1 /* 2 * linux/arch/arm/mm/pgd.c 3 * 4 * Copyright (C) 1998-2005 Russell King 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 #include <linux/mm.h> 11 #include <linux/gfp.h> 12 #include <linux/highmem.h> 13 14 #include <asm/pgalloc.h> 15 #include <asm/page.h> 16 #include <asm/tlbflush.h> 17 18 #include "mm.h" 19 20 /* 21 * need to get a 16k page for level 1 22 */ 23 pgd_t *pgd_alloc(struct mm_struct *mm) 24 { 25 pgd_t *new_pgd, *init_pgd; 26 pud_t *new_pud, *init_pud; 27 pmd_t *new_pmd, *init_pmd; 28 pte_t *new_pte, *init_pte; 29 30 new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2); 31 if (!new_pgd) 32 goto no_pgd; 33 34 memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 35 36 /* 37 * Copy over the kernel and IO PGD entries 38 */ 39 init_pgd = pgd_offset_k(0); 40 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD, 41 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 42 43 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t)); 44 45 if (!vectors_high()) { 46 /* 47 * On ARM, first page must always be allocated since it 48 * contains the machine vectors. 49 */ 50 new_pud = pud_alloc(mm, new_pgd, 0); 51 if (!new_pud) 52 goto no_pud; 53 54 new_pmd = pmd_alloc(mm, new_pud, 0); 55 if (!new_pmd) 56 goto no_pmd; 57 58 new_pte = pte_alloc_map(mm, NULL, new_pmd, 0); 59 if (!new_pte) 60 goto no_pte; 61 62 init_pud = pud_offset(init_pgd, 0); 63 init_pmd = pmd_offset(init_pud, 0); 64 init_pte = pte_offset_map(init_pmd, 0); 65 set_pte_ext(new_pte, *init_pte, 0); 66 pte_unmap(init_pte); 67 pte_unmap(new_pte); 68 } 69 70 return new_pgd; 71 72 no_pte: 73 pmd_free(mm, new_pmd); 74 no_pmd: 75 pud_free(mm, new_pud); 76 no_pud: 77 free_pages((unsigned long)new_pgd, 2); 78 no_pgd: 79 return NULL; 80 } 81 82 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base) 83 { 84 pgd_t *pgd; 85 pud_t *pud; 86 pmd_t *pmd; 87 pgtable_t pte; 88 89 if (!pgd_base) 90 return; 91 92 pgd = pgd_base + pgd_index(0); 93 if (pgd_none_or_clear_bad(pgd)) 94 goto no_pgd; 95 96 pud = pud_offset(pgd, 0); 97 if (pud_none_or_clear_bad(pud)) 98 goto no_pud; 99 100 pmd = pmd_offset(pud, 0); 101 if (pmd_none_or_clear_bad(pmd)) 102 goto no_pmd; 103 104 pte = pmd_pgtable(*pmd); 105 pmd_clear(pmd); 106 pte_free(mm, pte); 107 no_pmd: 108 pud_clear(pud); 109 pmd_free(mm, pmd); 110 no_pud: 111 pgd_clear(pgd); 112 pud_free(mm, pud); 113 no_pgd: 114 free_pages((unsigned long) pgd_base, 2); 115 } 116