[mirror_ubuntu-artful-kernel.git] / mm / kmemcheck.c

#include <linux/gfp.h>
#include <linux/mm_types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/kmemcheck.h>

void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
{
	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 | __GFP_NOTRACK, 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);
}

void kmemcheck_free_shadow(struct page *page, int order)
{
	struct page *shadow;
	int pages;
	int i;

	if (!kmemcheck_page_is_tracked(page))
		return;

	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);
}

void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
			       gfp_t gfpflags)
{
	int pages;

	if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
		return;

	pages = 1 << order;

	/*
	 * NOTE: We choose to track GFP_ZERO pages too; in fact, they
	 * can become uninitialized by copying uninitialized memory
	 * into them.
	 */

	/* XXX: Can use zone->node for node? */
	kmemcheck_alloc_shadow(page, order, gfpflags, -1);

	if (gfpflags & __GFP_ZERO)
		kmemcheck_mark_initialized_pages(page, pages);
	else
		kmemcheck_mark_uninitialized_pages(page, pages);
}
Commit	Line	Data
b1eeab67	1	#include <linux/gfp.h>
2dff4405 VN	2	#include <linux/mm_types.h>
	3	#include <linux/mm.h>
	4	#include <linux/slab.h>
	5	#include <linux/kmemcheck.h>
	6
b1eeab67	7	void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
2dff4405 VN	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	*/
b1eeab67	19	shadow = alloc_pages_node(node, flags \| __GFP_NOTRACK, order);
2dff4405 VN	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);
2dff4405 VN	36	}
2dff4405 VN	37
b1eeab67	38	void kmemcheck_free_shadow(struct page *page, int order)
2dff4405 VN	39	{
	40	struct page *shadow;
	41	int pages;
	42	int i;
	43
b1eeab67 VN	44	if (!kmemcheck_page_is_tracked(page))
	45	return;
	46
2dff4405 VN	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	/*
	63	* Has already been memset(), which initializes the shadow for us
	64	* as well.
	65	*/
	66	if (gfpflags & __GFP_ZERO)
	67	return;
	68
	69	/* No need to initialize the shadow of a non-tracked slab. */
	70	if (s->flags & SLAB_NOTRACK)
	71	return;
	72
	73	if (!kmemcheck_enabled \|\| gfpflags & __GFP_NOTRACK) {
	74	/*
	75	* Allow notracked objects to be allocated from
	76	* tracked caches. Note however that these objects
	77	* will still get page faults on access, they just
	78	* won't ever be flagged as uninitialized. If page
	79	* faults are not acceptable, the slab cache itself
	80	* should be marked NOTRACK.
	81	*/
	82	kmemcheck_mark_initialized(object, size);
	83	} else if (!s->ctor) {
	84	/*
	85	* New objects should be marked uninitialized before
	86	* they're returned to the called.
	87	*/
	88	kmemcheck_mark_uninitialized(object, size);
	89	}
	90	}
	91
	92	void kmemcheck_slab_free(struct kmem_cache s, void object, size_t size)
	93	{
	94	/* TODO: RCU freeing is unsupported for now; hide false positives. */
	95	if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU))
	96	kmemcheck_mark_freed(object, size);
	97	}
b1eeab67 VN	98
	99	void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
	100	gfp_t gfpflags)
	101	{
	102	int pages;
	103
	104	if (gfpflags & (__GFP_HIGHMEM \| __GFP_NOTRACK))
	105	return;
	106
	107	pages = 1 << order;
	108
	109	/*
	110	* NOTE: We choose to track GFP_ZERO pages too; in fact, they
	111	* can become uninitialized by copying uninitialized memory
	112	* into them.
	113	*/
	114
	115	/* XXX: Can use zone->node for node? */
	116	kmemcheck_alloc_shadow(page, order, gfpflags, -1);
	117
	118	if (gfpflags & __GFP_ZERO)
	119	kmemcheck_mark_initialized_pages(page, pages);
	120	else
	121	kmemcheck_mark_uninitialized_pages(page, pages);
	122	}