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#include <linux/slab.h>
14
15#include <asm/cp15.h>
16#include <asm/pgalloc.h>
17#include <asm/page.h>
18#include <asm/tlbflush.h>
19
20#include "mm.h"
21
22#ifdef CONFIG_ARM_LPAE
23#define __pgd_alloc()	kmalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL)
24#define __pgd_free(pgd)	kfree(pgd)
25#else
26#define __pgd_alloc()	(pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_REPEAT, 2)
27#define __pgd_free(pgd)	free_pages((unsigned long)pgd, 2)
28#endif
29
30/*
31 * need to get a 16k page for level 1
32 */
33pgd_t *pgd_alloc(struct mm_struct *mm)
34{
35	pgd_t *new_pgd, *init_pgd;
36	pud_t *new_pud, *init_pud;
37	pmd_t *new_pmd, *init_pmd;
38	pte_t *new_pte, *init_pte;
39
40	new_pgd = __pgd_alloc();
41	if (!new_pgd)
42		goto no_pgd;
43
44	memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
45
46	/*
47	 * Copy over the kernel and IO PGD entries
48	 */
49	init_pgd = pgd_offset_k(0);
50	memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
51		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
52
53	clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
54
55#ifdef CONFIG_ARM_LPAE
56	/*
57	 * Allocate PMD table for modules and pkmap mappings.
58	 */
59	new_pud = pud_alloc(mm, new_pgd + pgd_index(MODULES_VADDR),
60			    MODULES_VADDR);
61	if (!new_pud)
62		goto no_pud;
63
64	new_pmd = pmd_alloc(mm, new_pud, 0);
65	if (!new_pmd)
66		goto no_pmd;
67#endif
68
69	if (!vectors_high()) {
70		/*
71		 * On ARM, first page must always be allocated since it
72		 * contains the machine vectors. The vectors are always high
73		 * with LPAE.
74		 */
75		new_pud = pud_alloc(mm, new_pgd, 0);
76		if (!new_pud)
77			goto no_pud;
78
79		new_pmd = pmd_alloc(mm, new_pud, 0);
80		if (!new_pmd)
81			goto no_pmd;
82
83		new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
84		if (!new_pte)
85			goto no_pte;
86
87#ifndef CONFIG_ARM_LPAE
88		/*
89		 * Modify the PTE pointer to have the correct domain.  This
90		 * needs to be the vectors domain to avoid the low vectors
91		 * being unmapped.
92		 */
93		pmd_val(*new_pmd) &= ~PMD_DOMAIN_MASK;
94		pmd_val(*new_pmd) |= PMD_DOMAIN(DOMAIN_VECTORS);
95#endif
96
97		init_pud = pud_offset(init_pgd, 0);
98		init_pmd = pmd_offset(init_pud, 0);
99		init_pte = pte_offset_map(init_pmd, 0);
100		set_pte_ext(new_pte + 0, init_pte[0], 0);
101		set_pte_ext(new_pte + 1, init_pte[1], 0);
102		pte_unmap(init_pte);
103		pte_unmap(new_pte);
104	}
105
106	return new_pgd;
107
108no_pte:
109	pmd_free(mm, new_pmd);
110	mm_dec_nr_pmds(mm);
111no_pmd:
112	pud_free(mm, new_pud);
113no_pud:
114	__pgd_free(new_pgd);
115no_pgd:
116	return NULL;
117}
118
119void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
120{
121	pgd_t *pgd;
122	pud_t *pud;
123	pmd_t *pmd;
124	pgtable_t pte;
125
126	if (!pgd_base)
127		return;
128
129	pgd = pgd_base + pgd_index(0);
130	if (pgd_none_or_clear_bad(pgd))
131		goto no_pgd;
132
133	pud = pud_offset(pgd, 0);
134	if (pud_none_or_clear_bad(pud))
135		goto no_pud;
136
137	pmd = pmd_offset(pud, 0);
138	if (pmd_none_or_clear_bad(pmd))
139		goto no_pmd;
140
141	pte = pmd_pgtable(*pmd);
142	pmd_clear(pmd);
143	pte_free(mm, pte);
144	atomic_long_dec(&mm->nr_ptes);
145no_pmd:
146	pud_clear(pud);
147	pmd_free(mm, pmd);
148	mm_dec_nr_pmds(mm);
149no_pud:
150	pgd_clear(pgd);
151	pud_free(mm, pud);
152no_pgd:
153#ifdef CONFIG_ARM_LPAE
154	/*
155	 * Free modules/pkmap or identity pmd tables.
156	 */
157	for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
158		if (pgd_none_or_clear_bad(pgd))
159			continue;
160		if (pgd_val(*pgd) & L_PGD_SWAPPER)
161			continue;
162		pud = pud_offset(pgd, 0);
163		if (pud_none_or_clear_bad(pud))
164			continue;
165		pmd = pmd_offset(pud, 0);
166		pud_clear(pud);
167		pmd_free(mm, pmd);
168		mm_dec_nr_pmds(mm);
169		pgd_clear(pgd);
170		pud_free(mm, pud);
171	}
172#endif
173	__pgd_free(pgd_base);
174}
175