s390/cpum_sf: Add helper to read TOD from trailer entries

The trailer entry contains a timestamp of the time when the sample-data-block
became full.  The timestamp specifies a TOD (time-of-day) value in either the
STCK or STCKE format.

Provide a helper function to return the TOD value depending on the setting of
time format indicator.

Signed-off-by: Hendrik Brueckner <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>

Author: hbrueckner

arch/s390/include/asm/cpu_mf.h

@@ -125,8 +125,7 @@ struct hws_trailer_entry {
 		unsigned long long flags;	/* 0 - 63: All indicators     */
 	};
 	unsigned long long overflow;	 /* 64 - sample Overflow count	      */
-	unsigned long long timestamp;	 /* 16 - time-stamp		      */
-	unsigned long long timestamp1;	 /*				      */
+	unsigned char timestamp[16];	 /* 16 - 31 timestamp		      */
 	unsigned long long reserved1;	 /* 32 -Reserved		      */
 	unsigned long long reserved2;	 /*				      */
 	unsigned long long progusage1;	 /* 48 - reserved for programming use */
@@ -232,6 +231,17 @@ static inline unsigned long sample_rate_to_freq(struct hws_qsi_info_block *qsi,
 #define SDB_TE_ALERT_REQ_MASK	0x4000000000000000UL
 #define SDB_TE_BUFFER_FULL_MASK 0x8000000000000000UL
 
+/* Return TOD timestamp contained in an trailer entry */
+static inline unsigned long long trailer_timestamp(struct hws_trailer_entry *te)
+{
+	/* TOD in STCKE format */
+	if (te->t)
+		return *((unsigned long long *) &te->timestamp[1]);
+
+	/* TOD in STCK format */
+	return *((unsigned long long *) &te->timestamp[0]);
+}
+
 /* Return pointer to trailer entry of an sample data block */
 static inline unsigned long *trailer_entry_ptr(unsigned long v)
 {

arch/s390/kernel/perf_cpum_sf.c

@@ -981,7 +981,7 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
 		debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p "
 				    "overflow=%llu timestamp=0x%llx\n",
 				    sdbt, te->overflow,
-				    (te->f) ? te->timestamp : 0ULL);
+				    (te->f) ? trailer_timestamp(te) : 0ULL);
 
 		/* Collect all samples from a single sample-data-block and
 		 * flag if an (perf) event overflow happened.  If so, the PMU