141 lines
4.0 KiB
C
141 lines
4.0 KiB
C
/* $NetBSD: mutex.h,v 1.1 2014/09/19 17:36:26 matt Exp $ */
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/*-
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* Copyright (c) 2002, 2007 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe and Andrew Doran.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _RISCV_MUTEX_H_
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#define _RISCV_MUTEX_H_
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#ifndef __MUTEX_PRIVATE
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struct kmutex {
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uintptr_t mtx_pad1;
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};
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#else /* __MUTEX_PRIVATE */
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#include <sys/param.h>
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struct kmutex {
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volatile uintptr_t mtx_owner;
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};
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#ifdef _LP64
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#define MTX_ASMOP_SFX ".d" // doubleword atomic op
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#else
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#define MTX_ASMOP_SFX ".w" // word atomic op
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#endif
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#define MTX_LOCK __BIT(8) // just one bit
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#define MTX_IPL __BITS(7,4) // only need 4 bits
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#undef MUTEX_SPIN_IPL // override <sys/mutex.h>
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#define MUTEX_SPIN_IPL(a) riscv_mutex_spin_ipl(a)
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#define MUTEX_INITIALIZE_SPIN_IPL(a,b) riscv_mutex_initialize_spin_ipl(a,b)
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#define MUTEX_SPINBIT_LOCK_INIT(a) riscv_mutex_spinbit_lock_init(a)
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#define MUTEX_SPINBIT_LOCK_TRY(a) riscv_mutex_spinbit_lock_try(a)
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#define MUTEX_SPINBIT_LOCKED_P(a) riscv_mutex_spinbit_locked_p(a)
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#define MUTEX_SPINBIT_LOCK_UNLOCK(a) riscv_mutex_spinbit_lock_unlock(a)
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static inline ipl_cookie_t
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riscv_mutex_spin_ipl(kmutex_t *__mtx)
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{
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return (ipl_cookie_t){._spl = __SHIFTOUT(__mtx->mtx_owner, MTX_IPL)};
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}
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static inline void
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riscv_mutex_initialize_spin_ipl(kmutex_t *__mtx, int ipl)
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{
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__mtx->mtx_owner = (__mtx->mtx_owner & ~MTX_IPL)
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| __SHIFTIN(ipl, MTX_IPL);
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}
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static inline void
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riscv_mutex_spinbit_lock_init(kmutex_t *__mtx)
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{
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__mtx->mtx_owner &= ~MTX_LOCK;
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}
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static inline bool
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riscv_mutex_spinbit_locked_p(kmutex_t *__mtx)
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{
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return (__mtx->mtx_owner & MTX_LOCK) != 0;
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}
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static inline bool
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riscv_mutex_spinbit_lock_try(kmutex_t *__mtx)
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{
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uintptr_t __old;
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__asm __volatile(
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"amoor" MTX_ASMOP_SFX ".aq\t%0, %1, (%2)"
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: "=r"(__old)
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: "r"(MTX_LOCK), "r"(__mtx));
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return (__old & MTX_LOCK) == 0;
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}
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static inline void
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riscv_mutex_spinbit_lock_unlock(kmutex_t *__mtx)
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{
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__asm __volatile(
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"amoand" MTX_ASMOP_SFX ".rl\tx0, %0, (%1)"
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:: "r"(~MTX_LOCK), "r"(__mtx));
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}
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#if 0
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#define __HAVE_MUTEX_STUBS 1
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#define __HAVE_SPIN_MUTEX_STUBS 1
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#endif
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#define __HAVE_SIMPLE_MUTEXES 1
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/*
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* MUTEX_RECEIVE: no memory barrier required; we're synchronizing against
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* interrupts, not multiple processors.
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*/
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#ifdef MULTIPROCESSOR
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#define MUTEX_RECEIVE(mtx) membar_consumer()
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#else
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#define MUTEX_RECEIVE(mtx) /* nothing */
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#endif
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/*
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* MUTEX_GIVE: no memory barrier required; same reason.
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*/
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#ifdef MULTIPROCESSOR
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#define MUTEX_GIVE(mtx) membar_producer()
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#else
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#define MUTEX_GIVE(mtx) /* nothing */
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#endif
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#define MUTEX_CAS(p, o, n) \
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(atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
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#endif /* __MUTEX_PRIVATE */
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#endif /* _RISCV_MUTEX_H_ */
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