s390/cpum_sf: save TOD clock base in SDBs for time conversion

Processing the samples in the AUX-area by perf requires the computation
of respective time stamps.  The time stamps used by perf are based on
the monotonic clock.  To convert the TOD clock value contained in an
SDB to a monotonic clock value, the TOD clock base is required.  Hence,
also save the TOD clock base in the SDB.

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

Author: hbrueckner

arch/s390/include/asm/cpu_mf.h

@@ -2,7 +2,7 @@
 /*
  * CPU-measurement facilities
  *
- *  Copyright IBM Corp. 2012
+ *  Copyright IBM Corp. 2012, 2018
  *  Author(s): Hendrik Brueckner <[email protected]>
  *	       Jan Glauber <[email protected]>
  */
@@ -139,8 +139,14 @@ struct hws_trailer_entry {
 	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 */
-	unsigned long long progusage2;	 /*				      */
+	union {				 /* 48 - reserved for programming use */
+		struct {
+			unsigned int clock_base:1; /* in progusage2 */
+			unsigned long long progusage1:63;
+			unsigned long long progusage2;
+		};
+		unsigned long long progusage[2];
+	};
 } __packed;
 
 /* Load program parameter */

arch/s390/kernel/perf_cpum_sf.c

@@ -2,7 +2,7 @@
 /*
  * Performance event support for the System z CPU-measurement Sampling Facility
  *
- * Copyright IBM Corp. 2013
+ * Copyright IBM Corp. 2013, 2018
  * Author(s): Hendrik Brueckner <[email protected]>
  */
 #define KMSG_COMPONENT	"cpum_sf"
@@ -1587,6 +1587,17 @@ static void aux_buffer_free(void *data)
 			    "%lu SDBTs\n", num_sdbt);
 }
 
+static void aux_sdb_init(unsigned long sdb)
+{
+	struct hws_trailer_entry *te;
+
+	te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb);
+
+	/* Save clock base */
+	te->clock_base = 1;
+	memcpy(&te->progusage2, &tod_clock_base[1], 8);
+}
+
 /*
  * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling
  * @cpu:	On which to allocate, -1 means current
@@ -1666,6 +1677,7 @@ static void *aux_buffer_setup(int cpu, void **pages, int nr_pages,
 		/* Tail is the entry in a SDBT */
 		*tail = (unsigned long)pages[i];
 		aux->sdb_index[i] = (unsigned long)pages[i];
+		aux_sdb_init((unsigned long)pages[i]);
 	}
 	sfb->num_sdb = nr_pages;