linux-kernel - [PATCH 1/3] x86/alternative: Drop not needed test after call of alt_replace

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Message-ID: <20250929112947.27267-2-jgross@suse.com>
Date: Mon, 29 Sep 2025 13:29:45 +0200
From: Juergen Gross <jgross@...e.com>
To: linux-kernel@...r.kernel.org,
	x86@...nel.org
Cc: Juergen Gross <jgross@...e.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 1/3] x86/alternative: Drop not needed test after call of alt_replace_call()

alt_replace_call() will never return a negative value, so testing the
return value to be less than zero can be dropped.

This makes it possible to switch the return type of alt_replace_call()
and the type of insn_buff_sz to unsigned int.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
V2:
- new patch
---
 arch/x86/kernel/alternative.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 7bde68247b5f..05d3dbe7104e 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -559,7 +559,7 @@ EXPORT_SYMBOL(BUG_func);
  * Rewrite the "call BUG_func" replacement to point to the target of the
  * indirect pv_ops call "call *disp(%ip)".
  */
-static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
+static unsigned int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
 {
 	void *target, *bug = &BUG_func;
 	s32 disp;
@@ -643,7 +643,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 	 * order.
 	 */
 	for (a = start; a < end; a++) {
-		int insn_buff_sz = 0;
+		unsigned int insn_buff_sz = 0;
 
 		/*
 		 * In case of nested ALTERNATIVE()s the outer alternative might
@@ -683,11 +683,8 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 		memcpy(insn_buff, replacement, a->replacementlen);
 		insn_buff_sz = a->replacementlen;
 
-		if (a->flags & ALT_FLAG_DIRECT_CALL) {
+		if (a->flags & ALT_FLAG_DIRECT_CALL)
 			insn_buff_sz = alt_replace_call(instr, insn_buff, a);
-			if (insn_buff_sz < 0)
-				continue;
-		}
 
 		for (; insn_buff_sz < a->instrlen; insn_buff_sz++)
 			insn_buff[insn_buff_sz] = 0x90;
-- 
2.51.0