79f8b61995
processes to share semaphore by using shared memory area, in simplest case, only one atomic operation is needed in userland, waiter flag is maintained by kernel and userland only checks the flag, if the flag is set, user code enters kernel and does a wakeup() call. Move type definitions into file _umtx.h to minimize compiling time. Also type names need to be prefixed with underline character, this would reduce name conflict (still in progress).
67 lines
2.2 KiB
C
67 lines
2.2 KiB
C
/*-
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* Copyright (c) 2010, David Xu <davidxu@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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#include <sys/_types.h>
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struct umtx {
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volatile unsigned long u_owner; /* Owner of the mutex. */
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};
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struct umutex {
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volatile __lwpid_t m_owner; /* Owner of the mutex */
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__uint32_t m_flags; /* Flags of the mutex */
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__uint32_t m_ceilings[2]; /* Priority protect ceiling */
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__uint32_t m_spare[4];
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};
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struct ucond {
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volatile __uint32_t c_has_waiters; /* Has waiters in kernel */
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__uint32_t c_flags; /* Flags of the condition variable */
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__uint32_t c_spare[2]; /* Spare space */
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};
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struct urwlock {
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volatile __int32_t rw_state;
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__uint32_t rw_flags;
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__uint32_t rw_blocked_readers;
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__uint32_t rw_blocked_writers;
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__uint32_t rw_spare[4];
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};
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struct _usem {
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volatile __uint32_t _has_waiters;
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volatile __uint32_t _count;
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__uint32_t _flags;
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};
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#endif /* !_SYS__UMTX_H_ */
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