diff options
Diffstat (limited to 'arch/arm/mm/mmu.c')
| -rw-r--r-- | arch/arm/mm/mmu.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c new file mode 100644 index 0000000..9648e68 --- /dev/null +++ b/arch/arm/mm/mmu.c @@ -0,0 +1,229 @@ +/* + * 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/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; + +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); +} |
