Commit c7474da9 authored by Heiko Carstens's avatar Heiko Carstens Committed by Alexander Gordeev
Browse files

s390/uaccess: Use asm goto for __mvc_kernel_nofault() 



Use asm goto for __mvc_kernel_nofault() if available. This generates
slightly better code, since the error checking happens implicitly with
the goto (aka exception) and the good path comes without any checks and
branches.

Acked-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 5b629e64

arch/s390/include/asm/uaccess.h

+11 −15
Original line number Diff line number Diff line
@@ -343,29 +343,25 @@ static inline void *s390_kernel_write(void *dst, const void *src, size_t size) 


void __noreturn __mvc_kernel_nofault_bad(void);



#ifdef CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS

#if defined(CONFIG_CC_HAS_ASM_GOTO_OUTPUT) && defined(CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS)



#define __mvc_kernel_nofault(dst, src, type, err_label)			\

do {									\

	int __rc;							\

									\

	switch (sizeof(type)) {						\

	case 1:								\

	case 2:								\

	case 4:								\

	case 8:								\

		asm_inline volatile(					\

		asm goto(						\

			"0:	mvc	%O[_dst](%[_len],%R[_dst]),%[_src]\n" \

			"1:	lhi	%[_rc],0\n"			\

			"2:\n"						\

			EX_TABLE_UA_FAULT(0b, 2b, %[_rc])		\

			EX_TABLE_UA_FAULT(1b, 2b, %[_rc])		\

			: [_rc] "=d" (__rc),				\

			  [_dst] "=Q" (*(type *)dst)			\

			"1:	nopr	%%r7\n"				\

			EX_TABLE(0b, %l[err_label])			\

			EX_TABLE(1b, %l[err_label])			\

			: [_dst] "=Q" (*(type *)dst)			\

			: [_src] "Q" (*(type *)(src)),			\

			  [_len] "I" (sizeof(type)));			\

		if (__rc)						\

			goto err_label;					\

			  [_len] "I" (sizeof(type))			\

			:						\

			: err_label);					\

		break;							\

	default:							\

		__mvc_kernel_nofault_bad();				\
@@ -373,7 +369,7 @@ do { \ 
	}								\

} while (0)



#else /* CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS */

#else /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT) && CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS */



#define __mvc_kernel_nofault(dst, src, type, err_label)			\

do {									\
@@ -405,7 +401,7 @@ do { \ 
	}								\

} while (0)



#endif /* CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS */

#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT && CONFIG_CC_HAS_ASM_AOR_FORMAT_FLAGS */



#define __get_kernel_nofault __mvc_kernel_nofault

#define __put_kernel_nofault __mvc_kernel_nofault