linux-kernel - [tip: x86/alternatives] x86/alternatives: Simplify smp_text_poke_single() by using tp

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Message-ID: <174436572446.31282.13069052465341572273.tip-bot2@tip-bot2>
Date: Fri, 11 Apr 2025 10:02:04 -0000
From: "tip-bot2 for Ingo Molnar" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Ingo Molnar <mingo@...nel.org>, Juergen Gross <jgross@...e.com>,
 "H . Peter Anvin" <hpa@...or.com>,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 Peter Zijlstra <peterz@...radead.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/alternatives] x86/alternatives: Simplify
 smp_text_poke_single() by using tp_vec and existing APIs

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID:     c8976ade0c1b4c0629b8a080d712ff402e8343b3
Gitweb:        https://git.kernel.org/tip/c8976ade0c1b4c0629b8a080d712ff402e8343b3
Author:        Ingo Molnar <mingo@...nel.org>
AuthorDate:    Fri, 11 Apr 2025 07:40:36 +02:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 11 Apr 2025 11:01:34 +02:00

x86/alternatives: Simplify smp_text_poke_single() by using tp_vec and existing APIs

Instead of constructing a vector on-stack, just use the already
available batch-patching vector - which should always be empty
at this point.

This will allow subsequent simplifications.

Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: Juergen Gross <jgross@...e.com>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-25-mingo@kernel.org
---
 arch/x86/kernel/alternative.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 16a41e2..b4cb867 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2904,8 +2904,13 @@ void __ref smp_text_poke_batch_add(void *addr, const void *opcode, size_t len, c
  */
 void __ref smp_text_poke_single(void *addr, const void *opcode, size_t len, const void *emulate)
 {
-	struct smp_text_poke_loc tp;
+	struct smp_text_poke_loc *tp;
+
+	/* Batch-patching should not be mixed with single-patching: */
+	WARN_ON_ONCE(tp_vec_nr != 0);
+
+	tp = &tp_vec[tp_vec_nr++];
+	text_poke_int3_loc_init(tp, addr, opcode, len, emulate);

-	text_poke_int3_loc_init(&tp, addr, opcode, len, emulate);
-	smp_text_poke_batch_process(&tp, 1);
+	smp_text_poke_batch_finish();
 }