1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/events/amd/lbr.c b/arch/x86/events/amd/lbr.c
new file mode 100644
index 000000000000..4e5b5d35f35a
--- /dev/null
+++ b/arch/x86/events/amd/lbr.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/perf_event.h>
+#include <asm/perf_event.h>
+
+#include "../perf_event.h"
+
+__init int amd_pmu_lbr_init(void)
+{
+	union cpuid_0x80000022_ebx ebx;
+
+	if (x86_pmu.version < 2 || !boot_cpu_has(X86_FEATURE_AMD_LBR_V2))
+		return -EOPNOTSUPP;
+
+	/* Set number of entries */
+	ebx.full = cpuid_ebx(EXT_PERFMON_DEBUG_FEATURES);
+	x86_pmu.lbr_nr = ebx.split.lbr_v2_stack_sz;
+
+	pr_cont("%d-deep LBR, ", x86_pmu.lbr_nr);
+
+	return 0;
+}