linux-kernel - [RFC PATCH 49/56] x86/fpu: Qualify warning in os

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Message-ID: <20251013143444.3999-50-david.kaplan@amd.com>
Date: Mon, 13 Oct 2025 09:34:37 -0500
From: David Kaplan <david.kaplan@....com>
To: Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...en8.de>,
	Peter Zijlstra <peterz@...radead.org>, Josh Poimboeuf <jpoimboe@...nel.org>,
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, Ingo Molnar
	<mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>, "H . Peter Anvin" <hpa@...or.com>
CC: Alexander Graf <graf@...zon.com>, Boris Ostrovsky
	<boris.ostrovsky@...cle.com>, <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH 49/56] x86/fpu: Qualify warning in os_xsave

The warning about using FPU before alternatives are patched is only
relevant during boot.  Ignore the warning unless the system is booting.
This suppresses the erroneous warning that can occur during alternative
re-patching at runtime.

Signed-off-by: David Kaplan <david.kaplan@....com>
---
 arch/x86/kernel/fpu/xstate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 52ce19289989..924552a20db1 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -220,7 +220,7 @@ static inline void os_xsave(struct fpstate *fpstate)
 	u32 hmask = mask >> 32;
 	int err;
 
-	WARN_ON_FPU(!alternatives_patched);
+	WARN_ON_FPU(!alternatives_patched && system_state == SYSTEM_BOOTING);
 	xfd_validate_state(fpstate, mask, false);
 
 	XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err);
-- 
2.34.1