1 files changed, 59 insertions, 3 deletions

diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 732cfc53e260..e85f1962be02 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -70,7 +70,7 @@ static struct attribute_group format_group = {
 
 static struct attribute_group event_group = {
 	.name  = "events",
-	.attrs = hv_gpci_event_attrs,
+	/* .attrs is set in init */
 };
 
 #define HV_CAPS_ATTR(_name, _format)				\
@@ -153,6 +153,20 @@ 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;
@@ -217,6 +231,7 @@ 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)
@@ -247,13 +262,23 @@ 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;
 	}
@@ -280,6 +305,7 @@ static int hv_gpci_init(void)
 	int r;
 	unsigned long hret;
 	struct hv_perf_caps caps;
+	struct hv_gpci_request_buffer *arg;
 
 	hv_gpci_assert_offsets_correct();
 
@@ -298,6 +324,36 @@ static int hv_gpci_init(void)
 	/* sampling not supported */
 	h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
 
+	arg = (void *)get_cpu_var(hv_gpci_reqb);
+	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
+
+	/*
+	 * hcall H_GET_PERF_COUNTER_INFO populates the output
+	 * counter_info_version value based on the system hypervisor.
+	 * Pass the counter request 0x10 corresponds to request type
+	 * 'Dispatch_timebase_by_processor', to get the supported
+	 * counter_info_version.
+	 */
+	arg->params.counter_request = cpu_to_be32(0x10);
+
+	r = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
+			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
+	if (r) {
+		pr_devel("hcall failed, can't get supported counter_info_version: 0x%x\n", r);
+		arg->params.counter_info_version_out = 0x8;
+	}
+
+	/*
+	 * Use counter_info_version_out value to assign
+	 * required hv-gpci event list.
+	 */
+	if (arg->params.counter_info_version_out >= 0x8)
+		event_group.attrs = hv_gpci_event_attrs;
+	else
+		event_group.attrs = hv_gpci_event_attrs_v6;
+
+	put_cpu_var(hv_gpci_reqb);
+
 	r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
 	if (r)
 		return r;