The following commit has been merged in the linux branch: commit 2ee0a42961c942c6a2fb70700ef4e25c0acf5fca Author: Chris Dearman chris@mips.com Date: Fri Jul 10 02:06:38 2009 -0700

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

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); }