diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index bf82c6f7d690..85089c79a828 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -2474,28 +2474,29 @@ struct text_poke_loc { struct bp_patching_desc { struct text_poke_loc *vec; int nr_entries; - atomic_t refs; }; +static DEFINE_PER_CPU(atomic_t, bp_refs); + static struct bp_patching_desc bp_desc; static __always_inline struct bp_patching_desc *try_get_desc(void) { - struct bp_patching_desc *desc = &bp_desc; + atomic_t *refs = this_cpu_ptr(&bp_refs); - if (!raw_atomic_inc_not_zero(&desc->refs)) + if (!raw_atomic_inc_not_zero(refs)) return NULL; - return desc; + return &bp_desc; } static __always_inline void put_desc(void) { - struct bp_patching_desc *desc = &bp_desc; + atomic_t *refs = this_cpu_ptr(&bp_refs); smp_mb__before_atomic(); - raw_atomic_dec(&desc->refs); + raw_atomic_dec(refs); } static __always_inline void *text_poke_addr(struct text_poke_loc *tp) @@ -2528,9 +2529,9 @@ noinstr int poke_int3_handler(struct pt_regs *regs) * Having observed our INT3 instruction, we now must observe * bp_desc with non-zero refcount: * - * bp_desc.refs = 1 INT3 - * WMB RMB - * write INT3 if (bp_desc.refs != 0) + * bp_refs = 1 INT3 + * WMB RMB + * write INT3 if (bp_refs != 0) */ smp_rmb(); @@ -2636,7 +2637,8 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries * Corresponds to the implicit memory barrier in try_get_desc() to * ensure reading a non-zero refcount provides up to date bp_desc data. */ - atomic_set_release(&bp_desc.refs, 1); + for_each_possible_cpu(i) + atomic_set_release(per_cpu_ptr(&bp_refs, i), 1); /* * Function tracing can enable thousands of places that need to be @@ -2750,8 +2752,12 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries /* * Remove and wait for refs to be zero. */ - if (!atomic_dec_and_test(&bp_desc.refs)) - atomic_cond_read_acquire(&bp_desc.refs, !VAL); + for_each_possible_cpu(i) { + atomic_t *refs = per_cpu_ptr(&bp_refs, i); + + if (unlikely(!atomic_dec_and_test(refs))) + atomic_cond_read_acquire(refs, !VAL); + } } static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,