From 53fd4b8c22bbdf4598f87e701e9a6c6ee50172ff Mon Sep 17 00:00:00 2001
From: Alison Wang <b18965@freescale.com>
Date: Wed, 9 Sep 2015 10:22:02 +0800
Subject: [PATCH] arm: mmu: Add missing volatile for reading SCTLR register
Add 'volatile' qualifier to the asm statement in get_cr()
so that the statement is not optimized out by the compiler.
(http://comments.gmane.org/gmane.linux.linaro.toolchain/5163)
Without the 'volatile', get_cr() returns a wrong value which
prevents enabling the MMU and later causes a PCIE VA access
failure.
Signed-off-by: Alison Wang <alison.wang@freescale.com>
---
arch/arm/include/asm/system.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 868ea54b4f..cfc7834ed9 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -194,7 +194,7 @@ void save_boot_params_ret(void);
static inline unsigned int get_cr(void)
{
unsigned int val;
- asm("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc");
+ asm volatile("mrc p15, 0, %0, c1, c0, 0 @ get CR" : "=r" (val) : : "cc");
return val;
}
--
2.39.5