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s390/uaccess: Use asm goto for __mvc_kernel_nofault()

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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: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens
2025-01-13 13:37:00 +01:00
committed by Alexander Gordeev
parent 5b629e64e5
commit c7474da9fe
1 changed files with 11 additions and 15 deletions
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26
arch/s390/include/asm/uaccess.h
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@@ -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