s390/cpum_sf: do not register PMU if no sampling mode is authorized

Previously, the cpum_sf PMU was registered even if there is no
sampling mode authorized.  Add a check and register cpum_sf only
at least one sampling mode is authorized.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 4d8ddd8..7e9b9e6 100644 (file)
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1938,6 +1938,9 @@ static int __init init_cpum_sampling_pmu(void)
                return -ENODEV;
        }
 
+       if (!si.as && !si.ad)
+               return -ENODEV;
+
        if (si.bsdes != sizeof(struct hws_basic_entry)) {
                pr_cpumsf_err(RS_INIT_FAILURE_BSDES);
                return -EINVAL;