s390/cpumsf: Check for CPU Measurement sampling

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 <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: Thomas Richter

arch/s390/include/asm/cpu_mf.h

@@ -28,6 +28,8 @@ asm(".include \"asm/cpu_mf-insn.h\"\n");
 				 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)
 {
@@ -69,7 +71,8 @@ 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			 */

arch/s390/kernel/perf_cpum_sf.c

@@ -803,6 +803,12 @@ static int __hw_perf_event_init(struct perf_event *event)
 		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;