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		init_pud = pud_offset(init_pgd, 0);
88		init_pmd = pmd_offset(init_pud, 0);
89		init_pte = pte_offset_map(init_pmd, 0);
90		set_pte_ext(new_pte + 0, init_pte[0], 0);
91		set_pte_ext(new_pte + 1, init_pte[1], 0);
92		pte_unmap(init_pte);
93		pte_unmap(new_pte);
94	}
95
96	return new_pgd;
97
98no_pte:
99	pmd_free(mm, new_pmd);
100	mm_dec_nr_pmds(mm);
101no_pmd:
102	pud_free(mm, new_pud);
103no_pud:
104	__pgd_free(new_pgd);
105no_pgd:
106	return NULL;
107}
108
109void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
110{
111	pgd_t *pgd;
112	pud_t *pud;
113	pmd_t *pmd;
114	pgtable_t pte;
115
116	if (!pgd_base)
117		return;
118
119	pgd = pgd_base + pgd_index(0);
120	if (pgd_none_or_clear_bad(pgd))
121		goto no_pgd;
122
123	pud = pud_offset(pgd, 0);
124	if (pud_none_or_clear_bad(pud))
125		goto no_pud;
126
127	pmd = pmd_offset(pud, 0);
128	if (pmd_none_or_clear_bad(pmd))
129		goto no_pmd;
130
131	pte = pmd_pgtable(*pmd);
132	pmd_clear(pmd);
133	pte_free(mm, pte);
134	atomic_long_dec(&mm->nr_ptes);
135no_pmd:
136	pud_clear(pud);
137	pmd_free(mm, pmd);
138	mm_dec_nr_pmds(mm);
139no_pud:
140	pgd_clear(pgd);
141	pud_free(mm, pud);
142no_pgd:
143#ifdef CONFIG_ARM_LPAE
144	/*
145	 * Free modules/pkmap or identity pmd tables.
146	 */
147	for (pgd = pgd_base; pgd < pgd_base + PTRS_PER_PGD; pgd++) {
148		if (pgd_none_or_clear_bad(pgd))
149			continue;
150		if (pgd_val(*pgd) & L_PGD_SWAPPER)
151			continue;
152		pud = pud_offset(pgd, 0);
153		if (pud_none_or_clear_bad(pud))
154			continue;
155		pmd = pmd_offset(pud, 0);
156		pud_clear(pud);
157		pmd_free(mm, pmd);
158		mm_dec_nr_pmds(mm);
159		pgd_clear(pgd);
160		pud_free(mm, pud);
161	}
162#endif
163	__pgd_free(pgd_base);
164}
165