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 detects an AST when it is about to return from an
  73  * interrupt context, and calls ast_taken_kernel or ast_taken_user
  74  * depending on whether it was returning from userspace or kernelspace.
  75  *
  76  * Machine-dependent code is responsible for maintaining
  77  * a set of reasons for an AST.
  78  */
  79 typedef uint32_t ast_t;
  80
  81 /*
  82  * When returning from interrupt/trap context to kernel mode,
  83  * if AST_URGENT is set, then ast_taken_kernel is called, for
  84  * instance to effect preemption of a kernel thread by a realtime
  85  * thread.
  86  *
  87  * This is also done when re-enabling preemption or re-enabling
  88  * interrupts, since an AST may have been set while preemption
  89  * was disabled, and it should take effect as soon as possible.
  90  *
  91  * When returning from interrupt/trap/syscall context to user
  92  * mode, any and all ASTs that are pending should be handled by
  93  * calling ast_taken_user.
  94  *
  95  * If a thread context switches, only ASTs not in AST_PER_THREAD
  96  * remain active. The per-thread ASTs are stored in the thread_t
  97  * and re-enabled when the thread context switches back.
  98  *
  99  * Typically the preemption ASTs are set as a result of threads
 100  * becoming runnable, threads changing priority, or quantum
 101  * expiration. If a thread becomes runnable and is chosen
 102  * to run on another processor, cause_ast_check() may be called
 103  * to IPI that processor and request csw_check() be run there.
 104  */
 105
 106 /*
 107  *      Bits for reasons
 108  *      TODO: Split the context switch and return-to-user AST namespaces
 109  *      NOTE: Some of these are exported as the 'reason' code in scheduler tracepoints
 110  */
 111 #define AST_PREEMPT             0x01
 112 #define AST_QUANTUM             0x02
 113 #define AST_URGENT              0x04
 114 #define AST_HANDOFF             0x08
 115 #define AST_YIELD               0x10
 116 #define AST_APC                 0x20    /* migration APC hook */
 117 #define AST_LEDGER              0x40
 118 #define AST_BSD                 0x80
 119 #define AST_KPERF               0x100   /* kernel profiling */
 120 #define AST_MACF                0x200   /* MACF user ret pending */
 121 #define AST_RESET_PCS           0x400   /* restartable ranges */
 122 #define AST_ARCADE              0x800   /* arcade subsciption support */
 123 #define AST_GUARD               0x1000
 124 #define AST_TELEMETRY_USER      0x2000  /* telemetry sample requested on interrupt from userspace */
 125 #define AST_TELEMETRY_KERNEL    0x4000  /* telemetry sample requested on interrupt from kernel */
 126 #define AST_TELEMETRY_PMI       0x8000  /* telemetry sample requested on PMI */
 127 #define AST_SFI                 0x10000 /* Evaluate if SFI wait is needed before return to userspace */
 128 #define AST_DTRACE              0x20000
 129 #define AST_TELEMETRY_IO        0x40000 /* telemetry sample requested for I/O */
 130 #define AST_KEVENT              0x80000
 131 #define AST_REBALANCE           0x100000 /* thread context switched due to rebalancing */
 132 #define AST_UNQUIESCE           0x200000 /* catch unquiesced processor before returning to userspace */
 133
 134 #define AST_NONE                0x00
 135 #define AST_ALL                 (~AST_NONE)
 136
 137 #define AST_SCHEDULING  (AST_PREEMPTION | AST_YIELD | AST_HANDOFF)
 138 #define AST_PREEMPTION  (AST_PREEMPT | AST_QUANTUM | AST_URGENT)
 139
 140 #define AST_TELEMETRY_ALL (AST_TELEMETRY_USER | AST_TELEMETRY_KERNEL | \
 141                 AST_TELEMETRY_PMI | AST_TELEMETRY_IO)
 142
 143 /* Per-thread ASTs follow the thread at context-switch time. */
 144 #define AST_PER_THREAD  (AST_APC | AST_BSD | AST_MACF | AST_RESET_PCS | \
 145         AST_ARCADE | AST_LEDGER | AST_GUARD | AST_TELEMETRY_ALL | AST_KEVENT)
 146
 147 /* Handle AST_URGENT detected while in the kernel */
 148 extern void ast_taken_kernel(void);
 149
 150 /* Handle an AST flag set while returning to user mode (may continue via thread_exception_return) */
 151 extern void ast_taken_user(void);
 152
 153 /* Check for pending ASTs */
 154 extern void ast_check(processor_t processor);
 155
 156 /* Pending ast mask for the current processor */
 157 extern ast_t *ast_pending(void);
 158
 159 /* Set AST flags on current processor */
 160 extern void ast_on(ast_t reasons);
 161
 162 /* Clear AST flags on current processor */
 163 extern void ast_off(ast_t reasons);
 164
 165 /* Consume specified AST flags from current processor */
 166 extern ast_t ast_consume(ast_t reasons);
 167
 168 /* Read specified AST flags from current processor */
 169 extern ast_t ast_peek(ast_t reasons);
 170
 171 /* Re-set current processor's per-thread AST flags to those set on thread */
 172 extern void ast_context(thread_t thread);
 173
 174 /* Propagate ASTs set on a thread to the current processor */
 175 extern void ast_propagate(thread_t thread);
 176
 177 /*
 178  *      Set an AST on a thread with thread_ast_set.
 179  *
 180  *      You can then propagate it to the current processor with ast_propagate(),
 181  *      or tell another processor to act on it with cause_ast_check().
 182  *
 183  *      See act_set_ast() for an example.
 184  */
 185 #define thread_ast_set(act, reason)     ((void)os_atomic_or(&(act)->ast, (reason), relaxed))
 186 #define thread_ast_clear(act, reason)   ((void)os_atomic_andnot(&(act)->ast, (reason), relaxed))
 187
 188 #ifdef MACH_BSD
 189
 190 extern void act_set_astbsd(thread_t);
 191 extern void bsd_ast(thread_t);
 192
 193 #endif /* MACH_BSD */
 194
 195 #ifdef CONFIG_DTRACE
 196 extern void ast_dtrace_on(void);
 197 extern void dtrace_ast(void);
 198 #endif /* CONFIG_DTRACE */
 199
 200 extern void kevent_ast(thread_t thread, uint16_t bits);
 201 extern void act_set_astkevent(thread_t thread, uint16_t bits);
 202 extern uint16_t act_clear_astkevent(thread_t thread, uint16_t bits);
 203 extern void act_set_ast_reset_pcs(thread_t thread);
 204
 205 #endif  /* _KERN_AST_H_ */