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/waitq.h>
  82 #include <kern/ledger.h>
  83 #include <kperf/kperf_kpc.h>
  84 #include <mach/policy.h>
  85 #include <machine/trap.h> // for CHUD AST hook
  86 #include <machine/pal_routines.h>
  87 #include <security/mac_mach_internal.h> // for MACF AST hook
  88
  89 volatile perfASTCallback perfASTHook;
  90
  91
  92 void
  93 ast_init(void)
  94 {
  95 }
  96
  97 #ifdef CONFIG_DTRACE
  98 extern void dtrace_ast(void);
  99 #endif
 100
 101 /*
 102  * Called at splsched.
 103  */
 104 void
 105 ast_taken(
 106         ast_t           reasons,
 107         boolean_t       enable
 108 )
 109 {
 110         boolean_t               preempt_trap = (reasons == AST_PREEMPTION);
 111         ast_t                   *myast = ast_pending();
 112         thread_t                thread = current_thread();
 113         perfASTCallback perf_hook = perfASTHook;
 114
 115         /*
 116          * CHUD hook - all threads including idle processor threads
 117          */
 118         if (perf_hook) {
 119                 if (*myast & AST_CHUD_ALL) {
 120                         (*perf_hook)(reasons, myast);
 121
 122                         if (*myast == AST_NONE)
 123                                 return;
 124                 }
 125         }
 126         else
 127                 *myast &= ~AST_CHUD_ALL;
 128
 129         reasons &= *myast;
 130         *myast &= ~reasons;
 131
 132         /*
 133          * Handle ASTs for all threads
 134          * except idle processor threads.
 135          */
 136         if (!(thread->state & TH_IDLE)) {
 137                 /*
 138                  * Check for urgent preemption.
 139                  */
 140                 if (    (reasons & AST_URGENT)                          &&
 141                                 waitq_wait_possible(thread)             ) {
 142                         if (reasons & AST_PREEMPT) {
 143                                 counter(c_ast_taken_block++);
 144                                 thread_block_reason(THREAD_CONTINUE_NULL, NULL,
 145                                                                                 reasons & AST_PREEMPTION);
 146                         }
 147
 148                         reasons &= ~AST_PREEMPTION;
 149                 }
 150
 151                 /*
 152                  * The kernel preempt traps
 153                  * skip all other ASTs.
 154                  */
 155                 if (!preempt_trap) {
 156                         ml_set_interrupts_enabled(enable);
 157
 158 #if CONFIG_DTRACE
 159                         if (reasons & AST_DTRACE) {
 160                                 dtrace_ast();
 161                         }
 162 #endif
 163
 164 #ifdef  MACH_BSD
 165                         /*
 166                          * Handle BSD hook.
 167                          */
 168                         if (reasons & AST_BSD) {
 169                                 thread_ast_clear(thread, AST_BSD);
 170                                 bsd_ast(thread);
 171                         }
 172 #endif
 173 #if CONFIG_MACF
 174                         /*
 175                          * Handle MACF hook.
 176                          */
 177                         if (reasons & AST_MACF) {
 178                                 thread_ast_clear(thread, AST_MACF);
 179                                 mac_thread_userret(thread);
 180                         }
 181 #endif
 182                         /*
 183                          * Thread APC hook.
 184                          */
 185                         if (reasons & AST_APC) {
 186                                 thread_ast_clear(thread, AST_APC);
 187                                 thread_apc_ast(thread);
 188                         }
 189
 190                         if (reasons & AST_GUARD) {
 191                                 thread_ast_clear(thread, AST_GUARD);
 192                                 guard_ast(thread);
 193                         }
 194
 195                         if (reasons & AST_LEDGER) {
 196                                 thread_ast_clear(thread, AST_LEDGER);
 197                                 ledger_ast(thread);
 198                         }
 199
 200                         /*
 201                          * Kernel Profiling Hook
 202                          */
 203                         if (reasons & AST_KPERF) {
 204                                 thread_ast_clear(thread, AST_KPERF);
 205                                 kperf_kpc_thread_ast(thread);
 206                         }
 207
 208 #if CONFIG_TELEMETRY
 209                         if (reasons & AST_TELEMETRY_ALL) {
 210                                 boolean_t interrupted_userspace = FALSE;
 211                                 boolean_t io_telemetry = FALSE;
 212
 213                                 assert((reasons & AST_TELEMETRY_ALL) != AST_TELEMETRY_ALL); /* only one is valid at a time */
 214                                 interrupted_userspace = (reasons & AST_TELEMETRY_USER) ? TRUE : FALSE;
 215                                 io_telemetry = ((reasons & AST_TELEMETRY_IO) ? TRUE : FALSE);
 216                                 thread_ast_clear(thread, AST_TELEMETRY_ALL);
 217                                 telemetry_ast(thread, interrupted_userspace, io_telemetry);
 218                         }
 219 #endif
 220
 221                         ml_set_interrupts_enabled(FALSE);
 222
 223 #if CONFIG_SCHED_SFI
 224                         if (reasons & AST_SFI) {
 225                                 sfi_ast(thread);
 226                         }
 227 #endif
 228
 229                         /*
 230                          * Check for preemption. Conditions may have changed from when the AST_PREEMPT was originally set.
 231                          */
 232                         thread_lock(thread);
 233                         if (reasons & AST_PREEMPT)
 234                                 reasons = csw_check(current_processor(), reasons & AST_QUANTUM);
 235                         thread_unlock(thread);
 236
 237                         assert(waitq_wait_possible(thread));
 238
 239                         if (reasons & AST_PREEMPT) {
 240                                 counter(c_ast_taken_block++);
 241                                 thread_block_reason((thread_continue_t)thread_exception_return, NULL, reasons & AST_PREEMPTION);
 242                         }
 243                 }
 244         }
 245
 246         ml_set_interrupts_enabled(enable);
 247 }
 248
 249 /*
 250  * Called at splsched.
 251  */
 252 void
 253 ast_check(
 254         processor_t processor)
 255 {
 256         thread_t thread = processor->active_thread;
 257
 258         if (processor->state == PROCESSOR_RUNNING ||
 259             processor->state == PROCESSOR_SHUTDOWN) {
 260                 ast_t preempt;
 261
 262                 /*
 263                  *      Propagate thread ast to processor.
 264                  */
 265                 pal_ast_check(thread);
 266
 267                 ast_propagate(thread->ast);
 268
 269                 /*
 270                  *      Context switch check.
 271                  */
 272                 thread_lock(thread);
 273
 274                 processor->current_pri = thread->sched_pri;
 275                 processor->current_thmode = thread->sched_mode;
 276                 processor->current_sfi_class = thread->sfi_class = sfi_thread_classify(thread);
 277
 278                 if ((preempt = csw_check(processor, AST_NONE)) != AST_NONE)
 279                         ast_on(preempt);
 280
 281                 thread_unlock(thread);
 282         }
 283 }
 284
 285 /*
 286  * Set AST flags on current processor
 287  * Called at splsched
 288  */
 289 void
 290 ast_on(ast_t reasons)
 291 {
 292         ast_t *pending_ast = ast_pending();
 293
 294         *pending_ast |= reasons;
 295 }
 296
 297 /*
 298  * Clear AST flags on current processor
 299  * Called at splsched
 300  */
 301 void
 302 ast_off(ast_t reasons)
 303 {
 304         ast_t *pending_ast = ast_pending();
 305
 306         *pending_ast &= ~reasons;
 307 }
 308
 309 /*
 310  * Re-set current processor's per-thread AST flags to those set on thread
 311  * Called at splsched
 312  */
 313 void
 314 ast_context(thread_t thread)
 315 {
 316         ast_t *pending_ast = ast_pending();
 317
 318         *pending_ast = ((*pending_ast & ~AST_PER_THREAD) | thread->ast);
 319 }
 320
 321 void
 322 ast_dtrace_on(void)
 323 {
 324         ast_on(AST_DTRACE);
 325 }
 326