[SRU][F][PATCH 2/2] s390/cpumf: Support for CPU Measurement Sampling Facility LS bit

[Krzysztof Kozlowski]

From: Thomas Richter <tmricht at linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/1960182

Adds support for the CPU Measurement Sampling Facility limit sampling
bit in the sampling device driver.
Limited samples have no valueable information are not collected.

Signed-off-by: Thomas Richter <tmricht at linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk at linux.ibm.com>
Signed-off-by: Heiko Carstens <hca at linux.ibm.com>
(cherry picked from commit 745f5d20e7936931f924410f32d8b0e599b5990e)
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski at canonical.com>
---
 arch/s390/include/asm/cpu_mf.h  | 4 +++-
 arch/s390/kernel/perf_cpum_sf.c | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/s390/include/asm/cpu_mf.h b/arch/s390/include/asm/cpu_mf.h
index 819803a97c2b..4dfebb8705e4 100644
--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -109,7 +109,9 @@ struct hws_basic_entry {
 	unsigned int AS:2;	    /* 29-30 PSW address-space control	 */
 	unsigned int I:1;	    /* 31 entry valid or invalid	 */
 	unsigned int CL:2;	    /* 32-33 Configuration Level	 */
-	unsigned int:14;
+	unsigned int H:1;	    /* 34 Host Indicator		 */
+	unsigned int LS:1;	    /* 35 Limited Sampling		 */
+	unsigned int:12;
 	unsigned int prim_asn:16;   /* primary ASN			 */
 	unsigned long long ia;	    /* Instruction Address		 */
 	unsigned long long gpp;     /* Guest Program Parameter		 */
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index b83bddf35e06..15f055947b66 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1182,7 +1182,7 @@ static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt,
 	sample = (struct hws_basic_entry *) *sdbt;
 	while ((unsigned long *) sample < (unsigned long *) te) {
 		/* Check for an empty sample */
-		if (!sample->def)
+		if (!sample->def || sample->LS)
 			break;
 
 		/* Update perf event period */
-- 
2.32.0