thr_create.c revision 174112
1/* 2 * Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com> 3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the author nor the names of any co-contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD: head/lib/libkse/thread/thr_create.c 174112 2007-11-30 17:20:29Z deischen $ 31 */ 32 33#include "namespace.h" 34#include <errno.h> 35#include <stdlib.h> 36#include <string.h> 37#include <fcntl.h> 38#include <unistd.h> 39#include <stddef.h> 40#include <sys/time.h> 41#include <machine/reg.h> 42#include <pthread.h> 43#include "un-namespace.h" 44#include "thr_private.h" 45#include "libc_private.h" 46 47LT10_COMPAT_PRIVATE(_pthread_create); 48LT10_COMPAT_DEFAULT(pthread_create); 49 50static void free_thread(struct pthread *curthread, struct pthread *thread); 51static int create_stack(struct pthread_attr *pattr); 52static void free_stack(struct pthread_attr *pattr); 53static void thread_start(struct pthread *curthread, 54 void *(*start_routine) (void *), void *arg); 55 56__weak_reference(_pthread_create, pthread_create); 57 58/* 59 * Some notes on new thread creation and first time initializion 60 * to enable multi-threading. 61 * 62 * There are basically two things that need to be done. 63 * 64 * 1) The internal library variables must be initialized. 65 * 2) Upcalls need to be enabled to allow multiple threads 66 * to be run. 67 * 68 * The first may be done as a result of other pthread functions 69 * being called. When _thr_initial is null, _libpthread_init is 70 * called to initialize the internal variables; this also creates 71 * or sets the initial thread. It'd be nice to automatically 72 * have _libpthread_init called on program execution so we don't 73 * have to have checks throughout the library. 74 * 75 * The second part is only triggered by the creation of the first 76 * thread (other than the initial/main thread). If the thread 77 * being created is a scope system thread, then a new KSE/KSEG 78 * pair needs to be allocated. Also, if upcalls haven't been 79 * enabled on the initial thread's KSE, they must be now that 80 * there is more than one thread; this could be delayed until 81 * the initial KSEG has more than one thread. 82 */ 83int 84_pthread_create(pthread_t * thread, const pthread_attr_t * attr, 85 void *(*start_routine) (void *), void *arg) 86{ 87 struct pthread *curthread, *new_thread; 88 struct kse *kse = NULL; 89 struct kse_group *kseg = NULL; 90 kse_critical_t crit; 91 int ret = 0; 92 93 if (_thr_initial == NULL) 94 _libpthread_init(NULL); 95 96 /* 97 * Turn on threaded mode, if failed, it is unnecessary to 98 * do further work. 99 */ 100 if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) { 101 return (EAGAIN); 102 } 103 curthread = _get_curthread(); 104 105 /* 106 * Allocate memory for the thread structure. 107 * Some functions use malloc, so don't put it 108 * in a critical region. 109 */ 110 if ((new_thread = _thr_alloc(curthread)) == NULL) { 111 /* Insufficient memory to create a thread: */ 112 ret = EAGAIN; 113 } else { 114 /* Check if default thread attributes are required: */ 115 if (attr == NULL || *attr == NULL) 116 /* Use the default thread attributes: */ 117 new_thread->attr = _pthread_attr_default; 118 else { 119 new_thread->attr = *(*attr); 120 if ((*attr)->sched_inherit == PTHREAD_INHERIT_SCHED) { 121 /* inherit scheduling contention scop */ 122 if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) 123 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM; 124 else 125 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM; 126 /* 127 * scheduling policy and scheduling parameters will be 128 * inherited in following code. 129 */ 130 } 131 } 132 if (_thread_scope_system > 0) 133 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM; 134 else if ((_thread_scope_system < 0) 135 && (thread != &_thr_sig_daemon)) 136 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM; 137 if (create_stack(&new_thread->attr) != 0) { 138 /* Insufficient memory to create a stack: */ 139 ret = EAGAIN; 140 _thr_free(curthread, new_thread); 141 } 142 else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) && 143 (((kse = _kse_alloc(curthread, 1)) == NULL) 144 || ((kseg = _kseg_alloc(curthread)) == NULL))) { 145 /* Insufficient memory to create a new KSE/KSEG: */ 146 ret = EAGAIN; 147 if (kse != NULL) { 148 kse->k_kcb->kcb_kmbx.km_flags |= KMF_DONE; 149 _kse_free(curthread, kse); 150 } 151 free_stack(&new_thread->attr); 152 _thr_free(curthread, new_thread); 153 } 154 else { 155 if (kseg != NULL) { 156 /* Add the KSE to the KSEG's list of KSEs. */ 157 TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_kgqe); 158 kseg->kg_ksecount = 1; 159 kse->k_kseg = kseg; 160 kse->k_schedq = &kseg->kg_schedq; 161 } 162 /* 163 * Write a magic value to the thread structure 164 * to help identify valid ones: 165 */ 166 new_thread->magic = THR_MAGIC; 167 168 new_thread->slice_usec = -1; 169 new_thread->start_routine = start_routine; 170 new_thread->arg = arg; 171 new_thread->cancelflags = PTHREAD_CANCEL_ENABLE | 172 PTHREAD_CANCEL_DEFERRED; 173 174 /* No thread is wanting to join to this one: */ 175 new_thread->joiner = NULL; 176 177 /* 178 * Initialize the machine context. 179 * Enter a critical region to get consistent context. 180 */ 181 crit = _kse_critical_enter(); 182 THR_GETCONTEXT(&new_thread->tcb->tcb_tmbx.tm_context); 183 /* Initialize the thread for signals: */ 184 new_thread->sigmask = curthread->sigmask; 185 _kse_critical_leave(crit); 186 187 new_thread->tcb->tcb_tmbx.tm_udata = new_thread; 188 new_thread->tcb->tcb_tmbx.tm_context.uc_sigmask = 189 new_thread->sigmask; 190 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_size = 191 new_thread->attr.stacksize_attr; 192 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_sp = 193 new_thread->attr.stackaddr_attr; 194 makecontext(&new_thread->tcb->tcb_tmbx.tm_context, 195 (void (*)(void))thread_start, 3, new_thread, 196 start_routine, arg); 197 /* 198 * Check if this thread is to inherit the scheduling 199 * attributes from its parent: 200 */ 201 if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) { 202 /* 203 * Copy the scheduling attributes. 204 * Lock the scheduling lock to get consistent 205 * scheduling parameters. 206 */ 207 THR_SCHED_LOCK(curthread, curthread); 208 new_thread->base_priority = 209 curthread->base_priority & 210 ~THR_SIGNAL_PRIORITY; 211 new_thread->attr.prio = 212 curthread->base_priority & 213 ~THR_SIGNAL_PRIORITY; 214 new_thread->attr.sched_policy = 215 curthread->attr.sched_policy; 216 THR_SCHED_UNLOCK(curthread, curthread); 217 } else { 218 /* 219 * Use just the thread priority, leaving the 220 * other scheduling attributes as their 221 * default values: 222 */ 223 new_thread->base_priority = 224 new_thread->attr.prio; 225 } 226 new_thread->active_priority = new_thread->base_priority; 227 new_thread->inherited_priority = 0; 228 229 /* Initialize the mutex queue: */ 230 TAILQ_INIT(&new_thread->mutexq); 231 232 /* Initialise hooks in the thread structure: */ 233 new_thread->specific = NULL; 234 new_thread->specific_data_count = 0; 235 new_thread->cleanup = NULL; 236 new_thread->flags = 0; 237 new_thread->tlflags = 0; 238 new_thread->sigbackout = NULL; 239 new_thread->continuation = NULL; 240 new_thread->wakeup_time.tv_sec = -1; 241 new_thread->lock_switch = 0; 242 sigemptyset(&new_thread->sigpend); 243 new_thread->check_pending = 0; 244 new_thread->locklevel = 0; 245 new_thread->rdlock_count = 0; 246 new_thread->sigstk.ss_sp = 0; 247 new_thread->sigstk.ss_size = 0; 248 new_thread->sigstk.ss_flags = SS_DISABLE; 249 new_thread->oldsigmask = NULL; 250 251 if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) { 252 new_thread->state = PS_SUSPENDED; 253 new_thread->flags = THR_FLAGS_SUSPENDED; 254 } 255 else 256 new_thread->state = PS_RUNNING; 257 258 /* 259 * System scope threads have their own kse and 260 * kseg. Process scope threads are all hung 261 * off the main process kseg. 262 */ 263 if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) { 264 new_thread->kseg = _kse_initial->k_kseg; 265 new_thread->kse = _kse_initial; 266 } 267 else { 268 kse->k_curthread = NULL; 269 kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD; 270 new_thread->kse = kse; 271 new_thread->kseg = kse->k_kseg; 272 kse->k_kcb->kcb_kmbx.km_udata = kse; 273 kse->k_kcb->kcb_kmbx.km_curthread = NULL; 274 } 275 276 /* 277 * Schedule the new thread starting a new KSEG/KSE 278 * pair if necessary. 279 */ 280 ret = _thr_schedule_add(curthread, new_thread); 281 if (ret != 0) 282 free_thread(curthread, new_thread); 283 else { 284 /* Return a pointer to the thread structure: */ 285 (*thread) = new_thread; 286 } 287 } 288 } 289 290 /* Return the status: */ 291 return (ret); 292} 293 294static void 295free_thread(struct pthread *curthread, struct pthread *thread) 296{ 297 free_stack(&thread->attr); 298 if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) { 299 /* Free the KSE and KSEG. */ 300 _kseg_free(thread->kseg); 301 _kse_free(curthread, thread->kse); 302 } 303 _thr_free(curthread, thread); 304} 305 306static int 307create_stack(struct pthread_attr *pattr) 308{ 309 int ret; 310 311 /* Check if a stack was specified in the thread attributes: */ 312 if ((pattr->stackaddr_attr) != NULL) { 313 pattr->guardsize_attr = 0; 314 pattr->flags |= THR_STACK_USER; 315 ret = 0; 316 } 317 else 318 ret = _thr_stack_alloc(pattr); 319 return (ret); 320} 321 322static void 323free_stack(struct pthread_attr *pattr) 324{ 325 struct kse *curkse; 326 kse_critical_t crit; 327 328 if ((pattr->flags & THR_STACK_USER) == 0) { 329 crit = _kse_critical_enter(); 330 curkse = _get_curkse(); 331 KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock); 332 /* Stack routines don't use malloc/free. */ 333 _thr_stack_free(pattr); 334 KSE_LOCK_RELEASE(curkse, &_thread_list_lock); 335 _kse_critical_leave(crit); 336 } 337} 338 339static void 340thread_start(struct pthread *curthread __unused, void *(*start_routine) (void *), 341 void *arg) 342{ 343 /* Run the current thread's start routine with argument: */ 344 _pthread_exit(start_routine(arg)); 345 346 /* This point should never be reached. */ 347 PANIC("Thread has resumed after exit"); 348} 349