[Intel-gfx] [PATCH] drm/i915: Enforce execobject.alignment to be a power-of-two

[Chris Wilson]

Internal requirement for the alignment is that it must be a
power-of-two, so enforce rejection at the user interface to execbuffer
(which allows the caller to specify a stricter-than-expected alignment
criterion).

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index f4fb2bd33753..b14733908d8d 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1189,6 +1189,9 @@ validate_exec_list(const struct drm_i915_gem_execbuffer2 *args,
 		if (exec[i].flags & invalid_flags)
 			return -EINVAL;
 
+		if (exec[i].alignment && !is_power_of_2(exec[i].alignment))
+			return -EINVAL;
+
 		/* pad_to_size was once a reserved field, so sanitize it */
 		if (exec[i].flags & EXEC_OBJECT_PAD_TO_SIZE) {
 			if (offset_in_page(exec[i].pad_to_size))
-- 
2.1.4