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x86: Make jump_label use int3-based patching

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Make jump labels use text_poke_bp() for text patching instead of
text_poke_smp(), avoiding the need for stop_machine().

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307121120250.29788@pobox.suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Jiri Kosina 2013-07-12 11:22:09 +02:00 committed by H. Peter Anvin
parent fd4363fff3
commit 51b2c07b22
1 changed files with 14 additions and 2 deletions
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16
arch/x86/kernel/jump_label.c
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@ -37,7 +37,19 @@ static void __jump_label_transform(struct jump_entry *entry,
} else
memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
/*
* Make text_poke_bp() a default fallback poker.
*
* At the time the change is being done, just ignore whether we
* are doing nop -> jump or jump -> nop transition, and assume
* always nop being the 'currently valid' instruction
*
*/
if (poker)
(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
else
text_poke_bp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE,
(void *)entry->code + JUMP_LABEL_NOP_SIZE);
}
void arch_jump_label_transform(struct jump_entry *entry,
@ -45,7 +57,7 @@ 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, NULL);
mutex_unlock(&text_mutex);
put_online_cpus();
}