From: Thomas Gleixner tglx@linutronix.de
mainline inclusion from mainline-v5.13-rc3 commit 2621054535955fb78ea96b76b279eb481f40fcef category: bugfix bugzilla: 175148 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The driver uses irq_set_affinity_hint() to set the affinity for the PMU interrupts, which relies on the undocumented side effect that this function actually sets the affinity under the hood.
Setting an hint is clearly not a guarantee and for these PMU interrupts an affinity hint, which is supposed to guide userspace for setting affinity, is beyond pointless, because the affinity of these interrupts cannot be modified from user space.
Aside of that the error checks are bogus because the only error which is returned from irq_set_affinity_hint() is when there is no irq descriptor for the interrupt number, but not when the affinity set fails. That's on purpose because the hint can point to an offline CPU.
Replace the mindless abuse with irq_set_affinity().
Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Will Deacon will@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: linux-arm-kernel@lists.infradead.org Acked-by: Mark Rutland mark.rutland@arm.com Link: https://lore.kernel.org/r/20210518093118.603636289@linutronix.de Signed-off-by: Will Deacon will@kernel.org Reviewed-by: Shaokun Zhang zhangshaokun@hisilicon.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/perf/arm_smmuv3_pmu.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c index 74474bb322c3..461a9924207d 100644 --- a/drivers/perf/arm_smmuv3_pmu.c +++ b/drivers/perf/arm_smmuv3_pmu.c @@ -634,7 +634,7 @@ static int smmu_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
perf_pmu_migrate_context(&smmu_pmu->pmu, cpu, target); smmu_pmu->on_cpu = target; - WARN_ON(irq_set_affinity_hint(smmu_pmu->irq, cpumask_of(target))); + WARN_ON(irq_set_affinity(smmu_pmu->irq, cpumask_of(target)));
return 0; } @@ -845,15 +845,14 @@ static int smmu_pmu_probe(struct platform_device *pdev)
/* Pick one CPU to be the preferred one to use */ smmu_pmu->on_cpu = raw_smp_processor_id(); - WARN_ON(irq_set_affinity_hint(smmu_pmu->irq, - cpumask_of(smmu_pmu->on_cpu))); + WARN_ON(irq_set_affinity(smmu_pmu->irq, cpumask_of(smmu_pmu->on_cpu)));
err = cpuhp_state_add_instance_nocalls(cpuhp_state_num, &smmu_pmu->node); if (err) { dev_err(dev, "Error %d registering hotplug, PMU @%pa\n", err, &res_0->start); - goto out_clear_affinity; + return err; }
err = perf_pmu_register(&smmu_pmu->pmu, name, -1); @@ -872,8 +871,6 @@ static int smmu_pmu_probe(struct platform_device *pdev)
out_unregister: cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &smmu_pmu->node); -out_clear_affinity: - irq_set_affinity_hint(smmu_pmu->irq, NULL); return err; }
@@ -883,7 +880,6 @@ static int smmu_pmu_remove(struct platform_device *pdev)
perf_pmu_unregister(&smmu_pmu->pmu); cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &smmu_pmu->node); - irq_set_affinity_hint(smmu_pmu->irq, NULL);
return 0; }