osfmk/kern/ast.h

   1 /*
   2  * Copyright (c) 2000-2012 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  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58
  59 /*
  60  *      kern/ast.h: Definitions for Asynchronous System Traps.
  61  */
  62
  63 #ifndef _KERN_AST_H_
  64 #define _KERN_AST_H_
  65
  66
  67 #include <kern/assert.h>
  68 #include <kern/macro_help.h>
  69 #include <kern/spl.h>
  70 #include <machine/ast.h>
  71
  72 /*
  73  * A processor takes an AST when it is about to return from an
  74  * interrupt context, and calls ast_taken.
  75  *
  76  * Machine-dependent code is responsible for maintaining
  77  * a set of reasons for an AST, and passing this set to ast_taken.
  78  */
  79 typedef uint32_t                ast_t;
  80
  81 /*
  82  * When returning from interrupt/trap context to kernel mode,
  83  * the pending ASTs are masked with AST_URGENT to determine if
  84  * ast_taken(AST_PREEMPTION) should be called, for instance to
  85  * effect preemption of a kernel thread by a realtime thread.
  86  * This is also done when re-enabling preemption or re-enabling
  87  * interrupts, since an AST may have been set while preemption
  88  * was disabled, and it should take effect as soon as possible.
  89  *
  90  * When returning from interrupt/trap/syscall context to user
  91  * mode, any and all ASTs that are pending should be handled.
  92  *
  93  * If a thread context switches, only ASTs not in AST_PER_THREAD
  94  * remain active. The per-thread ASTs are stored in the thread_t
  95  * and re-enabled when the thread context switches back.
  96  *
  97  * Typically the preemption ASTs are set as a result of threads
  98  * becoming runnable, threads changing priority, or quantum
  99  * expiration. If a thread becomes runnable and is chosen
 100  * to run on another processor, cause_ast_check() may be called
 101  * to IPI that processor and request csw_check() be run there.
 102  */
 103
 104 /*
 105  *      Bits for reasons
 106  */
 107 #define AST_PREEMPT             0x01
 108 #define AST_QUANTUM             0x02
 109 #define AST_URGENT              0x04
 110 #define AST_HANDOFF             0x08
 111 #define AST_YIELD               0x10
 112 #define AST_APC                 0x20    /* migration APC hook */
 113 #define AST_LEDGER              0x40
 114
 115 /*
 116  * JMM - This is here temporarily. AST_BSD is used to simulate a
 117  * general purpose mechanism for setting asynchronous procedure calls
 118  * from the outside.
 119  */
 120 #define AST_BSD                 0x80
 121 #define AST_KPERF               0x100   /* kernel profiling */
 122 #define AST_MACF                0x200   /* MACF user ret pending */
 123 #define AST_CHUD                0x400
 124 #define AST_CHUD_URGENT         0x800
 125 #define AST_GUARD               0x1000
 126 #define AST_TELEMETRY_USER      0x2000  /* telemetry sample requested on interrupt from userspace */
 127 #define AST_TELEMETRY_KERNEL    0x4000  /* telemetry sample requested on interrupt from kernel */
 128 #define AST_TELEMETRY_WINDOWED  0x8000  /* telemetry sample meant for the window buffer */
 129
 130 #define AST_SFI                 0x10000 /* Evaluate if SFI wait is needed before return to userspace */
 131
 132 #define AST_NONE                0x00
 133 #define AST_ALL                 (~AST_NONE)
 134
 135 #define AST_SCHEDULING  (AST_PREEMPTION | AST_YIELD | AST_HANDOFF)
 136 #define AST_PREEMPTION  (AST_PREEMPT | AST_QUANTUM | AST_URGENT)
 137
 138 #define AST_CHUD_ALL    (AST_CHUD_URGENT|AST_CHUD)
 139 #define AST_TELEMETRY_ALL       (AST_TELEMETRY_USER | AST_TELEMETRY_KERNEL | AST_TELEMETRY_WINDOWED)
 140
 141 #ifdef  MACHINE_AST
 142 /*
 143  *      machine/ast.h is responsible for defining aston and astoff.
 144  */
 145 #else   /* MACHINE_AST */
 146
 147 #define aston(mycpu)
 148 #define astoff(mycpu)
 149
 150 #endif  /* MACHINE_AST */
 151
 152 /* Initialize module */
 153 extern void             ast_init(void);
 154
 155 /* Handle ASTs */
 156 extern void             ast_taken(
 157                                         ast_t           mask,
 158                                         boolean_t       enable);
 159
 160 /* Check for pending ASTs */
 161 extern void     ast_check(
 162                                         processor_t             processor);
 163
 164 /* Pending ast mask for the current processor */
 165 extern ast_t    *ast_pending(void);
 166
 167 /*
 168  * Per-thread ASTs are reset at context-switch time.
 169  */
 170 #ifndef MACHINE_AST_PER_THREAD
 171 #define MACHINE_AST_PER_THREAD  0
 172 #endif
 173
 174 #define AST_PER_THREAD  (AST_APC | AST_BSD | AST_MACF | MACHINE_AST_PER_THREAD | AST_LEDGER | AST_GUARD | AST_TELEMETRY_USER | AST_TELEMETRY_KERNEL | AST_TELEMETRY_WINDOWED)
 175 /*
 176  *      ast_pending(), ast_on(), ast_off(), ast_context(), and ast_propagate()
 177  *      assume splsched.
 178  */
 179
 180 #define ast_on_fast(reasons)                                    \
 181 MACRO_BEGIN                                                                             \
 182         ast_t   *_ast_myast = ast_pending();            \
 183                                                                                                 \
 184         if ((*_ast_myast |= (reasons)) != AST_NONE)     \
 185                 { aston(_ast_myast); }                                  \
 186 MACRO_END
 187
 188 #define ast_off_fast(reasons)                                   \
 189 MACRO_BEGIN                                                                             \
 190         ast_t   *_ast_myast = ast_pending();            \
 191                                                                                                 \
 192         if ((*_ast_myast &= ~(reasons)) == AST_NONE) \
 193                 { astoff(_ast_myast); }                                 \
 194 MACRO_END
 195
 196 #define ast_propagate(reasons)          ast_on(reasons)
 197
 198 #define ast_context(act)                                                                                                        \
 199 MACRO_BEGIN                                                                                                                                     \
 200         ast_t   *myast = ast_pending();                                                                                 \
 201                                                                                                                                                         \
 202         if ((*myast = ((*myast &~ AST_PER_THREAD) | (act)->ast)) != AST_NONE)   \
 203                 { aston(myast); }                                                                                                       \
 204         else                                                                                                                                    \
 205                 { astoff(myast); }                                                                                                      \
 206 MACRO_END
 207
 208 #define ast_on(reason)                       ast_on_fast(reason)
 209 #define ast_off(reason)                      ast_off_fast(reason)
 210
 211 /*
 212  *      NOTE: if thread is the current thread, thread_ast_set() should
 213  *  be followed by ast_propagate().
 214  */
 215 #define thread_ast_set(act, reason)             \
 216                                                 (hw_atomic_or_noret(&(act)->ast, (reason)))
 217 #define thread_ast_clear(act, reason)   \
 218                                                 (hw_atomic_and_noret(&(act)->ast, ~(reason)))
 219 #define thread_ast_clear_all(act)               \
 220                                                 (hw_atomic_and_noret(&(act)->ast, AST_NONE))
 221
 222 #ifdef MACH_BSD
 223
 224 extern void astbsd_on(void);
 225 extern void act_set_astbsd(thread_t);
 226 extern void bsd_ast(thread_t);
 227
 228 #endif /* MACH_BSD */
 229
 230 #endif  /* _KERN_AST_H_ */