diff --git a/arch/sh/include/asm/system_32.h b/arch/sh/include/asm/system_32.h
index 6c68a51f1cc5..d7299d69ff79 100644
--- a/arch/sh/include/asm/system_32.h
+++ b/arch/sh/include/asm/system_32.h
@@ -198,6 +198,11 @@ do {							\
 })
 #endif
 
+static inline reg_size_t register_align(void *val)
+{
+	return (unsigned long)(signed long)val;
+}
+
 int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
 			    struct mem_access *ma);
 
diff --git a/arch/sh/include/asm/system_64.h b/arch/sh/include/asm/system_64.h
index 943acf5ea07c..218b54d9d660 100644
--- a/arch/sh/include/asm/system_64.h
+++ b/arch/sh/include/asm/system_64.h
@@ -37,4 +37,9 @@ do {								\
 #define jump_to_uncached()	do { } while (0)
 #define back_to_cached()	do { } while (0)
 
+static inline reg_size_t register_align(void *val)
+{
+	return (unsigned long long)(signed long long)(signed long)val;
+}
+
 #endif /* __ASM_SH_SYSTEM_64_H */
diff --git a/arch/sh/include/asm/types.h b/arch/sh/include/asm/types.h
index c7f3c94837dd..f8421f7ad63a 100644
--- a/arch/sh/include/asm/types.h
+++ b/arch/sh/include/asm/types.h
@@ -11,8 +11,10 @@
 
 #ifdef CONFIG_SUPERH32
 typedef u16 insn_size_t;
+typedef u32 reg_size_t;
 #else
 typedef u32 insn_size_t;
+typedef u64 reg_size_t;
 #endif
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/sh/mm/flush-sh4.c b/arch/sh/mm/flush-sh4.c
index edefc53891a8..1b6b6a12a99b 100644
--- a/arch/sh/mm/flush-sh4.c
+++ b/arch/sh/mm/flush-sh4.c
@@ -10,10 +10,11 @@
  */
 void __weak __flush_wback_region(void *start, int size)
 {
-	unsigned long v, cnt, end;
+	reg_size_t aligned_start, v, cnt, end;
 
-	v = (unsigned long)start & ~(L1_CACHE_BYTES-1);
-	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
+	aligned_start = register_align(start);
+	v = aligned_start & ~(L1_CACHE_BYTES-1);
+	end = (aligned_start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	cnt = (end - v) / L1_CACHE_BYTES;
 
@@ -52,10 +53,11 @@ void __weak __flush_wback_region(void *start, int size)
  */
 void __weak __flush_purge_region(void *start, int size)
 {
-	unsigned long v, cnt, end;
+	reg_size_t aligned_start, v, cnt, end;
 
-	v = (unsigned long)start & ~(L1_CACHE_BYTES-1);
-	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
+	aligned_start = register_align(start);
+	v = aligned_start & ~(L1_CACHE_BYTES-1);
+	end = (aligned_start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	cnt = (end - v) / L1_CACHE_BYTES;
 
@@ -90,10 +92,11 @@ void __weak __flush_purge_region(void *start, int size)
  */
 void __weak __flush_invalidate_region(void *start, int size)
 {
-	unsigned long v, cnt, end;
+	reg_size_t aligned_start, v, cnt, end;
 
-	v = (unsigned long)start & ~(L1_CACHE_BYTES-1);
-	end = ((unsigned long)start + size + L1_CACHE_BYTES-1)
+	aligned_start = register_align(start);
+	v = aligned_start & ~(L1_CACHE_BYTES-1);
+	end = (aligned_start + size + L1_CACHE_BYTES-1)
 		& ~(L1_CACHE_BYTES-1);
 	cnt = (end - v) / L1_CACHE_BYTES;