linux_dsm_epyc7002/arch/arm64/mm/pgd.c
Catalin Marinas 2a0b5c0d19 arm64: Align less than PAGE_SIZE pgds naturally
When the pgd size is smaller than PAGE_SIZE, pgd_alloc() uses kzalloc()
to save space. However, this is not always naturally aligned as required
by the architecture. This patch creates a kmem_cache for pgd allocations
with the correct alignment.

The current kernel configurations with 4K pages + 39-bit VA and 64K
pages + 42-bit VA use a full page for the pgd and are not affected. The
patch is required for 48-bit VA with 64K pages where the pgd is 512
bytes.

Reported-by: Christoffer Dall <christoffer.dall@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-10-20 17:47:02 +01:00

62 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_zeroed_page(GFP_KERNEL);
else
return kmem_cache_zalloc(pgd_cache, GFP_KERNEL);
}
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);