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1da177e4 LT |
1 | /* pgalloc.c: page directory & page table allocation |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/sched.h> | |
5a0e3ad6 | 13 | #include <linux/gfp.h> |
1da177e4 LT |
14 | #include <linux/mm.h> |
15 | #include <linux/highmem.h> | |
8defab33 | 16 | #include <linux/quicklist.h> |
1da177e4 LT |
17 | #include <asm/pgalloc.h> |
18 | #include <asm/page.h> | |
19 | #include <asm/cacheflush.h> | |
20 | ||
21 | pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((aligned(PAGE_SIZE))); | |
1da177e4 LT |
22 | |
23 | pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) | |
24 | { | |
32d6bd90 | 25 | pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL); |
1da177e4 LT |
26 | if (pte) |
27 | clear_page(pte); | |
28 | return pte; | |
29 | } | |
30 | ||
2f569afd | 31 | pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) |
1da177e4 LT |
32 | { |
33 | struct page *page; | |
34 | ||
35 | #ifdef CONFIG_HIGHPTE | |
32d6bd90 | 36 | page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM, 0); |
1da177e4 | 37 | #else |
32d6bd90 | 38 | page = alloc_pages(GFP_KERNEL, 0); |
1da177e4 | 39 | #endif |
3b9cf77d KS |
40 | if (!page) |
41 | return NULL; | |
42 | ||
43 | clear_highpage(page); | |
44 | if (!pgtable_page_ctor(page)) { | |
45 | __free_page(page); | |
46 | return NULL; | |
2f569afd | 47 | } |
3b9cf77d | 48 | flush_dcache_page(page); |
1da177e4 LT |
49 | return page; |
50 | } | |
51 | ||
52 | void __set_pmd(pmd_t *pmdptr, unsigned long pmd) | |
53 | { | |
54 | unsigned long *__ste_p = pmdptr->ste; | |
55 | int loop; | |
56 | ||
57 | if (!pmd) { | |
58 | memset(__ste_p, 0, PME_SIZE); | |
59 | } | |
60 | else { | |
61 | BUG_ON(pmd & (0x3f00 | xAMPRx_SS | 0xe)); | |
62 | ||
63 | for (loop = PME_SIZE; loop > 0; loop -= 4) { | |
64 | *__ste_p++ = pmd; | |
65 | pmd += __frv_PT_SIZE; | |
66 | } | |
67 | } | |
68 | ||
69 | frv_dcache_writeback((unsigned long) pmdptr, (unsigned long) (pmdptr + 1)); | |
70 | } | |
71 | ||
72 | /* | |
73 | * List of all pgd's needed for non-PAE so it can invalidate entries | |
74 | * in both cached and uncached pgd's; not needed for PAE since the | |
75 | * kernel pmd is shared. If PAE were not to share the pmd a similar | |
76 | * tactic would be needed. This is essentially codepath-based locking | |
77 | * against pageattr.c; it is the unique case in which a valid change | |
78 | * of kernel pagetables can't be lazily synchronized by vmalloc faults. | |
79 | * vmalloc faults work because attached pagetables are never freed. | |
80 | * If the locking proves to be non-performant, a ticketing scheme with | |
81 | * checks at dup_mmap(), exec(), and other mmlist addition points | |
82 | * could be used. The locking scheme was chosen on the basis of | |
83 | * manfred's recommendations and having no core impact whatsoever. | |
6d49e352 | 84 | * -- nyc |
1da177e4 LT |
85 | */ |
86 | DEFINE_SPINLOCK(pgd_lock); | |
87 | struct page *pgd_list; | |
88 | ||
89 | static inline void pgd_list_add(pgd_t *pgd) | |
90 | { | |
91 | struct page *page = virt_to_page(pgd); | |
92 | page->index = (unsigned long) pgd_list; | |
93 | if (pgd_list) | |
8080f231 | 94 | set_page_private(pgd_list, (unsigned long) &page->index); |
1da177e4 | 95 | pgd_list = page; |
4c21e2f2 | 96 | set_page_private(page, (unsigned long)&pgd_list); |
1da177e4 LT |
97 | } |
98 | ||
99 | static inline void pgd_list_del(pgd_t *pgd) | |
100 | { | |
101 | struct page *next, **pprev, *page = virt_to_page(pgd); | |
102 | next = (struct page *) page->index; | |
8080f231 | 103 | pprev = (struct page **) page_private(page); |
1da177e4 LT |
104 | *pprev = next; |
105 | if (next) | |
8080f231 | 106 | set_page_private(next, (unsigned long) pprev); |
1da177e4 LT |
107 | } |
108 | ||
8defab33 | 109 | void pgd_ctor(void *pgd) |
1da177e4 LT |
110 | { |
111 | unsigned long flags; | |
112 | ||
113 | if (PTRS_PER_PMD == 1) | |
114 | spin_lock_irqsave(&pgd_lock, flags); | |
115 | ||
116 | memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4, | |
117 | swapper_pg_dir + USER_PGDS_IN_LAST_PML4, | |
118 | (PTRS_PER_PGD - USER_PGDS_IN_LAST_PML4) * sizeof(pgd_t)); | |
119 | ||
120 | if (PTRS_PER_PMD > 1) | |
121 | return; | |
122 | ||
123 | pgd_list_add(pgd); | |
124 | spin_unlock_irqrestore(&pgd_lock, flags); | |
125 | memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t)); | |
126 | } | |
127 | ||
128 | /* never called when PTRS_PER_PMD > 1 */ | |
8defab33 | 129 | void pgd_dtor(void *pgd) |
1da177e4 LT |
130 | { |
131 | unsigned long flags; /* can be called from interrupt context */ | |
132 | ||
133 | spin_lock_irqsave(&pgd_lock, flags); | |
134 | pgd_list_del(pgd); | |
135 | spin_unlock_irqrestore(&pgd_lock, flags); | |
136 | } | |
137 | ||
138 | pgd_t *pgd_alloc(struct mm_struct *mm) | |
139 | { | |
dbfe8987 | 140 | return quicklist_alloc(0, GFP_KERNEL, pgd_ctor); |
1da177e4 LT |
141 | } |
142 | ||
5e541973 | 143 | void pgd_free(struct mm_struct *mm, pgd_t *pgd) |
1da177e4 LT |
144 | { |
145 | /* in the non-PAE case, clear_page_tables() clears user pgd entries */ | |
8defab33 | 146 | quicklist_free(0, pgd_dtor, pgd); |
1da177e4 LT |
147 | } |
148 | ||
149 | void __init pgtable_cache_init(void) | |
150 | { | |
1da177e4 | 151 | } |
8defab33 CL |
152 | |
153 | void check_pgt_cache(void) | |
154 | { | |
155 | quicklist_trim(0, pgd_dtor, 25, 16); | |
156 | } | |
157 |