Commit | Line | Data |
---|---|---|
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> | |
13 | #include <linux/slab.h> | |
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 | { | |
25 | pte_t *pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT); | |
26 | if (pte) | |
27 | clear_page(pte); | |
28 | return pte; | |
29 | } | |
30 | ||
31 | struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address) | |
32 | { | |
33 | struct page *page; | |
34 | ||
35 | #ifdef CONFIG_HIGHPTE | |
36 | page = alloc_pages(GFP_KERNEL|__GFP_HIGHMEM|__GFP_REPEAT, 0); | |
37 | #else | |
38 | page = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0); | |
39 | #endif | |
40 | if (page) | |
41 | clear_highpage(page); | |
42 | flush_dcache_page(page); | |
43 | return page; | |
44 | } | |
45 | ||
46 | void __set_pmd(pmd_t *pmdptr, unsigned long pmd) | |
47 | { | |
48 | unsigned long *__ste_p = pmdptr->ste; | |
49 | int loop; | |
50 | ||
51 | if (!pmd) { | |
52 | memset(__ste_p, 0, PME_SIZE); | |
53 | } | |
54 | else { | |
55 | BUG_ON(pmd & (0x3f00 | xAMPRx_SS | 0xe)); | |
56 | ||
57 | for (loop = PME_SIZE; loop > 0; loop -= 4) { | |
58 | *__ste_p++ = pmd; | |
59 | pmd += __frv_PT_SIZE; | |
60 | } | |
61 | } | |
62 | ||
63 | frv_dcache_writeback((unsigned long) pmdptr, (unsigned long) (pmdptr + 1)); | |
64 | } | |
65 | ||
66 | /* | |
67 | * List of all pgd's needed for non-PAE so it can invalidate entries | |
68 | * in both cached and uncached pgd's; not needed for PAE since the | |
69 | * kernel pmd is shared. If PAE were not to share the pmd a similar | |
70 | * tactic would be needed. This is essentially codepath-based locking | |
71 | * against pageattr.c; it is the unique case in which a valid change | |
72 | * of kernel pagetables can't be lazily synchronized by vmalloc faults. | |
73 | * vmalloc faults work because attached pagetables are never freed. | |
74 | * If the locking proves to be non-performant, a ticketing scheme with | |
75 | * checks at dup_mmap(), exec(), and other mmlist addition points | |
76 | * could be used. The locking scheme was chosen on the basis of | |
77 | * manfred's recommendations and having no core impact whatsoever. | |
78 | * -- wli | |
79 | */ | |
80 | DEFINE_SPINLOCK(pgd_lock); | |
81 | struct page *pgd_list; | |
82 | ||
83 | static inline void pgd_list_add(pgd_t *pgd) | |
84 | { | |
85 | struct page *page = virt_to_page(pgd); | |
86 | page->index = (unsigned long) pgd_list; | |
87 | if (pgd_list) | |
8080f231 | 88 | set_page_private(pgd_list, (unsigned long) &page->index); |
1da177e4 | 89 | pgd_list = page; |
4c21e2f2 | 90 | set_page_private(page, (unsigned long)&pgd_list); |
1da177e4 LT |
91 | } |
92 | ||
93 | static inline void pgd_list_del(pgd_t *pgd) | |
94 | { | |
95 | struct page *next, **pprev, *page = virt_to_page(pgd); | |
96 | next = (struct page *) page->index; | |
8080f231 | 97 | pprev = (struct page **) page_private(page); |
1da177e4 LT |
98 | *pprev = next; |
99 | if (next) | |
8080f231 | 100 | set_page_private(next, (unsigned long) pprev); |
1da177e4 LT |
101 | } |
102 | ||
8defab33 | 103 | void pgd_ctor(void *pgd) |
1da177e4 LT |
104 | { |
105 | unsigned long flags; | |
106 | ||
107 | if (PTRS_PER_PMD == 1) | |
108 | spin_lock_irqsave(&pgd_lock, flags); | |
109 | ||
110 | memcpy((pgd_t *) pgd + USER_PGDS_IN_LAST_PML4, | |
111 | swapper_pg_dir + USER_PGDS_IN_LAST_PML4, | |
112 | (PTRS_PER_PGD - USER_PGDS_IN_LAST_PML4) * sizeof(pgd_t)); | |
113 | ||
114 | if (PTRS_PER_PMD > 1) | |
115 | return; | |
116 | ||
117 | pgd_list_add(pgd); | |
118 | spin_unlock_irqrestore(&pgd_lock, flags); | |
119 | memset(pgd, 0, USER_PGDS_IN_LAST_PML4 * sizeof(pgd_t)); | |
120 | } | |
121 | ||
122 | /* never called when PTRS_PER_PMD > 1 */ | |
8defab33 | 123 | void pgd_dtor(void *pgd) |
1da177e4 LT |
124 | { |
125 | unsigned long flags; /* can be called from interrupt context */ | |
126 | ||
127 | spin_lock_irqsave(&pgd_lock, flags); | |
128 | pgd_list_del(pgd); | |
129 | spin_unlock_irqrestore(&pgd_lock, flags); | |
130 | } | |
131 | ||
132 | pgd_t *pgd_alloc(struct mm_struct *mm) | |
133 | { | |
134 | pgd_t *pgd; | |
135 | ||
8defab33 | 136 | pgd = quicklist_alloc(0, GFP_KERNEL, pgd_ctor); |
1da177e4 LT |
137 | if (!pgd) |
138 | return pgd; | |
139 | ||
140 | return pgd; | |
141 | } | |
142 | ||
143 | void pgd_free(pgd_t *pgd) | |
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 |