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2dff4405 VN |
1 | #include <linux/mm_types.h> |
2 | #include <linux/mm.h> | |
3 | #include <linux/slab.h> | |
4 | #include <linux/kmemcheck.h> | |
5 | ||
6 | void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node, | |
7 | struct page *page, int order) | |
8 | { | |
9 | struct page *shadow; | |
10 | int pages; | |
11 | int i; | |
12 | ||
13 | pages = 1 << order; | |
14 | ||
15 | /* | |
16 | * With kmemcheck enabled, we need to allocate a memory area for the | |
17 | * shadow bits as well. | |
18 | */ | |
19 | shadow = alloc_pages_node(node, flags, order); | |
20 | if (!shadow) { | |
21 | if (printk_ratelimit()) | |
22 | printk(KERN_ERR "kmemcheck: failed to allocate " | |
23 | "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 | * Objects from caches that have a constructor don't get | |
39 | * cleared when they're allocated, so we need to do it here. | |
40 | */ | |
41 | if (s->ctor) | |
42 | kmemcheck_mark_uninitialized_pages(page, pages); | |
43 | else | |
44 | kmemcheck_mark_unallocated_pages(page, pages); | |
45 | } | |
46 | ||
47 | void kmemcheck_free_shadow(struct kmem_cache *s, struct page *page, int order) | |
48 | { | |
49 | struct page *shadow; | |
50 | int pages; | |
51 | int i; | |
52 | ||
53 | pages = 1 << order; | |
54 | ||
55 | kmemcheck_show_pages(page, pages); | |
56 | ||
57 | shadow = virt_to_page(page[0].shadow); | |
58 | ||
59 | for(i = 0; i < pages; ++i) | |
60 | page[i].shadow = NULL; | |
61 | ||
62 | __free_pages(shadow, order); | |
63 | } | |
64 | ||
65 | void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object, | |
66 | size_t size) | |
67 | { | |
68 | /* | |
69 | * Has already been memset(), which initializes the shadow for us | |
70 | * as well. | |
71 | */ | |
72 | if (gfpflags & __GFP_ZERO) | |
73 | return; | |
74 | ||
75 | /* No need to initialize the shadow of a non-tracked slab. */ | |
76 | if (s->flags & SLAB_NOTRACK) | |
77 | return; | |
78 | ||
79 | if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) { | |
80 | /* | |
81 | * Allow notracked objects to be allocated from | |
82 | * tracked caches. Note however that these objects | |
83 | * will still get page faults on access, they just | |
84 | * won't ever be flagged as uninitialized. If page | |
85 | * faults are not acceptable, the slab cache itself | |
86 | * should be marked NOTRACK. | |
87 | */ | |
88 | kmemcheck_mark_initialized(object, size); | |
89 | } else if (!s->ctor) { | |
90 | /* | |
91 | * New objects should be marked uninitialized before | |
92 | * they're returned to the called. | |
93 | */ | |
94 | kmemcheck_mark_uninitialized(object, size); | |
95 | } | |
96 | } | |
97 | ||
98 | void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size) | |
99 | { | |
100 | /* TODO: RCU freeing is unsupported for now; hide false positives. */ | |
101 | if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU)) | |
102 | kmemcheck_mark_freed(object, size); | |
103 | } |