[PATCH 05/10] accel/ivpu: Fix potential infinite loops in IRQ handlers

[Jacek Lawrynowicz]

Limit number of iterations in ivpu_mmu_irq_evtq_handler() and
ivpu_ipc_irq_handler().

Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
---
 drivers/accel/ivpu/ivpu_ipc.c |  6 ++++++
 drivers/accel/ivpu/ivpu_mmu.c | 21 +++++++++++++--------
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/accel/ivpu/ivpu_ipc.c b/drivers/accel/ivpu/ivpu_ipc.c
index e86621f16f85..f69780248803 100644
--- a/drivers/accel/ivpu/ivpu_ipc.c
+++ b/drivers/accel/ivpu/ivpu_ipc.c
@@ -389,12 +389,18 @@ void ivpu_ipc_irq_handler(struct ivpu_device *vdev, bool *wake_thread)
 	unsigned long flags;
 	bool dispatched;
 	u32 vpu_addr;
+	int msg_count = 0;
 
 	/*
 	 * Driver needs to purge all messages from IPC FIFO to clear IPC interrupt.
 	 * Without purge IPC FIFO to 0 next IPC interrupts won't be generated.
 	 */
 	while (ivpu_hw_reg_ipc_rx_count_get(vdev)) {
+		if (++msg_count > IPC_MAX_RX_MSG) {
+			ivpu_pm_schedule_recovery(vdev);
+			return;
+		}
+
 		vpu_addr = ivpu_hw_reg_ipc_rx_addr_get(vdev);
 		if (vpu_addr == REG_IO_ERROR) {
 			ivpu_err_ratelimited(vdev, "Failed to read IPC rx addr register\n");
diff --git a/drivers/accel/ivpu/ivpu_mmu.c b/drivers/accel/ivpu/ivpu_mmu.c
index 1f813625aab3..c82929b0ae9d 100644
--- a/drivers/accel/ivpu/ivpu_mmu.c
+++ b/drivers/accel/ivpu/ivpu_mmu.c
@@ -236,6 +236,8 @@
 #define IVPU_MMU_CERROR_ABT          0x2
 #define IVPU_MMU_CERROR_ATC_INV_SYNC 0x3
 
+#define IVPU_MMU_MAX_EVENT_COUNT     100
+
 static const char *ivpu_mmu_event_to_str(u32 cmd)
 {
 	switch (cmd) {
@@ -887,7 +889,7 @@ static u32 *ivpu_mmu_get_event(struct ivpu_device *vdev)
 
 void ivpu_mmu_irq_evtq_handler(struct ivpu_device *vdev)
 {
-	bool schedule_recovery = false;
+	int event_count = 0;
 	u32 *event;
 	u32 ssid;
 
@@ -895,16 +897,19 @@ void ivpu_mmu_irq_evtq_handler(struct ivpu_device *vdev)
 
 	while ((event = ivpu_mmu_get_event(vdev)) != NULL) {
 		ivpu_mmu_dump_event(vdev, event);
+		if (++event_count > IVPU_MMU_MAX_EVENT_COUNT) {
+			ivpu_pm_schedule_recovery(vdev);
+			return;
+		}
 
 		ssid = FIELD_GET(IVPU_MMU_EVT_SSID_MASK, event[0]);
-		if (ssid == IVPU_GLOBAL_CONTEXT_MMU_SSID)
-			schedule_recovery = true;
-		else
-			ivpu_mmu_user_context_mark_invalid(vdev, ssid);
-	}
+		if (ssid == IVPU_GLOBAL_CONTEXT_MMU_SSID) {
+			ivpu_pm_schedule_recovery(vdev);
+			return;
+		}
 
-	if (schedule_recovery)
-		ivpu_pm_schedule_recovery(vdev);
+		ivpu_mmu_user_context_mark_invalid(vdev, ssid);
+	}
 }
 
 void ivpu_mmu_evtq_dump(struct ivpu_device *vdev)
-- 
2.43.0