linux/arch/arm64/mm/pgd.c
Mark Rutland 15670ef1ea arm64: pgalloc: consistently use PGALLOC_GFP
We currently allocate different levels of page tables with a variety of
differing flags, and the PGALLOC_GFP flags, intended for use when
allocating any level of page table, are only used for ptes in
pte_alloc_one. On x86, PGALLOC_GFP is used for all page table
allocations.

Currently the major differences are:

* __GFP_NOTRACK -- Needed to ensure page tables are always accessible in
  the presence of kmemcheck to prevent recursive faults. Currently
  kmemcheck cannot be selected for arm64.

* __GFP_REPEAT -- Causes the allocator to try to reclaim pages and retry
  upon a failure to allocate.

* __GFP_ZERO -- Sometimes passed explicitly, sometimes zalloc variants
  are used.

While we've no encountered issues so far, it would be preferable to be
consistent. This patch ensures all levels of table are allocated in the
same manner, with PGALLOC_GFP.

Cc: Steve Capper <steve.capper@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2014-11-20 12:05:18 +00:00

61 lines
1.5 KiB
C

/*
* PGD allocation/freeing
*
* Copyright (C) 2012 ARM Ltd.
* Author: Catalin Marinas <catalin.marinas@arm.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include "mm.h"
#define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t))
static struct kmem_cache *pgd_cache;
pgd_t *pgd_alloc(struct mm_struct *mm)
{
if (PGD_SIZE == PAGE_SIZE)
return (pgd_t *)__get_free_page(PGALLOC_GFP);
else
return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
}
void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
if (PGD_SIZE == PAGE_SIZE)
free_page((unsigned long)pgd);
else
kmem_cache_free(pgd_cache, pgd);
}
static int __init pgd_cache_init(void)
{
/*
* Naturally aligned pgds required by the architecture.
*/
if (PGD_SIZE != PAGE_SIZE)
pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
SLAB_PANIC, NULL);
return 0;
}
core_initcall(pgd_cache_init);