osfmk/mach/i386/flipc_dep.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  *
  25  */
  26
  27 /*
  28  * mach/i386/flipc_dep.h
  29  *
  30  * This file will have all of the FLIPC implementation machine dependent
  31  * defines that need to be visible to both kernel and AIL (eg. bus locks
  32  * and bus synchronization primitives).
  33  */
  34
  35 #ifndef _MACH_FLIPC_DEP_H_
  36 #define _MACH_FLIPC_DEP_H_
  37
  38 /* For the 386, we don't need to wrap synchronization variable writes
  39    at all.  */
  40 #define SYNCVAR_WRITE(statement)  statement
  41
  42 /* And similarly (I believe; check on this), for the 386 there isn't any
  43    requirement for write fences.  */
  44 #define WRITE_FENCE()
  45
  46 /*
  47  * Flipc simple lock defines.  These are almost completely for the use
  48  * of the AIL; the reason they are in this file is that they need to
  49  * be initialized properly in the communications buffer initialization
  50  * routine.  Sigh.  Note in particular that the kernel has no defined
  51  * "simple_lock_yield_function", so it had better never expand the
  52  * macro simple_lock_acquire.
  53  *
  54  * These locks may be declared by "flipc_simple_lock lock;".  If they
  55  * are instead declared by FLIPC_DECL_SIMPLE_LOCK(class,lockname) they
  56  * may be used without initialization.
  57  */
  58
  59 #define SIMPLE_LOCK_INITIALIZER 0
  60 #define FLIPC_DECL_SIMPLE_LOCK(class,lockname) \
  61 class flipc_simple_lock (lockname) = SIMPLE_LOCK_INITIALIZER
  62
  63 /*
  64  * Lower case because they may be macros or functions.
  65  * I'll include the function prototypes just for examples here.
  66  */
  67
  68 #define flipc_simple_lock_init(lock)            \
  69 do {                                            \
  70     *(lock) = SIMPLE_LOCK_INITIALIZER;          \
  71 } while (0)
  72
  73 /*
  74  * Defines of the actual routines, for gcc.
  75  */
  76
  77 #define flipc_simple_lock_locked(lock) ((*lock) != SIMPLE_LOCK_INITIALIZER)
  78
  79 #ifdef __GNUC__
  80      extern __inline__ int flipc_simple_lock_try(flipc_simple_lock *lock)
  81 {
  82     int r;
  83     __asm__ volatile("movl $1, %0; xchgl %0, %1" : "=&r" (r), "=m" (*lock));
  84     return !r;
  85 }
  86
  87 /* I don't know why this requires an ASM, but I'll follow the leader. */
  88 extern __inline__ void flipc_simple_lock_release(flipc_simple_lock *lock)
  89 {
  90     register int t;
  91
  92     __asm__ volatile("xorl %0, %0; xchgl %0, %1" : "=&r" (t), "=m" (*lock));
  93 }
  94 #else   /* __GNUC__ */
  95 /* If we aren't compiling with gcc, the above need to be functions.  */
  96 #endif  /* __GNUC__ */
  97
  98 #endif /* _MACH_FLIPC_DEP_H_ */