osfmk/mach/i386/flipc_dep.h

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