Commit 8ded2909 authored by Will Deacon's avatar Will Deacon

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: default avatarJean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent bcfced15
...@@ -893,6 +893,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, ...@@ -893,6 +893,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq_ent *ent) struct arm_smmu_cmdq_ent *ent)
{ {
u64 cmd[CMDQ_ENT_DWORDS]; u64 cmd[CMDQ_ENT_DWORDS];
unsigned long flags;
bool wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV); bool wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV);
struct arm_smmu_queue *q = &smmu->cmdq.q; struct arm_smmu_queue *q = &smmu->cmdq.q;
...@@ -902,7 +903,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, ...@@ -902,7 +903,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
return; return;
} }
spin_lock(&smmu->cmdq.lock); spin_lock_irqsave(&smmu->cmdq.lock, flags);
while (queue_insert_raw(q, cmd) == -ENOSPC) { while (queue_insert_raw(q, cmd) == -ENOSPC) {
if (queue_poll_cons(q, false, wfe)) if (queue_poll_cons(q, false, wfe))
dev_err_ratelimited(smmu->dev, "CMDQ timeout\n"); dev_err_ratelimited(smmu->dev, "CMDQ timeout\n");
...@@ -910,7 +911,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu, ...@@ -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)) if (ent->opcode == CMDQ_OP_CMD_SYNC && queue_poll_cons(q, true, wfe))
dev_err_ratelimited(smmu->dev, "CMD_SYNC timeout\n"); 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 */ /* Context descriptor manipulation functions */
......
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