Commit-ID: e5a11016643d1ab7172193591506d33a844734cc
Gitweb: http://git.kernel.org/tip/e5a11016643d1ab7172193591506d33a844734cc
Author: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
AuthorDate: Wed, 3 Mar 2010 22:38:50 -0500
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 4 Mar 2010 11:39:21 +0100
x86: Issue at least one memory barrier in stop_machine_text_poke()
Fix stop_machine_text_poke() to issue smp_mb() before exiting
waiting loop, and use cpu_relax() for waiting.
Changes in v2:
- Don't use ACCESS_ONCE().
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: systemtap <systemtap@xxxxxxxxxxxxxxxxxx>
Cc: DLE <dle-develop@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
LKML-Reference: <20100304033850.3819.74590.stgit@xxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/alternative.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index c41f13c..e0b8770 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -595,8 +595,8 @@ static int __kprobes stop_machine_text_poke(void *data)
wrote_text = 1;
} else {
while (!wrote_text)
- smp_rmb();
- sync_core();
+ cpu_relax();
+ smp_mb(); /* Load wrote_text before following execution */
}
flush_icache_range((unsigned long)tpp->addr,
--
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