riscv: Avoid io read/write cause wrong result
io read/write may cause wrong result because they may read/write data
from/to register instead of memory. Add 'volatile' to avoid it.
Signed-off-by: Nick Hu <nick.hu@sifive.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index acf5a96..3540773 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -44,15 +44,15 @@
* read/writes. We define __arch_*[bl] here, and leave __arch_*w
* to the architecture specific code.
*/
-#define __arch_getb(a) (*(unsigned char *)(a))
-#define __arch_getw(a) (*(unsigned short *)(a))
-#define __arch_getl(a) (*(unsigned int *)(a))
-#define __arch_getq(a) (*(unsigned long long *)(a))
+#define __arch_getb(a) (*(volatile unsigned char *)(a))
+#define __arch_getw(a) (*(volatile unsigned short *)(a))
+#define __arch_getl(a) (*(volatile unsigned int *)(a))
+#define __arch_getq(a) (*(volatile unsigned long long *)(a))
-#define __arch_putb(v, a) (*(unsigned char *)(a) = (v))
-#define __arch_putw(v, a) (*(unsigned short *)(a) = (v))
-#define __arch_putl(v, a) (*(unsigned int *)(a) = (v))
-#define __arch_putq(v, a) (*(unsigned long long *)(a) = (v))
+#define __arch_putb(v, a) (*(volatile unsigned char *)(a) = (v))
+#define __arch_putw(v, a) (*(volatile unsigned short *)(a) = (v))
+#define __arch_putl(v, a) (*(volatile unsigned int *)(a) = (v))
+#define __arch_putq(v, a) (*(volatile unsigned long long *)(a) = (v))
#define __raw_writeb(v, a) __arch_putb(v, a)
#define __raw_writew(v, a) __arch_putw(v, a)