2 files changed, 13 insertions, 2 deletions

diff --git a/arch/s390/include/asm/perf_event.h b/arch/s390/include/asm/perf_event.h
index bd4573f1d65c..159a8ec6da9a 100644
--- a/arch/s390/include/asm/perf_event.h
+++ b/arch/s390/include/asm/perf_event.h
@@ -59,6 +59,7 @@ struct perf_sf_sde_regs {
 #define PERF_CPUM_SF_DIAG_MODE          0x0002    /* Diagnostic-sampling flag */
 #define PERF_CPUM_SF_MODE_MASK          (PERF_CPUM_SF_BASIC_MODE| \
                                          PERF_CPUM_SF_DIAG_MODE)
+#define PERF_CPUM_SF_FULL_BLOCKS        0x0004    /* Process full SDBs only */
 
 #define REG_NONE                0
 #define REG_OVERFLOW            1
@@ -69,6 +70,7 @@ struct perf_sf_sde_regs {
 #define SAMPL_RATE(hwc)         ((hwc)->event_base)
 #define SAMPL_FLAGS(hwc)        ((hwc)->config_base)
 #define SAMPL_DIAG_MODE(hwc)    (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_DIAG_MODE)
+#define SDB_FULL_BLOCKS(hwc)    (SAMPL_FLAGS(hwc) & PERF_CPUM_SF_FULL_BLOCKS)
 
 /* Structure for sampling data entries to be passed as perf raw sample data
  * to user space.  Note that raw sample data must be aligned and, thus, might
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index b4ec058c4f10..3c3bc8d7b220 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -733,6 +733,10 @@ static int __hw_perf_event_init(struct perf_event *event)
                 SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE;
         }
 
+        /* Check and set other sampling flags */
+        if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS)
+                SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS;
+
         /* The sampling information (si) contains information about the
          * min/max sampling intervals and the CPU speed.  So calculate the
          * correct sampling interval and avoid the whole period adjust
@@ -1203,8 +1207,10 @@ static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt,
  * register of the specified perf event.
  *
  * Only full sample-data-blocks are processed.  Specify the flash_all flag
- * to also walk through partially filled sample-data-blocks.
- *
+ * to also walk through partially filled sample-data-blocks.  It is ignored
+ * if PERF_CPUM_SF_FULL_BLOCKS is set.  The PERF_CPUM_SF_FULL_BLOCKS flag
+ * enforces the processing of full sample-data-blocks only (trailer entries
+ * with the block-full-indicator bit set).
  */
 static void hw_perf_event_update(struct perf_event *event, int flush_all)
 {
@@ -1214,6 +1220,9 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
         unsigned long long event_overflow, sampl_overflow, num_sdb, te_flags;
         int done;
 
+        if (flush_all && SDB_FULL_BLOCKS(hwc))
+                flush_all = 0;
+
         sdbt = (unsigned long *) TEAR_REG(hwc);
         done = event_overflow = sampl_overflow = num_sdb = 0;
         while (!done) {