linux-kernel - [PATCH v1 1/1] x86/nmi: Remove an unnecessary IS_ENABLED(CONFIG

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Date: Thu,  1 Feb 2024 01:46:04 -0800
From: "Xin Li (Intel)" <xin@...or.com>
To: linux-kernel@...r.kernel.org
Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com
Subject: [PATCH v1 1/1] x86/nmi: Remove an unnecessary IS_ENABLED(CONFIG_SMP)

IS_ENABLED(CONFIG_SMP) is unnecessary here: smp_processor_id() should
always return zero on UP, and arch_cpu_is_offline() reduces to
!(cpu == 0), so this is a statically false condition on UP.

Suggested-by: H. Peter Anvin (Intel) <hpa@...or.com>
Signed-off-by: Xin Li (Intel) <xin@...or.com>
---
 arch/x86/kernel/nmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index db1c1848a1e6..6ba713406262 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -503,7 +503,7 @@ DEFINE_IDTENTRY_RAW(exc_nmi)
 	if (IS_ENABLED(CONFIG_NMI_CHECK_CPU))
 		raw_atomic_long_inc(&nsp->idt_calls);
 
-	if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id())) {
+	if (arch_cpu_is_offline(smp_processor_id())) {
 		if (microcode_nmi_handler_enabled())
 			microcode_offline_nmi_handler();
 		return;

base-commit: b2803076903a83ea927c7f34deeaddf75ee38679
-- 
2.43.0