perf/x86: Use event_base_rdpmc for the RDPMC userspace support

The RDPMC index is always re-calculated for the RDPMC userspace support,
which is unnecessary.

The RDPMC index value is stored in the variable event_base_rdpmc for
the kernel usage, which can be used for RDPMC userspace support as well.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-2-kan.liang@linux.intel.com

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1cbf57d..8e108ea 100644 (file)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2208,17 +2208,12 @@ static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *m
 
 static int x86_pmu_event_idx(struct perf_event *event)
 {
-       int idx = event->hw.idx;
+       struct hw_perf_event *hwc = &event->hw;
 
-       if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
+       if (!(hwc->flags & PERF_X86_EVENT_RDPMC_ALLOWED))
                return 0;
 
-       if (x86_pmu.num_counters_fixed && idx >= INTEL_PMC_IDX_FIXED) {
-               idx -= INTEL_PMC_IDX_FIXED;
-               idx |= 1 << 30;
-       }
-
-       return idx + 1;
+       return hwc->event_base_rdpmc + 1;
 }
 
 static ssize_t get_attr_rdpmc(struct device *cdev,