Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame^] | 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 | } |