osfmk/kern/ast.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55
  56 /*
  57  *      kern/ast.h: Definitions for Asynchronous System Traps.
  58  */
  59
  60 #ifndef _KERN_AST_H_
  61 #define _KERN_AST_H_
  62
  63 #include <cpus.h>
  64 #include <platforms.h>
  65
  66 #include <kern/assert.h>
  67 #include <kern/cpu_number.h>
  68 #include <kern/macro_help.h>
  69 #include <kern/lock.h>
  70 #include <kern/spl.h>
  71 #include <machine/ast.h>
  72
  73 /*
  74  * A processor takes an AST when it is about to return from an
  75  * interrupt context, and calls ast_taken.
  76  *
  77  * Machine-dependent code is responsible for maintaining
  78  * a set of reasons for an AST, and passing this set to ast_taken.
  79  */
  80 typedef uint32_t                ast_t;
  81
  82 /*
  83  *      Bits for reasons
  84  */
  85 #define AST_BLOCK       0x01
  86 #define AST_QUANTUM     0x02
  87 #define AST_HANDOFF             0x04
  88 #define AST_YIELD               0x08
  89 #define AST_URGENT              0x10
  90 #define AST_APC                 0x20    /* migration APC hook */
  91 /*
  92  * JMM - This is here temporarily. AST_BSD is used to simulate a
  93  * general purpose mechanism for setting asynchronous procedure calls
  94  * from the outside.
  95  */
  96 #define AST_BSD                 0x80
  97
  98 #define AST_NONE                0x00
  99 #define AST_ALL                 (~AST_NONE)
 100
 101 #define AST_SCHEDULING  (AST_PREEMPT | AST_YIELD | AST_HANDOFF)
 102 #define AST_PREEMPT             (AST_BLOCK | AST_QUANTUM | AST_URGENT)
 103
 104 extern volatile ast_t   need_ast[NCPUS];
 105
 106 #ifdef  MACHINE_AST
 107 /*
 108  *      machine/ast.h is responsible for defining aston and astoff.
 109  */
 110 #else   /* MACHINE_AST */
 111
 112 #define aston(mycpu)
 113 #define astoff(mycpu)
 114
 115 #endif  /* MACHINE_AST */
 116
 117 /* Initialize module */
 118 extern void             ast_init(void);
 119
 120 /* Handle ASTs */
 121 extern void             ast_taken(
 122                                         ast_t           mask,
 123                                         boolean_t       enable);
 124
 125 /* Check for pending ASTs */
 126 extern void     ast_check(
 127                                         processor_t             processor);
 128
 129 /*
 130  * Per-thread ASTs are reset at context-switch time.
 131  */
 132 #ifndef MACHINE_AST_PER_THREAD
 133 #define MACHINE_AST_PER_THREAD  0
 134 #endif
 135
 136 #define AST_PER_THREAD  (AST_APC | AST_BSD | MACHINE_AST_PER_THREAD)
 137 /*
 138  *      ast_needed(), ast_on(), ast_off(), ast_context(), and ast_propagate()
 139  *      assume splsched.
 140  */
 141 #define ast_needed(mycpu)                       (need_ast[mycpu] != AST_NONE)
 142
 143 #define ast_on_fast(reasons)                                                    \
 144 MACRO_BEGIN                                                                                             \
 145         int             mycpu = cpu_number();                                           \
 146         if ((need_ast[mycpu] |= (reasons)) != AST_NONE)         \
 147                 { aston(mycpu); }                                                               \
 148 MACRO_END
 149
 150 #define ast_off_fast(reasons)                                                   \
 151 MACRO_BEGIN                                                                                             \
 152         int             mycpu = cpu_number();                                           \
 153         if ((need_ast[mycpu] &= ~(reasons)) == AST_NONE)        \
 154                 { astoff(mycpu); }                                                              \
 155 MACRO_END
 156
 157 #define ast_propagate(reasons)          ast_on(reasons)
 158
 159 #define ast_context(act, mycpu)                                                 \
 160 MACRO_BEGIN                                                                                             \
 161         assert((mycpu) == cpu_number());                                        \
 162         if ((need_ast[mycpu] =                                                          \
 163                         ((need_ast[mycpu] &~ AST_PER_THREAD) | (act)->ast)) != AST_NONE) \
 164                 { aston(mycpu); }                                                               \
 165         else                                                                                            \
 166                 { astoff(mycpu); }                                                              \
 167 MACRO_END
 168
 169 #define ast_on(reason)                       ast_on_fast(reason)
 170 #define ast_off(reason)                      ast_off_fast(reason)
 171
 172 #define thread_ast_set(act, reason)             \
 173                                                 (hw_atomic_or(&(act)->ast, (reason)))
 174 #define thread_ast_clear(act, reason)   \
 175                                                 (hw_atomic_and(&(act)->ast, ~(reason)))
 176 #define thread_ast_clear_all(act)               \
 177                                                 (hw_atomic_and(&(act)->ast, AST_NONE))
 178
 179 /*
 180  *      NOTE: if thread is the current thread, thread_ast_set() should
 181  *  be followed by ast_propagate().
 182  */
 183
 184 #ifdef MACH_KERNEL_PRIVATE
 185
 186 #define ast_urgency()           (need_ast[cpu_number()] & AST_URGENT)
 187
 188 #endif /* MACH_KERNEL_PRIVATE */
 189
 190 #endif  /* _KERN_AST_H_ */