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>
13 #include <linux/slab.h>
15 #include <asm/pgalloc.h>
17 #include <asm/tlbflush.h>
22 * need to get a 16k page for level 1
24 pgd_t *pgd_alloc(struct mm_struct *mm)
26 pgd_t *new_pgd, *init_pgd;
27 pud_t *new_pud, *init_pud;
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, USER_PTRS_PER_PGD * sizeof(pgd_t));
38 * Copy over the kernel and IO PGD entries
40 init_pgd = pgd_offset_k(0);
41 memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
42 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * 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_pud = pud_alloc(mm, new_pgd, 0);
55 new_pmd = pmd_alloc(mm, new_pud, 0);
59 new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
63 init_pud = pud_offset(init_pgd, 0);
64 init_pmd = pmd_offset(init_pud, 0);
65 init_pte = pte_offset_map(init_pmd, 0);
66 set_pte_ext(new_pte, *init_pte, 0);
71 #ifdef CONFIG_ARM_HUGETLB_SUPPORT
72 /* reset the hugepage linux pte pointer
73 * for new mm_struct when we do the fork
75 mm->context.huge_linux_pte = NULL;
80 pmd_free(mm, new_pmd);
82 pud_free(mm, new_pud);
84 free_pages((unsigned long)new_pgd, 2);
86 #ifdef CONFIG_ARM_HUGETLB_SUPPORT
87 /* free huge linux pte table */
88 if (mm->context.huge_linux_pte != NULL)
89 kfree(mm->context.huge_linux_pte);
94 void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
104 pgd = pgd_base + pgd_index(0);
105 if (pgd_none_or_clear_bad(pgd))
108 pud = pud_offset(pgd, 0);
109 if (pud_none_or_clear_bad(pud))
112 pmd = pmd_offset(pud, 0);
113 if (pmd_none_or_clear_bad(pmd))
116 pte = pmd_pgtable(*pmd);
126 free_pages((unsigned long) pgd_base, 2);