From: Raghu Gandham <raghu@mips.com>
To: linux-mips@linux-mips.org
Cc: raghu@mips.com, chris@mips.com
Subject: [PATCH] Add missing memory barriers for correct operation of amon_cpu_start
Date: Fri, 10 Jul 2009 02:06:38 -0700 [thread overview]
Message-ID: <20090710090637.26302.42976.stgit@linux-raghu> (raw)
From: Chris Dearman <chris@mips.com>
Signed-off-by: Chris Dearman (chris@mips.com)
---
arch/mips/mti-malta/malta-amon.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/mips/mti-malta/malta-amon.c b/arch/mips/mti-malta/malta-amon.c
index df9e526..469d9b0 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);
}
reply other threads:[~2009-07-10 9:07 UTC|newest]
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