- 根目录:
- arch
- unicore32
- mm
- mmu.c
/*
* linux/arch/unicore32/mm/mmu.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Copyright (C) 2001-2010 GUAN Xue-tao
*
* 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/mman.h>
#include <linux/nodemask.h>
#include <linux/memblock.h>
#include <linux/fs.h>
#include <linux/bootmem.h>
#include <linux/io.h>
#include <asm/cputype.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/sizes.h>
#include <asm/tlb.h>
#include <mach/map.h>
#include "mm.h"
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
/*
* empty_zero_page is a special page that is used for
* zero-initialized data and COW.
*/
struct page *empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);
/*
* The pmd table for the upper-most set of pages.
*/
pmd_t *top_pmd;
pgprot_t pgprot_user;
EXPORT_SYMBOL(pgprot_user);
pgprot_t pgprot_kernel;
EXPORT_SYMBOL(pgprot_kernel);
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);
void adjust_cr(unsigned long mask, unsigned long set)
{
unsigned long flags;
mask &= ~CR_A;
set &= mask;
local_irq_save(flags);
cr_no_alignment = (cr_no_alignment & ~mask) | set;
cr_alignment = (cr_alignment & ~mask) | set;
set_cr((get_cr() & ~mask) | set);
local_irq_restore(flags);
}
struct map_desc {
unsigned long virtual;
unsigned long pfn;
unsigned long length;
unsigned int type;
};
#define PROT_PTE_DEVICE (PTE_PRESENT | PTE_YOUNG | \
PTE_DIRTY | PTE_READ | PTE_WRITE)
#define PROT_SECT_DEVICE (PMD_TYPE_SECT | PMD_PRESENT | \
PMD_SECT_READ | PMD_SECT_WRITE)
static struct mem_type mem_types[] = {
[MT_DEVICE] = { /* Strongly ordered */
.prot_pte = PROT_PTE_DEVICE,
.prot_l1 = PMD_TYPE_TABLE | PMD_PRESENT,
.prot_sect = PROT_SECT_DEVICE,
},
/*
* MT_KUSER: pte for vecpage -- cacheable,
* and sect for unigfx mmap -- noncacheable
*/
[MT_KUSER] = {
.prot_pte = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
PTE_CACHEABLE | PTE_READ | PTE_EXEC,
.prot_l1 = PMD_TYPE_TABLE | PMD_PRESENT,
.prot_sect = PROT_SECT_DEVICE,
},
[MT_HIGH_VECTORS] = {
.prot_pte = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
PTE_CACHEABLE | PTE_READ | PTE_WRITE |
PTE_EXEC,
.prot_l1 = PMD_TYPE_TABLE | PMD_PRESENT,
},
[MT_MEMORY] = {
.prot_pte = PTE_PRESENT | PTE_YOUNG | PTE_DIRTY |
PTE_WRITE | PTE_EXEC,
.prot_l1 = PMD_TYPE_TABLE | PMD_PRESENT,
.prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
PMD_SECT_READ | PMD_SECT_WRITE | PMD_SECT_EXEC,
},
[MT_ROM] = {
.prot_sect = PMD_TYPE_SECT | PMD_PRESENT | PMD_SECT_CACHEABLE |
PMD_SECT_READ,
},
};
const struct mem_type *get_mem_type(unsigned int type)
{
return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
}
EXPORT_SYMBOL(get_mem_type);
/*
* Adjust the PMD section entries according to the CPU in use.
*/
static void __init build_mem_type_table(void)
{
pgprot_user = __pgprot(PTE_PRESENT | PTE_YOUNG | PTE_CACHEABLE);
pgprot_kernel = __pgprot(PTE_PRESENT | PTE_YOUNG |
PTE_DIRTY | PTE_READ | PTE_WRITE |
PTE_EXEC | PTE_CACHEABLE);
}
#define vectors_base() (vectors_high() ? 0xffff0000 : 0)
static void __init *early_alloc(unsigned long sz)
{
void *ptr = __va(memblock_alloc(sz, sz));
memset(ptr, 0, sz);
return ptr;
}
static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr,
unsigned long prot)
{
if (pmd_none(*pmd)) {
pte_t *pte = early_alloc(PTRS_PER_PTE * sizeof(pte_t));
__pmd_populate(pmd, __pa(pte) | prot);
}
BUG_ON(pmd_bad(*pmd));
return pte_offset_kernel(pmd, addr);
}
static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
unsigned long end, unsigned long pfn,
const struct mem_type *type)
{
pte_t *pte = early_pte_alloc(pmd, addr, type->prot_l1);
do {
set_pte(pte, pfn_pte(pfn, __pgprot(type->prot_pte)));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
}
static void __init alloc_init_section(pgd_t *pgd, unsigned long addr,
unsigned long end, unsigned long phys,
const struct mem_type *type)
{
pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
/*
* Try a section mapping - end, addr and phys must all be aligned
* to a section boundary.
*/
if (((addr | end | phys) & ~SECTION_MASK) == 0) {
pmd_t *p = pmd;
do {
set_pmd(pmd, __pmd(phys | type->prot_sect));
phys += SECTION_SIZE;
} while (pmd++, addr += SECTION_SIZE, addr != end);
flush_pmd_entry(p);
} else {
/*
* No need to loop; pte's aren't interested in the
* individual L1 entries.
*/
alloc_init_pte(pmd, addr, end, __phys_to_pfn(phys), type);
}
}
/*
* 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.
*/
static void __init create_mapping(struct map_desc *md)
{
unsigned long phys, addr, length, end;
const struct mem_type *type;
pgd_t *pgd;
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);
}
type = &mem_types[md->type];
addr = md->virtual & PAGE_MASK;
phys = (unsigned long)__pfn_to_phys(md->pfn);
length = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
if (type->prot_l1 == 0 && ((addr | phys | length) & ~SECTION_MASK)) {
printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
"be mapped using pages, ignoring.\n",
__pfn_to_phys(md->pfn), addr);
return;
}
pgd = pgd_offset_k(addr);
end = addr + length;
do {
unsigned long next = pgd_addr_end(addr, end);
alloc_init_section(pgd, addr, next, phys, type);
phys += next - addr;
addr = next;
} while (pgd++, addr != end);
}
static void * __initdata vmalloc_min = (void *)(VMALLOC_END - SZ_128M);
/*
* vmalloc=size forces the vmalloc area to be exactly 'size'
* bytes. This can be used to increase (or decrease) the vmalloc
* area - the default is 128m.
*/
static int __init early_vmalloc(char *arg)
{
unsigned long vmalloc_reserve = memparse(arg, NULL);
if (vmalloc_reserve < SZ_16M) {
vmalloc_reserve = SZ_16M;
printk(KERN_WARNING
"vmalloc area too small, limiting to %luMB\n",
vmalloc_reserve >> 20);
}
if (vmalloc_reserve > VMALLOC_END - (PAGE_OFFSET + SZ_32M)) {
vmalloc_reserve = VMALLOC_END - (PAGE_OFFSET + SZ_32M);
printk(KERN_WARNING
"vmalloc area is too big, limiting to %luMB\n",
vmalloc_reserve >> 20);
}
vmalloc_min = (void *)(VMALLOC_END - vmalloc_reserve);
return 0;
}
early_param("vmalloc", early_vmalloc);
static phys_addr_t lowmem_limit __initdata = SZ_1G;
static void __init sanity_check_meminfo(void)
{
int i, j;
lowmem_limit = __pa(vmalloc_min - 1) + 1;
memblock_set_current_limit(lowmem_limit);
for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
struct membank *bank = &meminfo.bank[j];
*bank = meminfo.bank[i];
j++;
}
meminfo.nr_banks = j;
}
static inline void prepare_page_table(void)
{
unsigned long addr;
phys_addr_t end;
/*
* Clear out all the mappings below the kernel image.
*/
for (addr = 0; addr < MODULES_VADDR; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
for ( ; addr < PAGE_OFFSET; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
/*
* Find the end of the first block of lowmem.
*/
end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
if (end >= lowmem_limit)
end = lowmem_limit;
/*
* 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(end);
addr < VMALLOC_END; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
}
/*
* Reserve the special regions of memory
*/
void __init uc32_mm_memblock_reserve(void)
{
/*
* Reserve the page tables. These are already in use,
* and can only be in node 0.
*/
memblock_reserve(__pa(swapper_pg_dir), PTRS_PER_PGD * sizeof(pgd_t));
}
/*
* 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(void)
{
struct map_desc map;
unsigned long addr;
void *vectors;
/*
* Allocate the vector page early.
*/
vectors = early_alloc(PAGE_SIZE);
for (addr = VMALLOC_END; addr; addr += PGDIR_SIZE)
pmd_clear(pmd_off_k(addr));
/*
* 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 = VECTORS_BASE;
map.length = PAGE_SIZE;
map.type = MT_HIGH_VECTORS;
create_mapping(&map);
/*
* Create a mapping for the kuser page at the special
* location (0xbfff0000) to the same vectors location.
*/
map.pfn = __phys_to_pfn(virt_to_phys(vectors));
map.virtual = KUSER_VECPAGE_BASE;
map.length = PAGE_SIZE;
map.type = MT_KUSER;
create_mapping(&map);
/*
* 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();
}
static void __init map_lowmem(void)
{
struct memblock_region *reg;
/* Map all the lowmem memory banks. */
for_each_memblock(memory, reg) {
phys_addr_t start = reg->base;
phys_addr_t end = start + reg->size;
struct map_desc map;
if (end > lowmem_limit)
end = lowmem_limit;
if (start >= end)
break;
map.pfn = __phys_to_pfn(start);
map.virtual = __phys_to_virt(start);
map.length = end - start;
map.type = MT_MEMORY;
create_mapping(&map);
}
}
/*
* 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(void)
{
void *zero_page;
build_mem_type_table();
sanity_check_meminfo();
prepare_page_table();
map_lowmem();
devicemaps_init();
top_pmd = pmd_off_k(0xffff0000);
/* allocate the zero page. */
zero_page = early_alloc(PAGE_SIZE);
bootmem_init();
empty_zero_page = virt_to_page(zero_page);
__flush_dcache_page(NULL, 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;
/*
* We need to access to user-mode page tables here. For kernel threads
* we don't have any user-mode mappings so we use the context that we
* "borrowed".
*/
pgd = current->active_mm->pgd;
base_pmdval = PMD_SECT_WRITE | PMD_SECT_READ | PMD_TYPE_SECT;
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);
set_pmd(pmd, __pmd(pmdval));
flush_pmd_entry(pmd);
}
local_flush_tlb_all();
}
/*
* Take care of architecture specific things when placing a new PTE into
* a page table, or changing an existing PTE. Basically, there are two
* things that we need to take care of:
*
* 1. If PG_dcache_clean is not set for the page, we need to ensure
* that any cache entries for the kernels virtual memory
* range are written back to the page.
* 2. If we have multiple shared mappings of the same space in
* an object, we need to deal with the cache aliasing issues.
*
* Note that the pte lock will be held.
*/
void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep)
{
unsigned long pfn = pte_pfn(*ptep);
struct address_space *mapping;
struct page *page;
if (!pfn_valid(pfn))
return;
/*
* The zero page is never written to, so never has any dirty
* cache lines, and therefore never needs to be flushed.
*/
page = pfn_to_page(pfn);
if (page == ZERO_PAGE(0))
return;
mapping = page_mapping(page);
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
__flush_dcache_page(mapping, page);
if (mapping)
if (vma->vm_flags & VM_EXEC)
__flush_icache_all();
}