diff options
| author |   Will Deacon <will.deacon@arm.com> | 2016-09-09 14:33:59 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-09-16 09:34:14 +0100 |
| commit | 8ded2909e2c6c34b70ebb45480f6ce68c64fbddc (patch) | |
| tree | eccb4b941bed09582c206b4444c1cb851db9e6d5 /drivers/iommu | |
| parent | iommu/arm-smmu: Fix polling of command queue (diff) | |
| download | linux-dev-8ded2909e2c6c34b70ebb45480f6ce68c64fbddc.tar.xz linux-dev-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.c | 5 |
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 */ |