drm/radeon: fix R600_PTE_GART handling

That didn't worked correctly any more and opened up a security problem.
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/cik_sdma.c

@@ -771,8 +771,7 @@ void cik_sdma_vm_set_page(struct radeon_device *rdev,
 
 	trace_radeon_vm_set_page(pe, addr, count, incr, flags);
 
-	/* XXX: How to distinguish between GART and other system memory pages? */
-	if (flags & R600_PTE_SYSTEM) {
+	if ((flags & R600_PTE_GART_MASK) == R600_PTE_GART_MASK) {
 		uint64_t src = rdev->gart.table_addr + (addr >> 12) * 8;
 		while (count) {
 			unsigned bytes = count * 8;

drivers/gpu/drm/radeon/radeon.h

@@ -864,9 +864,9 @@ struct radeon_mec {
 #define R600_PTE_FRAG_64KB	(4 << 7)
 #define R600_PTE_FRAG_256KB	(6 << 7)
 
-/* flags used for GART page table entries on R600+ */
-#define R600_PTE_GART	( R600_PTE_VALID | R600_PTE_SYSTEM | R600_PTE_SNOOPED \
-			| R600_PTE_READABLE | R600_PTE_WRITEABLE)
+/* flags needed to be set so we can copy directly from the GART table */
+#define R600_PTE_GART_MASK	( R600_PTE_READABLE | R600_PTE_WRITEABLE | \
+				  R600_PTE_SYSTEM | R600_PTE_VALID )
 
 struct radeon_vm_pt {
 	struct radeon_bo		*bo;

drivers/gpu/drm/radeon/si_dma.c

@@ -79,8 +79,7 @@ void si_dma_vm_set_page(struct radeon_device *rdev,
 
 	trace_radeon_vm_set_page(pe, addr, count, incr, flags);
 
-	/* XXX: How to distinguish between GART and other system memory pages? */
-	if (flags & R600_PTE_SYSTEM) {
+	if ((flags & R600_PTE_GART_MASK) == R600_PTE_GART_MASK) {
 		uint64_t src = rdev->gart.table_addr + (addr >> 12) * 8;
 		while (count) {
 			unsigned bytes = count * 8;