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#include <linux/mm_types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kmemcheck.h>
void kmemcheck_alloc_shadow(struct kmem_cache *s, gfp_t flags, int node,
struct page *page, int order)
{
struct page *shadow;
int pages;
int i;
pages = 1 << order;
/*
* With kmemcheck enabled, we need to allocate a memory area for the
* shadow bits as well.
*/
shadow = alloc_pages_node(node, flags, order);
if (!shadow) {
if (printk_ratelimit())
printk(KERN_ERR "kmemcheck: failed to allocate "
"shadow bitmap\n");
return;
}
for(i = 0; i < pages; ++i)
page[i].shadow = page_address(&shadow[i]);
/*
* Mark it as non-present for the MMU so that our accesses to
* this memory will trigger a page fault and let us analyze
* the memory accesses.
*/
kmemcheck_hide_pages(page, pages);
/*
* Objects from caches that have a constructor don't get
* cleared when they're allocated, so we need to do it here.
*/
if (s->ctor)
kmemcheck_mark_uninitialized_pages(page, pages);
else
kmemcheck_mark_unallocated_pages(page, pages);
}
void kmemcheck_free_shadow(struct kmem_cache *s, struct page *page, int order)
{
struct page *shadow;
int pages;
int i;
pages = 1 << order;
kmemcheck_show_pages(page, pages);
shadow = virt_to_page(page[0].shadow);
for(i = 0; i < pages; ++i)
page[i].shadow = NULL;
__free_pages(shadow, order);
}
void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
size_t size)
{
/*
* Has already been memset(), which initializes the shadow for us
* as well.
*/
if (gfpflags & __GFP_ZERO)
return;
/* No need to initialize the shadow of a non-tracked slab. */
if (s->flags & SLAB_NOTRACK)
return;
if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
/*
* Allow notracked objects to be allocated from
* tracked caches. Note however that these objects
* will still get page faults on access, they just
* won't ever be flagged as uninitialized. If page
* faults are not acceptable, the slab cache itself
* should be marked NOTRACK.
*/
kmemcheck_mark_initialized(object, size);
} else if (!s->ctor) {
/*
* New objects should be marked uninitialized before
* they're returned to the called.
*/
kmemcheck_mark_uninitialized(object, size);
}
}
void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
{
/* TODO: RCU freeing is unsupported for now; hide false positives. */
if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU))
kmemcheck_mark_freed(object, size);
}
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