[PATCH 1/3] perf/x86/intel: Factor out common code of PMI handler

kan.liang
2018-08-06T17:25:20Z

From: Kan Liang <kan.liang@linux.intel.com>

The Arch Perfmon v4 PMI handler is substantially different than
the older PMI handler. Instead of adding more and more ifs cleanly
fork the new handler into a new function, with the main common
code factored out into a common function.

Fix complaint from checkpatch.pl by removing "false" from "static bool
warned".

No functional change.

Based-on-code-from: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/events/intel/core.c | 109 ++++++++++++++++++++++++-------------------
1 file changed, 60 insertions(+), 49 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 035c374..9b320a5 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2200,59 +2200,15 @@ static void intel_pmu_reset(void)
local_irq_restore(flags);
}

-/*
- * This handler is triggered by the local APIC, so the APIC IRQ handling
- * rules apply:
- */
-static int intel_pmu_handle_irq(struct pt_regs *regs)
+static int handle_pmi_common(struct pt_regs *regs, u64 status)
{
struct perf_sample_data data;
- struct cpu_hw_events *cpuc;
- 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();
- status = intel_pmu_get_status();
- if (!status)
- goto done;
-
- loops = 0;
-again:
- intel_pmu_lbr_read();
- intel_pmu_ack_status(status);
- if (++loops > 100) {
- static bool warned = false;
- if (!warned) {
- WARN(1, "perfevents: irq loop stuck!\n");
- perf_event_print_debug();
- warned = true;
- }
- intel_pmu_reset();
- goto done;
- }
+ struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ int bit;
+ int handled = 0;

inc_irq_stat(apic_perf_irqs);

-
/*
* Ignore a range of extra bits in status that do not indicate
* overflow by themselves.
@@ -2261,7 +2217,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
GLOBAL_STATUS_ASIF |
GLOBAL_STATUS_LBRS_FROZEN);
if (!status)
- goto done;
+ return 0;
/*
* In case multiple PEBS events are sampled at the same time,
* it is possible to have GLOBAL_STATUS bit 62 set indicating
@@ -2331,6 +2287,61 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
x86_pmu_stop(event, 0);
}

+ return handled;
+}
+
+/*
+ * This handler is triggered by the local APIC, so the APIC IRQ handling
+ * rules apply:
+ */
+static int intel_pmu_handle_irq(struct pt_regs *regs)
+{
+ struct cpu_hw_events *cpuc;
+ int 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();
+ status = intel_pmu_get_status();
+ if (!status)
+ goto done;
+
+ loops = 0;
+again:
+ intel_pmu_lbr_read();
+ intel_pmu_ack_status(status);
+ if (++loops > 100) {
+ static bool warned;
+
+ if (!warned) {
+ WARN(1, "perfevents: irq loop stuck!\n");
+ perf_event_print_debug();
+ warned = true;
+ }
+ intel_pmu_reset();
+ goto done;
+ }
+
+ handled += handle_pmi_common(regs, status);
+
/*
* Repeat if there is more work to be done:
*/
--
2.7.4