original_kernel/arch/openrisc/include/asm/cmpxchg.h

84 lines
1.8 KiB
C

/*
* Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
*
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
#ifndef __ASM_OPENRISC_CMPXCHG_H
#define __ASM_OPENRISC_CMPXCHG_H
#include <linux/types.h>
/*
* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid cmpxchg().
*/
extern void __cmpxchg_called_with_bad_pointer(void);
#define __HAVE_ARCH_CMPXCHG 1
static inline unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
{
if (size != 4) {
__cmpxchg_called_with_bad_pointer();
return old;
}
__asm__ __volatile__(
"1: l.lwa %0, 0(%1) \n"
" l.sfeq %0, %2 \n"
" l.bnf 2f \n"
" l.nop \n"
" l.swa 0(%1), %3 \n"
" l.bnf 1b \n"
" l.nop \n"
"2: \n"
: "=&r"(old)
: "r"(ptr), "r"(old), "r"(new)
: "cc", "memory");
return old;
}
#define cmpxchg(ptr, o, n) \
({ \
(__typeof__(*(ptr))) __cmpxchg((ptr), \
(unsigned long)(o), \
(unsigned long)(n), \
sizeof(*(ptr))); \
})
/*
* This function doesn't exist, so you'll get a linker error if
* something tries to do an invalidly-sized xchg().
*/
extern void __xchg_called_with_bad_pointer(void);
static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
int size)
{
if (size != 4) {
__xchg_called_with_bad_pointer();
return val;
}
__asm__ __volatile__(
"1: l.lwa %0, 0(%1) \n"
" l.swa 0(%1), %2 \n"
" l.bnf 1b \n"
" l.nop \n"
: "=&r"(val)
: "r"(ptr), "r"(val)
: "cc", "memory");
return val;
}
#define xchg(ptr, with) \
((typeof(*(ptr)))__xchg((unsigned long)(with), (ptr), sizeof(*(ptr))))
#endif /* __ASM_OPENRISC_CMPXCHG_H */