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>
20 #define FIRST_KERNEL_PGD_NR (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
23 * need to get a 16k page for level 1
25 pgd_t *get_pgd_slow(struct mm_struct *mm)
27 pgd_t *new_pgd, *init_pgd;
28 pmd_t *new_pmd, *init_pmd;
29 pte_t *new_pte, *init_pte;
31 new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
35 memset(new_pgd, 0, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
38 * Copy over the kernel and IO PGD entries
40 init_pgd = pgd_offset_k(0);
41 memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
42 (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
44 clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
46 if (!vectors_high()) {
48 * On ARM, first page must always be allocated since it
49 * contains the machine vectors.
51 new_pmd = pmd_alloc(mm, new_pgd, 0);
55 new_pte = pte_alloc_map(mm, new_pmd, 0);
59 init_pmd = pmd_offset(init_pgd, 0);
60 init_pte = pte_offset_map_nested(init_pmd, 0);
61 set_pte_ext(new_pte, *init_pte, 0);
62 pte_unmap_nested(init_pte);
69 pmd_free(mm, new_pmd);
71 free_pages((unsigned long)new_pgd, 2);
76 void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
84 /* pgd is always present and good */
85 pmd = pmd_off(pgd, 0);
94 pte = pmd_pgtable(*pmd);
99 free_pages((unsigned long) pgd, 2);