diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-04-27 07:36:49 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-29 07:50:02 +0200 |
| commit | cf6bc919fa35e91dfc2055ad862ee8f68eafb1d9 (patch) | |
| tree | ffae539dd0ff888090a27604811e7ce4b4aa49c7 /arch | |
| parent | e24d6c4b5e19d6c168d8ca34e1859c83b30189d5 (diff) | |
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')
| -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 d68e11e0df5e..e903b28e7358 100644 --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -53,4 +53,28 @@ do { \ ___p1; \ }) +/** + * 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; +} + #endif /* __ASM_BARRIER_H */ |