[PATCH 50/53] x86/alternatives: Update the comments in smp_text_poke_batch_process()

From: Ingo Molnar
Date: Fri Apr 11 2025 - 01:54:49 EST


- Capitalize 'INT3' consistently,

- make it clear that 'sync cores' means an SMP sync to all CPUs,

- fix typos and spelling.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index c0be0663425e..9ee6f879bce5 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2561,24 +2561,26 @@ noinstr int smp_text_poke_int3_handler(struct pt_regs *regs)

/**
* smp_text_poke_batch_process() -- update instructions on live kernel on SMP
- * @text_poke_array.vec: vector of instructions to patch
- * @text_poke_array.nr_entries: number of entries in the vector
*
- * Modify multi-byte instruction by using int3 breakpoint on SMP.
- * We completely avoid stop_machine() here, and achieve the
- * synchronization using int3 breakpoint.
+ * Input state:
+ * text_poke_array.vec: vector of instructions to patch
+ * text_poke_array.nr_entries: number of entries in the vector
+ *
+ * Modify multi-byte instructions by using INT3 breakpoints on SMP.
+ * We completely avoid using stop_machine() here, and achieve the
+ * synchronization using INT3 breakpoints and SMP cross-calls.
*
* The way it is done:
* - For each entry in the vector:
- * - add a int3 trap to the address that will be patched
- * - sync cores
+ * - add an INT3 trap to the address that will be patched
+ * - SMP sync all CPUs
* - For each entry in the vector:
* - update all but the first byte of the patched range
- * - sync cores
+ * - SMP sync all CPUs
* - For each entry in the vector:
- * - replace the first byte (int3) by the first byte of
+ * - replace the first byte (INT3) by the first byte of the
* replacing opcode
- * - sync cores
+ * - SMP sync all CPUs
*/
static void smp_text_poke_batch_process(void)
{
@@ -2606,13 +2608,13 @@ static void smp_text_poke_batch_process(void)
cond_resched();

/*
- * Corresponding read barrier in int3 notifier for making sure the
+ * Corresponding read barrier in INT3 notifier for making sure the
* text_poke_array.nr_entries and handler are correctly ordered wrt. patching.
*/
smp_wmb();

/*
- * First step: add a int3 trap to the address that will be patched.
+ * First step: add a INT3 trap to the address that will be patched.
*/
for (i = 0; i < text_poke_array.nr_entries; i++) {
text_poke_array.vec[i].old = *(u8 *)text_poke_addr(&text_poke_array.vec[i]);
@@ -2685,7 +2687,7 @@ static void smp_text_poke_batch_process(void)
}

/*
- * Third step: replace the first byte (int3) by the first byte of
+ * Third step: replace the first byte (INT3) by the first byte of the
* replacing opcode.
*/
for (do_sync = 0, i = 0; i < text_poke_array.nr_entries; i++) {
--
2.45.2