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| author | Wei Huang <wei@redhat.com> | 2017-05-30 11:56:22 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-05-30 12:40:03 +0100 |
| commit | 477c50e8dc1c7b5004e099b8b74ca8b70be2f4fd (patch) | |
| tree | bf2e1d1460f04943a576021b0209b243bfbc568e | |
| parent | 717902cc93118119a6fce7765da6cf2786987418 (diff) | |
| download | lwn-477c50e8dc1c7b5004e099b8b74ca8b70be2f4fd.tar.gz lwn-477c50e8dc1c7b5004e099b8b74ca8b70be2f4fd.zip | |
drivers/perf: arm_pmu_acpi: avoid perf IRQ init when guest PMU is off
We saw perf IRQ init failures when running Linux kernel in an ACPI
guest without PMU (i.e. pmu=off). This is because perf IRQ is not
present when pmu=off, but arm_pmu_acpi still tries to register
or unregister GSI. This patch addresses the problem by checking
gicc->performance_interrupt. If it is 0, which is the value set
by qemu when pmu=off, we skip the IRQ register/unregister process.
[ 4.069470] bc00: 0000000000040b00 ffff0000089db190
[ 4.070267] [<ffff000008134f80>] enable_percpu_irq+0xdc/0xe4
[ 4.071192] [<ffff000008667cc4>] arm_perf_starting_cpu+0x108/0x10c
[ 4.072200] [<ffff0000080cbdd4>] cpuhp_invoke_callback+0x14c/0x4ac
[ 4.073210] [<ffff0000080ccd3c>] cpuhp_thread_fun+0xd4/0x11c
[ 4.074132] [<ffff0000080f1394>] smpboot_thread_fn+0x1b4/0x1c4
[ 4.075081] [<ffff0000080ec90c>] kthread+0x10c/0x138
[ 4.075921] [<ffff0000080833c0>] ret_from_fork+0x10/0x50
[ 4.076947] genirq: Setting trigger mode 4 for irq 43 failed
(gic_set_type+0x0/0x74)
Signed-off-by: Wei Huang <wei@redhat.com>
[will: add comment justifying deviation from ACPI spec, removed redundant hunk]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | drivers/perf/arm_pmu_acpi.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c index 34c862f213c7..0a9b78705ee8 100644 --- a/drivers/perf/arm_pmu_acpi.c +++ b/drivers/perf/arm_pmu_acpi.c @@ -29,6 +29,17 @@ static int arm_pmu_acpi_register_irq(int cpu) return -EINVAL; gsi = gicc->performance_interrupt; + + /* + * Per the ACPI spec, the MADT cannot describe a PMU that doesn't + * have an interrupt. QEMU advertises this by using a GSI of zero, + * which is not known to be valid on any hardware despite being + * valid per the spec. Take the pragmatic approach and reject a + * GSI of zero for now. + */ + if (!gsi) + return 0; + if (gicc->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE) trigger = ACPI_EDGE_SENSITIVE; else |