drm/amdkfd: Fix possible infinite loop

When the loop predicating timeout parameter passed happens to
not be a multiple of 20 the unsigned integer will overflow and
the loop will become unbounded.
Signed-off-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c

@@ -103,11 +103,11 @@ static bool kgd_hqd_is_occupied(struct kgd_dev *kgd, uint64_t queue_address,
 				uint32_t pipe_id, uint32_t queue_id);
 
 static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
-				unsigned int timeout, uint32_t pipe_id,
+				unsigned int utimeout, uint32_t pipe_id,
 				uint32_t queue_id);
 static bool kgd_hqd_sdma_is_occupied(struct kgd_dev *kgd, void *mqd);
 static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
-				unsigned int timeout);
+				unsigned int utimeout);
 static int kgd_address_watch_disable(struct kgd_dev *kgd);
 static int kgd_address_watch_execute(struct kgd_dev *kgd,
 					unsigned int watch_point_id,
@@ -437,11 +437,12 @@ static bool kgd_hqd_sdma_is_occupied(struct kgd_dev *kgd, void *mqd)
 }
 
 static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
-				unsigned int timeout, uint32_t pipe_id,
+				unsigned int utimeout, uint32_t pipe_id,
 				uint32_t queue_id)
 {
 	struct amdgpu_device *adev = get_amdgpu_device(kgd);
 	uint32_t temp;
+	int timeout = utimeout;
 
 	acquire_queue(kgd, pipe_id, queue_id);
 	WREG32(mmCP_HQD_PQ_DOORBELL_CONTROL, 0);
@@ -452,9 +453,8 @@ static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
 		temp = RREG32(mmCP_HQD_ACTIVE);
 		if (temp & CP_HQD_ACTIVE__ACTIVE_MASK)
 			break;
-		if (timeout == 0) {
-			pr_err("kfd: cp queue preemption time out (%dms)\n",
-				temp);
+		if (timeout <= 0) {
+			pr_err("kfd: cp queue preemption time out.\n");
 			release_queue(kgd);
 			return -ETIME;
 		}
@@ -467,12 +467,13 @@ static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
 }
 
 static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
-				unsigned int timeout)
+				unsigned int utimeout)
 {
 	struct amdgpu_device *adev = get_amdgpu_device(kgd);
 	struct cik_sdma_rlc_registers *m;
 	uint32_t sdma_base_addr;
 	uint32_t temp;
+	int timeout = utimeout;
 
 	m = get_sdma_mqd(mqd);
 	sdma_base_addr = get_sdma_base_addr(m);
@@ -485,7 +486,7 @@ static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
 		temp = RREG32(sdma_base_addr + mmSDMA0_RLC0_CONTEXT_STATUS);
 		if (temp & SDMA0_STATUS_REG__RB_CMD_IDLE__SHIFT)
 			break;
-		if (timeout == 0)
+		if (timeout <= 0)
 			return -ETIME;
 		msleep(20);
 		timeout -= 20;

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c

@@ -62,10 +62,10 @@ static bool kgd_hqd_is_occupied(struct kgd_dev *kgd, uint64_t queue_address,
 		uint32_t pipe_id, uint32_t queue_id);
 static bool kgd_hqd_sdma_is_occupied(struct kgd_dev *kgd, void *mqd);
 static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
-				unsigned int timeout, uint32_t pipe_id,
+				unsigned int utimeout, uint32_t pipe_id,
 				uint32_t queue_id);
 static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
-				unsigned int timeout);
+				unsigned int utimeout);
 static void write_vmid_invalidate_request(struct kgd_dev *kgd, uint8_t vmid);
 static int kgd_address_watch_disable(struct kgd_dev *kgd);
 static int kgd_address_watch_execute(struct kgd_dev *kgd,
@@ -349,11 +349,12 @@ static bool kgd_hqd_sdma_is_occupied(struct kgd_dev *kgd, void *mqd)
 }
 
 static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
-				unsigned int timeout, uint32_t pipe_id,
+				unsigned int utimeout, uint32_t pipe_id,
 				uint32_t queue_id)
 {
 	struct amdgpu_device *adev = get_amdgpu_device(kgd);
 	uint32_t temp;
+	int timeout = utimeout;
 
 	acquire_queue(kgd, pipe_id, queue_id);
 
@@ -363,9 +364,8 @@ static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
 		temp = RREG32(mmCP_HQD_ACTIVE);
 		if (temp & CP_HQD_ACTIVE__ACTIVE_MASK)
 			break;
-		if (timeout == 0) {
-			pr_err("kfd: cp queue preemption time out (%dms)\n",
-				temp);
+		if (timeout <= 0) {
+			pr_err("kfd: cp queue preemption time out.\n");
 			release_queue(kgd);
 			return -ETIME;
 		}
@@ -378,12 +378,13 @@ static int kgd_hqd_destroy(struct kgd_dev *kgd, uint32_t reset_type,
 }
 
 static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
-				unsigned int timeout)
+				unsigned int utimeout)
 {
 	struct amdgpu_device *adev = get_amdgpu_device(kgd);
 	struct cik_sdma_rlc_registers *m;
 	uint32_t sdma_base_addr;
 	uint32_t temp;
+	int timeout = utimeout;
 
 	m = get_sdma_mqd(mqd);
 	sdma_base_addr = get_sdma_base_addr(m);
@@ -396,7 +397,7 @@ static int kgd_hqd_sdma_destroy(struct kgd_dev *kgd, void *mqd,
 		temp = RREG32(sdma_base_addr + mmSDMA0_RLC0_CONTEXT_STATUS);
 		if (temp & SDMA0_STATUS_REG__RB_CMD_IDLE__SHIFT)
 			break;
-		if (timeout == 0)
+		if (timeout <= 0)
 			return -ETIME;
 		msleep(20);
 		timeout -= 20;