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From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org,tglx@linutronix.de,bp@alien8.de,rafael@kernel.org,lenb@kernel.org,Dave
	Hansen <dave.hansen@linux.intel.com>
Subject: [PATCH 03/11] x86/cpu: Remove unnecessary MwAIT leaf checks
Date: Wed, 30 Oct 2024 14:33:16 -0700	[thread overview]
Message-ID: <20241030213316.95FD3C59@davehans-spike.ostc.intel.com> (raw)
In-Reply-To: <20241030213310.C4861EC0@davehans-spike.ostc.intel.com>


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

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@linux.intel.com>
---

 b/arch/x86/kernel/hpet.c    |    3 ---
 b/arch/x86/kernel/smpboot.c |    2 --
 b/drivers/acpi/acpi_pad.c   |    2 --
 b/drivers/idle/intel_idle.c |    3 ---
 4 files changed, 10 deletions(-)

diff -puN arch/x86/kernel/hpet.c~mwait-leaf-checks-2 arch/x86/kernel/hpet.c
--- a/arch/x86/kernel/hpet.c~mwait-leaf-checks-2	2024-10-30 12:28:09.946351764 -0700
+++ b/arch/x86/kernel/hpet.c	2024-10-30 12:28:09.950351772 -0700
@@ -928,9 +928,6 @@ static bool __init mwait_pc10_supported(
 	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 -puN arch/x86/kernel/smpboot.c~mwait-leaf-checks-2 arch/x86/kernel/smpboot.c
--- a/arch/x86/kernel/smpboot.c~mwait-leaf-checks-2	2024-10-30 12:28:09.946351764 -0700
+++ b/arch/x86/kernel/smpboot.c	2024-10-30 12:28:09.950351772 -0700
@@ -1291,8 +1291,6 @@ 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 -puN drivers/acpi/acpi_pad.c~mwait-leaf-checks-2 drivers/acpi/acpi_pad.c
--- a/drivers/acpi/acpi_pad.c~mwait-leaf-checks-2	2024-10-30 12:28:09.946351764 -0700
+++ b/drivers/acpi/acpi_pad.c	2024-10-30 12:28:09.950351772 -0700
@@ -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 -puN drivers/idle/intel_idle.c~mwait-leaf-checks-2 drivers/idle/intel_idle.c
--- a/drivers/idle/intel_idle.c~mwait-leaf-checks-2	2024-10-30 12:28:09.946351764 -0700
+++ b/drivers/idle/intel_idle.c	2024-10-30 12:28:09.950351772 -0700
@@ -2269,9 +2269,6 @@ 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) ||
_

  parent reply	other threads:[~2024-10-30 21:33 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-30 21:33 [PATCH 00/11] x86/cpu: Centralize and standardize CPUID leaf naming Dave Hansen
2024-10-30 21:33 ` [PATCH 01/11] x86/cpu: Move MWAIT leaf definition to common header Dave Hansen
2024-10-30 21:33 ` [PATCH 02/11] x86/cpu: Use MWAIT leaf definition Dave Hansen
2024-10-30 21:33 ` Dave Hansen [this message]
2024-10-30 21:33 ` [PATCH 04/11] x86/acpi: Check MWAIT feature instead of CPUID level Dave Hansen
2024-10-30 21:33 ` [PATCH 05/11] x86/cpu: Move DCA leaf definition Dave Hansen
2024-10-30 21:33 ` [PATCH 06/11] x86/cpu: Move TSC CPUID " Dave Hansen
2024-10-30 21:33 ` [PATCH 07/11] x86/tsc: Move away from TSC leaf magic numbers Dave Hansen
2024-10-30 21:33 ` [PATCH 08/11] x86/tsc: Remove CPUID "frequency" " Dave Hansen
2024-10-30 21:33 ` [PATCH 09/11] x86/fpu: Move CPUID leaf definitions to common code Dave Hansen
2024-10-30 21:33 ` [PATCH 10/11] x86/fpu: Remove unnecessary CPUID level check Dave Hansen
2024-10-30 21:33 ` [PATCH 11/11] x86/cpu: Make all all CPUID leaf names consistent Dave Hansen
2024-10-31 10:18   ` Borislav Petkov
2024-10-31 17:19     ` Dave Hansen
2024-11-29 18:27       ` Borislav Petkov
2024-12-06 23:01         ` Dave Hansen
2024-12-09 16:27           ` Sean Christopherson
2024-12-09 17:25             ` Dave Hansen
2024-12-09 20:23               ` Sean Christopherson
2024-12-10 11:28             ` Borislav Petkov
2024-12-10 11:19       ` Borislav Petkov
2024-11-20 19:53 [PATCH 00/11] x86/cpu: Centralize and standardize CPUID leaf naming Dave Hansen
2024-11-20 19:53 ` [PATCH 03/11] x86/cpu: Remove unnecessary MwAIT leaf checks Dave Hansen

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