powerpc/uaccess: Split out __get_user_nocheck()

One part of __get_user_nocheck() is used for __get_user(),
the other part for unsafe_get_user().

Move the part dedicated to unsafe_get_user() in it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/618fe2e0626b308a5a063d5baac827b968e85c32.1615398265.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/uaccess.h

@@ -49,7 +49,7 @@ static inline bool __access_ok(unsigned long addr, unsigned long size)
 	__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 
 #define __get_user(x, ptr) \
-	__get_user_nocheck((x), (ptr), sizeof(*(ptr)), true)
+	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 #define __put_user(x, ptr) \
 	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 
@@ -216,19 +216,15 @@ do {								\
 #define __long_type(x) \
 	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 
-#define __get_user_nocheck(x, ptr, size, do_allow)			\
+#define __get_user_nocheck(x, ptr, size)			\
 ({								\
 	long __gu_err;						\
 	__long_type(*(ptr)) __gu_val;				\
 	__typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
 	__typeof__(size) __gu_size = (size);			\
 								\
-	if (do_allow) {								\
-		might_fault();					\
-		__get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err);	\
-	} else {									\
-		__get_user_size_allowed(__gu_val, __gu_addr, __gu_size, __gu_err); \
-	}									\
+	might_fault();					\
+	__get_user_size(__gu_val, __gu_addr, __gu_size, __gu_err);	\
 	(x) = (__typeof__(*(ptr)))__gu_val;			\
 								\
 	__gu_err;						\
@@ -385,8 +381,14 @@ user_write_access_begin(const void __user *ptr, size_t len)
 #define user_write_access_end		prevent_current_write_to_user
 
 #define unsafe_get_user(x, p, e) do {					\
-	if (unlikely(__get_user_nocheck((x), (p), sizeof(*(p)), false)))\
-		goto e;							\
+	long __gu_err;						\
+	__long_type(*(p)) __gu_val;				\
+	__typeof__(*(p)) __user *__gu_addr = (p);		\
+								\
+	__get_user_size_allowed(__gu_val, __gu_addr, sizeof(*(p)), __gu_err); \
+	if (__gu_err)						\
+		goto e;						\
+	(x) = (__typeof__(*(p)))__gu_val;			\
 } while (0)
 
 #define unsafe_put_user(x, p, e) \