From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH 1/3] x86/alternative: Drop not needed test after call of alt_replace_call()
Date: Mon, 29 Sep 2025 13:29:45 +0200 [thread overview]
Message-ID: <20250929112947.27267-2-jgross@suse.com> (raw)
In-Reply-To: <20250929112947.27267-1-jgross@suse.com>
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@suse.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
next prev parent reply other threads:[~2025-09-29 11:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-29 11:29 [PATCH 0/3] x86/alternative: Make alternative patching more robust Juergen Gross
2025-09-29 11:29 ` Juergen Gross [this message]
2025-10-14 8:42 ` [tip: x86/core] x86/alternative: Drop not needed test after call of alt_replace_call() tip-bot2 for Juergen Gross
2025-09-29 11:29 ` [PATCH 2/3] x86/alternative: Refactor apply_alternatives() Juergen Gross
2025-10-14 8:42 ` [tip: x86/core] " tip-bot2 for Juergen Gross
2025-09-29 11:29 ` [PATCH 3/3] x86/alternative: Patch a single alternative location only once Juergen Gross
2025-09-30 7:26 ` Peter Zijlstra
2025-09-30 7:33 ` Jürgen Groß
2025-09-30 7:39 ` Peter Zijlstra
2025-09-30 8:04 ` Jürgen Groß
2025-10-14 8:42 ` [tip: x86/core] " tip-bot2 for Juergen Gross
2025-10-14 12:59 ` Borislav Petkov
2025-10-14 13:25 ` Borislav Petkov
2025-10-14 14:13 ` Jürgen Groß
2025-10-14 14:17 ` Borislav Petkov
2025-10-14 14:18 ` Peter Zijlstra
2025-10-14 14:26 ` Juergen Gross
2025-10-14 14:29 ` Borislav Petkov
2025-10-14 14:08 ` Jürgen Groß
2025-10-14 14:12 ` Borislav Petkov
2025-10-14 14:22 ` Jürgen Groß
2025-10-14 14:26 ` Borislav Petkov
2025-10-14 14:31 ` Jürgen Groß
2025-10-14 14:39 ` Borislav Petkov
2025-10-14 14:46 ` Jürgen Groß
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