diff options
| -rw-r--r-- | arch/x86/kernel/jump_label.c | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index ae3d8fb8039f..24cf2b25ce73 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -26,16 +26,40 @@ union jump_code_union { static void __jump_label_transform(struct jump_entry *entry, enum jump_label_type type, - void *(*poker)(void *, const void *, size_t)) + void *(*poker)(void *, const void *, size_t), + int init) { union jump_code_union code; + const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; if (type == JUMP_LABEL_ENABLE) { + /* + * We are enabling this jump label. If it is not a nop + * then something must have gone wrong. + */ + BUG_ON(memcmp((void *)entry->code, ideal_nop, 5) != 0); + code.jump = 0xe9; code.offset = entry->target - (entry->code + JUMP_LABEL_NOP_SIZE); - } else + } else { + /* + * We are disabling this jump label. If it is not what + * we think it is, then something must have gone wrong. + * If this is the first initialization call, then we + * are converting the default nop to the ideal nop. + */ + if (init) { + const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; + BUG_ON(memcmp((void *)entry->code, default_nop, 5) != 0); + } else { + code.jump = 0xe9; + code.offset = entry->target - + (entry->code + JUMP_LABEL_NOP_SIZE); + BUG_ON(memcmp((void *)entry->code, &code, 5) != 0); + } memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); + } (*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE); } @@ -45,7 +69,7 @@ void arch_jump_label_transform(struct jump_entry *entry, { get_online_cpus(); mutex_lock(&text_mutex); - __jump_label_transform(entry, type, text_poke_smp); + __jump_label_transform(entry, type, text_poke_smp, 0); mutex_unlock(&text_mutex); put_online_cpus(); } @@ -76,7 +100,7 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, jlstate = JL_STATE_NO_UPDATE; } if (jlstate == JL_STATE_UPDATE) - __jump_label_transform(entry, type, text_poke_early); + __jump_label_transform(entry, type, text_poke_early, 1); } #endif |