arch/arm64/mm/pgd.c

   1 /*
   2  * PGD allocation/freeing
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  * Author: Catalin Marinas <catalin.marinas@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/mm.h>
  21 #include <linux/gfp.h>
  22 #include <linux/highmem.h>
  23 #include <linux/slab.h>
  24
  25 #include <asm/pgalloc.h>
  26 #include <asm/page.h>
  27 #include <asm/tlbflush.h>
  28
  29 #include "mm.h"
  30
  31 #define PGD_SIZE        (PTRS_PER_PGD * sizeof(pgd_t))
  32
  33 static struct kmem_cache *pgd_cache;
  34
  35 pgd_t *pgd_alloc(struct mm_struct *mm)
  36 {
  37         if (PGD_SIZE == PAGE_SIZE)
  38                 return (pgd_t *)get_zeroed_page(GFP_KERNEL);
  39         else
  40                 return kmem_cache_zalloc(pgd_cache, GFP_KERNEL);
  41 }
  42
  43 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  44 {
  45         if (PGD_SIZE == PAGE_SIZE)
  46                 free_page((unsigned long)pgd);
  47         else
  48                 kmem_cache_free(pgd_cache, pgd);
  49 }
  50
  51 static int __init pgd_cache_init(void)
  52 {
  53         /*
  54          * Naturally aligned pgds required by the architecture.
  55          */
  56         if (PGD_SIZE != PAGE_SIZE)
  57                 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
  58                                               SLAB_PANIC, NULL);
  59         return 0;
  60 }
  61 core_initcall(pgd_cache_init);