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drm/i915: Poison rings after use 

On retiring the request, we should not re-use these elements in the ring
(at least not until we fill the ringbuffer and knowingly reuse the space).
Leave behind some poison to (hopefully) trap ourselves if we make a
mistake.

Suggested-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211205615.1190127-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2020-02-11 20:56:14 +00:00
parent 42fb60de31
commit 89dd019a8a
1 changed files with 17 additions and 9 deletions
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26
drivers/gpu/drm/i915/i915_request.c
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@ -203,6 +203,19 @@ static void free_capture_list(struct i915_request *request)
}
}
static void __i915_request_fill(struct i915_request *rq, u8 val)
{
void *vaddr = rq->ring->vaddr;
u32 head;
head = rq->infix;
if (rq->postfix < head) {
memset(vaddr + head, val, rq->ring->size - head);
head = 0;
}
memset(vaddr + head, val, rq->postfix - head);
}
static void remove_from_engine(struct i915_request *rq)
{
struct intel_engine_cs *engine, *locked;
@ -247,6 +260,9 @@ bool i915_request_retire(struct i915_request *rq)
*/
GEM_BUG_ON(!list_is_first(&rq->link,
&i915_request_timeline(rq)->requests));
if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
/* Poison before we release our space in the ring */
__i915_request_fill(rq, POISON_FREE);
rq->ring->head = rq->postfix;
/*
@ -1179,9 +1195,6 @@ i915_request_await_object(struct i915_request *to,
void i915_request_skip(struct i915_request *rq, int error)
{
void *vaddr = rq->ring->vaddr;
u32 head;
GEM_BUG_ON(!IS_ERR_VALUE((long)error));
dma_fence_set_error(&rq->fence, error);
@ -1193,12 +1206,7 @@ void i915_request_skip(struct i915_request *rq, int error)
* context, clear out all the user operations leaving the
* breadcrumb at the end (so we get the fence notifications).
*/
head = rq->infix;
if (rq->postfix < head) {
memset(vaddr + head, 0, rq->ring->size - head);
head = 0;
}
memset(vaddr + head, 0, rq->postfix - head);
__i915_request_fill(rq, 0);
rq->infix = rq->postfix;
}