cd28f17da2
pointer to the corresponding struct thread to the thread ID (lwpid_t) assigned to that thread. The primary reason for this change is that libthr now internally uses the same ID as the debugger and the kernel when referencing to a kernel thread. This allows us to implement the support for debugging without additional translations and/or mappings. To preserve the ABI, the 1:1 threading syscalls, including the umtx locking API have not been changed to work on a lwpid_t. Instead the 1:1 threading syscalls operate on long and the umtx locking API has not been changed except for the contested bit. Previously this was the least significant bit. Now it's the most significant bit. Since the contested bit should not be tested by userland, this change is not expected to be visible. Just to be sure, UMTX_CONTESTED has been removed from <sys/umtx.h>. Reviewed by: mtm@ ABI preservation tested on: i386, ia64
86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
/*
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* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
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* All rights reserved.
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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 unmodified, this list of conditions, and the following
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* 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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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*/
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#ifndef _SYS_UMTX_H_
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#define _SYS_UMTX_H_
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/*
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* See pthread_*
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*/
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#define UMTX_UNOWNED 0x0
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struct umtx {
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void *u_owner; /* Owner of the mutex. */
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};
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#ifndef _KERNEL
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/*
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* System calls for acquiring and releasing contested mutexes.
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*/
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int _umtx_lock(struct umtx *mtx);
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int _umtx_unlock(struct umtx *mtx);
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/*
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* Standard api. Try uncontested acquire/release and asks the
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* kernel to resolve failures.
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*/
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static __inline int
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umtx_lock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
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(void *)id) == 0)
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if (_umtx_lock(umtx) == -1)
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return (errno);
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return (0);
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}
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static __inline int
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umtx_trylock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
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(void *)id) == 0)
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return (EBUSY);
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return (0);
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}
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static __inline int
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umtx_unlock(struct umtx *umtx, long id)
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{
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if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
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(void *)UMTX_UNOWNED) == 0)
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if (_umtx_unlock(umtx) == -1)
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return (errno);
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return (0);
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}
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#endif /* !_KERNEL */
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#endif /* !_SYS_UMTX_H_ */
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