/*
* 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, _etext, __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_user;
pgprot_t pgprot_kernel;
EXPORT_SYMBOL(pgprot_user);
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);
#ifndef CONFIG_SMP
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);
}
#endif
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_SHARED;
}
}
/*
* 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;
#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_user = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | user_pgprot);
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_ext(ptep, pfn_pte(phys >> PAGE_SHIFT, prot), 0);
}
/*
* 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;
/* H1940 and RX3715 need to reserve this for suspend */
if (machine_is_h1940() || machine_is_rx3715()) {
reserve_bootmem_node(pgdat, 0x30003000, 0x1000);
reserve_bootmem_node(pgdat, 0x30081000, 0x1000);
}
#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);
}
}
