[PATCH 27/41] x86/alternatives: Remove the tp_vec indirection
From: Ingo Molnar
Date: Thu Mar 27 2025 - 17:00:54 EST
At this point we are always working out of an uptodate
tp_array, there's no need for text_poke_int3_handler()
to read via the int3_vec indirection - remove it.
This simplifies the code:
1 file changed, 5 insertions(+), 15 deletions(-)
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/alternative.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index cf3bcaa97957..3baef1827f3c 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2466,15 +2466,6 @@ struct text_poke_int3_loc {
u8 old;
};
-struct text_poke_int3_vec {
- int nr_entries;
- struct text_poke_int3_loc *vec;
-};
-
-static DEFINE_PER_CPU(atomic_t, int3_refs);
-
-static struct text_poke_int3_vec int3_vec;
-
#define TP_ARRAY_NR_ENTRIES_MAX (PAGE_SIZE / sizeof(struct text_poke_int3_loc))
static struct text_poke_int3_array {
@@ -2482,15 +2473,17 @@ static struct text_poke_int3_array {
struct text_poke_int3_loc vec[TP_ARRAY_NR_ENTRIES_MAX];
} tp_array;
+static DEFINE_PER_CPU(atomic_t, int3_refs);
+
static __always_inline
-struct text_poke_int3_vec *try_get_desc(void)
+struct text_poke_int3_array *try_get_desc(void)
{
atomic_t *refs = this_cpu_ptr(&int3_refs);
if (!raw_atomic_inc_not_zero(refs))
return NULL;
- return &int3_vec;
+ return &tp_array;
}
static __always_inline void put_desc(void)
@@ -2519,7 +2512,7 @@ static __always_inline int patch_cmp(const void *key, const void *elt)
noinstr int text_poke_int3_handler(struct pt_regs *regs)
{
- struct text_poke_int3_vec *desc;
+ struct text_poke_int3_array *desc;
struct text_poke_int3_loc *tp;
int ret = 0;
void *ip;
@@ -2529,7 +2522,7 @@ noinstr int text_poke_int3_handler(struct pt_regs *regs)
/*
* Having observed our INT3 instruction, we now must observe
- * int3_vec with non-zero refcount:
+ * tp_array with non-zero refcount:
*
* int3_refs = 1 INT3
* WMB RMB
@@ -2633,12 +2626,9 @@ static void text_poke_int3_batch(struct text_poke_int3_loc *tp, unsigned int nr_
WARN_ON_ONCE(tp != tp_array.vec);
WARN_ON_ONCE(nr_entries != tp_array.nr_entries);
- int3_vec.vec = tp;
- int3_vec.nr_entries = nr_entries;
-
/*
* Corresponds to the implicit memory barrier in try_get_desc() to
- * ensure reading a non-zero refcount provides up to date int3_vec data.
+ * ensure reading a non-zero refcount provides up to date tp_array data.
*/
for_each_possible_cpu(i)
atomic_set_release(per_cpu_ptr(&int3_refs, i), 1);
--
2.45.2