osfmk/kern/ast.c

   1 /*
   2  * Copyright (c) 2000-2012 Apple 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
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  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 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  *
  61  *      This file contains routines to check whether an ast is needed.
  62  *
  63  *      ast_check() - check whether ast is needed for interrupt or context
  64  *      switch.  Usually called by clock interrupt handler.
  65  *
  66  */
  67
  68 #include <kern/ast.h>
  69 #include <kern/counters.h>
  70 #include <kern/cpu_number.h>
  71 #include <kern/misc_protos.h>
  72 #include <kern/queue.h>
  73 #include <kern/sched_prim.h>
  74 #include <kern/thread.h>
  75 #include <kern/processor.h>
  76 #include <kern/spl.h>
  77 #include <kern/sfi.h>
  78 #if CONFIG_TELEMETRY
  79 #include <kern/telemetry.h>
  80 #endif
  81 #include <kern/wait_queue.h>
  82 #include <kern/ledger.h>
  83 #include <mach/policy.h>
  84 #include <machine/trap.h> // for CHUD AST hook
  85 #include <machine/pal_routines.h>
  86 #include <security/mac_mach_internal.h> // for MACF AST hook
  87
  88 volatile perfASTCallback perfASTHook;
  89
  90
  91 void
  92 ast_init(void)
  93 {
  94 }
  95
  96 extern void chudxnu_thread_ast(thread_t); // XXX this should probably be in a header...
  97
  98 /*
  99  * Called at splsched.
 100  */
 101 void
 102 ast_taken(
 103         ast_t           reasons,
 104         boolean_t       enable
 105 )
 106 {
 107         boolean_t               preempt_trap = (reasons == AST_PREEMPTION);
 108         ast_t                   *myast = ast_pending();
 109         thread_t                thread = current_thread();
 110         perfASTCallback perf_hook = perfASTHook;
 111
 112         /*
 113          * CHUD hook - all threads including idle processor threads
 114          */
 115         if (perf_hook) {
 116                 if (*myast & AST_CHUD_ALL) {
 117                         (*perf_hook)(reasons, myast);
 118
 119                         if (*myast == AST_NONE)
 120                                 return;
 121                 }
 122         }
 123         else
 124                 *myast &= ~AST_CHUD_ALL;
 125
 126         reasons &= *myast;
 127         *myast &= ~reasons;
 128
 129         /*
 130          * Handle ASTs for all threads
 131          * except idle processor threads.
 132          */
 133         if (!(thread->state & TH_IDLE)) {
 134                 /*
 135                  * Check for urgent preemption.
 136                  */
 137                 if (    (reasons & AST_URGENT)                          &&
 138                                 wait_queue_assert_possible(thread)              ) {
 139                         if (reasons & AST_PREEMPT) {
 140                                 counter(c_ast_taken_block++);
 141                                 thread_block_reason(THREAD_CONTINUE_NULL, NULL,
 142                                                                                 reasons & AST_PREEMPTION);
 143                         }
 144
 145                         reasons &= ~AST_PREEMPTION;
 146                 }
 147
 148                 /*
 149                  * The kernel preempt traps
 150                  * skip all other ASTs.
 151                  */
 152                 if (!preempt_trap) {
 153                         ml_set_interrupts_enabled(enable);
 154
 155 #ifdef  MACH_BSD
 156                         /*
 157                          * Handle BSD hook.
 158                          */
 159                         if (reasons & AST_BSD) {
 160                                 thread_ast_clear(thread, AST_BSD);
 161                                 bsd_ast(thread);
 162                         }
 163 #endif
 164 #if CONFIG_MACF
 165                         /*
 166                          * Handle MACF hook.
 167                          */
 168                         if (reasons & AST_MACF) {
 169                                 thread_ast_clear(thread, AST_MACF);
 170                                 mac_thread_userret(thread);
 171                         }
 172 #endif
 173                         /*
 174                          * Thread APC hook.
 175                          */
 176                         if (reasons & AST_APC)
 177                                 act_execute_returnhandlers();
 178
 179                         if (reasons & AST_GUARD) {
 180                                 thread_ast_clear(thread, AST_GUARD);
 181                                 guard_ast(thread);
 182                         }
 183
 184                         if (reasons & AST_LEDGER) {
 185                                 thread_ast_clear(thread, AST_LEDGER);
 186                                 ledger_ast(thread);
 187                         }
 188
 189                         /*
 190                          * Kernel Profiling Hook
 191                          */
 192                         if (reasons & AST_KPERF) {
 193                                 thread_ast_clear(thread, AST_KPERF);
 194                                 chudxnu_thread_ast(thread);
 195                         }
 196
 197 #if CONFIG_TELEMETRY
 198                         if (reasons & AST_TELEMETRY_ALL) {
 199                                 boolean_t interrupted_userspace = FALSE;
 200                                 boolean_t is_windowed = FALSE;
 201
 202                                 assert((reasons & AST_TELEMETRY_ALL) != AST_TELEMETRY_ALL); /* only one is valid at a time */
 203                                 interrupted_userspace = (reasons & AST_TELEMETRY_USER) ? TRUE : FALSE;
 204                                 is_windowed = ((reasons & AST_TELEMETRY_WINDOWED) ? TRUE : FALSE);
 205                                 thread_ast_clear(thread, AST_TELEMETRY_ALL);
 206                                 telemetry_ast(thread, interrupted_userspace, is_windowed);
 207                         }
 208 #endif
 209
 210                         ml_set_interrupts_enabled(FALSE);
 211
 212                         if (reasons & AST_SFI) {
 213                                 sfi_ast(thread);
 214                         }
 215
 216                         /*
 217                          * Check for preemption. Conditions may have changed from when the AST_PREEMPT was originally set.
 218                          */
 219                         thread_lock(thread);
 220                         if (reasons & AST_PREEMPT)
 221                                 reasons = csw_check(current_processor(), reasons & AST_QUANTUM);
 222                         thread_unlock(thread);
 223
 224                         if (    (reasons & AST_PREEMPT)                         &&
 225                                         wait_queue_assert_possible(thread)              ) {
 226                                 counter(c_ast_taken_block++);
 227                                 thread_block_reason((thread_continue_t)thread_exception_return, NULL, reasons & AST_PREEMPTION);
 228                         }
 229                 }
 230         }
 231
 232         ml_set_interrupts_enabled(enable);
 233 }
 234
 235 /*
 236  * Called at splsched.
 237  */
 238 void
 239 ast_check(
 240         processor_t             processor)
 241 {
 242         thread_t                        thread = processor->active_thread;
 243
 244         if (    processor->state == PROCESSOR_RUNNING           ||
 245                         processor->state == PROCESSOR_SHUTDOWN          ) {
 246                 ast_t                   preempt;
 247
 248                 /*
 249                  *      Propagate thread ast to processor.
 250                  */
 251                 pal_ast_check(thread);
 252
 253                 ast_propagate(thread->ast);
 254
 255                 /*
 256                  *      Context switch check.
 257                  */
 258                 thread_lock(thread);
 259
 260                 processor->current_pri = thread->sched_pri;
 261                 processor->current_thmode = thread->sched_mode;
 262                 processor->current_sfi_class = thread->sfi_class = sfi_thread_classify(thread);
 263
 264                 if ((preempt = csw_check(processor, AST_NONE)) != AST_NONE)
 265                         ast_on(preempt);
 266                 thread_unlock(thread);
 267         }
 268 }