (machine_is_edb7211()) + res_size = 0x00020000; + if (machine_is_p720t()) + res_size = 0x00014000; + +#ifdef CONFIG_SA1111 + /* + * Because of the SA1111 DMA bug, we want to preserve our + * precious DMA-able memory... + */ + res_size = __pa(swapper_pg_dir) - PHYS_OFFSET; +#endif + if (res_size) + reserve_bootmem_node(pgdat, PHYS_OFFSET, res_size); +} + +/* + * Set up device the mappings. Since we clear out the page tables for all + * mappings above VMALLOC_END, we will remove any debug device mappings. + * This means you have to be careful how you debug this function, or any + * called function. This means you can't use any function or debugging + * method which may touch any device, otherwise the kernel _will_ crash. + */ +static void __init devicemaps_init(struct machine_desc *mdesc) +{ + struct map_desc map; + unsigned long addr; + void *vectors; + + /* + * Allocate the vector page early. + */ + vectors = alloc_bootmem_low_pages(PAGE_SIZE); + BUG_ON(!vectors); + + for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE) + pmd_clear(pmd_off_k(addr)); + + /* + * Map the kernel if it is XIP. + * It is always first in the modulearea. + */ +#ifdef CONFIG_XIP_KERNEL + map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & SECTION_MASK); + map.virtual = MODULE_START; + map.length = ((unsigned long)&_etext - map.virtual + ~SECTION_MASK) & SECTION_MASK; + map.type = MT_ROM; + create_mapping(&map); +#endif + + /* + * Map the cache flushing regions. + */ +#ifdef FLUSH_BASE + map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS); + map.virtual = FLUSH_BASE; + map.length = SZ_1M; + map.type = MT_CACHECLEAN; + create_mapping(&map); +#endif +#ifdef FLUSH_BASE_MINICACHE + map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M); + map.virtual = FLUSH_BASE_MINICACHE; + map.length = SZ_1M; + map.type = MT_MINICLEAN; + create_mapping(&map); +#endif + + /* + * Create a mapping for the machine vectors at the high-vectors + * location (0xffff0000). If we aren't using high-vectors, also + * create a mapping at the low-vectors virtual address. + */ + map.pfn = __phys_to_pfn(virt_to_phys(vectors)); + map.virtual = 0xffff0000; + map.length = PAGE_SIZE; + map.type = MT_HIGH_VECTORS; + create_mapping(&map); + + if (!vectors_high()) { + map.virtual = 0; + map.type = MT_LOW_VECTORS; + create_mapping(&map); + } + + /* + * Ask the machine support to map in the statically mapped devices. + */ + if (mdesc->map_io) + mdesc->map_io(); + + /* + * Finally flush the caches and tlb to ensure that we're in a + * consistent state wrt the writebuffer. This also ensures that + * any write-allocated cache lines in the vector page are written + * back. After this point, we can start to touch devices again. + */ + local_flush_tlb_all(); + flush_cache_all(); +} + +/* + * paging_init() sets up the page tables, initialises the zone memory + * maps, and sets up the zero page, bad page and bad page tables. + */ +void __init paging_init(struct meminfo *mi, struct machine_desc *mdesc) +{ + void *zero_page; + + build_mem_type_table(); + prepare_page_table(mi); + bootmem_init(mi); + devicemaps_init(mdesc); + + top_pmd = pmd_off_k(0xffff0000); + + /* + * allocate the zero page. Note that we count on this going ok. + */ + zero_page = alloc_bootmem_low_pages(PAGE_SIZE); + memzero(zero_page, PAGE_SIZE); + empty_zero_page = virt_to_page(zero_page); + flush_dcache_page(empty_zero_page); +} + +/* + * In order to soft-boot, we need to insert a 1:1 mapping in place of + * the user-mode pages. This will then ensure that we have predictable + * results when turning the mmu off + */ +void setup_mm_for_reboot(char mode) +{ + unsigned long base_pmdval; + pgd_t *pgd; + int i; + + if (current->mm && current->mm->pgd) + pgd = current->mm->pgd; + else + pgd = init_mm.pgd; + + base_pmdval = PMD_SECT_AP_WRITE | PMD_SECT_AP_READ | PMD_TYPE_SECT; + if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) + base_pmdval |= PMD_BIT4; + + for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) { + unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval; + pmd_t *pmd; + + pmd = pmd_off(pgd, i << PGDIR_SHIFT); + pmd[0] = __pmd(pmdval); + pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1))); + flush_pmd_entry(pmd); + } +} |