diff options
Diffstat (limited to 'arch/x86/kernel/alternative.c')
| -rw-r--r-- | arch/x86/kernel/alternative.c | 64 |
1 files changed, 58 insertions, 6 deletions
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 9ec463fe96f2..42e7f0af88da 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -936,6 +936,14 @@ static void do_sync_core(void *info) sync_core(); } +struct text_poke_loc { + void *addr; + int len; + s32 rel32; + u8 opcode; + const u8 text[POKE_MAX_OPCODE_SIZE]; +}; + static struct bp_patching_desc { struct text_poke_loc *vec; int nr_entries; @@ -1023,6 +1031,10 @@ int poke_int3_handler(struct pt_regs *regs) } NOKPROBE_SYMBOL(poke_int3_handler); +#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc)) +static struct text_poke_loc tp_vec[TP_VEC_MAX]; +static int tp_vec_nr; + /** * text_poke_bp_batch() -- update instructions on live kernel on SMP * @tp: vector of instructions to patch @@ -1044,7 +1056,7 @@ NOKPROBE_SYMBOL(poke_int3_handler); * replacing opcode * - sync cores */ -void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) +static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) { unsigned char int3 = INT3_INSN_OPCODE; unsigned int i; @@ -1118,11 +1130,7 @@ void text_poke_loc_init(struct text_poke_loc *tp, void *addr, { struct insn insn; - if (!opcode) - opcode = (void *)tp->text; - else - memcpy((void *)tp->text, opcode, len); - + memcpy((void *)tp->text, opcode, len); if (!emulate) emulate = opcode; @@ -1167,6 +1175,50 @@ void text_poke_loc_init(struct text_poke_loc *tp, void *addr, } } +/* + * We hard rely on the tp_vec being ordered; ensure this is so by flushing + * early if needed. + */ +static bool tp_order_fail(void *addr) +{ + struct text_poke_loc *tp; + + if (!tp_vec_nr) + return false; + + if (!addr) /* force */ + return true; + + tp = &tp_vec[tp_vec_nr - 1]; + if ((unsigned long)tp->addr > (unsigned long)addr) + return true; + + return false; +} + +static void text_poke_flush(void *addr) +{ + if (tp_vec_nr == TP_VEC_MAX || tp_order_fail(addr)) { + text_poke_bp_batch(tp_vec, tp_vec_nr); + tp_vec_nr = 0; + } +} + +void text_poke_finish(void) +{ + text_poke_flush(NULL); +} + +void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate) +{ + struct text_poke_loc *tp; + + text_poke_flush(addr); + + tp = &tp_vec[tp_vec_nr++]; + text_poke_loc_init(tp, addr, opcode, len, emulate); +} + /** * text_poke_bp() -- update instructions on live kernel on SMP * @addr: address to patch |