FreeBSD/Linux Kernel Cross Reference
sys/sys/umtx.h

     /*-
      * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
      * All rights reserved.
      *
      * 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 unmodified, 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 AUTHOR ``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 AUTHOR 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.
     *
     * $FreeBSD: releng/8.4/sys/sys/umtx.h 234937 2012-05-03 03:05:18Z davidxu $
     *
     */
    
    #ifndef _SYS_UMTX_H_
    #define _SYS_UMTX_H_
    
    #include <sys/_types.h>
    #include <sys/limits.h>
    
    /* 
     * See pthread_*
     */
    
    #define UMTX_UNOWNED    0x0
    #define UMTX_CONTESTED  LONG_MIN
    
    struct umtx {
            volatile u_long u_owner;        /* Owner of the mutex. */
    };
    
    #define USYNC_PROCESS_SHARED    0x0001  /* Process shared sync objs */
    
    #define UMUTEX_UNOWNED          0x0
    #define UMUTEX_CONTESTED        0x80000000U
    
    #define UMUTEX_ERROR_CHECK      0x0002  /* Error-checking mutex */
    #define UMUTEX_PRIO_INHERIT     0x0004  /* Priority inherited mutex */
    #define UMUTEX_PRIO_PROTECT     0x0008  /* Priority protect mutex */
    
    struct umutex {
            volatile __lwpid_t      m_owner;        /* Owner of the mutex */
            uint32_t                m_flags;        /* Flags of the mutex */
            uint32_t                m_ceilings[2];  /* Priority protect ceiling */
            uint32_t                m_spare[4];
    };
    
    struct ucond {
            volatile uint32_t       c_has_waiters;  /* Has waiters in kernel */
            uint32_t                c_flags;        /* Flags of the condition variable */
            uint32_t                c_spare[2];     /* Spare space */
    };
    
    struct urwlock {
            volatile int32_t        rw_state;
            uint32_t                rw_flags;
            uint32_t                rw_blocked_readers;
            uint32_t                rw_blocked_writers;
            uint32_t                rw_spare[4];
    };
    
    /* urwlock flags */
    #define URWLOCK_PREFER_READER   0x0002
    
    #define URWLOCK_WRITE_OWNER     0x80000000U
    #define URWLOCK_WRITE_WAITERS   0x40000000U
    #define URWLOCK_READ_WAITERS    0x20000000U
    #define URWLOCK_MAX_READERS     0x1fffffffU
    #define URWLOCK_READER_COUNT(c) ((c) & URWLOCK_MAX_READERS)
    
    /* op code for _umtx_op */
    #define UMTX_OP_LOCK            0
    #define UMTX_OP_UNLOCK          1
    #define UMTX_OP_WAIT            2
    #define UMTX_OP_WAKE            3
    #define UMTX_OP_MUTEX_TRYLOCK   4
    #define UMTX_OP_MUTEX_LOCK      5
    #define UMTX_OP_MUTEX_UNLOCK    6
    #define UMTX_OP_SET_CEILING     7
    #define UMTX_OP_CV_WAIT         8
    #define UMTX_OP_CV_SIGNAL       9
    #define UMTX_OP_CV_BROADCAST    10
    #define UMTX_OP_WAIT_UINT       11
    #define UMTX_OP_RW_RDLOCK       12
   #define UMTX_OP_RW_WRLOCK       13
   #define UMTX_OP_RW_UNLOCK       14
   #define UMTX_OP_WAIT_UINT_PRIVATE       15
   #define UMTX_OP_WAKE_PRIVATE    16
   #define UMTX_OP_MUTEX_WAIT      17
   #define UMTX_OP_MUTEX_WAKE      18
   #define UMTX_OP_MUTEX_WAKE2     22
   #define UMTX_OP_MAX             23
   
   /* flags for UMTX_OP_CV_WAIT */
   #define UMTX_CHECK_UNPARKING    0x01
   
   #ifndef _KERNEL
   
   int _umtx_op(void *obj, int op, u_long val, void *uaddr, void *uaddr2);
   
   /*
    * Old (deprecated) userland mutex system calls.
    */
   int _umtx_lock(struct umtx *mtx);
   int _umtx_unlock(struct umtx *mtx);
   
   /*
    * Standard api.  Try uncontested acquire/release and asks the
    * kernel to resolve failures.
    */
   static __inline void
   umtx_init(struct umtx *umtx)
   {
           umtx->u_owner = UMTX_UNOWNED;
   }
   
   static __inline u_long
   umtx_owner(struct umtx *umtx)
   {
           return (umtx->u_owner & ~LONG_MIN);
   }
   
   static __inline int
   umtx_lock(struct umtx *umtx, u_long id)
   {
           if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
                   if (_umtx_lock(umtx) == -1)
                           return (errno);
           return (0);
   }
   
   static __inline int
   umtx_trylock(struct umtx *umtx, u_long id)
   {
           if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
                   return (EBUSY);
           return (0);
   }
   
   static __inline int
   umtx_timedlock(struct umtx *umtx, u_long id, const struct timespec *timeout)
   {
           if (atomic_cmpset_acq_long(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
                   if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0,
                       __DECONST(void *, timeout)) == -1)
                           return (errno);
           return (0);
   }
   
   static __inline int
   umtx_unlock(struct umtx *umtx, u_long id)
   {
           if (atomic_cmpset_rel_long(&umtx->u_owner, id, UMTX_UNOWNED) == 0)
                   if (_umtx_unlock(umtx) == -1)
                           return (errno);
           return (0);
   }
   
   static __inline int
   umtx_wait(u_long *p, long val, const struct timespec *timeout)
   {
           if (_umtx_op(p, UMTX_OP_WAIT, val, 0,
               __DECONST(void *, timeout)) == -1)
                   return (errno);
           return (0);
   }
   
   /* Wake threads waiting on a user address. */
   static __inline int
   umtx_wake(u_long *p, int nr_wakeup)
   {
           if (_umtx_op(p, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
                   return (errno);
           return (0);
   }
   
   #else
   
   /*
    * The umtx_key structure is used by both the Linux futex code and the
    * umtx implementation to map userland addresses to unique keys.
    */
   
   enum {
           TYPE_SIMPLE_WAIT,
           TYPE_CV,
           TYPE_SIMPLE_LOCK,
           TYPE_NORMAL_UMUTEX,
           TYPE_PI_UMUTEX,
           TYPE_PP_UMUTEX,
           TYPE_RWLOCK,
           TYPE_FUTEX
   };
   
   /* Key to represent a unique userland synchronous object */
   struct umtx_key {
           int     hash;
           int     type;
           int     shared;
           union {
                   struct {
                           struct vm_object *object;
                           uintptr_t       offset;
                   } shared;
                   struct {
                           struct vmspace  *vs;
                           uintptr_t       addr;
                   } private;
                   struct {
                           void            *a;
                           uintptr_t       b;
                   } both;
           } info;
   };
   
   #define THREAD_SHARE            0
   #define PROCESS_SHARE           1
   #define AUTO_SHARE              2
   
   struct thread;
   
   static inline int
   umtx_key_match(const struct umtx_key *k1, const struct umtx_key *k2)
   {
           return (k1->type == k2->type &&
                   k1->info.both.a == k2->info.both.a &&
                   k1->info.both.b == k2->info.both.b);
   }
   
   int umtx_copyin_timeout(const void *, struct timespec *);
   int umtx_key_get(void *, int, int, struct umtx_key *);
   void umtx_key_release(struct umtx_key *);
   struct umtx_q *umtxq_alloc(void);
   void umtxq_free(struct umtx_q *);
   int kern_umtx_wake(struct thread *, void *, int, int);
   void umtx_pi_adjust(struct thread *, u_char);
   void umtx_thread_init(struct thread *);
   void umtx_thread_fini(struct thread *);
   void umtx_thread_alloc(struct thread *);
   void umtx_thread_exit(struct thread *);
   #endif /* !_KERNEL */
   #endif /* !_SYS_UMTX_H_ */

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