drm/i915: compile-time consistency check on __EXEC_OBJECT flags
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@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468504324-12690-1-git-send-email-david.s.gordon@intel.com
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 1978633..1bb1f25 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 @@
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;