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authorZhen Lei <thunder.leizhen@huawei.com>2018-10-31 07:02:07 +0300
committerWill Deacon <will.deacon@arm.com>2018-12-10 17:55:58 +0300
commit84a9a75774961612d0c7dd34a1777e8f98a65abd (patch)
tree05efc386c3cc2ae62fddfdf053ab301b095a44cb /drivers/iommu/arm-smmu-v3.c
parent3cd508a8c1379427afb5e16c2e0a7c986d907853 (diff)
downloadlinux-84a9a75774961612d0c7dd34a1777e8f98a65abd.tar.xz
iommu/arm-smmu-v3: Avoid memory corruption from Hisilicon MSI payloads
The GITS_TRANSLATER MMIO doorbell register in the ITS hardware is architected to be 4 bytes in size, yet on hi1620 and earlier, Hisilicon have allocated the adjacent 4 bytes to carry some IMPDEF sideband information which results in an 8-byte MSI payload being delivered when signalling an interrupt: MSIAddr: |----4bytes----|----4bytes----| | MSIData | IMPDEF | This poses no problem for the ITS hardware because the adjacent 4 bytes are reserved in the memory map. However, when delivering MSIs to memory, as we do in the SMMUv3 driver for signalling the completion of a SYNC command, the extended payload will corrupt the 4 bytes adjacent to the "sync_count" member in struct arm_smmu_device. Fortunately, the current layout allocates these bytes to padding, but this is fragile and we should make this explicit. Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> [will: Rewrote commit message and comment] Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu/arm-smmu-v3.c')
-rw-r--r--drivers/iommu/arm-smmu-v3.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 71eda422c926..62ef4afc9ee5 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -576,7 +576,11 @@ struct arm_smmu_device {
struct arm_smmu_strtab_cfg strtab_cfg;
- u32 sync_count;
+ /* Hi16xx adds an extra 32 bits of goodness to its MSI payload */
+ union {
+ u32 sync_count;
+ u64 padding;
+ };
/* IOMMU core code handle */
struct iommu_device iommu;