1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  24  * Copyright 2017 RackTop Systems.
  25  */
  26 
  27 #ifndef _SYS_MUTEX_H
  28 #define _SYS_MUTEX_H
  29 
  30 #include <sys/synch.h>    /* lwp_mutex_t */
  31 
  32 #ifdef  __cplusplus
  33 extern "C" {
  34 #endif
  35 
  36 /*
  37  * Public interface to mutual exclusion locks.  See mutex(9F) for details.
  38  *
  39  * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
  40  * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
  41  * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
  42  * cookie argument to mutex_init() encodes the interrupt level to block.
  43  * The iblock cookie must be NULL for adaptive locks.
  44  *
  45  * MUTEX_DEFAULT is the type usually specified (except in drivers) to
  46  * mutex_init().  It is identical to MUTEX_ADAPTIVE.
  47  *
  48  * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
  49  * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
  50  *
  51  * Mutex statistics can be gathered on the fly, without rebooting or
  52  * recompiling the kernel, via the lockstat driver (lockstat(7D)).
  53  */
  54 typedef enum {
  55         MUTEX_ADAPTIVE = 0,     /* spin if owner is running, otherwise block */
  56         MUTEX_SPIN = 1,         /* block interrupts and spin */
  57         MUTEX_DRIVER = 4,       /* driver (DDI) mutex */
  58         MUTEX_DEFAULT = 6       /* kernel default mutex */
  59 } kmutex_type_t;
  60 
  61 struct _kmutex {
  62         lwp_mutex_t m_lock;
  63         void *m_owner;
  64 };
  65 typedef struct _kmutex kmutex_t;
  66 
  67 #if defined(_KERNEL) || defined(_FAKE_KERNEL)
  68 /* See the real sys/mutex.h */
  69 typedef struct pad_mutex {
  70         kmutex_t        pad_mutex;
  71 #ifdef _LP64
  72         char            pad_pad[64 - sizeof (kmutex_t)];
  73 #endif
  74 } pad_mutex_t;
  75 #endif  /* _KERNEL */
  76 
  77 extern char *volatile panicstr;  /* panic string pointer */
  78 
  79 #define MUTEX_HELD(x)           (mutex_owned(x))
  80 #define MUTEX_NOT_HELD(x)       (!mutex_owned(x) || panicstr)
  81 
  82 /*
  83  * We're simulating the kernel mutex API here, and the
  84  * user-level has a different signature, so rename.
  85  */
  86 #define mutex_init      kmutex_init
  87 #define mutex_destroy   kmutex_destroy
  88 
  89 /*
  90  * We want to avoid binding against the versions of these
  91  * functions in libc which causes bad things to happen.
  92  */
  93 #define mutex_enter     kmutex_enter
  94 #define mutex_exit      kmutex_exit
  95 
  96 extern  void    kmutex_init(kmutex_t *, char *, kmutex_type_t, void *);
  97 extern  void    kmutex_destroy(kmutex_t *);
  98 
  99 extern  void    kmutex_enter(kmutex_t *);
 100 extern  void    kmutex_exit(kmutex_t *);
 101 
 102 extern  int     mutex_tryenter(kmutex_t *);
 103 extern  int     mutex_owned(const kmutex_t *);
 104 
 105 extern  void *mutex_owner(const kmutex_t *);
 106 
 107 #ifdef  __cplusplus
 108 }
 109 #endif
 110 
 111 #endif  /* _SYS_MUTEX_H */