7f2d47d84c
Boot stuff dependencies from NetBSD. Patch by Antoine Leca. Relocated to src/sys. The port is using the same libminc.a as usual MINIX services (and does not use NetBSD libkern); the headers imported from NetBSD sys/ tree have been kept to a minimum (still numbers higher than 30 though.) Note the peculiar way to use libraries (libsa, libi386, etc.): the source code is shared, but each component builds its own copy of the library, with its own set of preprocessor defines.
122 lines
4 KiB
C
122 lines
4 KiB
C
/* $NetBSD: rwlock.h,v 1.10 2010/02/08 09:54:27 skrll Exp $ */
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/*-
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* Copyright (c) 2002, 2006, 2007, 2008 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 _SYS_RWLOCK_H_
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#define _SYS_RWLOCK_H_
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/*
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* The rwlock provides exclusive access when held as a "writer",
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* and shared access when held as a "reader".
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*
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* Architectures may optionally provide stubs for the following functions to
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* implement the easy (unlocked, no waiters) cases. If these stubs are
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* provided, __HAVE_RW_STUBS should be defined.
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*
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* rw_enter()
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* rw_exit()
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* rw_tryenter()
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*/
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#if defined(_KERNEL_OPT)
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#include "opt_lockdebug.h"
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#endif
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#if !defined(_KERNEL)
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#include <sys/types.h>
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#include <sys/inttypes.h>
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#endif
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typedef enum krw_t {
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RW_READER = 0,
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RW_WRITER = 1
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} krw_t;
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typedef struct krwlock krwlock_t;
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#ifdef __RWLOCK_PRIVATE
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/*
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* Bits in the owner field of the lock that indicate lock state. If the
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* WRITE_LOCKED bit is clear, then the owner field is actually a count of
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* the number of readers. The rw_owner field is laid out like so:
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*
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* N 4 3 2 1 0
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* +---------------------------------------------------------+
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* | owner or read count | nodbug | wrlock | wrwant | wait |
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* +---------------------------------------------------------+
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*/
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#define RW_HAS_WAITERS 0x01UL /* lock has waiters */
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#define RW_WRITE_WANTED 0x02UL /* >= 1 waiter is a writer */
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#define RW_WRITE_LOCKED 0x04UL /* lock is currently write locked */
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#if defined(LOCKDEBUG)
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#define RW_NODEBUG 0x08UL /* LOCKDEBUG disabled */
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#else
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#define RW_NODEBUG 0x00UL /* do nothing */
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#endif /* LOCKDEBUG */
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#define RW_READ_COUNT_SHIFT 4
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#define RW_READ_INCR (1UL << RW_READ_COUNT_SHIFT)
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#define RW_THREAD ((uintptr_t)-RW_READ_INCR)
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#define RW_OWNER(rw) ((rw)->rw_owner & RW_THREAD)
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#define RW_COUNT(rw) ((rw)->rw_owner & RW_THREAD)
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#define RW_FLAGS(rw) ((rw)->rw_owner & ~RW_THREAD)
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void rw_vector_enter(krwlock_t *, const krw_t);
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void rw_vector_exit(krwlock_t *);
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int rw_vector_tryenter(krwlock_t *, const krw_t);
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#endif /* __RWLOCK_PRIVATE */
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#include <machine/rwlock.h>
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#ifdef _KERNEL
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void rw_init(krwlock_t *);
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void rw_destroy(krwlock_t *);
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int rw_tryenter(krwlock_t *, const krw_t);
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int rw_tryupgrade(krwlock_t *);
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void rw_downgrade(krwlock_t *);
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int rw_read_held(krwlock_t *);
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int rw_write_held(krwlock_t *);
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int rw_lock_held(krwlock_t *);
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void rw_enter(krwlock_t *, const krw_t);
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void rw_exit(krwlock_t *);
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void rw_obj_init(void);
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krwlock_t *rw_obj_alloc(void);
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void rw_obj_hold(krwlock_t *);
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bool rw_obj_free(krwlock_t *);
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#endif /* _KERNEL */
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#endif /* _SYS_RWLOCK_H_ */
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