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/*
* linux/arch/arm/mm/mm-armv.c
*
* Copyright (C) 1998-2000 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.
*
* Page table sludge for ARM v3 and v4 processor architectures.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/io.h>
#include <asm/setup.h>
#include <asm/mach/map.h>
/*
* 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 int __init nocache_setup(char *__unused)
{
cr_alignment &= ~4;
cr_no_alignment &= ~4;
flush_cache_all();
set_cr(cr_alignment);
return 1;
}
static int __init nowrite_setup(char *__unused)
{
cr_alignment &= ~(8|4);
cr_no_alignment &= ~(8|4);
flush_cache_all();
set_cr(cr_alignment);
return 1;
}
static int __init noalign_setup(char *__unused)
{
cr_alignment &= ~2;
cr_no_alignment &= ~2;
set_cr(cr_alignment);
return 1;
}
__setup("noalign", noalign_setup);
__setup("nocache", nocache_setup);
__setup("nowb", nowrite_setup);
#define FIRST_KERNEL_PGD_NR (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
#define clean_cache_area(start,size) \
cpu_cache_clean_invalidate_range((unsigned long)start, ((unsigned long)start) + size, 0);
/*
* need to get a 16k page for level 1
*/
pgd_t *get_pgd_slow(struct mm_struct *mm)
{
pgd_t *new_pgd, *init_pgd;
pmd_t *new_pmd, *init_pmd;
pte_t *new_pte, *init_pte;
new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
if (!new_pgd)
goto no_pgd;
memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
init_pgd = pgd_offset_k(0);
if (vectors_base() == 0) {
init_pmd = pmd_offset(init_pgd, 0);
init_pte = pte_offset(init_pmd, 0);
/*
* This lock is here just to satisfy pmd_alloc and pte_lock
*/
spin_lock(&mm->page_table_lock);
/*
* On ARM, first page must always be allocated since it
* contains the machine vectors.
*/
new_pmd = pmd_alloc(mm, new_pgd, 0);
if (!new_pmd)
goto no_pmd;
new_pte = pte_alloc(mm, new_pmd, 0);
if (!new_pte)
goto no_pte;
set_pte(new_pte, *init_pte);
spin_unlock(&mm->page_table_lock);
}
/*
* Copy over the kernel and IO PGD entries
*/
memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
(PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
/*
* FIXME: this should not be necessary
*/
clean_cache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
return new_pgd;
no_pte:
spin_unlock(&mm->page_table_lock);
pmd_free(new_pmd);
free_pages((unsigned long)new_pgd, 2);
return NULL;
no_pmd:
spin_unlock(&mm->page_table_lock);
free_pages((unsigned long)new_pgd, 2);
return NULL;
no_pgd:
return NULL;
}
void free_pgd_slow(pgd_t *pgd)
{
pmd_t *pmd;
pte_t *pte;
if (!pgd)
return;
/* pgd is always present and good */
pmd = (pmd_t *)pgd;
if (pmd_none(*pmd))
goto free;
if (pmd_bad(*pmd)) {
pmd_ERROR(*pmd);
pmd_clear(pmd);
goto free;
}
pte = pte_offset(pmd, 0);
pmd_clear(pmd);
pte_free(pte);
pmd_free(pmd);
free:
free_pages((unsigned long) pgd, 2);
}
/*
* Create a SECTION PGD between VIRT and PHYS in domain
* DOMAIN with protection PROT
*/
static inline void
alloc_init_section(unsigned long virt, unsigned long phys, int prot)
{
pmd_t pmd;
pmd_val(pmd) = phys | prot;
set_pmd(pmd_offset(pgd_offset_k(virt), virt), pmd);
}
/*
* 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, int domain, int prot)
{
pmd_t *pmdp;
pte_t *ptep;
pmdp = pmd_offset(pgd_offset_k(virt), virt);
if (pmd_none(*pmdp)) {
pte_t *ptep = alloc_bootmem_low_pages(2 * PTRS_PER_PTE *
sizeof(pte_t));
ptep += PTRS_PER_PTE;
set_pmd(pmdp, __mk_pmd(ptep, PMD_TYPE_TABLE | PMD_DOMAIN(domain)));
}
ptep = pte_offset(pmdp, virt);
set_pte(ptep, mk_pte_phys(phys, __pgprot(prot)));
}
/*
* Clear any PGD mapping. On a two-level page table system,
* the clearance is done by the middle-level functions (pmd)
* rather than the top-level (pgd) functions.
*/
static inline void clear_mapping(unsigned long virt)
{
pmd_clear(pmd_offset(pgd_offset_k(virt), virt));
}
/*
* 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 virt, length;
int prot_sect, prot_pte;
long off;
prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
(md->prot_read ? L_PTE_USER : 0) |
(md->prot_write ? L_PTE_WRITE : 0) |
(md->cacheable ? L_PTE_CACHEABLE : 0) |
(md->bufferable ? L_PTE_BUFFERABLE : 0);
prot_sect = PMD_TYPE_SECT | PMD_DOMAIN(md->domain) |
(md->prot_read ? PMD_SECT_AP_READ : 0) |
(md->prot_write ? PMD_SECT_AP_WRITE : 0) |
(md->cacheable ? PMD_SECT_CACHEABLE : 0) |
(md->bufferable ? PMD_SECT_BUFFERABLE : 0);
virt = md->virtual;
off = md->physical - virt;
length = md->length;
while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) {
alloc_init_page(virt, virt + off, md->domain, prot_pte);
virt += PAGE_SIZE;
length -= PAGE_SIZE;
}
while (length >= PGDIR_SIZE) {
alloc_init_section(virt, virt + off, prot_sect);
virt += PGDIR_SIZE;
length -= PGDIR_SIZE;
}
while (length >= PAGE_SIZE) {
alloc_init_page(virt, virt + off, md->domain, prot_pte);
virt += PAGE_SIZE;
length -= PAGE_SIZE;
}
}
/*
* 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)
{
pgd_t *pgd;
pmd_t pmd;
int i;
if (current->mm && current->mm->pgd)
pgd = current->mm->pgd;
else
pgd = init_mm.pgd;
for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++) {
pmd_val(pmd) = (i << PGDIR_SHIFT) |
PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
PMD_TYPE_SECT;
set_pmd(pmd_offset(pgd + i, i << PGDIR_SHIFT), pmd);
}
}
/*
* Setup initial mappings. We use the page we allocated for zero page to hold
* the mappings, which will get overwritten by the vectors in traps_init().
* The mappings must be in virtual address order.
*/
void __init memtable_init(struct meminfo *mi)
{
struct map_desc *init_maps, *p, *q;
unsigned long address = 0;
int i;
init_maps = p = alloc_bootmem_low_pages(PAGE_SIZE);
for (i = 0; i < mi->nr_banks; i++) {
if (mi->bank[i].size == 0)
continue;
p->physical = mi->bank[i].start;
p->virtual = __phys_to_virt(p->physical);
p->length = mi->bank[i].size;
p->domain = DOMAIN_KERNEL;
p->prot_read = 0;
p->prot_write = 1;
p->cacheable = 1;
p->bufferable = 1;
p ++;
}
#ifdef FLUSH_BASE
p->physical = FLUSH_BASE_PHYS;
p->virtual = FLUSH_BASE;
p->length = PGDIR_SIZE;
p->domain = DOMAIN_KERNEL;
p->prot_read = 1;
p->prot_write = 0;
p->cacheable = 1;
p->bufferable = 1;
p ++;
#endif
#ifdef FLUSH_BASE_MINICACHE
p->physical = FLUSH_BASE_PHYS + PGDIR_SIZE;
p->virtual = FLUSH_BASE_MINICACHE;
p->length = PGDIR_SIZE;
p->domain = DOMAIN_KERNEL;
p->prot_read = 1;
p->prot_write = 0;
p->cacheable = 1;
p->bufferable = 0;
p ++;
#endif
/*
* Go through the initial mappings, but clear out any
* pgdir entries that are not in the description.
*/
q = init_maps;
do {
if (address < q->virtual || q == p) {
clear_mapping(address);
address += PGDIR_SIZE;
} else {
create_mapping(q);
address = q->virtual + q->length;
address = (address + PGDIR_SIZE - 1) & PGDIR_MASK;
q ++;
}
} while (address != 0);
/*
* Create a mapping for the machine vectors at virtual address 0
* or 0xffff0000. We should always try the high mapping.
*/
init_maps->physical = virt_to_phys(init_maps);
init_maps->virtual = vectors_base();
init_maps->length = PAGE_SIZE;
init_maps->domain = DOMAIN_USER;
init_maps->prot_read = 0;
init_maps->prot_write = 0;
init_maps->cacheable = 1;
init_maps->bufferable = 0;
create_mapping(init_maps);
flush_cache_all();
}
/*
* Create the architecture specific mappings
*/
void __init iotable_init(struct map_desc *io_desc)
{
int i;
for (i = 0; io_desc[i].last == 0; i++)
create_mapping(io_desc + i);
}
static inline void free_memmap(int node, unsigned long start, unsigned long end)
{
unsigned long pg, pgend;
start = __phys_to_virt(start);
end = __phys_to_virt(end);
pg = PAGE_ALIGN((unsigned long)(virt_to_page(start)));
pgend = ((unsigned long)(virt_to_page(end))) & PAGE_MASK;
start = __virt_to_phys(pg);
end = __virt_to_phys(pgend);
free_bootmem_node(NODE_DATA(node), start, end - start);
}
static inline void free_unused_memmap_node(int node, struct meminfo *mi)
{
unsigned long bank_start, prev_bank_end = 0;
unsigned int i;
/*
* [FIXME] This relies on each bank being in address order. This
* may not be the case, especially if the user has provided the
* information on the command line.
*/
for (i = 0; i < mi->nr_banks; i++) {
if (mi->bank[i].size == 0 || mi->bank[i].node != node)
continue;
bank_start = mi->bank[i].start & PAGE_MASK;
/*
* If we had a previous bank, and there is a space
* between the current bank and the previous, free it.
*/
if (prev_bank_end && prev_bank_end != bank_start)
free_memmap(node, prev_bank_end, bank_start);
prev_bank_end = PAGE_ALIGN(mi->bank[i].start +
mi->bank[i].size);
}
}
/*
* The mem_map array can get very big. Free
* the unused area of the memory map.
*/
void __init create_memmap_holes(struct meminfo *mi)
{
int node;
for (node = 0; node < numnodes; node++)
free_unused_memmap_node(node, mi);
}
/*
* PTE table allocation cache.
*
* This is a move away from our custom 2K page allocator. We now use the
* slab cache to keep track of these objects.
*
* With this, it is questionable as to whether the PGT cache gains us
* anything. We may be better off dropping the PTE stuff from our PGT
* cache implementation.
*/
kmem_cache_t *pte_cache;
/*
* The constructor gets called for each object within the cache when the
* cache page is created. Note that if slab tries to misalign the blocks,
* we BUG() loudly.
*/
static void pte_cache_ctor(void *pte, kmem_cache_t *cache, unsigned long flags)
{
unsigned long block = (unsigned long)pte;
if (block & 2047)
BUG();
memzero(pte, 2 * PTRS_PER_PTE * sizeof(pte_t));
cpu_cache_clean_invalidate_range(block, block +
PTRS_PER_PTE * sizeof(pte_t), 0);
}
void __init pgtable_cache_init(void)
{
pte_cache = kmem_cache_create("pte-cache",
2 * PTRS_PER_PTE * sizeof(pte_t), 0, 0,
pte_cache_ctor, NULL);
if (!pte_cache)
BUG();
}
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