From: Paul Mundt <lethal@linux-sh.org>
Date: Fri, 15 Jan 2010 05:21:37 +0000 (+0900)
Subject: sh: Guard against early IPIs in flush_cache_all().
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a6198a238baceae9d4e0ce3915f6d239c89b5c08;p=linux-beck.git

sh: Guard against early IPIs in flush_cache_all().

flush_cache_all() gets called in to when we do some early ioremapping.
Unfortunately on SDK7786 the interrupt controller itself requires
ioremapping, leading to a bit of a chicken and egg scenario. For now,
don't bother with IPI crosscalls if there aren't any other CPUs online.

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

diff --git a/arch/sh/mm/cache.c b/arch/sh/mm/cache.c
index b8607fa7ae12..0f4095d7ac8b 100644
--- a/arch/sh/mm/cache.c
+++ b/arch/sh/mm/cache.c
@@ -2,7 +2,7 @@
  * arch/sh/mm/cache.c
  *
  * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
- * Copyright (C) 2002 - 2009  Paul Mundt
+ * Copyright (C) 2002 - 2010  Paul Mundt
  *
  * Released under the terms of the GNU GPL v2.0.
  */
@@ -41,8 +41,17 @@ static inline void cacheop_on_each_cpu(void (*func) (void *info), void *info,
                                    int wait)
 {
 	preempt_disable();
-	smp_call_function(func, info, wait);
+
+	/*
+	 * It's possible that this gets called early on when IRQs are
+	 * still disabled due to ioremapping by the boot CPU, so don't
+	 * even attempt IPIs unless there are other CPUs online.
+	 */
+	if (num_online_cpus() > 1)
+		smp_call_function(func, info, wait);
+
 	func(info);
+
 	preempt_enable();
 }