From 955102eacf035b19080dc659a15d9b8fbd8fae7f Mon Sep 17 00:00:00 2001
From: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Date: Tue, 28 Apr 2015 18:47:58 -0400
Subject: [PATCH 1/1] powerpc/perf/hv-24x7: Check support before registering
PMU
We currently try to register the 24x7 PMU unconditionally. Not all
Power systems support 24x7 counters (eg: Power7). On these systems
we get a backtrace during boot when trying to register the 24x7 PMU.
Check if the hypervisor supports 24x7 counters before attempting to
register the 24x7 PMU.
Reported-by: Gustavo Luiz Duarte <gu...@br.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
---
Changelog[v2]
- [Michael Ellerman] Simplify check with bogus parameters.
---
arch/powerpc/perf/hv-24x7.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index ec2eb20..c04a332 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -1268,12 +1268,33 @@ static struct pmu h_24x7_pmu = {
.read = h_24x7_event_read,
};
+/*
+ * Return 1 if we can access the 24x7 counter catalog from the hypervisor.
+ * Return 0 otherwise.
+ */
+static bool hv_has_24x7(void)
+{
+ unsigned long hret;
+
+ hret = h_get_24x7_catalog_page(0, 0, 0);
+
+ if (hret != H_FUNCTION)
+ pr_err("Error %ld reading catalog, disabling 24x7 PMU\n", hret);
+
+ return hret == 0;
+
+}
+
+
static int hv_24x7_init(void)
{
int r;
unsigned long hret;
struct hv_perf_caps caps;
+ if (!hv_has_24x7())
+ return -ENODEV;
+
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
pr_debug("not a virtualized system, not enabling\n");
return -ENODEV;
--
1.7.9.5
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