This is a note to let you know that I've just added the patch titled
iommu/arm-smmu: Clarify MMU-500 CPRE workaround
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-arm-smmu-clarify-mmu-500-cpre-workaround.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f03b8b36c14bede6fac42ae5680b538e3d3a9535
Author: Robin Murphy <robin.murphy@xxxxxxx>
Date: Tue Oct 8 16:21:17 2024 +0100
iommu/arm-smmu: Clarify MMU-500 CPRE workaround
[ Upstream commit 0dfe314cdd0d378f96bb9c6bdc05c8120f48606d ]
CPRE workarounds are implicated in at least 5 MMU-500 errata, some of
which remain unfixed. The comment and warning message have proven to be
unhelpfully misleading about this scope, so reword them to get the point
across with less risk of going out of date or confusing users.
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Link: https://lore.kernel.org/r/dfa82171b5248ad7cf1f25592101a6eec36b8c9a.1728400877.git.robin.murphy@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
index 9dc772f2cbb27..99030e6b16e7a 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
@@ -130,7 +130,7 @@ int arm_mmu500_reset(struct arm_smmu_device *smmu)
/*
* Disable MMU-500's not-particularly-beneficial next-page
- * prefetcher for the sake of errata #841119 and #826419.
+ * prefetcher for the sake of at least 5 known errata.
*/
for (i = 0; i < smmu->num_context_banks; ++i) {
reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR);
@@ -138,7 +138,7 @@ int arm_mmu500_reset(struct arm_smmu_device *smmu)
arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_ACTLR, reg);
reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR);
if (reg & ARM_MMU500_ACTLR_CPRE)
- dev_warn_once(smmu->dev, "Failed to disable prefetcher [errata #841119 and #826419], check ACR.CACHE_LOCK\n");
+ dev_warn_once(smmu->dev, "Failed to disable prefetcher for errata workarounds, check SACR.CACHE_LOCK\n");
}
return 0;
