[v1] Simplify, reorganize and clean up the x86 text-patching code (alternative.c)

[PATCH 36/53] x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()

Posted by Ingo Molnar 8 months, 1 week ago

At this point smp_text_poke_single(addr, opcode, len, emulate) is equivalent to:

	smp_text_poke_batch_add(addr, opcode, len, emulate);
	smp_text_poke_batch_finish();

So remove the restriction on mixing single-instruction patching
with multi-instruction patching.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/alternative.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index eb0da270043b..f0bb2158f27b 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2892,9 +2892,6 @@ 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)
 {
-	/* Batch-patching should not be mixed with single-patching: */
-	WARN_ON_ONCE(text_poke_array.nr_entries != 0);
-
 	__smp_text_poke_batch_add(addr, opcode, len, emulate);
 	smp_text_poke_batch_finish();
 }
-- 
2.45.2

[tip: x86/alternatives] x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()

Posted by tip-bot2 for Ingo Molnar 8 months, 1 week ago

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

Commit-ID:     8a6a1b4e0ef15dab908a365588e06f23f9c0bad5
Gitweb:        https://git.kernel.org/tip/8a6a1b4e0ef15dab908a365588e06f23f9c0bad5
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Fri, 11 Apr 2025 07:40:48 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Fri, 11 Apr 2025 11:01:34 +02:00

x86/alternatives: Remove the mixed-patching restriction on smp_text_poke_single()

At this point smp_text_poke_single(addr, opcode, len, emulate) is equivalent to:

	smp_text_poke_batch_add(addr, opcode, len, emulate);
	smp_text_poke_batch_finish();

So remove the restriction on mixing single-instruction patching
with multi-instruction patching.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-37-mingo@kernel.org
---
 arch/x86/kernel/alternative.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index eb0da27..f0bb215 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2892,9 +2892,6 @@ 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)
 {
-	/* Batch-patching should not be mixed with single-patching: */
-	WARN_ON_ONCE(text_poke_array.nr_entries != 0);
-
 	__smp_text_poke_batch_add(addr, opcode, len, emulate);
 	smp_text_poke_batch_finish();
 }