[PATCH 22/49] x86/alternatives: Remove the 'addr == NULL means forced-flush' hack from smp_text_poke_batch_finish()/smp_text_poke_batch_flush()/text_poke_addr_ordered()

From: Ingo Molnar
Date: Fri Mar 28 2025 - 09:35:20 EST


There's this weird hack used by smp_text_poke_batch_finish() to indicate
a 'forced flush':

smp_text_poke_batch_flush(NULL);

Just open-code the vector-flush in a straightforward fashion:

smp_text_poke_batch_process(tp_vec, tp_vec_nr);
tp_vec_nr = 0;

And get rid of !addr hack from text_poke_addr_ordered().

Leave a WARN_ON_ONCE(), just in case some external code learned
to rely on this behavior.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 66778dac257f..ffffec4597b7 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2847,12 +2847,11 @@ static bool text_poke_addr_ordered(void *addr)
{
struct smp_text_poke_loc *tp;

+ WARN_ON_ONCE(!addr);
+
if (!tp_vec_nr)
return true;

- if (!addr) /* force */
- return false;
-
/*
* If the last current entry's address is higher than the
* new entry's address we'd like to add, then ordering
@@ -2866,6 +2865,14 @@ static bool text_poke_addr_ordered(void *addr)
return true;
}

+void smp_text_poke_batch_finish(void)
+{
+ if (tp_vec_nr) {
+ smp_text_poke_batch_process(tp_vec, tp_vec_nr);
+ tp_vec_nr = 0;
+ }
+}
+
static void smp_text_poke_batch_flush(void *addr)
{
lockdep_assert_held(&text_mutex);
@@ -2876,11 +2883,6 @@ static void smp_text_poke_batch_flush(void *addr)
}
}

-void smp_text_poke_batch_finish(void)
-{
- smp_text_poke_batch_flush(NULL);
-}
-
void __ref smp_text_poke_batch_add(void *addr, const void *opcode, size_t len, const void *emulate)
{
struct smp_text_poke_loc *tp;
--
2.45.2