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Commit 464fd83e authored Jan 05, 2011 by Kevin Cernekee Committed by Ralf Baechle Jul 25, 2011

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>

parent 273f2d7e

arch/mips/mm/init.c

+3 −3

Original line number	Original line	Diff line number	Diff line
	@@ -277,11 +277,11 @@ void __init fixrange_init(unsigned long start, unsigned long end,
	k = __pmd_offset(vaddr);		k = __pmd_offset(vaddr);
	pgd = pgd_base + i;		pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {		for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
	pud = (pud_t *)pgd;		pud = (pud_t *)pgd;
	for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) {		for ( ; (j < PTRS_PER_PUD) && (vaddr < end); pud++, j++) {
	pmd = (pmd_t *)pud;		pmd = (pmd_t *)pud;
	for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {		for (; (k < PTRS_PER_PMD) && (vaddr < end); pmd++, k++) {
	if (pmd_none(*pmd)) {		if (pmd_none(*pmd)) {
	pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);		pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
	set_pmd(pmd, __pmd((unsigned long)pte));		set_pmd(pmd, __pmd((unsigned long)pte));

arch/mips/mm/pgtable-32.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -52,7 +52,7 @@ void __init pagetable_init(void)
	* Fixed mappings:		* Fixed mappings:
	*/		*/
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;		vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	fixrange_init(vaddr, 0, pgd_base);		fixrange_init(vaddr, vaddr + FIXADDR_SIZE, pgd_base);

	#ifdef CONFIG_HIGHMEM		#ifdef CONFIG_HIGHMEM
	/*		/*

arch/mips/mm/pgtable-64.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -76,5 +76,5 @@ void __init pagetable_init(void)
	* Fixed mappings:		* Fixed mappings:
	*/		*/
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;		vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	fixrange_init(vaddr, 0, pgd_base);		fixrange_init(vaddr, vaddr + FIXADDR_SIZE, pgd_base);
	}		}