Two different sets of flag bits are stored in the 'flags' member of a
'struct drm_i915_gem_exec_object2', and they're defined in two different
source files, increasing the risk of an accidental clash.
Some flags in this field are supplied by the user; these are defined in
i915_drm.h, and they start from the LSB and work up.
Other flags are defined in i915_gem_execbuffer, for internal use within
that file only; they start from the MSB and work down.
So here we add a compile-time check that the two sets of flags do not
overlap, which would cause all sorts of confusion.
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 12 ++++++++----
include/uapi/drm/i915_drm.h | 11 ++++++-----
2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 7941f1f..608fdc4 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -34,10 +34,11 @@
#include <linux/dma_remapping.h>
#include <linux/uaccess.h>
-#define __EXEC_OBJECT_HAS_PIN (1<<31)
-#define __EXEC_OBJECT_HAS_FENCE (1<<30)
-#define __EXEC_OBJECT_NEEDS_MAP (1<<29)
-#define __EXEC_OBJECT_NEEDS_BIAS (1<<28)
+#define __EXEC_OBJECT_HAS_PIN (1<<31)
+#define __EXEC_OBJECT_HAS_FENCE (1<<30)
+#define __EXEC_OBJECT_NEEDS_MAP (1<<29)
+#define __EXEC_OBJECT_NEEDS_BIAS (1<<28)
+#define __EXEC_OBJECT_INTERNAL_FLAGS (0xf<<28) /* all of the above */
#define BATCH_OFFSET_BIAS (256*1024)
@@ -1007,6 +1008,9 @@ static bool only_mappable_for_reloc(unsigned int flags)
unsigned invalid_flags;
int i;
+ /* INTERNAL flags must not overlap with external ones */
+ BUILD_BUG_ON(__EXEC_OBJECT_INTERNAL_FLAGS & ~__EXEC_OBJECT_UNKNOWN_FLAGS);
+
invalid_flags = __EXEC_OBJECT_UNKNOWN_FLAGS;
if (USES_FULL_PPGTT(dev))
invalid_flags |= EXEC_OBJECT_NEEDS_GTT;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index c17d63d..079d274 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -696,12 +696,13 @@ struct drm_i915_gem_exec_object2 {
*/
__u64 offset;
-#define EXEC_OBJECT_NEEDS_FENCE (1<<0)
-#define EXEC_OBJECT_NEEDS_GTT (1<<1)
-#define EXEC_OBJECT_WRITE (1<<2)
+#define EXEC_OBJECT_NEEDS_FENCE (1<<0)
+#define EXEC_OBJECT_NEEDS_GTT (1<<1)
+#define EXEC_OBJECT_WRITE (1<<2)
#define EXEC_OBJECT_SUPPORTS_48B_ADDRESS (1<<3)
-#define EXEC_OBJECT_PINNED (1<<4)
-#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_PINNED<<1)
+#define EXEC_OBJECT_PINNED (1<<4)
+/* All remaining bits are MBZ and RESERVED FOR FUTURE USE */
+#define __EXEC_OBJECT_UNKNOWN_FLAGS (-(EXEC_OBJECT_PINNED<<1))
__u64 flags;
__u64 rsvd1;
--
1.9.1
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