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Subject[PATCH 02/13] perf/x86/amd/core: Refactor branch attributes
Date
AMD processors that are capable of recording branches support either Branch
Sampling (BRS) or Last Branch Record (LBR). In preparation for adding Last
Branch Record Extension Version 2 (LbrExtV2) support, reuse the "branches"
capability to advertise information about both BRS and LBR but make the
"branch-brs" event exclusive to Family 19h processors that support BRS.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
arch/x86/events/amd/core.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index e32a27899e11..2f524cf84528 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1247,23 +1247,25 @@ static ssize_t branches_show(struct device *cdev,

static DEVICE_ATTR_RO(branches);

-static struct attribute *amd_pmu_brs_attrs[] = {
+static struct attribute *amd_pmu_branches_attrs[] = {
&dev_attr_branches.attr,
NULL,
};

static umode_t
-amd_brs_is_visible(struct kobject *kobj, struct attribute *attr, int i)
+amd_branches_is_visible(struct kobject *kobj, struct attribute *attr, int i)
{
return x86_pmu.lbr_nr ? attr->mode : 0;
}

-static struct attribute_group group_caps_amd_brs = {
+static struct attribute_group group_caps_amd_branches = {
.name = "caps",
- .attrs = amd_pmu_brs_attrs,
- .is_visible = amd_brs_is_visible,
+ .attrs = amd_pmu_branches_attrs,
+ .is_visible = amd_branches_is_visible,
};

+#ifdef CONFIG_PERF_EVENTS_AMD_BRS
+
EVENT_ATTR_STR(branch-brs, amd_branch_brs,
"event=" __stringify(AMD_FAM19H_BRS_EVENT)"\n");

@@ -1272,15 +1274,26 @@ static struct attribute *amd_brs_events_attrs[] = {
NULL,
};

+static umode_t
+amd_brs_is_visible(struct kobject *kobj, struct attribute *attr, int i)
+{
+ return static_cpu_has(X86_FEATURE_BRS) && x86_pmu.lbr_nr ?
+ attr->mode : 0;
+}
+
static struct attribute_group group_events_amd_brs = {
.name = "events",
.attrs = amd_brs_events_attrs,
.is_visible = amd_brs_is_visible,
};

+#endif /* CONFIG_PERF_EVENTS_AMD_BRS */
+
static const struct attribute_group *amd_attr_update[] = {
- &group_caps_amd_brs,
+ &group_caps_amd_branches,
+#ifdef CONFIG_PERF_EVENTS_AMD_BRS
&group_events_amd_brs,
+#endif
NULL,
};

--
2.34.1
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