4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kan Liang kan.liang@linux.intel.com
[ Upstream commit 82d71ed0277efc45360828af8c4e4d40e1b45352 ]
The PMU is disabled in intel_pmu_handle_irq(), but cpuc->enabled is not updated accordingly.
This is fine in current usage because no-one checks it - but fix it for future code: for example, the drain_pebs() will be modified to fix an auto-reload bug.
Properly save/restore the old PMU state.
Signed-off-by: Kan Liang kan.liang@linux.intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Stephane Eranian eranian@google.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vince Weaver vincent.weaver@maine.edu Cc: acme@kernel.org Cc: kernel test robot fengguang.wu@intel.com Link: http://lkml.kernel.org/r/6f44ee84-56f8-79f1-559b-08e371eaeb78@linux.intel.co... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/events/intel/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2201,16 +2201,23 @@ static int intel_pmu_handle_irq(struct p int bit, loops; u64 status; int handled; + int pmu_enabled;
cpuc = this_cpu_ptr(&cpu_hw_events);
/* + * Save the PMU state. + * It needs to be restored when leaving the handler. + */ + pmu_enabled = cpuc->enabled; + /* * No known reason to not always do late ACK, * but just in case do it opt-in. */ if (!x86_pmu.late_ack) apic_write(APIC_LVTPC, APIC_DM_NMI); intel_bts_disable_local(); + cpuc->enabled = 0; __intel_pmu_disable_all(); handled = intel_pmu_drain_bts_buffer(); handled += intel_bts_interrupt(); @@ -2320,7 +2327,8 @@ again:
done: /* Only restore PMU state when it's active. See x86_pmu_disable(). */ - if (cpuc->enabled) + cpuc->enabled = pmu_enabled; + if (pmu_enabled) __intel_pmu_enable_all(0, true); intel_bts_enable_local();