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>
---
arch/powerpc/perf/hv-24x7.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index ec2eb20..19a59a3 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -1268,12 +1268,44 @@ 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 int hv_has_24x7(void)
+{
+ int page_size = 4096;
+ unsigned long hret;
+ void *page;
+ struct hv_24x7_catalog_page_0 *page_0;
+
+ page_0 = kmalloc(page_size*2, GFP_KERNEL);
+ if (!page_0)
+ return 0;
+
+ /* buffer for catalog needs to be 4K-aligned */
+ page = (void *)((long)page_0 & (~page_size-1)) + page_size;
+ hret = h_get_24x7_catalog_page(page, 0, 0);
+ kfree(page_0);
+
+ if (hret) {
+ pr_devel("Error %ld reading catalog, disabling 24x7 PMU\n",
hret);
+ return 0;
+ }
+
+ return 1;
+}
+
+
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;
--
1.8.3.1
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