kern_kthread.c revision 230984
1139804Simp/*- 248391Speter * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org> 348391Speter * All rights reserved. 448391Speter * 548391Speter * Redistribution and use in source and binary forms, with or without 648391Speter * modification, are permitted provided that the following conditions 748391Speter * are met: 848391Speter * 1. Redistributions of source code must retain the above copyright 948391Speter * notice, this list of conditions and the following disclaimer. 1048391Speter * 2. Redistributions in binary form must reproduce the above copyright 1148391Speter * notice, this list of conditions and the following disclaimer in the 1248391Speter * documentation and/or other materials provided with the distribution. 1348391Speter * 1448391Speter * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1548391Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1648391Speter * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1748391Speter * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1848391Speter * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1948391Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2048391Speter * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2148391Speter * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2248391Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2348391Speter * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2448391Speter * SUCH DAMAGE. 2548391Speter */ 2648391Speter 27116182Sobrien#include <sys/cdefs.h> 28116182Sobrien__FBSDID("$FreeBSD: head/sys/kern/kern_kthread.c 230984 2012-02-04 16:49:29Z rstone $"); 29116182Sobrien 3048391Speter#include <sys/param.h> 3148391Speter#include <sys/systm.h> 32230984Srstone#include <sys/cpuset.h> 3348391Speter#include <sys/kthread.h> 3470317Sjake#include <sys/lock.h> 3574927Sjhb#include <sys/mutex.h> 3674927Sjhb#include <sys/proc.h> 3755722Simp#include <sys/resourcevar.h> 38214238Sdavidxu#include <sys/rwlock.h> 3955539Sluoqi#include <sys/signalvar.h> 4074927Sjhb#include <sys/sx.h> 4148391Speter#include <sys/unistd.h> 4248391Speter#include <sys/wait.h> 43166188Sjeff#include <sys/sched.h> 44173004Sjulian#include <vm/vm.h> 45173004Sjulian#include <vm/vm_extern.h> 4648391Speter 4748391Speter#include <machine/stdarg.h> 4848391Speter 4948391Speter/* 5048391Speter * Start a kernel process. This is called after a fork() call in 5148391Speter * mi_startup() in the file kern/init_main.c. 5248391Speter * 5348391Speter * This function is used to start "internal" daemons and intended 5448391Speter * to be called from SYSINIT(). 5548391Speter */ 5648391Spetervoid 5748391Speterkproc_start(udata) 5848391Speter const void *udata; 5948391Speter{ 6048391Speter const struct kproc_desc *kp = udata; 6148391Speter int error; 6248391Speter 63172836Sjulian error = kproc_create((void (*)(void *))kp->func, NULL, 64104354Sscottl kp->global_procpp, 0, 0, "%s", kp->arg0); 6548391Speter if (error) 6648391Speter panic("kproc_start: %s: error %d", kp->arg0, error); 6748391Speter} 6848391Speter 6948391Speter/* 7065557Sjasone * Create a kernel process/thread/whatever. It shares its address space 7148391Speter * with proc0 - ie: kernel only. 7265557Sjasone * 7365557Sjasone * func is the function to start. 7465557Sjasone * arg is the parameter to pass to function on first startup. 7565557Sjasone * newpp is the return value pointing to the thread's struct proc. 7665557Sjasone * flags are flags to fork1 (in unistd.h) 7765557Sjasone * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 7848391Speter */ 7948391Speterint 80172836Sjuliankproc_create(void (*func)(void *), void *arg, 81104354Sscottl struct proc **newpp, int flags, int pages, const char *fmt, ...) 8248391Speter{ 8348391Speter int error; 8448391Speter va_list ap; 85103216Sjulian struct thread *td; 8648391Speter struct proc *p2; 8748391Speter 88114434Sdes if (!proc0.p_stats) 89172836Sjulian panic("kproc_create called too soon"); 9065557Sjasone 9190375Speter error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 92224987Sjonathan pages, &p2, NULL, 0); 9348391Speter if (error) 9448391Speter return error; 9548391Speter 9648391Speter /* save a global descriptor, if desired */ 9748391Speter if (newpp != NULL) 9848391Speter *newpp = p2; 9948391Speter 10048391Speter /* this is a non-swapped system process */ 10171559Sjhb PROC_LOCK(p2); 102173004Sjulian td = FIRST_THREAD_IN_PROC(p2); 10371559Sjhb p2->p_flag |= P_SYSTEM | P_KTHREAD; 104173004Sjulian td->td_pflags |= TDP_KTHREAD; 105114983Sjhb mtx_lock(&p2->p_sigacts->ps_mtx); 106114983Sjhb p2->p_sigacts->ps_flag |= PS_NOCLDWAIT; 107114983Sjhb mtx_unlock(&p2->p_sigacts->ps_mtx); 10871559Sjhb PROC_UNLOCK(p2); 10948391Speter 11048391Speter /* set up arg0 for 'ps', et al */ 11148391Speter va_start(ap, fmt); 11248391Speter vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 11348391Speter va_end(ap); 114173004Sjulian /* set up arg0 for 'ps', et al */ 115173004Sjulian va_start(ap, fmt); 116173004Sjulian vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 117173004Sjulian va_end(ap); 11848391Speter 11948391Speter /* call the processes' main()... */ 120103216Sjulian cpu_set_fork_handler(td, func, arg); 121230984Srstone 122230984Srstone /* Avoid inheriting affinity from a random parent. */ 123230984Srstone cpuset_setthread(td->td_tid, cpuset_root); 124217079Sjhb thread_lock(td); 125103216Sjulian TD_SET_CAN_RUN(td); 126217079Sjhb sched_prio(td, PVM); 127217079Sjhb sched_user_prio(td, PUSER); 12848391Speter 12969657Sjhb /* Delay putting it on the run queue until now. */ 130217079Sjhb if (!(flags & RFSTOPPED)) 131166188Sjeff sched_add(td, SRQ_BORING); 132217079Sjhb thread_unlock(td); 13369657Sjhb 13448391Speter return 0; 13548391Speter} 13648391Speter 13748391Spetervoid 138172836Sjuliankproc_exit(int ecode) 13948391Speter{ 14086293Speter struct thread *td; 14186293Speter struct proc *p; 14270317Sjake 14386293Speter td = curthread; 14486293Speter p = td->td_proc; 145155400Sjhb 146155400Sjhb /* 147155400Sjhb * Reparent curthread from proc0 to init so that the zombie 148155400Sjhb * is harvested. 149155400Sjhb */ 15074927Sjhb sx_xlock(&proctree_lock); 15186292Sdillon PROC_LOCK(p); 15286292Sdillon proc_reparent(p, initproc); 15386292Sdillon PROC_UNLOCK(p); 15474927Sjhb sx_xunlock(&proctree_lock); 155155400Sjhb 156155400Sjhb /* 157155400Sjhb * Wakeup anyone waiting for us to exit. 158155400Sjhb */ 159155400Sjhb wakeup(p); 160155400Sjhb 161155400Sjhb /* Buh-bye! */ 16286293Speter exit1(td, W_EXITCODE(ecode, 0)); 16348391Speter} 16448391Speter 16555539Sluoqi/* 16655539Sluoqi * Advise a kernel process to suspend (or resume) in its main loop. 16755539Sluoqi * Participation is voluntary. 16855539Sluoqi */ 16955539Sluoqiint 170172836Sjuliankproc_suspend(struct proc *p, int timo) 17155539Sluoqi{ 17255539Sluoqi /* 17355539Sluoqi * Make sure this is indeed a system process and we can safely 174104306Sjmallett * use the p_siglist field. 17555539Sluoqi */ 17673911Sjhb PROC_LOCK(p); 17773911Sjhb if ((p->p_flag & P_KTHREAD) == 0) { 17873911Sjhb PROC_UNLOCK(p); 17955539Sluoqi return (EINVAL); 18073911Sjhb } 181104306Sjmallett SIGADDSET(p->p_siglist, SIGSTOP); 18288160Speter wakeup(p); 183173004Sjulian return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 18455539Sluoqi} 18555539Sluoqi 18655539Sluoqiint 187172836Sjuliankproc_resume(struct proc *p) 18855539Sluoqi{ 18955539Sluoqi /* 19055539Sluoqi * Make sure this is indeed a system process and we can safely 19155539Sluoqi * use the p_siglist field. 19255539Sluoqi */ 19373911Sjhb PROC_LOCK(p); 19473911Sjhb if ((p->p_flag & P_KTHREAD) == 0) { 19573911Sjhb PROC_UNLOCK(p); 19655539Sluoqi return (EINVAL); 19773911Sjhb } 198104306Sjmallett SIGDELSET(p->p_siglist, SIGSTOP); 19973911Sjhb PROC_UNLOCK(p); 200104306Sjmallett wakeup(&p->p_siglist); 20155539Sluoqi return (0); 20255539Sluoqi} 20355539Sluoqi 20455539Sluoqivoid 205172836Sjuliankproc_suspend_check(struct proc *p) 20655539Sluoqi{ 20773911Sjhb PROC_LOCK(p); 208104306Sjmallett while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 209104306Sjmallett wakeup(&p->p_siglist); 210173004Sjulian msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 21155539Sluoqi } 21273911Sjhb PROC_UNLOCK(p); 21355539Sluoqi} 214173004Sjulian 215173004Sjulian 216173004Sjulian/* 217173004Sjulian * Start a kernel thread. 218173004Sjulian * 219173004Sjulian * This function is used to start "internal" daemons and intended 220173004Sjulian * to be called from SYSINIT(). 221173004Sjulian */ 222173004Sjulian 223173004Sjulianvoid 224173004Sjuliankthread_start(udata) 225173004Sjulian const void *udata; 226173004Sjulian{ 227173004Sjulian const struct kthread_desc *kp = udata; 228173004Sjulian int error; 229173004Sjulian 230173004Sjulian error = kthread_add((void (*)(void *))kp->func, NULL, 231173004Sjulian NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 232173004Sjulian if (error) 233173004Sjulian panic("kthread_start: %s: error %d", kp->arg0, error); 234173004Sjulian} 235173004Sjulian 236173004Sjulian/* 237173004Sjulian * Create a kernel thread. It shares its address space 238173004Sjulian * with proc0 - ie: kernel only. 239173004Sjulian * 240173004Sjulian * func is the function to start. 241173004Sjulian * arg is the parameter to pass to function on first startup. 242173004Sjulian * newtdp is the return value pointing to the thread's struct thread. 243173004Sjulian * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 244173004Sjulian * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 245173004Sjulian */ 246173004Sjulianint 247173004Sjuliankthread_add(void (*func)(void *), void *arg, struct proc *p, 248173004Sjulian struct thread **newtdp, int flags, int pages, const char *fmt, ...) 249173004Sjulian{ 250173004Sjulian va_list ap; 251173004Sjulian struct thread *newtd, *oldtd; 252173004Sjulian 253173004Sjulian if (!proc0.p_stats) 254173004Sjulian panic("kthread_add called too soon"); 255173004Sjulian 256173052Sjulian /* If no process supplied, put it on proc0 */ 257173004Sjulian if (p == NULL) { 258173004Sjulian p = &proc0; 259173004Sjulian oldtd = &thread0; 260173004Sjulian } else { 261173052Sjulian oldtd = FIRST_THREAD_IN_PROC(p); 262173004Sjulian } 263173004Sjulian 264173052Sjulian /* Initialize our new td */ 265196730Skib newtd = thread_alloc(pages); 266173004Sjulian if (newtd == NULL) 267173004Sjulian return (ENOMEM); 268173004Sjulian 269173004Sjulian bzero(&newtd->td_startzero, 270173004Sjulian __rangeof(struct thread, td_startzero, td_endzero)); 271173004Sjulian/* XXX check if we should zero. */ 272173004Sjulian bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 273173004Sjulian __rangeof(struct thread, td_startcopy, td_endcopy)); 274173004Sjulian 275173004Sjulian /* set up arg0 for 'ps', et al */ 276173004Sjulian va_start(ap, fmt); 277173004Sjulian vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap); 278173004Sjulian va_end(ap); 279173004Sjulian 280173004Sjulian newtd->td_proc = p; /* needed for cpu_set_upcall */ 281173004Sjulian 282173004Sjulian /* XXX optimise this probably? */ 283173004Sjulian /* On x86 (and probably the others too) it is way too full of junk */ 284173004Sjulian /* Needs a better name */ 285173004Sjulian cpu_set_upcall(newtd, oldtd); 286173004Sjulian /* put the designated function(arg) as the resume context */ 287173004Sjulian cpu_set_fork_handler(newtd, func, arg); 288173004Sjulian 289173004Sjulian newtd->td_pflags |= TDP_KTHREAD; 290173004Sjulian newtd->td_ucred = crhold(p->p_ucred); 291173004Sjulian 292173004Sjulian /* this code almost the same as create_thread() in kern_thr.c */ 293173004Sjulian PROC_LOCK(p); 294173004Sjulian p->p_flag |= P_HADTHREADS; 295173004Sjulian newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */ 296173004Sjulian thread_link(newtd, p); 297173004Sjulian thread_lock(oldtd); 298173004Sjulian /* let the scheduler know about these things. */ 299173004Sjulian sched_fork_thread(oldtd, newtd); 300173004Sjulian TD_SET_CAN_RUN(newtd); 301173004Sjulian thread_unlock(oldtd); 302173004Sjulian PROC_UNLOCK(p); 303173004Sjulian 304213642Sdavidxu tidhash_add(newtd); 305173004Sjulian 306230984Srstone /* Avoid inheriting affinity from a random parent. */ 307230984Srstone cpuset_setthread(newtd->td_tid, cpuset_root); 308230984Srstone 309173004Sjulian /* Delay putting it on the run queue until now. */ 310173004Sjulian if (!(flags & RFSTOPPED)) { 311173004Sjulian thread_lock(newtd); 312173004Sjulian sched_add(newtd, SRQ_BORING); 313173004Sjulian thread_unlock(newtd); 314173004Sjulian } 315173004Sjulian if (newtdp) 316173004Sjulian *newtdp = newtd; 317173004Sjulian return 0; 318173004Sjulian} 319173004Sjulian 320173004Sjulianvoid 321173031Sjuliankthread_exit(void) 322173004Sjulian{ 323173658Sjhb struct proc *p; 324173658Sjhb 325204087Sattilio p = curthread->td_proc; 326204087Sattilio 327173658Sjhb /* A module may be waiting for us to exit. */ 328173052Sjulian wakeup(curthread); 329216921Sjhb 330216921Sjhb /* 331216921Sjhb * The last exiting thread in a kernel process must tear down 332216921Sjhb * the whole process. 333216921Sjhb */ 334214238Sdavidxu rw_wlock(&tidhash_lock); 335204087Sattilio PROC_LOCK(p); 336204089Sattilio if (p->p_numthreads == 1) { 337204087Sattilio PROC_UNLOCK(p); 338214238Sdavidxu rw_wunlock(&tidhash_lock); 339204087Sattilio kproc_exit(0); 340204087Sattilio } 341214238Sdavidxu LIST_REMOVE(curthread, td_hash); 342214238Sdavidxu rw_wunlock(&tidhash_lock); 343173658Sjhb PROC_SLOCK(p); 344173004Sjulian thread_exit(); 345173004Sjulian} 346173004Sjulian 347173004Sjulian/* 348173004Sjulian * Advise a kernel process to suspend (or resume) in its main loop. 349173004Sjulian * Participation is voluntary. 350173004Sjulian */ 351173004Sjulianint 352173004Sjuliankthread_suspend(struct thread *td, int timo) 353173004Sjulian{ 354202933Sattilio struct proc *p; 355202933Sattilio 356202933Sattilio p = td->td_proc; 357202933Sattilio 358202933Sattilio /* 359204088Sattilio * td_pflags should not be read by any thread other than 360202933Sattilio * curthread, but as long as this flag is invariant during the 361204088Sattilio * thread's lifetime, it is OK to check its state. 362202933Sattilio */ 363202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 364173004Sjulian return (EINVAL); 365202933Sattilio 366202933Sattilio /* 367202933Sattilio * The caller of the primitive should have already checked that the 368202933Sattilio * thread is up and running, thus not being blocked by other 369202933Sattilio * conditions. 370202933Sattilio */ 371202933Sattilio PROC_LOCK(p); 372173004Sjulian thread_lock(td); 373173004Sjulian td->td_flags |= TDF_KTH_SUSP; 374173004Sjulian thread_unlock(td); 375202933Sattilio return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 376202933Sattilio timo)); 377173004Sjulian} 378173004Sjulian 379173004Sjulian/* 380202933Sattilio * Resume a thread previously put asleep with kthread_suspend(). 381173004Sjulian */ 382173004Sjulianint 383173004Sjuliankthread_resume(struct thread *td) 384173004Sjulian{ 385202933Sattilio struct proc *p; 386202933Sattilio 387202933Sattilio p = td->td_proc; 388202933Sattilio 389202933Sattilio /* 390204088Sattilio * td_pflags should not be read by any thread other than 391202933Sattilio * curthread, but as long as this flag is invariant during the 392204088Sattilio * thread's lifetime, it is OK to check its state. 393202933Sattilio */ 394202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 395173004Sjulian return (EINVAL); 396202933Sattilio 397202933Sattilio PROC_LOCK(p); 398173004Sjulian thread_lock(td); 399173004Sjulian td->td_flags &= ~TDF_KTH_SUSP; 400173004Sjulian thread_unlock(td); 401202933Sattilio wakeup(&td->td_flags); 402202933Sattilio PROC_UNLOCK(p); 403173004Sjulian return (0); 404173004Sjulian} 405173004Sjulian 406173004Sjulian/* 407173004Sjulian * Used by the thread to poll as to whether it should yield/sleep 408173004Sjulian * and notify the caller that is has happened. 409173004Sjulian */ 410173004Sjulianvoid 411202933Sattiliokthread_suspend_check() 412173004Sjulian{ 413202933Sattilio struct proc *p; 414202933Sattilio struct thread *td; 415202933Sattilio 416202933Sattilio td = curthread; 417202933Sattilio p = td->td_proc; 418202933Sattilio 419202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 420202933Sattilio panic("%s: curthread is not a valid kthread", __func__); 421202933Sattilio 422202933Sattilio /* 423202933Sattilio * As long as the double-lock protection is used when accessing the 424202933Sattilio * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex 425202933Sattilio * is fine. 426202933Sattilio */ 427202933Sattilio PROC_LOCK(p); 428173004Sjulian while (td->td_flags & TDF_KTH_SUSP) { 429173004Sjulian wakeup(&td->td_flags); 430202933Sattilio msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 431173004Sjulian } 432202933Sattilio PROC_UNLOCK(p); 433173004Sjulian} 434173004Sjulian 435173004Sjulianint 436173004Sjuliankproc_kthread_add(void (*func)(void *), void *arg, 437173004Sjulian struct proc **procptr, struct thread **tdptr, 438208390Sjhb int flags, int pages, const char *procname, const char *fmt, ...) 439173004Sjulian{ 440173004Sjulian int error; 441173004Sjulian va_list ap; 442173004Sjulian char buf[100]; 443173004Sjulian struct thread *td; 444173004Sjulian 445173004Sjulian if (*procptr == 0) { 446173004Sjulian error = kproc_create(func, arg, 447173004Sjulian procptr, flags, pages, "%s", procname); 448173004Sjulian if (error) 449173004Sjulian return (error); 450173004Sjulian td = FIRST_THREAD_IN_PROC(*procptr); 451178682Sjulian if (tdptr) 452178682Sjulian *tdptr = td; 453173004Sjulian va_start(ap, fmt); 454173004Sjulian vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 455173004Sjulian va_end(ap); 456173004Sjulian return (0); 457173004Sjulian } 458173004Sjulian va_start(ap, fmt); 459173004Sjulian vsnprintf(buf, sizeof(buf), fmt, ap); 460173004Sjulian va_end(ap); 461173004Sjulian error = kthread_add(func, arg, *procptr, 462173004Sjulian tdptr, flags, pages, "%s", buf); 463173004Sjulian return (error); 464173004Sjulian} 465