[PATCH v2 0/3] iommu/arm-smmu: adreno-smmu page fault handling

[PATCH v2 0/3] iommu/arm-smmu: adreno-smmu page fault handling

[Jordan Crouse]

This is a stack to add an Adreno GPU specific handler for pagefaults. The first
patch starts by wiring up report_iommu_fault for arm-smmu. The next patch adds
a adreno-smmu-priv function hook to capture a handful of important debugging
registers such as TTBR0, CONTEXTIDR, FSYNR0 and others. This is used by the
third patch to print more detailed information on page fault such as the TTBR0
for the pagetable that caused the fault and the source of the fault as
determined by a combination of the FSYNR1 register and an internal GPU
register.

This code provides a solid base that we can expand on later for even more
extensive GPU side page fault debugging capabilities.

v2: Fix comment wording and function pointer check per Rob Clark

Jordan Crouse (3):
  iommu/arm-smmu: Add support for driver IOMMU fault handlers
  drm/msm: Add an adreno-smmu-priv callback to get pagefault info
  drm/msm: Improve the a6xx page fault handler

 drivers/gpu/drm/msm/adreno/a5xx_gpu.c      |  4 +-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c      | 76 +++++++++++++++++++++-
 drivers/gpu/drm/msm/msm_iommu.c            | 11 +++-
 drivers/gpu/drm/msm/msm_mmu.h              |  4 +-
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 19 ++++++
 drivers/iommu/arm/arm-smmu/arm-smmu.c      | 16 ++++-
 drivers/iommu/arm/arm-smmu/arm-smmu.h      |  2 +
 include/linux/adreno-smmu-priv.h           | 31 ++++++++-
 8 files changed, 151 insertions(+), 12 deletions(-)

-- 
2.25.1

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[PATCH v2 3/3] drm/msm: Improve the a6xx page fault handler

[Jordan Crouse]

Use the new adreno-smmu-priv fault info function to get more SMMU
debug registers and print the current TTBR0 to debug per-instance
pagetables and figure out which GPU block generated the request.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 drivers/gpu/drm/msm/adreno/a5xx_gpu.c |  4 +-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 76 +++++++++++++++++++++++++--
 drivers/gpu/drm/msm/msm_iommu.c       | 11 +++-
 drivers/gpu/drm/msm/msm_mmu.h         |  4 +-
 4 files changed, 87 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index d6804a802355..ed4cb81af874 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -933,7 +933,7 @@ bool a5xx_idle(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 	return true;
 }
 
-static int a5xx_fault_handler(void *arg, unsigned long iova, int flags)
+static int a5xx_fault_handler(void *arg, unsigned long iova, int flags, void *data)
 {
 	struct msm_gpu *gpu = arg;
 	pr_warn_ratelimited("*** gpu fault: iova=%08lx, flags=%d (%u,%u,%u,%u)\n",
@@ -943,7 +943,7 @@ static int a5xx_fault_handler(void *arg, unsigned long iova, int flags)
 			gpu_read(gpu, REG_A5XX_CP_SCRATCH_REG(6)),
 			gpu_read(gpu, REG_A5XX_CP_SCRATCH_REG(7)));
 
-	return -EFAULT;
+	return 0;
 }
 
 static void a5xx_cp_err_irq(struct msm_gpu *gpu)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 948f3656c20c..ac6e8cd5cf1a 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -905,18 +905,88 @@ static void a6xx_recover(struct msm_gpu *gpu)
 	msm_gpu_hw_init(gpu);
 }
 
-static int a6xx_fault_handler(void *arg, unsigned long iova, int flags)
+static const char *a6xx_uche_fault_block(struct msm_gpu *gpu, u32 mid)
+{
+	static const char *uche_clients[7] = {
+		"VFD", "SP", "VSC", "VPC", "HLSQ", "PC", "LRZ",
+	};
+	u32 val;
+
+	if (mid < 1 || mid > 3)
+		return "UNKNOWN";
+
+	/*
+	 * The source of the data depends on the mid ID read from FSYNR1.
+	 * and the client ID read from the UCHE block
+	 */
+	val = gpu_read(gpu, REG_A6XX_UCHE_CLIENT_PF);
+
+	/* mid = 3 is most precise and refers to only one block per client */
+	if (mid == 3)
+		return uche_clients[val & 7];
+
+	/* For mid=2 the source is TP or VFD except when the client id is 0 */
+	if (mid == 2)
+		return ((val & 7) == 0) ? "TP" : "TP|VFD";
+
+	/* For mid=1 just return "UCHE" as a catchall for everything else */
+	return "UCHE";
+}
+
+static const char *a6xx_fault_block(struct msm_gpu *gpu, u32 id)
+{
+	if (id == 0)
+		return "CP";
+	else if (id == 4)
+		return "CCU";
+	else if (id == 6)
+		return "CDP Prefetch";
+
+	return a6xx_uche_fault_block(gpu, id);
+}
+
+#define ARM_SMMU_FSR_TF                 BIT(1)
+#define ARM_SMMU_FSR_PF			BIT(3)
+#define ARM_SMMU_FSR_EF			BIT(4)
+
+static int a6xx_fault_handler(void *arg, unsigned long iova, int flags, void *data)
 {
 	struct msm_gpu *gpu = arg;
+	struct adreno_smmu_fault_info *info = data;
+	const char *type = "UNKNOWN";
 
-	pr_warn_ratelimited("*** gpu fault: iova=%08lx, flags=%d (%u,%u,%u,%u)\n",
+	/*
+	 * Print a default message if we couldn't get the data from the
+	 * adreno-smmu-priv
+	 */
+	if (!info) {
+		pr_warn_ratelimited("*** gpu fault: iova=%.16lx flags=%d (%u,%u,%u,%u)\n",
 			iova, flags,
 			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(4)),
 			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(5)),
 			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(6)),
 			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(7)));
 
-	return -EFAULT;
+		return 0;
+	}
+
+	if (info->fsr & ARM_SMMU_FSR_TF)
+		type = "TRANSLATION";
+	else if (info->fsr & ARM_SMMU_FSR_PF)
+		type = "PERMISSION";
+	else if (info->fsr & ARM_SMMU_FSR_EF)
+		type = "EXTERNAL";
+
+	pr_warn_ratelimited("*** gpu fault: ttbr0=%.16llx iova=%.16lx dir=%s type=%s source=%s (%u,%u,%u,%u)\n",
+			info->ttbr0, iova,
+			flags & IOMMU_FAULT_WRITE ? "WRITE" : "READ", type,
+			a6xx_fault_block(gpu, info->fsynr1 & 0xff),
+			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(4)),
+			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(5)),
+			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(6)),
+			gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(7)));
+
+	return 0;
 }
 
 static void a6xx_cp_hw_err_irq(struct msm_gpu *gpu)
diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index 22ac7c692a81..73db30dfda0a 100644
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -212,8 +212,17 @@ static int msm_fault_handler(struct iommu_domain *domain, struct device *dev,
 		unsigned long iova, int flags, void *arg)
 {
 	struct msm_iommu *iommu = arg;
+	struct adreno_smmu_priv *adreno_smmu = dev_get_drvdata(iommu->base.dev);
+	struct adreno_smmu_fault_info info, *ptr = NULL;
+
+	if (adreno_smmu->get_fault_info) {
+		adreno_smmu->get_fault_info(adreno_smmu->cookie, &info);
+		ptr = &info;
+	}
+
 	if (iommu->base.handler)
-		return iommu->base.handler(iommu->base.arg, iova, flags);
+		return iommu->base.handler(iommu->base.arg, iova, flags, ptr);
+
 	pr_warn_ratelimited("*** fault: iova=%16lx, flags=%d\n", iova, flags);
 	return 0;
 }
diff --git a/drivers/gpu/drm/msm/msm_mmu.h b/drivers/gpu/drm/msm/msm_mmu.h
index 61ade89d9e48..a88f44c3268d 100644
--- a/drivers/gpu/drm/msm/msm_mmu.h
+++ b/drivers/gpu/drm/msm/msm_mmu.h
@@ -26,7 +26,7 @@ enum msm_mmu_type {
 struct msm_mmu {
 	const struct msm_mmu_funcs *funcs;
 	struct device *dev;
-	int (*handler)(void *arg, unsigned long iova, int flags);
+	int (*handler)(void *arg, unsigned long iova, int flags, void *data);
 	void *arg;
 	enum msm_mmu_type type;
 };
@@ -43,7 +43,7 @@ struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain);
 struct msm_mmu *msm_gpummu_new(struct device *dev, struct msm_gpu *gpu);
 
 static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
-		int (*handler)(void *arg, unsigned long iova, int flags))
+		int (*handler)(void *arg, unsigned long iova, int flags, void *data))
 {
 	mmu->arg = arg;
 	mmu->handler = handler;
-- 
2.25.1

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