ARC: IO: add volatile to accessors
We must use 'volatile' in C-version read/write IO accessors
implementation to avoid merging several reads (writes) into
one read (write), or optimizing them out by compiler.
Fixes commit 07906b3dad15 ("ARC: Switch to generic accessors")
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h
index 70d0505..1f1ae88 100644
--- a/arch/arc/include/asm/io.h
+++ b/arch/arc/include/asm/io.h
@@ -54,15 +54,21 @@
/* Not yet implemented */
}
-#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))
+/*
+ * We must use 'volatile' in C-version read/write IO accessors implementation
+ * to avoid merging several reads (writes) into one read (write), or optimizing
+ * them out by compiler.
+ */
+#define __arch_getb(a) (*(volatile u8 *)(a))
+#define __arch_getw(a) (*(volatile u16 *)(a))
+#define __arch_getl(a) (*(volatile u32 *)(a))
+#define __arch_getq(a) (*(volatile u64 *)(a))
+
+#define __arch_putb(v, a) (*(volatile u8 *)(a) = (v))
+#define __arch_putw(v, a) (*(volatile u16 *)(a) = (v))
+#define __arch_putl(v, a) (*(volatile u32 *)(a) = (v))
+#define __arch_putq(v, a) (*(volatile u64 *)(a) = (v))
-#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 __raw_writeb(v, a) __arch_putb(v, a)
#define __raw_writew(v, a) __arch_putw(v, a)