From: Stephane Eranian <eranian@google.com>
Date: Tue, 22 Mar 2022 22:15:08 +0000 (-0700)
Subject: perf/x86/amd: Add branch-brs helper event for Fam19h BRS
X-Git-Tag: v5.19-rc1~205^2~29
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44175993efbae04e8b2d7f7795ff512c3a726db0;p=thirdparty%2Fkernel%2Flinux.git

perf/x86/amd: Add branch-brs helper event for Fam19h BRS

Add a pseudo event called branch-brs to help use the FAM Fam19h
Branch Sampling feature (BRS). BRS samples taken branches, so it is best used
when sampling on a retired taken branch event (0xc4) which is what BRS
captures.  Instead of trying to remember the event code or actual event name,
users can simply do:

$ perf record -b -e cpu/branch-brs/ -c 1000037 .....

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220322221517.2510440-5-eranian@google.com
---

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index c7ac70d8ed9a1..f7bce8364fe40 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1145,8 +1145,23 @@ static struct attribute_group group_caps_amd_brs = {
 	.is_visible = amd_brs_is_visible,
 };
 
+EVENT_ATTR_STR(branch-brs, amd_branch_brs,
+	       "event=" __stringify(AMD_FAM19H_BRS_EVENT)"\n");
+
+static struct attribute *amd_brs_events_attrs[] = {
+	EVENT_PTR(amd_branch_brs),
+	NULL,
+};
+
+static struct attribute_group group_events_amd_brs = {
+	.name       = "events",
+	.attrs      = amd_brs_events_attrs,
+	.is_visible = amd_brs_is_visible,
+};
+
 static const struct attribute_group *amd_attr_update[] = {
 	&group_caps_amd_brs,
+	&group_events_amd_brs,
 	NULL,
 };