metag/usercopy: Switch to RAW_COPY_USER

Switch to using raw user copy instead of providing metag specific
[__]copy_{to,from}_user[_inatomic](). This simplifies the metag
uaccess.h and allows us to take advantage of extra checking in the
generic versions.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/metag/Kconfig

@@ -1,5 +1,6 @@
 config METAG
 	def_bool y
+	select ARCH_HAS_RAW_COPY_USER
 	select EMBEDDED
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS

arch/metag/include/asm/uaccess.h

@@ -174,35 +174,8 @@ extern long __must_check strnlen_user(const char __user *src, long count);
 
 extern unsigned long raw_copy_from_user(void *to, const void __user *from,
 					unsigned long n);
-
-static inline unsigned long
-copy_from_user(void *to, const void __user *from, unsigned long n)
-{
-	unsigned long res = n;
-	if (likely(access_ok(VERIFY_READ, from, n)))
-		res = raw_copy_from_user(to, from, n);
-	if (unlikely(res))
-		memset(to + (n - res), 0, res);
-	return res;
-}
-
-#define __copy_from_user(to, from, n) raw_copy_from_user(to, from, n)
-#define __copy_from_user_inatomic __copy_from_user
-
-extern unsigned long __must_check __copy_user(void __user *to,
-					      const void *from,
-					      unsigned long n);
-
-static inline unsigned long copy_to_user(void __user *to, const void *from,
-					 unsigned long n)
-{
-	if (access_ok(VERIFY_WRITE, to, n))
-		return __copy_user(to, from, n);
-	return n;
-}
-
-#define __copy_to_user(to, from, n) __copy_user(to, from, n)
-#define __copy_to_user_inatomic __copy_to_user
+extern unsigned long raw_copy_to_user(void __user *to, const void *from,
+				      unsigned long n);
 
 /*
  * Zero Userspace

arch/metag/lib/usercopy.c

@@ -548,8 +548,8 @@
 		"SUB	%1,	%1,	D0Ar2\n"			\
 		"SUB	%3, %3, D1Ar1\n")
 
-unsigned long __copy_user(void __user *pdst, const void *psrc,
-			  unsigned long n)
+unsigned long raw_copy_to_user(void __user *pdst, const void *psrc,
+			       unsigned long n)
 {
 	register char __user *dst asm ("A0.2") = pdst;
 	register const char *src asm ("A1.2") = psrc;
@@ -654,7 +654,7 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
 	 */
 	return retn;
 }
-EXPORT_SYMBOL(__copy_user);
+EXPORT_SYMBOL(raw_copy_to_user);
 
 #define __asm_copy_from_user_1(to, from, ret) \
 	__asm_copy_user_cont(to, from, ret,	\