linux-kernel - [tip: x86/cpu] x86/cpu: Remove unnecessary MwAIT leaf checks

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Message-ID: <173453175758.7135.9823105454576594179.tip-bot2@tip-bot2>
Date: Wed, 18 Dec 2024 14:22:37 -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>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/cpu] x86/cpu: Remove unnecessary MwAIT leaf checks

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

Commit-ID:     262fba55708b60a063b30d103963477dc5026f8c
Gitweb:        https://git.kernel.org/tip/262fba55708b60a063b30d103963477dc5026f8c
Author:        Dave Hansen <dave.hansen@...ux.intel.com>
AuthorDate:    Fri, 13 Dec 2024 12:50:30 -08:00
Committer:     Dave Hansen <dave.hansen@...ux.intel.com>
CommitterDate: Wed, 18 Dec 2024 06:17:30 -08:00

x86/cpu: Remove unnecessary MwAIT leaf checks

The CPUID leaf dependency checker will remove X86_FEATURE_MWAIT if
the CPUID level is below the required level (CPUID_MWAIT_LEAF).
Thus, if you check X86_FEATURE_MWAIT you do not need to also
check the CPUID level.

Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Link: https://lore.kernel.org/all/20241213205030.9B42B458%40davehans-spike.ostc.intel.com
---
 arch/x86/kernel/hpet.c    | 3 ---
 arch/x86/kernel/smpboot.c | 2 --
 drivers/acpi/acpi_pad.c   | 2 --
 drivers/idle/intel_idle.c | 3 ---
 4 files changed, 10 deletions(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 2593504..953de5b 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -928,9 +928,6 @@ static bool __init mwait_pc10_supported(void)
 	if (!cpu_feature_enabled(X86_FEATURE_MWAIT))
 		return false;
 
-	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
-		return false;
-
 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
 
 	return (ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) &&
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 52b0d30..116c46f 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1292,8 +1292,6 @@ static inline void mwait_play_dead(void)
 		return;
 	if (!this_cpu_has(X86_FEATURE_CLFLUSH))
 		return;
-	if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
-		return;
 
 	eax = CPUID_MWAIT_LEAF;
 	ecx = 0;
diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index b561974..f3cffae 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -47,8 +47,6 @@ static void power_saving_mwait_init(void)
 
 	if (!boot_cpu_has(X86_FEATURE_MWAIT))
 		return;
-	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
-		return;
 
 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
 
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 5d8ed1a..efa32d2 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -2317,9 +2317,6 @@ static int __init intel_idle_init(void)
 			return -ENODEV;
 	}
 
-	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
-		return -ENODEV;
-
 	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
 
 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||