osfmk/mach/i386/flipc_dep.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * @OSF_COPYRIGHT@
  32  *
  33  */
  34
  35 /*
  36  * mach/i386/flipc_dep.h
  37  *
  38  * This file will have all of the FLIPC implementation machine dependent
  39  * defines that need to be visible to both kernel and AIL (eg. bus locks
  40  * and bus synchronization primitives).
  41  */
  42
  43 #ifndef _MACH_FLIPC_DEP_H_
  44 #define _MACH_FLIPC_DEP_H_
  45
  46 /* For the 386, we don't need to wrap synchronization variable writes
  47    at all.  */
  48 #define SYNCVAR_WRITE(statement)  statement
  49
  50 /* And similarly (I believe; check on this), for the 386 there isn't any
  51    requirement for write fences.  */
  52 #define WRITE_FENCE()
  53
  54 /*
  55  * Flipc simple lock defines.  These are almost completely for the use
  56  * of the AIL; the reason they are in this file is that they need to
  57  * be initialized properly in the communications buffer initialization
  58  * routine.  Sigh.  Note in particular that the kernel has no defined
  59  * "simple_lock_yield_function", so it had better never expand the
  60  * macro simple_lock_acquire.
  61  *
  62  * These locks may be declared by "flipc_simple_lock lock;".  If they
  63  * are instead declared by FLIPC_DECL_SIMPLE_LOCK(class,lockname) they
  64  * may be used without initialization.
  65  */
  66
  67 #define SIMPLE_LOCK_INITIALIZER 0
  68 #define FLIPC_DECL_SIMPLE_LOCK(class,lockname) \
  69 class flipc_simple_lock (lockname) = SIMPLE_LOCK_INITIALIZER
  70
  71 /*
  72  * Lower case because they may be macros or functions.
  73  * I'll include the function prototypes just for examples here.
  74  */
  75
  76 #define flipc_simple_lock_init(lock)            \
  77 do {                                            \
  78     *(lock) = SIMPLE_LOCK_INITIALIZER;          \
  79 } while (0)
  80
  81 /*
  82  * Defines of the actual routines, for gcc.
  83  */
  84
  85 #define flipc_simple_lock_locked(lock) ((*lock) != SIMPLE_LOCK_INITIALIZER)
  86
  87 #ifdef __GNUC__
  88      extern __inline__ int flipc_simple_lock_try(flipc_simple_lock *lock)
  89 {
  90     int r;
  91     __asm__ volatile("movl $1, %0; xchgl %0, %1" : "=&r" (r), "=m" (*lock));
  92     return !r;
  93 }
  94
  95 /* I don't know why this requires an ASM, but I'll follow the leader. */
  96 extern __inline__ void flipc_simple_lock_release(flipc_simple_lock *lock)
  97 {
  98     register int t;
  99
 100     __asm__ volatile("xorl %0, %0; xchgl %0, %1" : "=&r" (t), "=m" (*lock));
 101 }
 102 #else   /* __GNUC__ */
 103 /* If we aren't compiling with gcc, the above need to be functions.  */
 104 #endif  /* __GNUC__ */
 105
 106 #endif /* _MACH_FLIPC_DEP_H_ */