From 2ee0a42961c942c6a2fb70700ef4e25c0acf5fca Mon Sep 17 00:00:00 2001
From: Chris Dearman <chris@mips.com>
Date: Fri, 10 Jul 2009 02:06:38 -0700
Subject: MIPS: CMP: Fix memory barriers for correct operation of
amon_cpu_start
Signed-off-by: Chris Dearman (chris@mips.com)
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
arch/mips/mti-malta/malta-amon.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
(limited to 'arch/mips/mti-malta/malta-amon.c')
diff --git a/arch/mips/mti-malta/malta-amon.c b/arch/mips/mti-malta/malta-amon.c
index df9e526312a..469d9b0cee6 100644
--- a/arch/mips/mti-malta/malta-amon.c
+++ b/arch/mips/mti-malta/malta-amon.c
@@ -70,11 +70,12 @@ void amon_cpu_start(int cpu,
launch->sp = sp;
launch->a0 = a0;
- /* Make sure target sees parameters before the go bit */
- smp_mb();
-
+ smp_wmb(); /* Target must see parameters before go */
launch->flags |= LAUNCH_FGO;
+ smp_wmb(); /* Target must see go before we poll */
+
while ((launch->flags & LAUNCH_FGONE) == 0)
;
+ smp_rmb(); /* Target will be updating flags soon */
pr_debug("launch: cpu%d gone!\n", cpu);
}
--
cgit v1.2.3-70-g09d2