linux-kernel - [PATCH 06/10] x86/tsc: Move away from TSC leaf magic numbers

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Message-Id: <20241213205034.B79D6224@davehans-spike.ostc.intel.com>
Date: Fri, 13 Dec 2024 12:50:34 -0800
From: Dave Hansen <dave.hansen@...ux.intel.com>
To: linux-kernel@...r.kernel.org
Cc: x86@...nel.org,tglx@...utronix.de,bp@...en8.de,rafael@...nel.org,lenb@...nel.org,dave.jiang@...el.com,irenic.rajneesh@...il.com,david.e.box@...el.com,Dave Hansen <dave.hansen@...ux.intel.com>
Subject: [PATCH 06/10] x86/tsc: Move away from TSC leaf magic numbers


From: Dave Hansen <dave.hansen@...ux.intel.com>

The TSC code has a bunch of hard-coded references to leaf 0x15.  Change
them over to the symbolic name.  Also zap the 'ART_CPUID_LEAF' definition.
It was a duplicate of 'CPUID_TSC_LEAF'.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
---

 b/arch/x86/kernel/tsc.c                 |   11 +++++------
 b/drivers/platform/x86/intel/pmc/core.c |    7 ++++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff -puN arch/x86/kernel/tsc.c~tsc-leaf-checks-2 arch/x86/kernel/tsc.c
--- a/arch/x86/kernel/tsc.c~tsc-leaf-checks-2	2024-12-13 12:45:35.323159598 -0800
+++ b/arch/x86/kernel/tsc.c	2024-12-13 12:45:35.331159936 -0800
@@ -16,6 +16,7 @@
 #include <linux/static_key.h>
 #include <linux/static_call.h>
 
+#include <asm/cpuid.h>
 #include <asm/hpet.h>
 #include <asm/timer.h>
 #include <asm/vgtod.h>
@@ -665,13 +666,13 @@ unsigned long native_calibrate_tsc(void)
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 		return 0;
 
-	if (boot_cpu_data.cpuid_level < 0x15)
+	if (boot_cpu_data.cpuid_level < CPUID_TSC_LEAF)
 		return 0;
 
 	eax_denominator = ebx_numerator = ecx_hz = edx = 0;
 
 	/* CPUID 15H TSC/Crystal ratio, plus optionally Crystal Hz */
-	cpuid(0x15, &eax_denominator, &ebx_numerator, &ecx_hz, &edx);
+	cpuid(CPUID_TSC_LEAF, &eax_denominator, &ebx_numerator, &ecx_hz, &edx);
 
 	if (ebx_numerator == 0 || eax_denominator == 0)
 		return 0;
@@ -1067,10 +1068,8 @@ core_initcall(cpufreq_register_tsc_scali
 
 #endif /* CONFIG_CPU_FREQ */
 
-#define ART_CPUID_LEAF (0x15)
 #define ART_MIN_DENOMINATOR (1)
 
-
 /*
  * If ART is present detect the numerator:denominator to convert to TSC
  */
@@ -1078,7 +1077,7 @@ static void __init detect_art(void)
 {
 	unsigned int unused;
 
-	if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF)
+	if (boot_cpu_data.cpuid_level < CPUID_TSC_LEAF)
 		return;
 
 	/*
@@ -1091,7 +1090,7 @@ static void __init detect_art(void)
 	    tsc_async_resets)
 		return;
 
-	cpuid(ART_CPUID_LEAF, &art_base_clk.denominator,
+	cpuid(CPUID_TSC_LEAF, &art_base_clk.denominator,
 	      &art_base_clk.numerator, &art_base_clk.freq_khz, &unused);
 
 	art_base_clk.freq_khz /= KHZ;
diff -puN drivers/platform/x86/intel/pmc/core.c~tsc-leaf-checks-2 drivers/platform/x86/intel/pmc/core.c
--- a/drivers/platform/x86/intel/pmc/core.c~tsc-leaf-checks-2	2024-12-13 12:45:35.327159767 -0800
+++ b/drivers/platform/x86/intel/pmc/core.c	2024-12-13 12:45:35.331159936 -0800
@@ -22,6 +22,7 @@
 #include <linux/suspend.h>
 #include <linux/units.h>
 
+#include <asm/cpuid.h>
 #include <asm/cpu_device_id.h>
 #include <asm/intel-family.h>
 #include <asm/msr.h>
@@ -935,13 +936,13 @@ static unsigned int pmc_core_get_crystal
 {
 	unsigned int eax_denominator, ebx_numerator, ecx_hz, edx;
 
-	if (boot_cpu_data.cpuid_level < 0x15)
+	if (boot_cpu_data.cpuid_level < CPUID_TSC_LEAF)
 		return 0;
 
 	eax_denominator = ebx_numerator = ecx_hz = edx = 0;
 
-	/* CPUID 15H TSC/Crystal ratio, plus optionally Crystal Hz */
-	cpuid(0x15, &eax_denominator, &ebx_numerator, &ecx_hz, &edx);
+	/* TSC/Crystal ratio, plus optionally Crystal Hz */
+	cpuid(CPUID_TSC_LEAF, &eax_denominator, &ebx_numerator, &ecx_hz, &edx);
 
 	if (ebx_numerator == 0 || eax_denominator == 0)
 		return 0;
_