linux-kernel - [tip: x86/cpu] x86/tsc: Remove CPUID "frequency" leaf magic numbers.

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Message-ID: <173453175400.7135.9551373560447754310.tip-bot2@tip-bot2>
Date: Wed, 18 Dec 2024 14:22:34 -0000
From: "tip-bot2 for Dave Hansen" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Dave Hansen <dave.hansen@...ux.intel.com>, Zhao Liu <zhao1.liu@...el.com>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/cpu] x86/tsc: Remove CPUID "frequency" leaf magic numbers.

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     e558eadf6bd6199a3f454299de3c6338931d4e46
Gitweb:        https://git.kernel.org/tip/e558eadf6bd6199a3f454299de3c6338931d4e46
Author:        Dave Hansen <dave.hansen@...ux.intel.com>
AuthorDate:    Fri, 13 Dec 2024 12:50:36 -08:00
Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Wed, 18 Dec 2024 06:17:40 -08:00

x86/tsc: Remove CPUID "frequency" leaf magic numbers.

All the code that reads the CPUID frequency information leaf hard-codes
a magic number.  Give it a symbolic name and use it.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@...el.com>
Link: https://lore.kernel.org/all/20241213205036.4397658F%40davehans-spike.ostc.intel.com
---
 arch/x86/include/asm/cpuid.h |  1 +
 arch/x86/kernel/tsc.c        | 12 ++++++------
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
index 9b0d14b..e7803c2 100644
--- a/arch/x86/include/asm/cpuid.h
+++ b/arch/x86/include/asm/cpuid.h
@@ -24,6 +24,7 @@ enum cpuid_regs_idx {
 #define CPUID_MWAIT_LEAF	0x5
 #define CPUID_DCA_LEAF		0x9
 #define CPUID_TSC_LEAF		0x15
+#define CPUID_FREQ_LEAF		0x16
 
 #ifdef CONFIG_X86_32
 bool have_cpuid_p(void);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 8091b0e..678c36f 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -681,8 +681,8 @@ unsigned long native_calibrate_tsc(void)
 
 	/*
 	 * Denverton SoCs don't report crystal clock, and also don't support
-	 * CPUID.0x16 for the calculation below, so hardcode the 25MHz crystal
-	 * clock.
+	 * CPUID_FREQ_LEAF for the calculation below, so hardcode the 25MHz
+	 * crystal clock.
 	 */
 	if (crystal_khz == 0 &&
 			boot_cpu_data.x86_vfm == INTEL_ATOM_GOLDMONT_D)
@@ -701,10 +701,10 @@ unsigned long native_calibrate_tsc(void)
 	 * clock, but we can easily calculate it to a high degree of accuracy
 	 * by considering the crystal ratio and the CPU speed.
 	 */
-	if (crystal_khz == 0 && boot_cpu_data.cpuid_level >= 0x16) {
+	if (crystal_khz == 0 && boot_cpu_data.cpuid_level >= CPUID_FREQ_LEAF) {
 		unsigned int eax_base_mhz, ebx, ecx, edx;
 
-		cpuid(0x16, &eax_base_mhz, &ebx, &ecx, &edx);
+		cpuid(CPUID_FREQ_LEAF, &eax_base_mhz, &ebx, &ecx, &edx);
 		crystal_khz = eax_base_mhz * 1000 *
 			eax_denominator / ebx_numerator;
 	}
@@ -739,12 +739,12 @@ static unsigned long cpu_khz_from_cpuid(void)
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 		return 0;
 
-	if (boot_cpu_data.cpuid_level < 0x16)
+	if (boot_cpu_data.cpuid_level < CPUID_FREQ_LEAF)
 		return 0;
 
 	eax_base_mhz = ebx_max_mhz = ecx_bus_mhz = edx = 0;
 
-	cpuid(0x16, &eax_base_mhz, &ebx_max_mhz, &ecx_bus_mhz, &edx);
+	cpuid(CPUID_FREQ_LEAF, &eax_base_mhz, &ebx_max_mhz, &ecx_bus_mhz, &edx);
 
 	return eax_base_mhz * 1000;
 }