perf/x86/amd/core: Define a proper ref-cycles event for Zen 4 and later

Add the "ref-cycles" event for AMD processors based on Zen 4 and later
microarchitectures. The backing event is based on PMCx120 which counts
cycles not in halt state in P0 frequency (same as MPERF).

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/089155f19f7c7e65aeb1caa727a882e2ca9b8b04.1711352180.git.sandipan.das@amd.com

Author: sandip4n

arch/x86/events/amd/core.c

@@ -273,8 +273,23 @@ static const u64 amd_zen2_perfmon_event_map[PERF_COUNT_HW_MAX] =
 	[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND]	= 0x00a9,
 };
 
+static const u64 amd_zen4_perfmon_event_map[PERF_COUNT_HW_MAX] =
+{
+	[PERF_COUNT_HW_CPU_CYCLES]		= 0x0076,
+	[PERF_COUNT_HW_INSTRUCTIONS]		= 0x00c0,
+	[PERF_COUNT_HW_CACHE_REFERENCES]	= 0xff60,
+	[PERF_COUNT_HW_CACHE_MISSES]		= 0x0964,
+	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= 0x00c2,
+	[PERF_COUNT_HW_BRANCH_MISSES]		= 0x00c3,
+	[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND]	= 0x00a9,
+	[PERF_COUNT_HW_REF_CPU_CYCLES]		= 0x100000120,
+};
+
 static u64 amd_pmu_event_map(int hw_event)
 {
+	if (cpu_feature_enabled(X86_FEATURE_ZEN4) || boot_cpu_data.x86 >= 0x1a)
+		return amd_zen4_perfmon_event_map[hw_event];
+
 	if (cpu_feature_enabled(X86_FEATURE_ZEN2) || boot_cpu_data.x86 >= 0x19)
 		return amd_zen2_perfmon_event_map[hw_event];