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
  71 /*
  72  * A processor takes an AST when it is about to return from an
  73  * interrupt context, and calls ast_taken.
  74  *
  75  * Machine-dependent code is responsible for maintaining
  76  * a set of reasons for an AST, and passing this set to ast_taken.
  77  */
  78 typedef uint32_t                ast_t;
  79
  80 /*
  81  * When returning from interrupt/trap context to kernel mode,
  82  * the pending ASTs are masked with AST_URGENT to determine if
  83  * ast_taken(AST_PREEMPTION) should be called, for instance to
  84  * effect preemption of a kernel thread by a realtime thread.
  85  * This is also done when re-enabling preemption or re-enabling
  86  * interrupts, since an AST may have been set while preemption
  87  * was disabled, and it should take effect as soon as possible.
  88  *
  89  * When returning from interrupt/trap/syscall context to user
  90  * mode, any and all ASTs that are pending should be handled.
  91  *
  92  * If a thread context switches, only ASTs not in AST_PER_THREAD
  93  * remain active. The per-thread ASTs are stored in the thread_t
  94  * and re-enabled when the thread context switches back.
  95  *
  96  * Typically the preemption ASTs are set as a result of threads
  97  * becoming runnable, threads changing priority, or quantum
  98  * expiration. If a thread becomes runnable and is chosen
  99  * to run on another processor, cause_ast_check() may be called
 100  * to IPI that processor and request csw_check() be run there.
 101  */
 102
 103 /*
 104  *      Bits for reasons
 105  */
 106 #define AST_PREEMPT             0x01
 107 #define AST_QUANTUM             0x02
 108 #define AST_URGENT              0x04
 109 #define AST_HANDOFF             0x08
 110 #define AST_YIELD               0x10
 111 #define AST_APC                 0x20    /* migration APC hook */
 112 #define AST_LEDGER              0x40
 113 #define AST_BSD                 0x80
 114 #define AST_KPERF               0x100   /* kernel profiling */
 115 #define AST_MACF                0x200   /* MACF user ret pending */
 116 #define AST_CHUD                0x400
 117 #define AST_CHUD_URGENT         0x800
 118 #define AST_GUARD               0x1000
 119 #define AST_TELEMETRY_USER      0x2000  /* telemetry sample requested on interrupt from userspace */
 120 #define AST_TELEMETRY_KERNEL    0x4000  /* telemetry sample requested on interrupt from kernel */
 121 #define AST_SFI                 0x10000 /* Evaluate if SFI wait is needed before return to userspace */
 122 #define AST_DTRACE              0x20000
 123 #define AST_TELEMETRY_IO        0x40000 /* telemetry sample requested for I/O */
 124
 125 #define AST_NONE                0x00
 126 #define AST_ALL                 (~AST_NONE)
 127
 128 #define AST_SCHEDULING  (AST_PREEMPTION | AST_YIELD | AST_HANDOFF)
 129 #define AST_PREEMPTION  (AST_PREEMPT | AST_QUANTUM | AST_URGENT)
 130
 131 #define AST_CHUD_ALL    (AST_CHUD_URGENT|AST_CHUD)
 132 #define AST_TELEMETRY_ALL       (AST_TELEMETRY_USER | AST_TELEMETRY_KERNEL | AST_TELEMETRY_IO)
 133
 134 /* Per-thread ASTs follow the thread at context-switch time. */
 135 #define AST_PER_THREAD  (AST_APC | AST_BSD | AST_MACF | AST_LEDGER | AST_GUARD | AST_TELEMETRY_ALL )
 136
 137 /* Initialize module */
 138 extern void             ast_init(void);
 139
 140 /* Handle ASTs */
 141 extern void             ast_taken(
 142                                         ast_t           mask,
 143                                         boolean_t       enable);
 144
 145 /* Check for pending ASTs */
 146 extern void ast_check(processor_t processor);
 147
 148 /* Pending ast mask for the current processor */
 149 extern ast_t *ast_pending(void);
 150
 151 /* Set AST flags on current processor */
 152 extern void ast_on(ast_t reasons);
 153
 154 /* Clear AST flags on current processor */
 155 extern void ast_off(ast_t reasons);
 156
 157 /* Re-set current processor's per-thread AST flags to those set on thread */
 158 extern void ast_context(thread_t thread);
 159
 160 #define ast_propagate(reasons) ast_on(reasons)
 161
 162 /*
 163  *      Set an AST on a thread with thread_ast_set.
 164  *
 165  *      You can then propagate it to the current processor with ast_propagate(),
 166  *      or tell another processor to act on it with cause_ast_check().
 167  *
 168  *      See act_set_ast() for an example.
 169  */
 170 #define thread_ast_set(act, reason)     (hw_atomic_or_noret(&(act)->ast, (reason)))
 171 #define thread_ast_clear(act, reason)   (hw_atomic_and_noret(&(act)->ast, ~(reason)))
 172
 173 #ifdef MACH_BSD
 174
 175 extern void act_set_astbsd(thread_t);
 176 extern void bsd_ast(thread_t);
 177
 178 #endif /* MACH_BSD */
 179
 180 #ifdef CONFIG_DTRACE
 181 extern void ast_dtrace_on(void);
 182 #endif /* CONFIG_DTRACE */
 183
 184 #endif  /* _KERN_AST_H_ */