[PATCH v4 0/6] iommu/arm-smmu: adreno-smmu page fault handling

[PATCH v4 0/6] iommu/arm-smmu: adreno-smmu page fault handling

[Rob Clark]

From: Rob Clark <robdclark@chromium.org>

This picks up an earlier series[1] from Jordan, and adds additional
support needed to generate GPU devcore dumps on iova faults.  Original
description:

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.

v4: [Rob] Add support to stall SMMU on fault, and let the GPU driver
    resume translation after it has had a chance to snapshot the GPUs
    state
v3: Always clear FSR even if the target driver is going to handle resume
v2: Fix comment wording and function pointer check per Rob Clark

[1] https://lore.kernel.org/dri-devel/20210225175135.91922-1-jcrouse@codeaurora.org/

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

Rob Clark (3):
  iommu/arm-smmu-qcom: Add stall support
  drm/msm: Add crashdump support for stalled SMMU
  drm/msm: devcoredump iommu fault support

 drivers/gpu/drm/msm/adreno/a2xx_gpu.c       |   2 +-
 drivers/gpu/drm/msm/adreno/a3xx_gpu.c       |   2 +-
 drivers/gpu/drm/msm/adreno/a4xx_gpu.c       |   2 +-
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c       |   9 +-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c       | 101 +++++++++++++++++++-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.h       |   2 +-
 drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c |  43 +++++++--
 drivers/gpu/drm/msm/adreno/adreno_gpu.c     |  15 +++
 drivers/gpu/drm/msm/msm_debugfs.c           |   2 +-
 drivers/gpu/drm/msm/msm_gem.h               |   1 +
 drivers/gpu/drm/msm/msm_gem_submit.c        |   1 +
 drivers/gpu/drm/msm/msm_gpu.c               |  55 ++++++++++-
 drivers/gpu/drm/msm/msm_gpu.h               |  19 +++-
 drivers/gpu/drm/msm/msm_gpummu.c            |   5 +
 drivers/gpu/drm/msm/msm_iommu.c             |  22 ++++-
 drivers/gpu/drm/msm/msm_mmu.h               |   5 +-
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c  |  50 ++++++++++
 drivers/iommu/arm/arm-smmu/arm-smmu.c       |   9 +-
 drivers/iommu/arm/arm-smmu/arm-smmu.h       |   2 +
 include/linux/adreno-smmu-priv.h            |  38 +++++++-
 20 files changed, 354 insertions(+), 31 deletions(-)

-- 
2.31.1


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[PATCH v4 1/6] iommu/arm-smmu: Add support for driver IOMMU fault handlers

[Rob Clark]

From: Jordan Crouse <jcrouse@codeaurora.org>

Call report_iommu_fault() to allow upper-level drivers to register their
own fault handlers.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 6f72c4d208ca..b4b32d31fc06 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -408,6 +408,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	int idx = smmu_domain->cfg.cbndx;
+	int ret;
 
 	fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
 	if (!(fsr & ARM_SMMU_FSR_FAULT))
@@ -417,8 +418,12 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 	iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR);
 	cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx));
 
-	dev_err_ratelimited(smmu->dev,
-	"Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
+	ret = report_iommu_fault(domain, NULL, iova,
+		fsynr & ARM_SMMU_FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ);
+
+	if (ret == -ENOSYS)
+		dev_err_ratelimited(smmu->dev,
+		"Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
 			    fsr, iova, fsynr, cbfrsynra, idx);
 
 	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr);
-- 
2.31.1


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[PATCH v4 2/6] iommu/arm-smmu-qcom: Add an adreno-smmu-priv callback to get pagefault info

[Rob Clark]

From: Jordan Crouse <jcrouse@codeaurora.org>

Add a callback in adreno-smmu-priv to read interesting SMMU
registers to provide an opportunity for a richer debug experience
in the GPU driver.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 17 ++++++++++++
 drivers/iommu/arm/arm-smmu/arm-smmu.h      |  2 ++
 include/linux/adreno-smmu-priv.h           | 31 +++++++++++++++++++++-
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 98b3a1c2a181..b2e31ea84128 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -32,6 +32,22 @@ static void qcom_adreno_smmu_write_sctlr(struct arm_smmu_device *smmu, int idx,
 	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
 }
 
+static void qcom_adreno_smmu_get_fault_info(const void *cookie,
+		struct adreno_smmu_fault_info *info)
+{
+	struct arm_smmu_domain *smmu_domain = (void *)cookie;
+	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+	info->fsr = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_FSR);
+	info->fsynr0 = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_FSYNR0);
+	info->fsynr1 = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_FSYNR1);
+	info->far = arm_smmu_cb_readq(smmu, cfg->cbndx, ARM_SMMU_CB_FAR);
+	info->cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(cfg->cbndx));
+	info->ttbr0 = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_TTBR0);
+	info->contextidr = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_CONTEXTIDR);
+}
+
 #define QCOM_ADRENO_SMMU_GPU_SID 0
 
 static bool qcom_adreno_smmu_is_gpu_device(struct device *dev)
@@ -156,6 +172,7 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	priv->cookie = smmu_domain;
 	priv->get_ttbr1_cfg = qcom_adreno_smmu_get_ttbr1_cfg;
 	priv->set_ttbr0_cfg = qcom_adreno_smmu_set_ttbr0_cfg;
+	priv->get_fault_info = qcom_adreno_smmu_get_fault_info;
 
 	return 0;
 }
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index c31a59d35c64..84c21c4b0691 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -224,6 +224,8 @@ enum arm_smmu_cbar_type {
 #define ARM_SMMU_CB_FSYNR0		0x68
 #define ARM_SMMU_FSYNR0_WNR		BIT(4)
 
+#define ARM_SMMU_CB_FSYNR1		0x6c
+
 #define ARM_SMMU_CB_S1_TLBIVA		0x600
 #define ARM_SMMU_CB_S1_TLBIASID		0x610
 #define ARM_SMMU_CB_S1_TLBIVAL		0x620
diff --git a/include/linux/adreno-smmu-priv.h b/include/linux/adreno-smmu-priv.h
index a889f28afb42..53fe32fb9214 100644
--- a/include/linux/adreno-smmu-priv.h
+++ b/include/linux/adreno-smmu-priv.h
@@ -8,6 +8,32 @@
 
 #include <linux/io-pgtable.h>
 
+/**
+ * struct adreno_smmu_fault_info - container for key fault information
+ *
+ * @far: The faulting IOVA from ARM_SMMU_CB_FAR
+ * @ttbr0: The current TTBR0 pagetable from ARM_SMMU_CB_TTBR0
+ * @contextidr: The value of ARM_SMMU_CB_CONTEXTIDR
+ * @fsr: The fault status from ARM_SMMU_CB_FSR
+ * @fsynr0: The value of FSYNR0 from ARM_SMMU_CB_FSYNR0
+ * @fsynr1: The value of FSYNR1 from ARM_SMMU_CB_FSYNR0
+ * @cbfrsynra: The value of CBFRSYNRA from ARM_SMMU_GR1_CBFRSYNRA(idx)
+ *
+ * This struct passes back key page fault information to the GPU driver
+ * through the get_fault_info function pointer.
+ * The GPU driver can use this information to print informative
+ * log messages and provide deeper GPU specific insight into the fault.
+ */
+struct adreno_smmu_fault_info {
+	u64 far;
+	u64 ttbr0;
+	u32 contextidr;
+	u32 fsr;
+	u32 fsynr0;
+	u32 fsynr1;
+	u32 cbfrsynra;
+};
+
 /**
  * struct adreno_smmu_priv - private interface between adreno-smmu and GPU
  *
@@ -17,6 +43,8 @@
  * @set_ttbr0_cfg: Set the TTBR0 config for the GPUs context bank.  A
  *                 NULL config disables TTBR0 translation, otherwise
  *                 TTBR0 translation is enabled with the specified cfg
+ * @get_fault_info: Called by the GPU fault handler to get information about
+ *                  the fault
  *
  * The GPU driver (drm/msm) and adreno-smmu work together for controlling
  * the GPU's SMMU instance.  This is by necessity, as the GPU is directly
@@ -31,6 +59,7 @@ struct adreno_smmu_priv {
     const void *cookie;
     const struct io_pgtable_cfg *(*get_ttbr1_cfg)(const void *cookie);
     int (*set_ttbr0_cfg)(const void *cookie, const struct io_pgtable_cfg *cfg);
+    void (*get_fault_info)(const void *cookie, struct adreno_smmu_fault_info *info);
 };
 
-#endif /* __ADRENO_SMMU_PRIV_H */
\ No newline at end of file
+#endif /* __ADRENO_SMMU_PRIV_H */
-- 
2.31.1


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[PATCH v4 4/6] iommu/arm-smmu-qcom: Add stall support

[Rob Clark]

From: Rob Clark <robdclark@chromium.org>

Add, via the adreno-smmu-priv interface, a way for the GPU to request
the SMMU to stall translation on faults, and then later resume the
translation, either retrying or terminating the current translation.

This will be used on the GPU side to "freeze" the GPU while we snapshot
useful state for devcoredump.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 33 ++++++++++++++++++++++
 include/linux/adreno-smmu-priv.h           |  7 +++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index b2e31ea84128..61fc645c1325 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -13,6 +13,7 @@ struct qcom_smmu {
 	struct arm_smmu_device smmu;
 	bool bypass_quirk;
 	u8 bypass_cbndx;
+	u32 stall_enabled;
 };
 
 static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
@@ -23,12 +24,17 @@ static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
 static void qcom_adreno_smmu_write_sctlr(struct arm_smmu_device *smmu, int idx,
 		u32 reg)
 {
+	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
+
 	/*
 	 * On the GPU device we want to process subsequent transactions after a
 	 * fault to keep the GPU from hanging
 	 */
 	reg |= ARM_SMMU_SCTLR_HUPCF;
 
+	if (qsmmu->stall_enabled & BIT(idx))
+		reg |= ARM_SMMU_SCTLR_CFCFG;
+
 	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
 }
 
@@ -48,6 +54,31 @@ static void qcom_adreno_smmu_get_fault_info(const void *cookie,
 	info->contextidr = arm_smmu_cb_read(smmu, cfg->cbndx, ARM_SMMU_CB_CONTEXTIDR);
 }
 
+static void qcom_adreno_smmu_set_stall(const void *cookie, bool enabled)
+{
+	struct arm_smmu_domain *smmu_domain = (void *)cookie;
+	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+	struct qcom_smmu *qsmmu = to_qcom_smmu(smmu_domain->smmu);
+
+	if (enabled)
+		qsmmu->stall_enabled |= BIT(cfg->cbndx);
+	else
+		qsmmu->stall_enabled &= ~BIT(cfg->cbndx);
+}
+
+static void qcom_adreno_smmu_resume_translation(const void *cookie, bool terminate)
+{
+	struct arm_smmu_domain *smmu_domain = (void *)cookie;
+	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	u32 reg = 0;
+
+	if (terminate)
+		reg |= ARM_SMMU_RESUME_TERMINATE;
+
+	arm_smmu_cb_write(smmu, cfg->cbndx, ARM_SMMU_CB_RESUME, reg);
+}
+
 #define QCOM_ADRENO_SMMU_GPU_SID 0
 
 static bool qcom_adreno_smmu_is_gpu_device(struct device *dev)
@@ -173,6 +204,8 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 	priv->get_ttbr1_cfg = qcom_adreno_smmu_get_ttbr1_cfg;
 	priv->set_ttbr0_cfg = qcom_adreno_smmu_set_ttbr0_cfg;
 	priv->get_fault_info = qcom_adreno_smmu_get_fault_info;
+	priv->set_stall = qcom_adreno_smmu_set_stall;
+	priv->resume_translation = qcom_adreno_smmu_resume_translation;
 
 	return 0;
 }
diff --git a/include/linux/adreno-smmu-priv.h b/include/linux/adreno-smmu-priv.h
index 53fe32fb9214..c637e0997f6d 100644
--- a/include/linux/adreno-smmu-priv.h
+++ b/include/linux/adreno-smmu-priv.h
@@ -45,6 +45,11 @@ struct adreno_smmu_fault_info {
  *                 TTBR0 translation is enabled with the specified cfg
  * @get_fault_info: Called by the GPU fault handler to get information about
  *                  the fault
+ * @set_stall:     Configure whether stall on fault (CFCFG) is enabled.  Call
+ *                 before set_ttbr0_cfg().  If stalling on fault is enabled,
+ *                 the GPU driver must call resume_translation()
+ * @resume_translation: Resume translation after a fault
+ *
  *
  * The GPU driver (drm/msm) and adreno-smmu work together for controlling
  * the GPU's SMMU instance.  This is by necessity, as the GPU is directly
@@ -60,6 +65,8 @@ struct adreno_smmu_priv {
     const struct io_pgtable_cfg *(*get_ttbr1_cfg)(const void *cookie);
     int (*set_ttbr0_cfg)(const void *cookie, const struct io_pgtable_cfg *cfg);
     void (*get_fault_info)(const void *cookie, struct adreno_smmu_fault_info *info);
+    void (*set_stall)(const void *cookie, bool enabled);
+    void (*resume_translation)(const void *cookie, bool terminate);
 };
 
 #endif /* __ADRENO_SMMU_PRIV_H */
-- 
2.31.1


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