linux/arch/mips/mm/pgtable-64.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

81 lines
1.6 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) 1999, 2000 by Silicon Graphics
* Copyright (C) 2003 by Ralf Baechle
*/
#include <linux/init.h>
#include <linux/mm.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
void pgd_init(unsigned long page)
{
unsigned long *p, *end;
unsigned long entry;
#ifdef __PAGETABLE_PMD_FOLDED
entry = (unsigned long)invalid_pte_table;
#else
entry = (unsigned long)invalid_pmd_table;
#endif
p = (unsigned long *) page;
end = p + PTRS_PER_PGD;
while (p < end) {
p[0] = entry;
p[1] = entry;
p[2] = entry;
p[3] = entry;
p[4] = entry;
p[5] = entry;
p[6] = entry;
p[7] = entry;
p += 8;
}
}
#ifndef __PAGETABLE_PMD_FOLDED
void pmd_init(unsigned long addr, unsigned long pagetable)
{
unsigned long *p, *end;
p = (unsigned long *) addr;
end = p + PTRS_PER_PMD;
while (p < end) {
p[0] = pagetable;
p[1] = pagetable;
p[2] = pagetable;
p[3] = pagetable;
p[4] = pagetable;
p[5] = pagetable;
p[6] = pagetable;
p[7] = pagetable;
p += 8;
}
}
#endif
void __init pagetable_init(void)
{
unsigned long vaddr;
pgd_t *pgd_base;
/* Initialize the entire pgd. */
pgd_init((unsigned long)swapper_pg_dir);
#ifndef __PAGETABLE_PMD_FOLDED
pmd_init((unsigned long)invalid_pmd_table, (unsigned long)invalid_pte_table);
#endif
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);
}