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/* $NetBSD: mutex.h,v 1.4 2021/08/25 04:13:41 thorpej Exp $ */
/*-
* Copyright (c) 2002, 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe 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.
*/
#ifndef _RISCV_MUTEX_H_
#define _RISCV_MUTEX_H_
#ifndef __MUTEX_PRIVATE
struct kmutex {
uintptr_t mtx_pad1;
};
#else /* __MUTEX_PRIVATE */
#include <sys/param.h>
struct kmutex {
volatile uintptr_t mtx_owner;
};
#ifdef _LP64
#define MTX_ASMOP_SFX ".d" // doubleword atomic op
#else
#define MTX_ASMOP_SFX ".w" // word atomic op
#endif
#define MTX_LOCK __BIT(8) // just one bit
#define MTX_IPL __BITS(7,4) // only need 4 bits
#undef MUTEX_SPIN_IPL // override <sys/mutex.h>
#define MUTEX_SPIN_IPL(a) riscv_mutex_spin_ipl(a)
#define MUTEX_INITIALIZE_SPIN_IPL(a,b) riscv_mutex_initialize_spin_ipl(a,b)
#define MUTEX_SPINBIT_LOCK_INIT(a) riscv_mutex_spinbit_lock_init(a)
#define MUTEX_SPINBIT_LOCK_TRY(a) riscv_mutex_spinbit_lock_try(a)
#define MUTEX_SPINBIT_LOCKED_P(a) riscv_mutex_spinbit_locked_p(a)
#define MUTEX_SPINBIT_LOCK_UNLOCK(a) riscv_mutex_spinbit_lock_unlock(a)
static inline ipl_cookie_t
riscv_mutex_spin_ipl(kmutex_t *__mtx)
{
return (ipl_cookie_t){._spl = __SHIFTOUT(__mtx->mtx_owner, MTX_IPL)};
}
static inline void
riscv_mutex_initialize_spin_ipl(kmutex_t *__mtx, int ipl)
{
__mtx->mtx_owner = (__mtx->mtx_owner & ~MTX_IPL)
| __SHIFTIN(ipl, MTX_IPL);
}
static inline void
riscv_mutex_spinbit_lock_init(kmutex_t *__mtx)
{
__mtx->mtx_owner &= ~MTX_LOCK;
}
static inline bool
riscv_mutex_spinbit_locked_p(const kmutex_t *__mtx)
{
return (__mtx->mtx_owner & MTX_LOCK) != 0;
}
static inline bool
riscv_mutex_spinbit_lock_try(kmutex_t *__mtx)
{
uintptr_t __old;
__asm __volatile(
"amoor" MTX_ASMOP_SFX ".aq\t%0, %1, (%2)"
: "=r"(__old)
: "r"(MTX_LOCK), "r"(__mtx));
return (__old & MTX_LOCK) == 0;
}
static inline void
riscv_mutex_spinbit_lock_unlock(kmutex_t *__mtx)
{
__asm __volatile(
"amoand" MTX_ASMOP_SFX ".rl\tx0, %0, (%1)"
:: "r"(~MTX_LOCK), "r"(__mtx));
}
#if 0
#define __HAVE_MUTEX_STUBS 1
#define __HAVE_SPIN_MUTEX_STUBS 1
#endif
#define __HAVE_SIMPLE_MUTEXES 1
#endif /* __MUTEX_PRIVATE */
#endif /* _RISCV_MUTEX_H_ */
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