@@ -686,8 +686,7 @@ static struct iommu_gather_ops arm_smmu_gather_ops = {
static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
{
- int flags, ret;
- u32 fsr, fsynr, resume;
+ u32 fsr, fsynr;
unsigned long iova;
struct iommu_domain *domain = dev;
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
@@ -701,34 +700,15 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
if (!(fsr & FSR_FAULT))
return IRQ_NONE;
- if (fsr & FSR_IGN)
- dev_err_ratelimited(smmu->dev,
- "Unexpected context fault (fsr 0x%x)\n",
- fsr);
-
fsynr = readl_relaxed(cb_base + ARM_SMMU_CB_FSYNR0);
- flags = fsynr & FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ;
-
iova = readq_relaxed(cb_base + ARM_SMMU_CB_FAR);
- if (!report_iommu_fault(domain, smmu->dev, iova, flags)) {
- ret = IRQ_HANDLED;
- resume = RESUME_RETRY;
- } else {
- dev_err_ratelimited(smmu->dev,
- "Unhandled context fault: iova=0x%08lx, fsynr=0x%x, cb=%d\n",
- iova, fsynr, cfg->cbndx);
- ret = IRQ_NONE;
- resume = RESUME_TERMINATE;
- }
-
- /* Clear the faulting FSR */
- writel(fsr, cb_base + ARM_SMMU_CB_FSR);
- /* Retry or terminate any stalled transactions */
- if (fsr & FSR_SS)
- writel_relaxed(resume, cb_base + ARM_SMMU_CB_RESUME);
+ dev_err_ratelimited(smmu->dev,
+ "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cb=%d\n",
+ fsr, iova, fsynr, cfg->cbndx);
- return ret;
+ writel(fsr, cb_base + ARM_SMMU_CB_FSR);
+ return IRQ_HANDLED;
}
static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
@@ -837,7 +817,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
}
/* SCTLR */
- reg = SCTLR_CFCFG | SCTLR_CFIE | SCTLR_CFRE | SCTLR_M | SCTLR_EAE_SBOP;
+ reg = SCTLR_CFIE | SCTLR_CFRE | SCTLR_M | SCTLR_EAE_SBOP;
if (stage1)
reg |= SCTLR_S1_ASIDPNE;
#ifdef __BIG_ENDIAN
Enabling stalling faults can result in hardware deadlock on poorly designed systems, particularly those with a PCI root complex upstream of the SMMU. Although it's not really Linux's job to save hardware integrators from their own misfortune, it *is* our job to stop userspace (e.g. VFIO clients) from hosing the system for everybody else, even if they might already be required to have elevated privileges. Given that the fault handling code currently executes entirely in IRQ context, there is nothing that can sensibly be done to recover from things like page faults anyway, so let's rip this code out for now and avoid the potential for deadlock. Cc: <stable@vger.kernel.org> Reported-by: Matt Evans <matt.evans@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- drivers/iommu/arm-smmu.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html