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

[tip-bot2 for Ingo Molnar]

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@xxxxxxxxxx>
AuthorDate:    Fri, 11 Apr 2025 07:40:36 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250411054105.2341982-25-mingo@xxxxxxxxxx
---
 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();
 }