[Intel-gfx] [PATCH] drm/i915/guc: Add debug capture of GuC exception

[Robert M. Fosha]

Detect GuC firmware load failure due to an exception during execution
in GuC firmware. Output the GuC EIP where excpetion occured to dmesg
for GuC debug information.

Signed-off-by: Robert M. Fosha <robert.m.fosha at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_fw.c  | 7 +++++++
 drivers/gpu/drm/i915/intel_guc_reg.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_guc_fw.c b/drivers/gpu/drm/i915/intel_guc_fw.c
index 72cdafd9636a..90cb65641d60 100644
--- a/drivers/gpu/drm/i915/intel_guc_fw.c
+++ b/drivers/gpu/drm/i915/intel_guc_fw.c
@@ -197,6 +197,7 @@ static inline bool guc_ready(struct intel_guc *guc, u32 *status)
 
 static int guc_wait_ucode(struct intel_guc *guc)
 {
+	struct drm_i915_private *i915 = guc_to_i915(guc);
 	u32 status;
 	int ret;
 
@@ -216,6 +217,12 @@ static int guc_wait_ucode(struct intel_guc *guc)
 		ret = -ENOEXEC;
 	}
 
+	if ((status & GS_UKERNEL_MASK) == GS_UKERNEL_EXCEPTION) {
+		DRM_ERROR("GuC fw exception. GuC uKernel EIP: %#x\n",
+			  intel_uncore_read(&i915->uncore, SOFT_SCRATCH(13)));
+		ret = -ENOEXEC;
+	}
+
 	if (ret == 0 && !guc_xfer_completed(guc, &status)) {
 		DRM_ERROR("GuC is ready, but the xfer %08x is incomplete\n",
 			  status);
diff --git a/drivers/gpu/drm/i915/intel_guc_reg.h b/drivers/gpu/drm/i915/intel_guc_reg.h
index a214f8b71929..d90b88fadb5e 100644
--- a/drivers/gpu/drm/i915/intel_guc_reg.h
+++ b/drivers/gpu/drm/i915/intel_guc_reg.h
@@ -37,6 +37,7 @@
 #define   GS_UKERNEL_MASK		  (0xFF << GS_UKERNEL_SHIFT)
 #define   GS_UKERNEL_LAPIC_DONE		  (0x30 << GS_UKERNEL_SHIFT)
 #define   GS_UKERNEL_DPC_ERROR		  (0x60 << GS_UKERNEL_SHIFT)
+#define   GS_UKERNEL_EXCEPTION		  (0x70 << GS_UKERNEL_SHIFT)
 #define   GS_UKERNEL_READY		  (0xF0 << GS_UKERNEL_SHIFT)
 #define   GS_MIA_SHIFT			16
 #define   GS_MIA_MASK			  (0x07 << GS_MIA_SHIFT)
-- 
2.21.0.5.gaeb582a983