linux-kernel - [PATCH v2 5/5] x86/bugs: Remove uses of cpu_mitigations

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Message-ID: <20250819192200.2003074-6-david.kaplan@amd.com>
Date: Tue, 19 Aug 2025 14:22:00 -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: <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 5/5] x86/bugs: Remove uses of cpu_mitigations_off()

cpu_mitigations_off() is no longer needed because all bugs use attack
vector controls to select a mitigation, and cpu_mitigations_off() is
equivalent to no attack vectors being selected.

Remove the few remaining unnecessary uses of this function in this file.

Signed-off-by: David Kaplan <david.kaplan@....com>
---
 arch/x86/kernel/cpu/bugs.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 059269f3f56f..556b3ba638f0 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -670,8 +670,7 @@ static const char * const mmio_strings[] = {
 
 static void __init mmio_select_mitigation(void)
 {
-	if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA) ||
-	     cpu_mitigations_off()) {
+	if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA)) {
 		mmio_mitigation = MMIO_MITIGATION_OFF;
 		return;
 	}
@@ -3201,14 +3200,15 @@ static void __init srso_select_mitigation(void)
 
 static void __init srso_update_mitigation(void)
 {
+	if (!boot_cpu_has_bug(X86_BUG_SRSO))
+		return;
+
 	/* If retbleed is using IBPB, that works for SRSO as well */
 	if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB &&
 	    boot_cpu_has(X86_FEATURE_IBPB_BRTYPE))
 		srso_mitigation = SRSO_MITIGATION_IBPB;
 
-	if (boot_cpu_has_bug(X86_BUG_SRSO) &&
-	    !cpu_mitigations_off())
-		pr_info("%s\n", srso_strings[srso_mitigation]);
+	pr_info("%s\n", srso_strings[srso_mitigation]);
 }
 
 static void __init srso_apply_mitigation(void)
-- 
2.34.1