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@redhat.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <20100304033850.3819.74590.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Masami Hiramatsu 2010-03-03 22:38:50 -05:00 committed by Ingo Molnar
parent 32cb0dd506
commit e5a1101664

View file

@ -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,