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/* $NetBSD: lock.h,v 1.21 2020/08/05 05:24:44 simonb Exp $ */
/*-
* Copyright (c) 2001, 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Wayne Knowles and Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Machine-dependent spin lock operations for MIPS processors.
*
* Note: R2000/R3000 doesn't have any atomic update instructions; this
* will cause problems for user applications using this header.
*/
#ifndef _MIPS_LOCK_H_
#define _MIPS_LOCK_H_
#include <sys/param.h>
static __inline int
__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
{
return *__ptr != __SIMPLELOCK_UNLOCKED;
}
static __inline int
__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
{
return *__ptr == __SIMPLELOCK_UNLOCKED;
}
static __inline void
__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
{
*__ptr = __SIMPLELOCK_UNLOCKED;
}
static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
{
*__ptr = __SIMPLELOCK_LOCKED;
}
#ifndef _HARDKERNEL
static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *lp)
{
unsigned long t0, v0;
__asm volatile(
"# -- BEGIN __cpu_simple_lock_try\n"
" .set push \n"
" .set mips2 \n"
"1: ll %0, %4 \n"
" bnez %0, 2f \n"
" nop \n"
" li %0, %3 \n"
" sc %0, %2 \n"
" beqz %0, 2f \n"
" nop \n"
" li %1, 1 \n"
" sync \n"
" j 3f \n"
" nop \n"
" nop \n"
"2: li %1, 0 \n"
"3: \n"
" .set pop \n"
"# -- END __cpu_simple_lock_try \n"
: "=r" (t0), "=r" (v0), "+m" (*lp)
: "i" (__SIMPLELOCK_LOCKED), "m" (*lp));
return (v0 != 0);
}
#ifdef MIPS1
static __inline void
mb_read(void)
{
__insn_barrier();
}
static __inline void
mb_write(void)
{
__insn_barrier();
}
static __inline void
mb_memory(void)
{
__insn_barrier();
}
#else /* MIPS1*/
static __inline void
mb_read(void)
{
__asm volatile(
" .set push \n"
" .set mips2 \n"
" sync \n"
" .set pop"
::: "memory"
);
}
static __inline void
mb_write(void)
{
mb_read();
}
static __inline void
mb_memory(void)
{
mb_read();
}
#endif /* MIPS1 */
#else /* !_HARDKERNEL */
u_int _atomic_cas_uint(volatile u_int *, u_int, u_int);
u_long _atomic_cas_ulong(volatile u_long *, u_long, u_long);
void * _atomic_cas_ptr(volatile void *, void *, void *);
void mb_read(void);
void mb_write(void);
void mb_memory(void);
static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *lp)
{
return _atomic_cas_uint(lp,
__SIMPLELOCK_UNLOCKED, __SIMPLELOCK_LOCKED) ==
__SIMPLELOCK_UNLOCKED;
}
#endif /* _HARDKERNEL */
static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t *lp)
{
*lp = __SIMPLELOCK_UNLOCKED;
mb_memory();
}
static __inline void
__cpu_simple_lock(__cpu_simple_lock_t *lp)
{
while (!__cpu_simple_lock_try(lp)) {
while (*lp == __SIMPLELOCK_LOCKED)
/* spin */;
}
}
static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *lp)
{
#ifndef _MIPS_ARCH_OCTEONP
mb_memory();
#endif
*lp = __SIMPLELOCK_UNLOCKED;
#ifdef _MIPS_ARCH_OCTEONP
mb_write();
#endif
}
#endif /* _MIPS_LOCK_H_ */
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