diff options
| -rw-r--r-- | arch/x86/include/asm/jump_label.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/jump_label.c | 69 |
2 files changed, 71 insertions, 0 deletions
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index 65191ce8e1cf..06c3cc22a058 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_JUMP_LABEL_H #define _ASM_X86_JUMP_LABEL_H +#define HAVE_JUMP_LABEL_BATCH + #define JUMP_LABEL_NOP_SIZE 5 #ifdef CONFIG_X86_64 diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index f33408f1c3f6..ea13808bf6da 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -101,6 +101,75 @@ void arch_jump_label_transform(struct jump_entry *entry, mutex_unlock(&text_mutex); } +#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc)) +static struct text_poke_loc tp_vec[TP_VEC_MAX]; +int tp_vec_nr = 0; + +bool arch_jump_label_transform_queue(struct jump_entry *entry, + enum jump_label_type type) +{ + struct text_poke_loc *tp; + void *entry_code; + + if (system_state == SYSTEM_BOOTING) { + /* + * Fallback to the non-batching mode. + */ + arch_jump_label_transform(entry, type); + return true; + } + + /* + * No more space in the vector, tell upper layer to apply + * the queue before continuing. + */ + if (tp_vec_nr == TP_VEC_MAX) + return false; + + tp = &tp_vec[tp_vec_nr]; + + entry_code = (void *)jump_entry_code(entry); + + /* + * The INT3 handler will do a bsearch in the queue, so we need entries + * to be sorted. We can survive an unsorted list by rejecting the entry, + * forcing the generic jump_label code to apply the queue. Warning once, + * to raise the attention to the case of an unsorted entry that is + * better not happen, because, in the worst case we will perform in the + * same way as we do without batching - with some more overhead. + */ + if (tp_vec_nr > 0) { + int prev = tp_vec_nr - 1; + struct text_poke_loc *prev_tp = &tp_vec[prev]; + + if (WARN_ON_ONCE(prev_tp->addr > entry_code)) + return false; + } + + __jump_label_set_jump_code(entry, type, + (union jump_code_union *) &tp->opcode, 0); + + tp->addr = entry_code; + tp->detour = entry_code + JUMP_LABEL_NOP_SIZE; + tp->len = JUMP_LABEL_NOP_SIZE; + + tp_vec_nr++; + + return true; +} + +void arch_jump_label_transform_apply(void) +{ + if (!tp_vec_nr) + return; + + mutex_lock(&text_mutex); + text_poke_bp_batch(tp_vec, tp_vec_nr); + mutex_unlock(&text_mutex); + + tp_vec_nr = 0; +} + static enum { JL_STATE_START, JL_STATE_NO_UPDATE, |