From: Paul Mundt <lethal@linux-sh.org>
Date: Wed, 6 Aug 2008 09:39:32 +0000 (+0900)
Subject: sh: smp: shove a cpu_relax() in the plat_start_cpu() busy loop.
X-Git-Tag: v2.6.28-rc1~99^2~93
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=71f0bdcab69ab36b1e939d36063aaf6c4a164ed3;p=linux-2.6-omap-h63xx.git

sh: smp: shove a cpu_relax() in the plat_start_cpu() busy loop.

Without this, certain versions of GCC will happily optimize the entire
loop out.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
---

diff --git a/arch/sh/kernel/cpu/sh4a/smp-shx3.c b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
index edb4da037e0..b8869aa20de 100644
--- a/arch/sh/kernel/cpu/sh4a/smp-shx3.c
+++ b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
@@ -82,7 +82,7 @@ void plat_start_cpu(unsigned int cpu, unsigned long entry_point)
 		ctrl_outl(STBCR_MSTP, STBCR_REG(cpu));
 
 	while (!(ctrl_inl(STBCR_REG(cpu)) & STBCR_MSTP))
-		;
+		cpu_relax();
 
 	/* Start up secondary processor by sending a reset */
 	ctrl_outl(STBCR_AP_VAL, STBCR_REG(cpu));