From: Anton Blanchard <anton@samba.org>
Date: Wed, 28 Sep 2005 04:45:38 +0000 (-0700)
Subject: [PATCH] ppc64: Add missing barrier() in kexec code
X-Git-Tag: v2.6.14-rc3~83
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=b3ca80935100af47f226be439cb266378dab7bf7;p=linux-2.6-omap-h63xx.git

[PATCH] ppc64: Add missing barrier() in kexec code

Mikey and I were testing kexec and hit a lockup.  It turns out gcc 4.0
optimises the kexec_prepare_cpus loop so we avoid reloading paca.hw_cpu_id.
 A gcc barrier() fixes the problem.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/ppc64/kernel/machine_kexec.c b/arch/ppc64/kernel/machine_kexec.c
index 4775f12a013..bf7cc4f8210 100644
--- a/arch/ppc64/kernel/machine_kexec.c
+++ b/arch/ppc64/kernel/machine_kexec.c
@@ -205,6 +205,7 @@ static void kexec_prepare_cpus(void)
 			continue;
 
 		while (paca[i].hw_cpu_id != -1) {
+			barrier();
 			if (!cpu_possible(i)) {
 				printk("kexec: cpu %d hw_cpu_id %d is not"
 						" possible, ignoring\n",