From: Thomas Richter <tmricht@linux.ibm.com>
Date: Fri, 20 Sep 2019 11:57:43 +0200
Subject: s390/cpumsf: Check for CPU Measurement sampling
Git-commit: 932bfc5aae08f3cb20c1c9f051542f5933710151
Patch-mainline: v5.4-rc2
References: bsc#1153681 LTC#181855
s390 IBM z15 introduces a check if the CPU Mesurement Facility
sampling is temporarily unavailable. If this is the case return -EBUSY
and abort the setup of CPU Measuement facility sampling.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
arch/s390/include/asm/cpu_mf.h | 5 ++++-
arch/s390/kernel/perf_cpum_sf.c | 6 ++++++
2 files changed, 10 insertions(+), 1 deletion(-)
--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -29,6 +29,8 @@
CPU_MF_INT_SF_PRA|CPU_MF_INT_SF_SACA| \
CPU_MF_INT_SF_LSDA)
+#define CPU_MF_SF_RIBM_NOTAV 0x1 /* Sampling unavailable */
+
/* CPU measurement facility support */
static inline int cpum_cf_avail(void)
{
@@ -70,7 +72,8 @@ struct hws_qsi_info_block { /* Bit(s
unsigned long max_sampl_rate; /* 16-23: maximum sampling interval*/
unsigned long tear; /* 24-31: TEAR contents */
unsigned long dear; /* 32-39: DEAR contents */
- unsigned int rsvrd0; /* 40-43: reserved */
+ unsigned int rsvrd0:24; /* 40-42: reserved */
+ unsigned int ribm:8; /* 43: Reserved by IBM */
unsigned int cpu_speed; /* 44-47: CPU speed */
unsigned long long rsvrd1; /* 48-55: reserved */
unsigned long long rsvrd2; /* 56-63: reserved */
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -714,6 +714,12 @@ static int __hw_perf_event_init(struct p
goto out;
}
+ if (si.ribm & CPU_MF_SF_RIBM_NOTAV) {
+ pr_warn("CPU Measurement Facility sampling is temporarily not available\n");
+ err = -EBUSY;
+ goto out;
+ }
+
/* Always enable basic sampling */
SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE;