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| author | Pranjal Shrivastava <praan@google.com> | 2026-07-28 21:11:23 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-08-02 10:05:44 +0000 |
| commit | eced8058c82a3a81ae480a6546e2da32100dddfa (patch) | |
| tree | cdf6ff0b376b33f1e7f00a3f8ab02382b09e7008 | |
| parent | f99d3b4bb095c4966cf58154077e8bb69ee4827f (diff) | |
| download | linux-next-eced8058c82a3a81ae480a6546e2da32100dddfa.tar.gz linux-next-eced8058c82a3a81ae480a6546e2da32100dddfa.zip | |
iommu/arm-smmu-v3: Convert to use atomic poll timeout
The arm_smmu_write_reg_sync() helper is currently implemented using
readl_relaxed_poll_timeout() (that relies on usleep_range() internally)
which becomes a critical issue when used in the gerror irq handler.
If the SMMU hits a gerror and enters Service Failure Mode
(GERROR_SFM_ERR), the gerror handler calls arm_smmu_device_disable() in
hard-irq context. This becomes a problem as arm_smmu_device_disable()
inevitably calls arm_smmu_write_reg_sync() which might attempt to sleep
inside a hard-irq context.
Fix this by converting the arm_smmu_write_reg_sync to use the
readl_relaxed_poll_timeout_atomic() polling helper.
(Discovered while running Sashiko locally on another patch series).
Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 48ec83bcbcf5 ("iommu/arm-smmu: Add initial driver support for ARM SMMUv3 devices")
Signed-off-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 |
1 files changed, 3 insertions, 2 deletions
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 267dfc40919c..de5fba0b6d09 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -4618,8 +4618,9 @@ static int arm_smmu_write_reg_sync(struct arm_smmu_device *smmu, u32 val, u32 reg; writel_relaxed(val, smmu->base + reg_off); - return readl_relaxed_poll_timeout(smmu->base + ack_off, reg, reg == val, - 1, ARM_SMMU_POLL_TIMEOUT_US); + return readl_relaxed_poll_timeout_atomic(smmu->base + ack_off, reg, + reg == val, 1, + ARM_SMMU_POLL_TIMEOUT_US); } /* GBPA is "special" */ |