[PATCH] Add missing memory barriers for correct operation of amon_cpu_start
From: Raghu Gandham <hidden>
Date: 2009-07-10 09:07:06
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
From: Chris Dearman <redacted> 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); }