Commit-ID: 51b2c07b22261f19188d9a9071943d60a067481c
Gitweb: http://git.kernel.org/tip/51b2c07b22261f19188d9a9071943d60a067481c
Author: Jiri Kosina <jkosina@xxxxxxx>
AuthorDate: Fri, 12 Jul 2013 11:22:09 +0200
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 16 Jul 2013 17:55:37 -0700
x86: Make jump_label use int3-based patching
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@xxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1307121120250.29788@xxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/jump_label.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 2889b3d..460f5d9 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -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();
}
--
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