linux-kernel - [RFC PATCH 14/15] perf/x86: Simplify p6_pmu

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Message-ID: <20241220213711.1892696-15-sohil.mehta@intel.com>
Date: Fri, 20 Dec 2024 21:37:09 +0000
From: Sohil Mehta <sohil.mehta@...el.com>
To: x86@...nel.org,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Tony Luck <tony.luck@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	"H . Peter Anvin" <hpa@...or.com>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Len Brown <lenb@...nel.org>,
	Andy Lutomirski <luto@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Fenghua Yu <fenghua.yu@...el.com>,
	Jean Delvare <jdelvare@...e.com>,
	Guenter Roeck <linux@...ck-us.net>,
	Sohil Mehta <sohil.mehta@...el.com>,
	Zhang Rui <rui.zhang@...el.com>,
	linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	linux-pm@...r.kernel.org,
	linux-hwmon@...r.kernel.org
Subject: [RFC PATCH 14/15] perf/x86: Simplify p6_pmu_init()

A switch case is unnecessary when only a single case matters. Also, the
gaps in the case numbers are due to no CPU with those model numbers
being released.

Avoid the switch case and combine the cases into simpler VFM checks.
Also, this gets rid of one last few Intel x86_model comparisons. No
functional change intended.

Signed-off-by: Sohil Mehta <sohil.mehta@...el.com>
---
 arch/x86/events/intel/p6.c | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/arch/x86/events/intel/p6.c b/arch/x86/events/intel/p6.c
index a6cffb4f4ef5..37e3beb6d633 100644
--- a/arch/x86/events/intel/p6.c
+++ b/arch/x86/events/intel/p6.c
@@ -2,6 +2,8 @@
 #include <linux/perf_event.h>
 #include <linux/types.h>
 
+#include <asm/cpu_device_id.h>
+
 #include "../perf_event.h"
 
 /*
@@ -244,35 +246,19 @@ static __init void p6_pmu_rdpmc_quirk(void)
 	}
 }
 
+/* Only called for Family 6 CPUs without X86_FEATURE_ARCH_PERFMON */
 __init int p6_pmu_init(void)
 {
 	x86_pmu = p6_pmu;
 
-	switch (boot_cpu_data.x86_model) {
-	case  1: /* Pentium Pro */
-		x86_add_quirk(p6_pmu_rdpmc_quirk);
-		break;
-
-	case  3: /* Pentium II - Klamath */
-	case  5: /* Pentium II - Deschutes */
-	case  6: /* Pentium II - Mendocino */
-		break;
-
-	case  7: /* Pentium III - Katmai */
-	case  8: /* Pentium III - Coppermine */
-	case 10: /* Pentium III Xeon */
-	case 11: /* Pentium III - Tualatin */
-		break;
-
-	case  9: /* Pentium M - Banias */
-	case 13: /* Pentium M - Dothan */
-		break;
-
-	default:
+	if (boot_cpu_data.x86_vfm >= INTEL_CORE_YONAH) {
 		pr_cont("unsupported p6 CPU model %d ", boot_cpu_data.x86_model);
 		return -ENODEV;
 	}
 
+	if (boot_cpu_data.x86_vfm == INTEL_PENTIUM_PRO)
+		x86_add_quirk(p6_pmu_rdpmc_quirk);
+
 	memcpy(hw_cache_event_ids, p6_hw_cache_event_ids,
 		sizeof(hw_cache_event_ids));
 
-- 
2.43.0