[RFC][PATCH 3/6] perf, x86: Implement userspace RDPMC

[Peter Zijlstra]

Implement a correct pmu::event_idx for the x86 counter index rules and
set CR4.PCE on CPU_STARTING.

Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Arun Sharma <asharma@xxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
 arch/x86/kernel/cpu/perf_event.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -1211,6 +1211,7 @@ x86_pmu_notifier(struct notifier_block *
 		break;
 
 	case CPU_STARTING:
+		set_in_cr4(X86_CR4_PCE);
 		if (x86_pmu.cpu_starting)
 			x86_pmu.cpu_starting(cpu);
 		break;
@@ -1536,6 +1537,18 @@ static int x86_pmu_event_init(struct per
 	return err;
 }
 
+static int x86_pmu_event_idx(struct perf_event *event)
+{
+	int idx = event->hw.idx;
+
+	if (x86_pmu.num_counters_fixed && idx >= X86_PMC_IDX_FIXED) {
+		idx -= X86_PMC_IDX_FIXED;
+		idx |= 1 << 30;
+	}
+
+	return idx + 1;
+}
+
 static struct pmu pmu = {
 	.pmu_enable	= x86_pmu_enable,
 	.pmu_disable	= x86_pmu_disable,
@@ -1551,6 +1564,8 @@ static struct pmu pmu = {
 	.start_txn	= x86_pmu_start_txn,
 	.cancel_txn	= x86_pmu_cancel_txn,
 	.commit_txn	= x86_pmu_commit_txn,
+
+	.event_idx	= x86_pmu_event_idx,
 };
 
 /*


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