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Commit 9e2793f6 authored by Dave Gordon's avatar Dave Gordon Committed by Daniel Vetter
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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: default avatarDave Gordon <david.s.gordon@intel.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468504324-12690-1-git-send-email-david.s.gordon@intel.com
parent a8784875

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+8 −4
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#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 @@ validate_exec_list(struct drm_device *dev, 
	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;

include/uapi/drm/i915_drm.h

+6 −5
Original line number Diff line number Diff line
@@ -703,7 +703,8 @@ struct drm_i915_gem_exec_object2 { 
#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)

/* All remaining bits are MBZ and RESERVED FOR FUTURE USE */

#define __EXEC_OBJECT_UNKNOWN_FLAGS	(-(EXEC_OBJECT_PINNED<<1))

	__u64 flags;



	__u64 rsvd1;