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authorWill Deacon <will@kernel.org>2020-01-15 18:21:47 +0300
committerWill Deacon <will@kernel.org>2020-01-15 19:30:27 +0300
commitd71e01716b3606a6648df7e5646ae12c75babde4 (patch)
tree6c36ad589a8008d4dd1dcca5570b4ef081a60c8a /drivers/iommu
parent73af06f589fe5656b07baa92e390d2d48464b18a (diff)
downloadlinux-d71e01716b3606a6648df7e5646ae12c75babde4.tar.xz
iommu/arm-smmu-v3: Use WRITE_ONCE() when changing validity of an STE
If, for some bizarre reason, the compiler decided to split up the write of STE DWORD 0, we could end up making a partial structure valid. Although this probably won't happen, follow the example of the context-descriptor code and use WRITE_ONCE() to ensure atomicity of the write. Reported-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/arm-smmu-v3.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index c2d1325c9d39..3aa6538d85e2 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1873,7 +1873,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
STRTAB_STE_1_EATS_TRANS));
arm_smmu_sync_ste_for_sid(smmu, sid);
- dst[0] = cpu_to_le64(val);
+ /* See comment in arm_smmu_write_ctx_desc() */
+ WRITE_ONCE(dst[0], cpu_to_le64(val));
arm_smmu_sync_ste_for_sid(smmu, sid);
/* It's likely that we'll want to use the new STE soon */