* [PATCH] Add missing memory barriers for correct operation of amon_cpu_start
@ 2009-07-10 9:06 Raghu Gandham
0 siblings, 0 replies; only message in thread
From: Raghu Gandham @ 2009-07-10 9:06 UTC (permalink / raw)
To: linux-mips; +Cc: raghu, chris
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);
}
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2009-07-10 9:06 [PATCH] Add missing memory barriers for correct operation of amon_cpu_start Raghu Gandham
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