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-rw-r--r--arch/powerpc/perf/hv-gpci.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 7ff8ff350..943248a0e 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -164,6 +164,20 @@ static unsigned long single_gpci_request(u32 req, u32 starting_index,
ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+
+ /*
+ * ret value as 'H_PARAMETER' with detail_rc as 'GEN_BUF_TOO_SMALL',
+ * specifies that the current buffer size cannot accommodate
+ * all the information and a partial buffer returned.
+ * Since in this function we are only accessing data for a given starting index,
+ * we don't need to accommodate whole data and can get required count by
+ * accessing first entry data.
+ * Hence hcall fails only incase the ret value is other than H_SUCCESS or
+ * H_PARAMETER with detail_rc value as GEN_BUF_TOO_SMALL(0x1B).
+ */
+ if (ret == H_PARAMETER && be32_to_cpu(arg->params.detail_rc) == 0x1B)
+ ret = 0;
+
if (ret) {
pr_devel("hcall failed: 0x%lx\n", ret);
goto out;
@@ -228,6 +242,7 @@ static int h_gpci_event_init(struct perf_event *event)
{
u64 count;
u8 length;
+ unsigned long ret;
/* Not our event */
if (event->attr.type != event->pmu->type)
@@ -258,13 +273,23 @@ static int h_gpci_event_init(struct perf_event *event)
}
/* check if the request works... */
- if (single_gpci_request(event_get_request(event),
+ ret = single_gpci_request(event_get_request(event),
event_get_starting_index(event),
event_get_secondary_index(event),
event_get_counter_info_version(event),
event_get_offset(event),
length,
- &count)) {
+ &count);
+
+ /*
+ * ret value as H_AUTHORITY implies that partition is not permitted to retrieve
+ * performance information, and required to set
+ * "Enable Performance Information Collection" option.
+ */
+ if (ret == H_AUTHORITY)
+ return -EPERM;
+
+ if (ret) {
pr_devel("gpci hcall failed\n");
return -EINVAL;
}