On s390 perf can be executed on a LPAR with support
for hardware events (i. e. cycles) or on a z/VM or KVM guest
where no hardware events are supported. In this
environment use software event named cpu-clock
for this test case.

Use the cpuid infrastructure functions to determine
the cpuid on s390 which contains an indication of the
cpu counter facility availability.

Signed-off-by: Thomas Richter <tmri...@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueck...@linux.vnet.ibm.com>
---
 tools/perf/tests/code-reading.c | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 3bf7b145b826..c7115d369511 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -482,6 +482,34 @@ static void fs_something(void)
        }
 }
 
+static const char *do_determine_event(bool excl_kernel)
+{
+       const char *event = excl_kernel ? "cycles:u" : "cycles";
+
+#ifdef __s390x__
+       char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
+       unsigned int family;
+       int ret, cpum_cf_a;
+
+       if (get_cpuid(cpuid, sizeof(cpuid)))
+               goto out_clocks;
+       ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
+                    model, cpum_cf_v, &cpum_cf_a);
+       if (ret != 5)            /* Not available */
+               goto out_clocks;
+       if (excl_kernel && (cpum_cf_a & 4))
+               return event;
+       if (!excl_kernel && (cpum_cf_a & 2))
+               return event;
+
+       /* Fall through: missing authorization */
+out_clocks:
+       event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
+
+#endif
+       return event;
+}
+
 static void do_something(void)
 {
        fs_something();
@@ -592,10 +620,7 @@ static int do_test_code_reading(bool try_kcore)
 
                perf_evlist__set_maps(evlist, cpus, threads);
 
-               if (excl_kernel)
-                       str = "cycles:u";
-               else
-                       str = "cycles";
+               str = do_determine_event(excl_kernel);
                pr_debug("Parsing event '%s'\n", str);
                ret = parse_events(evlist, str, NULL);
                if (ret < 0) {
-- 
2.14.3

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