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1 | #include <linux/gfp.h> | |
2 | #include <linux/mm_types.h> | |
3 | #include <linux/mm.h> | |
4 | #include <linux/slab.h> | |
5 | #include "slab.h" | |
6 | #include <linux/kmemcheck.h> | |
7 | ||
8 | void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node) | |
9 | { | |
10 | struct page *shadow; | |
11 | int pages; | |
12 | int i; | |
13 | ||
14 | pages = 1 << order; | |
15 | ||
16 | /* | |
17 | * With kmemcheck enabled, we need to allocate a memory area for the | |
18 | * shadow bits as well. | |
19 | */ | |
20 | shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order); | |
21 | if (!shadow) { | |
22 | if (printk_ratelimit()) | |
23 | pr_err("kmemcheck: failed to allocate shadow bitmap\n"); | |
24 | return; | |
25 | } | |
26 | ||
27 | for(i = 0; i < pages; ++i) | |
28 | page[i].shadow = page_address(&shadow[i]); | |
29 | ||
30 | /* | |
31 | * Mark it as non-present for the MMU so that our accesses to | |
32 | * this memory will trigger a page fault and let us analyze | |
33 | * the memory accesses. | |
34 | */ | |
35 | kmemcheck_hide_pages(page, pages); | |
36 | } | |
37 | ||
38 | void kmemcheck_free_shadow(struct page *page, int order) | |
39 | { | |
40 | struct page *shadow; | |
41 | int pages; | |
42 | int i; | |
43 | ||
44 | if (!kmemcheck_page_is_tracked(page)) | |
45 | return; | |
46 | ||
47 | pages = 1 << order; | |
48 | ||
49 | kmemcheck_show_pages(page, pages); | |
50 | ||
51 | shadow = virt_to_page(page[0].shadow); | |
52 | ||
53 | for(i = 0; i < pages; ++i) | |
54 | page[i].shadow = NULL; | |
55 | ||
56 | __free_pages(shadow, order); | |
57 | } | |
58 | ||
59 | void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object, | |
60 | size_t size) | |
61 | { | |
62 | if (unlikely(!object)) /* Skip object if allocation failed */ | |
63 | return; | |
64 | ||
65 | /* | |
66 | * Has already been memset(), which initializes the shadow for us | |
67 | * as well. | |
68 | */ | |
69 | if (gfpflags & __GFP_ZERO) | |
70 | return; | |
71 | ||
72 | /* No need to initialize the shadow of a non-tracked slab. */ | |
73 | if (s->flags & SLAB_NOTRACK) | |
74 | return; | |
75 | ||
76 | if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) { | |
77 | /* | |
78 | * Allow notracked objects to be allocated from | |
79 | * tracked caches. Note however that these objects | |
80 | * will still get page faults on access, they just | |
81 | * won't ever be flagged as uninitialized. If page | |
82 | * faults are not acceptable, the slab cache itself | |
83 | * should be marked NOTRACK. | |
84 | */ | |
85 | kmemcheck_mark_initialized(object, size); | |
86 | } else if (!s->ctor) { | |
87 | /* | |
88 | * New objects should be marked uninitialized before | |
89 | * they're returned to the called. | |
90 | */ | |
91 | kmemcheck_mark_uninitialized(object, size); | |
92 | } | |
93 | } | |
94 | ||
95 | void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size) | |
96 | { | |
97 | /* TODO: RCU freeing is unsupported for now; hide false positives. */ | |
98 | if (!s->ctor && !(s->flags & SLAB_TYPESAFE_BY_RCU)) | |
99 | kmemcheck_mark_freed(object, size); | |
100 | } | |
101 | ||
102 | void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order, | |
103 | gfp_t gfpflags) | |
104 | { | |
105 | int pages; | |
106 | ||
107 | if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK)) | |
108 | return; | |
109 | ||
110 | pages = 1 << order; | |
111 | ||
112 | /* | |
113 | * NOTE: We choose to track GFP_ZERO pages too; in fact, they | |
114 | * can become uninitialized by copying uninitialized memory | |
115 | * into them. | |
116 | */ | |
117 | ||
118 | /* XXX: Can use zone->node for node? */ | |
119 | kmemcheck_alloc_shadow(page, order, gfpflags, -1); | |
120 | ||
121 | if (gfpflags & __GFP_ZERO) | |
122 | kmemcheck_mark_initialized_pages(page, pages); | |
123 | else | |
124 | kmemcheck_mark_uninitialized_pages(page, pages); | |
125 | } |