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Commit bdf0f17e authored by Russell King's avatar Russell King Committed by Greg Kroah-Hartman
Browse files

ARM: use __inttype() in get_user() 



Commit d09fbb327d670737ab40fd8bbb0765ae06b8b739 upstream.

Borrow the x86 implementation of __inttype() to use in get_user() to
select an integer type suitable to temporarily hold the result value.
This is necessary to avoid propagating the volatile nature of the
result argument, which can cause the following warning:

lib/iov_iter.c:413:5: warning: optimization may eliminate reads and/or writes to register variables [-Wvolatile-register-var]

Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDavid A. Long <dave.long@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d609e4aa

arch/arm/include/asm/uaccess.h

+8 −1
Original line number Diff line number Diff line
@@ -114,6 +114,13 @@ static inline void set_fs(mm_segment_t fs) 
		: "cc"); \

	flag; })



/*

 * This is a type: either unsigned long, if the argument fits into

 * that type, or otherwise unsigned long long.

 */

#define __inttype(x) \

	__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))



/*

 * Single-value transfer routines.  They automatically use the right

 * size if we just have the right pointer type.  Note that the functions
@@ -183,7 +190,7 @@ extern int __get_user_64t_4(void *); 
	({								\

		unsigned long __limit = current_thread_info()->addr_limit - 1; \

		register const typeof(*(p)) __user *__p asm("r0") = (p);\

		register typeof(x) __r2 asm("r2");			\

		register __inttype(x) __r2 asm("r2");			\

		register unsigned long __l asm("r1") = __limit;		\

		register int __e asm("r0");				\

		unsigned int __ua_flags = uaccess_save_and_enable();	\