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 static struct kmem_cache *pgd_cache __ro_after_init; 30 31 pgd_t *pgd_alloc(struct mm_struct *mm) 32 { 33 if (PGD_SIZE == PAGE_SIZE) 34 return (pgd_t *)__get_free_page(PGALLOC_GFP); 35 else 36 return kmem_cache_alloc(pgd_cache, PGALLOC_GFP); 37 } 38 39 void pgd_free(struct mm_struct *mm, pgd_t *pgd) 40 { 41 if (PGD_SIZE == PAGE_SIZE) 42 free_page((unsigned long)pgd); 43 else 44 kmem_cache_free(pgd_cache, pgd); 45 } 46 47 void __init pgd_cache_init(void) 48 { 49 if (PGD_SIZE == PAGE_SIZE) 50 return; 51 52 #ifdef CONFIG_ARM64_PA_BITS_52 53 /* 54 * With 52-bit physical addresses, the architecture requires the 55 * top-level table to be aligned to at least 64 bytes. 56 */ 57 BUILD_BUG_ON(PGD_SIZE < 64); 58 #endif 59 60 /* 61 * Naturally aligned pgds required by the architecture. 62 */ 63 pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE, 64 SLAB_PANIC, NULL); 65 } 66