linux-kernel - [PATCH 09/10] x86/fpu: Remove unnecessary CPUID level check

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Message-Id: <20241213205038.6E71F9A4@davehans-spike.ostc.intel.com>
Date: Fri, 13 Dec 2024 12:50:38 -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 09/10] x86/fpu: Remove unnecessary CPUID level check


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

The CPUID level dependency table will entirely zap X86_FEATURE_XSAVE
if the CPUID level is too low.  This code is unreachable.  Kill it.

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

 b/arch/x86/kernel/fpu/xstate.c |    5 -----
 1 file changed, 5 deletions(-)

diff -puN arch/x86/kernel/fpu/xstate.c~xsave-leaf-checks-2 arch/x86/kernel/fpu/xstate.c
--- a/arch/x86/kernel/fpu/xstate.c~xsave-leaf-checks-2	2024-12-13 12:45:36.903226562 -0800
+++ b/arch/x86/kernel/fpu/xstate.c	2024-12-13 12:45:36.907226732 -0800
@@ -764,11 +764,6 @@ void __init fpu__init_system_xstate(unsi
 		return;
 	}
 
-	if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
-		WARN_ON_FPU(1);
-		return;
-	}
-
 	/*
 	 * Find user xstates supported by the processor.
 	 */
_