linux/arch/arm64/mm/pgd.c

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/*
* 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>
static struct kmem_cache *pgd_cache __ro_after_init;
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);
}
void __init pgd_cache_init(void)
{
if (PGD_SIZE == PAGE_SIZE)
return;
#ifdef CONFIG_ARM64_PA_BITS_52
/*
* With 52-bit physical addresses, the architecture requires the
* top-level table to be aligned to at least 64 bytes.
*/
BUILD_BUG_ON(PGD_SIZE < 64);
#endif
/*
* Naturally aligned pgds required by the architecture.
*/
pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
SLAB_PANIC, NULL);
}