[RFC] Add implicit barriers to irqsave/restore class of functions

[Christian Ruppert <christian.ruppert@abilis.com>]

This patch adds implicit memory barriers to irqsave/restore functions of
the ARC architecture port in line with what is done in other architectures.

It seems to fix several seemingly unrelated issues in our platform but for
the moment it is insufficiently tested (and might even be incomplete).
Please comment.

Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
---
 arch/arc/include/asm/irqflags.h |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arc/include/asm/irqflags.h b/arch/arc/include/asm/irqflags.h
index ccd8480..c8147d1 100644
--- a/arch/arc/include/asm/irqflags.h
+++ b/arch/arc/include/asm/irqflags.h
@@ -39,7 +39,7 @@ static inline long arch_local_irq_save(void)
 	"	flag.nz %0		\n"
 	: "=r"(temp), "=r"(flags)
 	: "n"((STATUS_E1_MASK | STATUS_E2_MASK))
-	: "cc");
+	: "memory", "cc");
 
 	return flags;
 }
@@ -53,7 +53,7 @@ static inline void arch_local_irq_restore(unsigned long flags)
 	__asm__ __volatile__(
 	"	flag %0			\n"
 	:
-	: "r"(flags));
+	: "r"(flags) : "memory");
 }
 
 /*
@@ -73,7 +73,7 @@ static inline void arch_local_irq_disable(void)
 	"	and %0, %0, %1		\n"
 	"	flag %0			\n"
 	: "=&r"(temp)
-	: "n"(~(STATUS_E1_MASK | STATUS_E2_MASK)));
+	: "n"(~(STATUS_E1_MASK | STATUS_E2_MASK)) : "memory");
 }
 
 /*
@@ -85,7 +85,7 @@ static inline long arch_local_save_flags(void)
 
 	__asm__ __volatile__(
 	"	lr  %0, [status32]	\n"
-	: "=&r"(temp));
+	: "=&r"(temp) : : "memory");
 
 	return temp;
 }
-- 
1.7.1