drm/amdgpu: Restore uncached behaviour on GFX12

Always use MTYPE_UC if UNCACHED flag is specified.

This makes kernarg region uncached and it restores
usermode cache disable debug flag functionality.

Do not set MTYPE_UC for COHERENT flag, on GFX12 coherence is handled by
shader code.

Signed-off-by: David Belanger <david.belanger@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit eb6cdfb)
Cc: stable@vger.kernel.org # 6.12.x

Author: dpbelanger

drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c

@@ -501,9 +501,6 @@ static void gmc_v12_0_get_vm_pte(struct amdgpu_device *adev,
 				 uint64_t *flags)
 {
 	struct amdgpu_bo *bo = mapping->bo_va->base.bo;
-	struct amdgpu_device *bo_adev;
-	bool coherent, is_system;
-
 
 	*flags &= ~AMDGPU_PTE_EXECUTABLE;
 	*flags |= mapping->flags & AMDGPU_PTE_EXECUTABLE;
@@ -519,26 +516,11 @@ static void gmc_v12_0_get_vm_pte(struct amdgpu_device *adev,
 		*flags &= ~AMDGPU_PTE_VALID;
 	}
 
-	if (!bo)
-		return;
-
-	if (bo->flags & (AMDGPU_GEM_CREATE_COHERENT |
-			       AMDGPU_GEM_CREATE_UNCACHED))
-		*flags = AMDGPU_PTE_MTYPE_GFX12(*flags, MTYPE_UC);
-
-	bo_adev = amdgpu_ttm_adev(bo->tbo.bdev);
-	coherent = bo->flags & AMDGPU_GEM_CREATE_COHERENT;
-	is_system = bo->tbo.resource &&
-		(bo->tbo.resource->mem_type == TTM_PL_TT ||
-		 bo->tbo.resource->mem_type == AMDGPU_PL_PREEMPT);
-
 	if (bo && bo->flags & AMDGPU_GEM_CREATE_GFX12_DCC)
 		*flags |= AMDGPU_PTE_DCC;
 
-	/* WA for HW bug */
-	if (is_system || ((bo_adev != adev) && coherent))
-		*flags = AMDGPU_PTE_MTYPE_GFX12(*flags, MTYPE_NC);
-
+	if (bo && bo->flags & AMDGPU_GEM_CREATE_UNCACHED)
+		*flags = AMDGPU_PTE_MTYPE_GFX12(*flags, MTYPE_UC);
 }
 
 static unsigned gmc_v12_0_get_vbios_fb_size(struct amdgpu_device *adev)

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

@@ -1286,13 +1286,7 @@ svm_range_get_pte_flags(struct kfd_node *node,
 		break;
 	case IP_VERSION(12, 0, 0):
 	case IP_VERSION(12, 0, 1):
-		if (domain == SVM_RANGE_VRAM_DOMAIN) {
-			if (bo_node != node)
-				mapping_flags |= AMDGPU_VM_MTYPE_NC;
-		} else {
-			mapping_flags |= coherent ?
-				AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
-		}
+		mapping_flags |= AMDGPU_VM_MTYPE_NC;
 		break;
 	default:
 		mapping_flags |= coherent ?