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x86/alternatives: Remove the tp_vec indirection

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At this point we are always working out of an uptodate
text_poke_array, there's no need for smp_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@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/20250411054105.2341982-29-mingo@kernel.org
This commit is contained in:
Ingo Molnar 2025-04-11 07:40:40 +02:00
parent 6e7dc03aee
commit 0494b16b9c
1 changed files with 7 additions and 17 deletions
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24
arch/x86/kernel/alternative.c
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@ -2466,15 +2466,6 @@ struct smp_text_poke_loc {
u8 old;
};
struct text_poke_int3_vec {
int nr_entries;
struct smp_text_poke_loc *vec;
};
static DEFINE_PER_CPU(atomic_t, text_poke_array_refs);
static struct text_poke_int3_vec int3_vec;
#define TP_ARRAY_NR_ENTRIES_MAX (PAGE_SIZE / sizeof(struct smp_text_poke_loc))
static struct smp_text_poke_array {
@ -2482,15 +2473,17 @@ static struct smp_text_poke_array {
struct smp_text_poke_loc vec[TP_ARRAY_NR_ENTRIES_MAX];
} text_poke_array;
static DEFINE_PER_CPU(atomic_t, text_poke_array_refs);
static __always_inline
struct text_poke_int3_vec *try_get_desc(void)
struct smp_text_poke_array *try_get_desc(void)
{
atomic_t *refs = this_cpu_ptr(&text_poke_array_refs);
if (!raw_atomic_inc_not_zero(refs))
return NULL;
return &int3_vec;
return &text_poke_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 smp_text_poke_int3_handler(struct pt_regs *regs)
{
struct text_poke_int3_vec *desc;
struct smp_text_poke_array *desc;
struct smp_text_poke_loc *tp;
int ret = 0;
void *ip;
@ -2529,7 +2522,7 @@ noinstr int smp_text_poke_int3_handler(struct pt_regs *regs)
/*
* Having observed our INT3 instruction, we now must observe
* int3_vec with non-zero refcount:
* text_poke_array with non-zero refcount:
*
* text_poke_array_refs = 1 INT3
* WMB RMB
@ -2633,12 +2626,9 @@ static void smp_text_poke_batch_process(struct smp_text_poke_loc *tp, unsigned i
WARN_ON_ONCE(tp != text_poke_array.vec);
WARN_ON_ONCE(nr_entries != text_poke_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 text_poke_array data.
*/
for_each_possible_cpu(i)
atomic_set_release(per_cpu_ptr(&text_poke_array_refs, i), 1);