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authorWill Deacon <will.deacon@arm.com>2016-09-09 15:33:59 +0200
committerWill Deacon <will.deacon@arm.com>2016-09-16 10:34:14 +0200
commit8ded2909e2c6c34b70ebb45480f6ce68c64fbddc (patch)
treeeccb4b941bed09582c206b4444c1cb851db9e6d5 /drivers/iommu
parentiommu/arm-smmu: Fix polling of command queue (diff)
downloadlinux-8ded2909e2c6c34b70ebb45480f6ce68c64fbddc.tar.xz
linux-8ded2909e2c6c34b70ebb45480f6ce68c64fbddc.zip
iommu/arm-smmu: Disable interrupts whilst holding the cmdq lock
The cmdq lock is taken whenever we issue commands into the command queue, which can occur in IRQ context (as a result of unmap) or in process context (as a result of a threaded IRQ handler or device probe). This can lead to a theoretical deadlock if the interrupt handler performing the unmap hits whilst the lock is taken, so explicitly use the {irqsave,irqrestore} spin_lock accessors for the cmdq lock. Tested-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/arm-smmu-v3.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index c040e246bc59..5db6931c715c 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -893,6 +893,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq_ent *ent)
{
u64 cmd[CMDQ_ENT_DWORDS];
+ unsigned long flags;
bool wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV);
struct arm_smmu_queue *q = &smmu->cmdq.q;
@@ -902,7 +903,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
return;
}
- spin_lock(&smmu->cmdq.lock);
+ spin_lock_irqsave(&smmu->cmdq.lock, flags);
while (queue_insert_raw(q, cmd) == -ENOSPC) {
if (queue_poll_cons(q, false, wfe))
dev_err_ratelimited(smmu->dev, "CMDQ timeout\n");
@@ -910,7 +911,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
if (ent->opcode == CMDQ_OP_CMD_SYNC && queue_poll_cons(q, true, wfe))
dev_err_ratelimited(smmu->dev, "CMD_SYNC timeout\n");
- spin_unlock(&smmu->cmdq.lock);
+ spin_unlock_irqrestore(&smmu->cmdq.lock, flags);
}
/* Context descriptor manipulation functions */