/* ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio. This file is part of ChibiOS. ChibiOS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. ChibiOS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /** * @file chthreads.c * @brief Threads code. * * @addtogroup threads * @details Threads related APIs and services. *

Operation mode

* A thread is an abstraction of an independent instructions flow. * In ChibiOS/RT a thread is represented by a "C" function owning * a processor context, state informations and a dedicated stack * area. In this scenario static variables are shared among all * threads while automatic variables are local to the thread.
* Operations defined for threads: * - Create, a thread is started on the specified thread * function. This operation is available in multiple variants, * both static and dynamic. * - Exit, a thread terminates by returning from its top * level function or invoking a specific API, the thread can * return a value that can be retrieved by other threads. * - Wait, a thread waits for the termination of another * thread and retrieves its return value. * - Resume, a thread created in suspended state is started. * - Sleep, the execution of a thread is suspended for the * specified amount of time or the specified future absolute time * is reached. * - SetPriority, a thread changes its own priority level. * - Yield, a thread voluntarily renounces to its time slot. * . * The threads subsystem is implicitly included in kernel however * some of its part may be excluded by disabling them in @p chconf.h, * see the @p CH_CFG_USE_WAITEXIT and @p CH_CFG_USE_DYNAMIC configuration * options. * @{ */ #include "ch.h" /*===========================================================================*/ /* Module local definitions. */ /*===========================================================================*/ /*===========================================================================*/ /* Module exported variables. */ /*===========================================================================*/ /*===========================================================================*/ /* Module local types. */ /*===========================================================================*/ /*===========================================================================*/ /* Module local variables. */ /*===========================================================================*/ /*===========================================================================*/ /* Module local functions. */ /*===========================================================================*/ /*===========================================================================*/ /* Module exported functions. */ /*===========================================================================*/ /** * @brief Initializes a thread structure. * @note This is an internal functions, do not use it in application code. * * @param[in] tp pointer to the thread * @param[in] prio the priority level for the new thread * @return The same thread pointer passed as parameter. * * @notapi */ thread_t *_thread_init(thread_t *tp, tprio_t prio) { tp->p_prio = prio; tp->p_state = CH_STATE_WTSTART; tp->p_flags = CH_FLAG_MODE_STATIC; #if CH_CFG_TIME_QUANTUM > 0 tp->p_preempt = CH_CFG_TIME_QUANTUM; #endif #if CH_CFG_USE_MUTEXES tp->p_realprio = prio; tp->p_mtxlist = NULL; #endif #if CH_CFG_USE_EVENTS tp->p_epending = 0; #endif #if CH_DBG_THREADS_PROFILING tp->p_time = 0; #endif #if CH_CFG_USE_DYNAMIC tp->p_refs = 1; #endif #if CH_CFG_USE_REGISTRY tp->p_name = NULL; REG_INSERT(tp); #endif #if CH_CFG_USE_WAITEXIT list_init(&tp->p_waiting); #endif #if CH_CFG_USE_MESSAGES queue_init(&tp->p_msgqueue); #endif #if CH_DBG_ENABLE_STACK_CHECK tp->p_stklimit = (stkalign_t *)(tp + 1); #endif #if CH_DBG_STATISTICS || defined(__DOXYGEN__) chTMObjectInit(&tp->p_stats); chTMStartMeasurementX(&tp->p_stats); #endif #if defined(CH_CFG_THREAD_INIT_HOOK) CH_CFG_THREAD_INIT_HOOK(tp); #endif return tp; } #if CH_DBG_FILL_THREADS || defined(__DOXYGEN__) /** * @brief Memory fill utility. * * @param[in] startp first address to fill * @param[in] endp last address to fill +1 * @param[in] v filler value * * @notapi */ void _thread_memfill(uint8_t *startp, uint8_t *endp, uint8_t v) { while (startp < endp) *startp++ = v; } #endif /* CH_DBG_FILL_THREADS */ /** * @brief Creates a new thread into a static memory area. * @details The new thread is initialized but not inserted in the ready list, * the initial state is @p CH_STATE_WTSTART. * @post The initialized thread can be subsequently started by invoking * @p chThdStart(), @p chThdStartI() or @p chSchWakeupS() * depending on the execution context. * @note A thread can terminate by calling @p chThdExit() or by simply * returning from its main function. * @note Threads created using this function do not obey to the * @p CH_DBG_FILL_THREADS debug option because it would keep * the kernel locked for too much time. * * @param[out] wsp pointer to a working area dedicated to the thread stack * @param[in] size size of the working area * @param[in] prio the priority level for the new thread * @param[in] pf the thread function * @param[in] arg an argument passed to the thread function. It can be * @p NULL. * @return The pointer to the @p thread_t structure allocated for * the thread into the working space area. * * @iclass */ thread_t *chThdCreateI(void *wsp, size_t size, tprio_t prio, tfunc_t pf, void *arg) { /* The thread structure is laid out in the lower part of the thread workspace.*/ thread_t *tp = wsp; chDbgCheckClassI(); chDbgCheck((wsp != NULL) && (size >= THD_WORKING_AREA_SIZE(0)) && (prio <= HIGHPRIO) && (pf != NULL)); PORT_SETUP_CONTEXT(tp, wsp, size, pf, arg); return _thread_init(tp, prio); } /** * @brief Creates a new thread into a static memory area. * @note A thread can terminate by calling @p chThdExit() or by simply * returning from its main function. * * @param[out] wsp pointer to a working area dedicated to the thread stack * @param[in] size size of the working area * @param[in] prio the priority level for the new thread * @param[in] pf the thread function * @param[in] arg an argument passed to the thread function. It can be * @p NULL. * @return The pointer to the @p thread_t structure allocated for * the thread into the working space area. * * @api */ thread_t *chThdCreateStatic(void *wsp, size_t size, tprio_t prio, tfunc_t pf, void *arg) { thread_t *tp; #if CH_DBG_FILL_THREADS _thread_memfill((uint8_t *)wsp, (uint8_t *)wsp + sizeof(thread_t), CH_DBG_THREAD_FILL_VALUE); _thread_memfill((uint8_t *)wsp + sizeof(thread_t), (uint8_t *)wsp + size, CH_DBG_STACK_FILL_VALUE); #endif chSysLock(); chSchWakeupS(tp = chThdCreateI(wsp, size, prio, pf, arg), MSG_OK); chSysUnlock(); return tp; } /** * @brief Resumes a thread created with @p chThdCreateI(). * * @param[in] tp pointer to the thread * @return The pointer to the @p thread_t structure allocated for * the thread into the working space area. * * @api */ thread_t *chThdStart(thread_t *tp) { chSysLock(); tp = chThdStartI(tp); chSysUnlock(); return tp; } /** * @brief Changes the running thread priority level then reschedules if * necessary. * @note The function returns the real thread priority regardless of the * current priority that could be higher than the real priority * because the priority inheritance mechanism. * * @param[in] newprio the new priority level of the running thread * @return The old priority level. * * @api */ tprio_t chThdSetPriority(tprio_t newprio) { tprio_t oldprio; chDbgCheck(newprio <= HIGHPRIO); chSysLock(); #if CH_CFG_USE_MUTEXES oldprio = currp->p_realprio; if ((currp->p_prio == currp->p_realprio) || (newprio > currp->p_prio)) currp->p_prio = newprio; currp->p_realprio = newprio; #else oldprio = currp->p_prio; currp->p_prio = newprio; #endif chSchRescheduleS(); chSysUnlock(); return oldprio; } /** * @brief Requests a thread termination. * @pre The target thread must be written to invoke periodically * @p chThdShouldTerminate() and terminate cleanly if it returns * @p true. * @post The specified thread will terminate after detecting the termination * condition. * * @param[in] tp pointer to the thread * * @api */ void chThdTerminate(thread_t *tp) { chSysLock(); tp->p_flags |= CH_FLAG_TERMINATE; chSysUnlock(); } /** * @brief Suspends the invoking thread for the specified time. * * @param[in] time the delay in system ticks, the special values are * handled as follow: * - @a TIME_INFINITE the thread enters an infinite sleep * state. * - @a TIME_IMMEDIATE this value is not allowed. * . * * @api */ void chThdSleep(systime_t time) { chSysLock(); chThdSleepS(time); chSysUnlock(); } /** * @brief Suspends the invoking thread until the system time arrives to the * specified value. * @note The function has no concept of "past", all specifiable times * are in the future, this means that if you call this function * exceeding your calculated intervals then the function will * return in a far future time, not immediately. * @see chThdSleepUntilWindowed() * * @param[in] time absolute system time * * @api */ void chThdSleepUntil(systime_t time) { chSysLock(); if ((time -= chVTGetSystemTimeX()) > 0) chThdSleepS(time); chSysUnlock(); } /** * @brief Suspends the invoking thread until the system time arrives to the * specified value. * @note The system time is assumed to be between @p prev and @p time * else the call is assumed to have been called outside the * allowed time interval, in this case no sleep is performed. * @see chThdSleepUntilWindowed() * * @param[in] prev absolute system time of the previous deadline * @param[in] next absolute system time of the next deadline * @return the @p next parameter * * @api */ systime_t chThdSleepUntilWindowed(systime_t prev, systime_t next) { systime_t time; chSysLock(); time = chVTGetSystemTimeX(); if (chVTIsTimeWithinX(time, prev, next)) chThdSleepS(next - time); chSysUnlock(); return next; } /** * @brief Yields the time slot. * @details Yields the CPU control to the next thread in the ready list with * equal priority, if any. * * @api */ void chThdYield(void) { chSysLock(); chSchDoYieldS(); chSysUnlock(); } /** * @brief Terminates the current thread. * @details The thread goes in the @p CH_STATE_FINAL state holding the * specified exit status code, other threads can retrieve the * exit status code by invoking the function @p chThdWait(). * @post Eventual code after this function will never be executed, * this function never returns. The compiler has no way to * know this so do not assume that the compiler would remove * the dead code. * * @param[in] msg thread exit code * * @api */ void chThdExit(msg_t msg) { chSysLock(); chThdExitS(msg); /* The thread never returns here.*/ } /** * @brief Terminates the current thread. * @details The thread goes in the @p CH_STATE_FINAL state holding the * specified exit status code, other threads can retrieve the * exit status code by invoking the function @p chThdWait(). * @post Eventual code after this function will never be executed, * this function never returns. The compiler has no way to * know this so do not assume that the compiler would remove * the dead code. * * @param[in] msg thread exit code * * @sclass */ void chThdExitS(msg_t msg) { thread_t *tp = currp; tp->p_u.exitcode = msg; #if defined(CH_CFG_THREAD_EXIT_HOOK) CH_CFG_THREAD_EXIT_HOOK(tp); #endif #if CH_CFG_USE_WAITEXIT while (list_notempty(&tp->p_waiting)) chSchReadyI(list_remove(&tp->p_waiting)); #endif #if CH_CFG_USE_REGISTRY /* Static threads are immediately removed from the registry because there is no memory to recover.*/ if ((tp->p_flags & CH_FLAG_MODE_MASK) == CH_FLAG_MODE_STATIC) REG_REMOVE(tp); #endif chSchGoSleepS(CH_STATE_FINAL); /* The thread never returns here.*/ chDbgAssert(false, "zombies apocalypse"); } #if CH_CFG_USE_WAITEXIT || defined(__DOXYGEN__) /** * @brief Blocks the execution of the invoking thread until the specified * thread terminates then the exit code is returned. * @details This function waits for the specified thread to terminate then * decrements its reference counter, if the counter reaches zero then * the thread working area is returned to the proper allocator.
* The memory used by the exited thread is handled in different ways * depending on the API that spawned the thread: * - If the thread was spawned by @p chThdCreateStatic() or by * @p chThdCreateI() then nothing happens and the thread working * area is not released or modified in any way. This is the * default, totally static, behavior. * - If the thread was spawned by @p chThdCreateFromHeap() then * the working area is returned to the system heap. * - If the thread was spawned by @p chThdCreateFromMemoryPool() * then the working area is returned to the owning memory pool. * . * @pre The configuration option @p CH_CFG_USE_WAITEXIT must be enabled in * order to use this function. * @post Enabling @p chThdWait() requires 2-4 (depending on the * architecture) extra bytes in the @p thread_t structure. * @post After invoking @p chThdWait() the thread pointer becomes invalid * and must not be used as parameter for further system calls. * @note If @p CH_CFG_USE_DYNAMIC is not specified this function just waits for * the thread termination, no memory allocators are involved. * * @param[in] tp pointer to the thread * @return The exit code from the terminated thread. * * @api */ msg_t chThdWait(thread_t *tp) { msg_t msg; chDbgCheck(tp != NULL); chSysLock(); chDbgAssert(tp != currp, "waiting self"); #if CH_CFG_USE_DYNAMIC chDbgAssert(tp->p_refs > 0, "not referenced"); #endif if (tp->p_state != CH_STATE_FINAL) { list_insert(currp, &tp->p_waiting); chSchGoSleepS(CH_STATE_WTEXIT); } msg = tp->p_u.exitcode; chSysUnlock(); #if CH_CFG_USE_DYNAMIC chThdRelease(tp); #endif return msg; } #endif /* CH_CFG_USE_WAITEXIT */ /** * @brief Sends the current thread sleeping and sets a reference variable. * @note This function must reschedule, it can only be called from thread * context. * * @param[in] trp a pointer to a thread reference object * @return The wake up message. * * @sclass */ msg_t chThdSuspendS(thread_reference_t *trp) { thread_t *tp = chThdGetSelfX(); chDbgAssert(*trp == NULL, "not NULL"); *trp = tp; tp->p_u.wtobjp = &trp; chSchGoSleepS(CH_STATE_SUSPENDED); return chThdGetSelfX()->p_u.rdymsg; } /** * @brief Sends the current thread sleeping and sets a reference variable. * @note This function must reschedule, it can only be called from thread * context. * * @param[in] trp a pointer to a thread reference object * @param[in] timeout the timeout in system ticks, the special values are * handled as follow: * - @a TIME_INFINITE the thread enters an infinite sleep * state. * - @a TIME_IMMEDIATE the thread is not enqueued and * the function returns @p MSG_TIMEOUT as if a timeout * occurred. * . * @return The wake up message. * @retval MSG_TIMEOUT if the operation timed out. * * @sclass */ msg_t chThdSuspendTimeoutS(thread_reference_t *trp, systime_t timeout) { thread_t *tp = chThdGetSelfX(); chDbgAssert(*trp == NULL, "not NULL"); if (TIME_IMMEDIATE == timeout) return MSG_TIMEOUT; *trp = tp; tp->p_u.wtobjp = &trp; return chSchGoSleepTimeoutS(CH_STATE_SUSPENDED, timeout); } /** * @brief Wakes up a thread waiting on a thread reference object. * @note This function must not reschedule because it can be called from * ISR context. * * @param[in] trp a pointer to a thread reference object * @param[in] msg the message code * * @iclass */ void chThdResumeI(thread_reference_t *trp, msg_t msg) { if (*trp != NULL) { thread_t *tp = *trp; chDbgAssert(tp->p_state == CH_STATE_SUSPENDED, "not THD_STATE_SUSPENDED"); *trp = NULL; tp->p_u.rdymsg = msg; chSchReadyI(tp); } } /** * @brief Wakes up a thread waiting on a thread reference object. * @note This function must reschedule, it can only be called from thread * context. * * @param[in] trp a pointer to a thread reference object * @param[in] msg the message code * * @iclass */ void chThdResumeS(thread_reference_t *trp, msg_t msg) { if (*trp != NULL) { thread_t *tp = *trp; chDbgAssert(tp->p_state == CH_STATE_SUSPENDED, "not THD_STATE_SUSPENDED"); *trp = NULL; chSchWakeupS(tp, msg); } } /** * @brief Wakes up a thread waiting on a thread reference object. * @note This function must reschedule, it can only be called from thread * context. * * @param[in] trp a pointer to a thread reference object * @param[in] msg the message code * * @api */ void chThdResume(thread_reference_t *trp, msg_t msg) { chSysLock(); chThdResumeS(trp, msg); chSysUnlock(); } /** * @brief Enqueues the caller thread on a threads queue object. * @details The caller thread is enqueued and put to sleep until it is * dequeued or the specified timeouts expires. * * @param[in] tqp pointer to the threads queue object * @param[in] timeout the timeout in system ticks, the special values are * handled as follow: * - @a TIME_INFINITE the thread enters an infinite sleep * state. * - @a TIME_IMMEDIATE the thread is not enqueued and * the function returns @p MSG_TIMEOUT as if a timeout * occurred. * . * @return The message from @p osalQueueWakeupOneI() or * @p osalQueueWakeupAllI() functions. * @retval MSG_TIMEOUT if the thread has not been dequeued within the * specified timeout or if the function has been * invoked with @p TIME_IMMEDIATE as timeout * specification. * * @sclass */ msg_t chThdEnqueueTimeoutS(threads_queue_t *tqp, systime_t timeout) { if (TIME_IMMEDIATE == timeout) return MSG_TIMEOUT; queue_insert(currp, tqp); return chSchGoSleepTimeoutS(CH_STATE_QUEUED, timeout); } /** * @brief Dequeues and wakes up one thread from the threads queue object, * if any. * * @param[in] tqp pointer to the threads queue object * @param[in] msg the message code * * @iclass */ void chThdDequeueNextI(threads_queue_t *tqp, msg_t msg) { if (queue_notempty(tqp)) chThdDoDequeueNextI(tqp, msg); } /** * @brief Dequeues and wakes up all threads from the threads queue object. * * @param[in] tqp pointer to the threads queue object * @param[in] msg the message code * * @iclass */ void chThdDequeueAllI(threads_queue_t *tqp, msg_t msg) { while (queue_notempty(tqp)) chThdDoDequeueNextI(tqp, msg); } /** @} */ > 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395