[PATCH v11 11/11] iommu/arm-smmu-v3: Detect ARM_SMMU_OPT_KDUMP_ADOPT in probe()

[Nicolin Chen <nicolinc@nvidia.com>]

arm_smmu_device_hw_probe() runs before arm_smmu_init_structures(), so it's
natural to decide whether the kdump kernel must adopt the crashed kernel's
stream table.

Given that memremap is used to adopt the old stream table, set this option
only on a coherent SMMU.

And make sure SMMU isn't in Service Failure Mode.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Tested-by: Breno Leitao <leitao@kernel.org>
Tested-by: Cristian Prundeanu <cpru@amazon.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  5 ++++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-kexec.c | 27 +++++++++++++++++++
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  4 +++
 3 files changed, 36 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 49604550e3b9f..228ccdf9c6f5d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1335,6 +1335,7 @@ int arm_smmu_kdump_adopt_deferred_l2_strtab(struct arm_smmu_device *smmu,
 					    u32 sid, phys_addr_t base, u32 span,
 					    struct arm_smmu_strtab_l2 **l2table);
 bool arm_smmu_kdump_is_attach_deferred(struct arm_smmu_master *master);
+void arm_smmu_device_kdump_probe(struct arm_smmu_device *smmu);
 #else /* CONFIG_CRASH_DUMP */
 static inline int arm_smmu_kdump_adopt_strtab(struct arm_smmu_device *smmu)
 {
@@ -1354,6 +1355,10 @@ arm_smmu_kdump_is_attach_deferred(struct arm_smmu_master *master)
 {
 	return false;
 }
+
+static inline void arm_smmu_device_kdump_probe(struct arm_smmu_device *smmu)
+{
+}
 #endif /* CONFIG_CRASH_DUMP */
 
 struct arm_vsmmu {
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kexec.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kexec.c
index 8a76b8cb4ef0a..f664de3697e0e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kexec.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kexec.c
@@ -716,4 +716,31 @@ bool arm_smmu_kdump_is_attach_deferred(struct arm_smmu_master *master)
 
 	return false;
 }
+
+void arm_smmu_device_kdump_probe(struct arm_smmu_device *smmu)
+{
+	u32 gerror, gerrorn, active;
+
+	/* No adoption if SMMU is disabled (i.e., there is no in-flight DMA) */
+	if (!(readl_relaxed(smmu->base + ARM_SMMU_CR0) & CR0_SMMUEN))
+		return;
+
+	/* For now, only support a coherent SMMU that works with MEMREMAP_WB */
+	if (!(smmu->features & ARM_SMMU_FEAT_COHERENCY)) {
+		dev_warn(smmu->dev,
+			 "non-coherent SMMU unsupported; reset to block all DMAs\n");
+		return;
+	}
+
+	gerror = readl_relaxed(smmu->base + ARM_SMMU_GERROR);
+	gerrorn = readl_relaxed(smmu->base + ARM_SMMU_GERRORN);
+	active = gerror ^ gerrorn;
+	if (active & GERROR_SFM_ERR) {
+		dev_warn(smmu->dev,
+			 "SMMU in Service Failure Mode, must reset\n");
+		return;
+	}
+
+	smmu->options |= ARM_SMMU_OPT_KDUMP_ADOPT;
+}
 #endif /* CONFIG_CRASH_DUMP */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 78a24bca44202..3ada71fe7239f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -5647,6 +5647,10 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 
 	dev_info(smmu->dev, "oas %lu-bit (features 0x%08x)\n",
 		 smmu->oas, smmu->features);
+
+	if (is_kdump_kernel())
+		arm_smmu_device_kdump_probe(smmu);
+
 	return 0;
 }
 
-- 
2.43.0