| From 1be5003814767b849cb0723d4f8de1d07ffdec68 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 15 Jan 2020 15:21:47 +0000 |
| Subject: iommu/arm-smmu-v3: Use WRITE_ONCE() when changing validity of an STE |
| |
| From: Will Deacon <will@kernel.org> |
| |
| [ Upstream commit d71e01716b3606a6648df7e5646ae12c75babde4 ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/iommu/arm-smmu-v3.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c |
| index eff1f3aa5ef43..6b7664052b5be 100644 |
| --- a/drivers/iommu/arm-smmu-v3.c |
| +++ b/drivers/iommu/arm-smmu-v3.c |
| @@ -1185,7 +1185,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, |
| } |
| |
| 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 */ |
| -- |
| 2.20.1 |
| |
