linux/arch/mips/mm/pgtable-32.c
Kevin Cernekee 464fd83e84 MIPS: Limit fixrange_init() to the FIXMAP region
fixrange_init() allocates page tables for all addresses higher than
FIXADDR_TOP.  On processors that override the default FIXADDR_TOP
address of 0xfffe_0000, this can consume up to 4 pages (1 page per 4MB)
for pgd's that are never used.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1980/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2011-07-25 17:26:54 +01:00

70 lines
1.7 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2003 by Ralf Baechle
*/
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
void pgd_init(unsigned long page)
{
unsigned long *p = (unsigned long *) page;
int i;
for (i = 0; i < USER_PTRS_PER_PGD; i+=8) {
p[i + 0] = (unsigned long) invalid_pte_table;
p[i + 1] = (unsigned long) invalid_pte_table;
p[i + 2] = (unsigned long) invalid_pte_table;
p[i + 3] = (unsigned long) invalid_pte_table;
p[i + 4] = (unsigned long) invalid_pte_table;
p[i + 5] = (unsigned long) invalid_pte_table;
p[i + 6] = (unsigned long) invalid_pte_table;
p[i + 7] = (unsigned long) invalid_pte_table;
}
}
void __init pagetable_init(void)
{
unsigned long vaddr;
pgd_t *pgd_base;
#ifdef CONFIG_HIGHMEM
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
#endif
/* Initialize the entire pgd. */
pgd_init((unsigned long)swapper_pg_dir);
pgd_init((unsigned long)swapper_pg_dir
+ sizeof(pgd_t) * USER_PTRS_PER_PGD);
pgd_base = swapper_pg_dir;
/*
* Fixed mappings:
*/
vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
fixrange_init(vaddr, vaddr + FIXADDR_SIZE, pgd_base);
#ifdef CONFIG_HIGHMEM
/*
* Permanent kmaps:
*/
vaddr = PKMAP_BASE;
fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
pgd = swapper_pg_dir + __pgd_offset(vaddr);
pud = pud_offset(pgd, vaddr);
pmd = pmd_offset(pud, vaddr);
pte = pte_offset_kernel(pmd, vaddr);
pkmap_page_table = pte;
#endif
}