From: Thomas Richter <tmricht@linux.ibm.com>
Date: Thu, 13 Jan 2022 12:51:56 +0100
Subject: s390/cpumf: Support for CPU Measurement Sampling Facility LS bit
Git-commit: 745f5d20e7936931f924410f32d8b0e599b5990e
Patch-mainline: v5.17-rc1
References: bsc#1195080 LTC#196090

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@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 arch/s390/include/asm/cpu_mf.h  |    4 +++-
 arch/s390/kernel/perf_cpum_sf.c |    2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -112,7 +112,9 @@ 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		 */
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1051,7 +1051,7 @@ static void hw_collect_samples(struct pe
 	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 */