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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-04-27 07:36:43 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-29 11:31:58 +0200 |
| commit | 2dcf46aa49acc4c432ebefe3d4d413f428adc120 (patch) | |
| tree | 4a96b5b9b17258d7dc016fe52143750c0aa59ff3 /arch/s390/include | |
| parent | c225febe980f6f112fc0bfce58148d8b390d4cbf (diff) | |
| download | linux-rt-2dcf46aa49acc4c432ebefe3d4d413f428adc120.tar.gz | |
s390: add optimized array_index_mask_nospec
[ Upstream commit e2dd833389cc4069a96b57bdd24227b5f52288f5 ]
Add an optimized version of the array_index_mask_nospec function for
s390 based on a compare and a subtract with borrow.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/include')
| -rw-r--r-- | arch/s390/include/asm/barrier.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h index 5c8db3ce61c8..03b2e5bf1206 100644 --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -48,6 +48,30 @@ do { \ #define __smp_mb__before_atomic() barrier() #define __smp_mb__after_atomic() barrier() +/** + * array_index_mask_nospec - generate a mask for array_idx() that is + * ~0UL when the bounds check succeeds and 0 otherwise + * @index: array element index + * @size: number of elements in array + */ +#define array_index_mask_nospec array_index_mask_nospec +static inline unsigned long array_index_mask_nospec(unsigned long index, + unsigned long size) +{ + unsigned long mask; + + if (__builtin_constant_p(size) && size > 0) { + asm(" clgr %2,%1\n" + " slbgr %0,%0\n" + :"=d" (mask) : "d" (size-1), "d" (index) :"cc"); + return mask; + } + asm(" clgr %1,%2\n" + " slbgr %0,%0\n" + :"=d" (mask) : "d" (size), "d" (index) :"cc"); + return ~mask; +} + #include <asm-generic/barrier.h> #endif /* __ASM_BARRIER_H */ |