linux-stable/arch/s390/include/asm/barrier.h
Martin Schwidefsky e2dd833389 s390: add optimized array_index_mask_nospec
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>
2018-02-05 07:51:41 +01:00

78 lines
1.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright IBM Corp. 1999, 2009
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#ifndef __ASM_BARRIER_H
#define __ASM_BARRIER_H
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
* to devices.
*/
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
/* Fast-BCR without checkpoint synchronization */
#define __ASM_BARRIER "bcr 14,0\n"
#else
#define __ASM_BARRIER "bcr 15,0\n"
#endif
#define mb() do { asm volatile(__ASM_BARRIER : : : "memory"); } while (0)
#define rmb() barrier()
#define wmb() barrier()
#define dma_rmb() mb()
#define dma_wmb() mb()
#define __smp_mb() mb()
#define __smp_rmb() rmb()
#define __smp_wmb() wmb()
#define __smp_store_release(p, v) \
do { \
compiletime_assert_atomic_type(*p); \
barrier(); \
WRITE_ONCE(*p, v); \
} while (0)
#define __smp_load_acquire(p) \
({ \
typeof(*p) ___p1 = READ_ONCE(*p); \
compiletime_assert_atomic_type(*p); \
barrier(); \
___p1; \
})
#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 */