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/*
* arch/arm/mm/mm-armo.c
*
* Page table sludge for older ARM processor architectures.
*
* Copyright (C) 1998-2000 Russell King
*/
#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/arch/memory.h>
#include "map.h"
#define MEMC_TABLE_SIZE (256*sizeof(unsigned long))
#define PGD_TABLE_SIZE (PTRS_PER_PGD * BYTES_PER_PTR)
int page_nr;
extern unsigned long get_page_2k(int prio);
extern void free_page_2k(unsigned long);
extern pte_t *get_bad_pte_table(void);
/*
* Allocate a page table. Note that we place the MEMC
* table before the page directory. This means we can
* easily get to both tightly-associated data structures
* with a single pointer.
*
* We actually only need 1152 bytes, 896 bytes is wasted.
* We could try to fit 7 PTEs into that slot somehow.
*/
static inline void *alloc_pgd_table(int priority)
{
unsigned long pg2k;
pg2k = get_page_2k(priority);
if (pg2k)
pg2k += MEMC_TABLE_SIZE;
return (void *)pg2k;
}
void free_pgd_slow(pgd_t *pgd)
{
unsigned long tbl = (unsigned long)pgd;
tbl -= MEMC_TABLE_SIZE;
free_page_2k(tbl);
}
/*
* FIXME: the following over-allocates by 1600%
*/
static inline void *alloc_pte_table(int size, int prio)
{
if (size != 128)
printk("invalid table size\n");
return (void *)get_page_2k(prio);
}
void free_pte_slow(pte_t *pte)
{
unsigned long tbl = (unsigned long)pte;
free_page_2k(tbl);
}
pgd_t *get_pgd_slow(void)
{
pgd_t *pgd = (pgd_t *)alloc_pgd_table(GFP_KERNEL);
pmd_t *new_pmd;
if (pgd) {
pgd_t *init = pgd_offset(&init_mm, 0);
memzero(pgd, USER_PTRS_PER_PGD * sizeof(pgd_t));
memcpy(pgd + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
/*
* On ARM, first page must always be allocated
*/
if (!pmd_alloc(pgd, 0))
goto nomem;
else {
pmd_t *old_pmd = pmd_offset(init, 0);
new_pmd = pmd_offset(pgd, 0);
if (!pte_alloc(new_pmd, 0))
goto nomem_pmd;
else {
pte_t *new_pte = pte_offset(new_pmd, 0);
pte_t *old_pte = pte_offset(old_pmd, 0);
set_pte (new_pte, *old_pte);
}
}
/* update MEMC tables */
cpu_memc_update_all(pgd);
}
return pgd;
nomem_pmd:
pmd_free(new_pmd);
nomem:
free_pgd_slow(pgd);
return NULL;
}
pte_t *get_pte_slow(pmd_t *pmd, unsigned long offset)
{
pte_t *pte;
pte = (pte_t *)alloc_pte_table(PTRS_PER_PTE * sizeof(pte_t), GFP_KERNEL);
if (pmd_none(*pmd)) {
if (pte) {
memzero(pte, PTRS_PER_PTE * sizeof(pte_t));
set_pmd(pmd, mk_user_pmd(pte));
return pte + offset;
}
set_pmd(pmd, mk_user_pmd(get_bad_pte_table()));
return NULL;
}
free_pte_slow(pte);
if (pmd_bad(*pmd)) {
__handle_bad_pmd(pmd);
return NULL;
}
return (pte_t *) pmd_page(*pmd) + offset;
}
/*
* No special code is required here.
*/
void setup_mm_for_reboot(char mode)
{
}
/*
* This contains the code to setup the memory map on an ARM2/ARM250/ARM3
* machine. This is both processor & architecture specific, and requires
* some more work to get it to fit into our separate processor and
* architecture structure.
*/
void __init pagetable_init(void)
{
pte_t *pte;
int i;
page_nr = max_low_pfn;
pte = alloc_bootmem_low_pages(PTRS_PER_PTE * sizeof(pte_t));
pte[0] = mk_pte_phys(PAGE_OFFSET + 491520, PAGE_READONLY);
set_pmd(pmd_offset(swapper_pg_dir, 0), mk_kernel_pmd(pte));
for (i = 1; i < PTRS_PER_PGD; i++)
pgd_val(swapper_pg_dir[i]) = 0;
}
/*
* We never have holes in the memmap
*/
void __init create_memmap_holes(void)
{
}
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