osfmk/kern/ast.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  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52
  53 /*
  54  *      kern/ast.h: Definitions for Asynchronous System Traps.
  55  */
  56
  57 #ifndef _KERN_AST_H_
  58 #define _KERN_AST_H_
  59
  60 #include <cpus.h>
  61 #include <platforms.h>
  62
  63 #include <kern/assert.h>
  64 #include <kern/cpu_number.h>
  65 #include <kern/macro_help.h>
  66 #include <kern/lock.h>
  67 #include <kern/spl.h>
  68 #include <machine/ast.h>
  69
  70 /*
  71  * A processor takes an AST when it is about to return from an
  72  * interrupt context, and calls ast_taken.
  73  *
  74  * Machine-dependent code is responsible for maintaining
  75  * a set of reasons for an AST, and passing this set to ast_taken.
  76  */
  77 typedef uint32_t                ast_t;
  78
  79 /*
  80  *      Bits for reasons
  81  */
  82 #define AST_BLOCK       0x01
  83 #define AST_QUANTUM     0x02
  84 #define AST_HANDOFF             0x04
  85 #define AST_YIELD               0x08
  86 #define AST_URGENT              0x10
  87 #define AST_APC                 0x20    /* migration APC hook */
  88 /*
  89  * JMM - This is here temporarily. AST_BSD is used to simulate a
  90  * general purpose mechanism for setting asynchronous procedure calls
  91  * from the outside.
  92  */
  93 #define AST_BSD                 0x80
  94
  95 #define AST_NONE                0x00
  96 #define AST_ALL                 (~AST_NONE)
  97
  98 #define AST_SCHEDULING  (AST_PREEMPT | AST_YIELD | AST_HANDOFF)
  99 #define AST_PREEMPT             (AST_BLOCK | AST_QUANTUM | AST_URGENT)
 100
 101 extern volatile ast_t   need_ast[NCPUS];
 102
 103 #ifdef  MACHINE_AST
 104 /*
 105  *      machine/ast.h is responsible for defining aston and astoff.
 106  */
 107 #else   /* MACHINE_AST */
 108
 109 #define aston(mycpu)
 110 #define astoff(mycpu)
 111
 112 #endif  /* MACHINE_AST */
 113
 114 /* Initialize module */
 115 extern void             ast_init(void);
 116
 117 /* Handle ASTs */
 118 extern void             ast_taken(
 119                                         ast_t           mask,
 120                                         boolean_t       enable);
 121
 122 /* Check for pending ASTs */
 123 extern void     ast_check(
 124                                         processor_t             processor);
 125
 126 /*
 127  * Per-thread ASTs are reset at context-switch time.
 128  */
 129 #ifndef MACHINE_AST_PER_THREAD
 130 #define MACHINE_AST_PER_THREAD  0
 131 #endif
 132
 133 #define AST_PER_THREAD  (AST_APC | AST_BSD | MACHINE_AST_PER_THREAD)
 134 /*
 135  *      ast_needed(), ast_on(), ast_off(), ast_context(), and ast_propagate()
 136  *      assume splsched.
 137  */
 138 #define ast_needed(mycpu)                       (need_ast[mycpu] != AST_NONE)
 139
 140 #define ast_on_fast(reasons)                                                    \
 141 MACRO_BEGIN                                                                                             \
 142         int             mycpu = cpu_number();                                           \
 143         if ((need_ast[mycpu] |= (reasons)) != AST_NONE)         \
 144                 { aston(mycpu); }                                                               \
 145 MACRO_END
 146
 147 #define ast_off_fast(reasons)                                                   \
 148 MACRO_BEGIN                                                                                             \
 149         int             mycpu = cpu_number();                                           \
 150         if ((need_ast[mycpu] &= ~(reasons)) == AST_NONE)        \
 151                 { astoff(mycpu); }                                                              \
 152 MACRO_END
 153
 154 #define ast_propagate(reasons)          ast_on(reasons)
 155
 156 #define ast_context(act, mycpu)                                                 \
 157 MACRO_BEGIN                                                                                             \
 158         assert((mycpu) == cpu_number());                                        \
 159         if ((need_ast[mycpu] =                                                          \
 160                         ((need_ast[mycpu] &~ AST_PER_THREAD) | (act)->ast)) != AST_NONE) \
 161                 { aston(mycpu); }                                                               \
 162         else                                                                                            \
 163                 { astoff(mycpu); }                                                              \
 164 MACRO_END
 165
 166 #define ast_on(reason)                       ast_on_fast(reason)
 167 #define ast_off(reason)                      ast_off_fast(reason)
 168
 169 #define thread_ast_set(act, reason)             \
 170                                                 (hw_atomic_or(&(act)->ast, (reason)))
 171 #define thread_ast_clear(act, reason)   \
 172                                                 (hw_atomic_and(&(act)->ast, ~(reason)))
 173 #define thread_ast_clear_all(act)               \
 174                                                 (hw_atomic_and(&(act)->ast, AST_NONE))
 175
 176 /*
 177  *      NOTE: if thread is the current thread, thread_ast_set() should
 178  *  be followed by ast_propagate().
 179  */
 180
 181 #ifdef MACH_KERNEL_PRIVATE
 182
 183 #define ast_urgency()           (need_ast[cpu_number()] & AST_URGENT)
 184
 185 #endif /* MACH_KERNEL_PRIVATE */
 186
 187 #endif  /* _KERN_AST_H_ */