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