2 * linux/arch/arm/mm/pgd.c
4 * Copyright (C) 1998-2005 Russell King
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.
11 #include <linux/gfp.h>
12 #include <linux/highmem.h>
14 #include <asm/pgalloc.h>
16 #include <asm/tlbflush.h>
21 * need to get a 16k page for level 1
23 pgd_t *pgd_alloc(struct mm_struct *mm)
25 pgd_t *new_pgd, *init_pgd;
26 pmd_t *new_pmd, *init_pmd;
27 pte_t *new_pte, *init_pte;
29 new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
33 memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
36 * Copy over the kernel and IO PGD entries
38 init_pgd = pgd_offset_k(0);
39 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
40 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
42 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
44 if (!vectors_high()) {
46 * On ARM, first page must always be allocated since it
47 * contains the machine vectors.
49 new_pmd = pmd_alloc(mm, new_pgd, 0);
53 new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
57 init_pmd = pmd_offset(init_pgd, 0);
58 init_pte = pte_offset_map(init_pmd, 0);
59 set_pte_ext(new_pte, *init_pte, 0);
67 pmd_free(mm, new_pmd);
69 free_pages((unsigned long)new_pgd, 2);
74 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
83 pgd = pgd_base + pgd_index(0);
84 if (pgd_none_or_clear_bad(pgd))
87 pmd = pmd_offset(pgd, 0);
88 if (pmd_none_or_clear_bad(pmd))
91 pte = pmd_pgtable(*pmd);
98 free_pages((unsigned long) pgd_base, 2);