kern_kthread.c revision 204089
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 204089 2010-02-19 15:10:05Z attilio $"); 29116182Sobrien 3048391Speter#include <sys/param.h> 3148391Speter#include <sys/systm.h> 3248391Speter#include <sys/kthread.h> 3370317Sjake#include <sys/lock.h> 3474927Sjhb#include <sys/mutex.h> 3574927Sjhb#include <sys/proc.h> 3655722Simp#include <sys/resourcevar.h> 3755539Sluoqi#include <sys/signalvar.h> 3874927Sjhb#include <sys/sx.h> 3948391Speter#include <sys/unistd.h> 4048391Speter#include <sys/wait.h> 41166188Sjeff#include <sys/sched.h> 42173004Sjulian#include <vm/vm.h> 43173004Sjulian#include <vm/vm_extern.h> 4448391Speter 4548391Speter#include <machine/stdarg.h> 4648391Speter 4748391Speter/* 4848391Speter * Start a kernel process. This is called after a fork() call in 4948391Speter * mi_startup() in the file kern/init_main.c. 5048391Speter * 5148391Speter * This function is used to start "internal" daemons and intended 5248391Speter * to be called from SYSINIT(). 5348391Speter */ 5448391Spetervoid 5548391Speterkproc_start(udata) 5648391Speter const void *udata; 5748391Speter{ 5848391Speter const struct kproc_desc *kp = udata; 5948391Speter int error; 6048391Speter 61172836Sjulian error = kproc_create((void (*)(void *))kp->func, NULL, 62104354Sscottl kp->global_procpp, 0, 0, "%s", kp->arg0); 6348391Speter if (error) 6448391Speter panic("kproc_start: %s: error %d", kp->arg0, error); 6548391Speter} 6648391Speter 6748391Speter/* 6865557Sjasone * Create a kernel process/thread/whatever. It shares its address space 6948391Speter * with proc0 - ie: kernel only. 7065557Sjasone * 7165557Sjasone * func is the function to start. 7265557Sjasone * arg is the parameter to pass to function on first startup. 7365557Sjasone * newpp is the return value pointing to the thread's struct proc. 7465557Sjasone * flags are flags to fork1 (in unistd.h) 7565557Sjasone * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.). 7648391Speter */ 7748391Speterint 78172836Sjuliankproc_create(void (*func)(void *), void *arg, 79104354Sscottl struct proc **newpp, int flags, int pages, const char *fmt, ...) 8048391Speter{ 8148391Speter int error; 8248391Speter va_list ap; 83103216Sjulian struct thread *td; 8448391Speter struct proc *p2; 8548391Speter 86114434Sdes if (!proc0.p_stats) 87172836Sjulian panic("kproc_create called too soon"); 8865557Sjasone 8990375Speter error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags, 90104354Sscottl pages, &p2); 9148391Speter if (error) 9248391Speter return error; 9348391Speter 9448391Speter /* save a global descriptor, if desired */ 9548391Speter if (newpp != NULL) 9648391Speter *newpp = p2; 9748391Speter 9848391Speter /* this is a non-swapped system process */ 9971559Sjhb PROC_LOCK(p2); 100173004Sjulian td = FIRST_THREAD_IN_PROC(p2); 10171559Sjhb p2->p_flag |= P_SYSTEM | P_KTHREAD; 102173004Sjulian td->td_pflags |= TDP_KTHREAD; 103114983Sjhb mtx_lock(&p2->p_sigacts->ps_mtx); 104114983Sjhb p2->p_sigacts->ps_flag |= PS_NOCLDWAIT; 105114983Sjhb mtx_unlock(&p2->p_sigacts->ps_mtx); 10671559Sjhb PROC_UNLOCK(p2); 10748391Speter 10848391Speter /* set up arg0 for 'ps', et al */ 10948391Speter va_start(ap, fmt); 11048391Speter vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap); 11148391Speter va_end(ap); 112173004Sjulian /* set up arg0 for 'ps', et al */ 113173004Sjulian va_start(ap, fmt); 114173004Sjulian vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 115173004Sjulian va_end(ap); 11648391Speter 11748391Speter /* call the processes' main()... */ 118103216Sjulian cpu_set_fork_handler(td, func, arg); 119103216Sjulian TD_SET_CAN_RUN(td); 12048391Speter 12169657Sjhb /* Delay putting it on the run queue until now. */ 12269657Sjhb if (!(flags & RFSTOPPED)) { 123170307Sjeff thread_lock(td); 124166188Sjeff sched_add(td, SRQ_BORING); 125170307Sjeff thread_unlock(td); 12669657Sjhb } 12769657Sjhb 12848391Speter return 0; 12948391Speter} 13048391Speter 13148391Spetervoid 132172836Sjuliankproc_exit(int ecode) 13348391Speter{ 13486293Speter struct thread *td; 13586293Speter struct proc *p; 13670317Sjake 13786293Speter td = curthread; 13886293Speter p = td->td_proc; 139155400Sjhb 140155400Sjhb /* 141155400Sjhb * Reparent curthread from proc0 to init so that the zombie 142155400Sjhb * is harvested. 143155400Sjhb */ 14474927Sjhb sx_xlock(&proctree_lock); 14586292Sdillon PROC_LOCK(p); 14686292Sdillon proc_reparent(p, initproc); 14786292Sdillon PROC_UNLOCK(p); 14874927Sjhb sx_xunlock(&proctree_lock); 149155400Sjhb 150155400Sjhb /* 151155400Sjhb * Wakeup anyone waiting for us to exit. 152155400Sjhb */ 153155400Sjhb wakeup(p); 154155400Sjhb 155155400Sjhb /* Buh-bye! */ 15686293Speter exit1(td, W_EXITCODE(ecode, 0)); 15748391Speter} 15848391Speter 15955539Sluoqi/* 16055539Sluoqi * Advise a kernel process to suspend (or resume) in its main loop. 16155539Sluoqi * Participation is voluntary. 16255539Sluoqi */ 16355539Sluoqiint 164172836Sjuliankproc_suspend(struct proc *p, int timo) 16555539Sluoqi{ 16655539Sluoqi /* 16755539Sluoqi * Make sure this is indeed a system process and we can safely 168104306Sjmallett * use the p_siglist field. 16955539Sluoqi */ 17073911Sjhb PROC_LOCK(p); 17173911Sjhb if ((p->p_flag & P_KTHREAD) == 0) { 17273911Sjhb PROC_UNLOCK(p); 17355539Sluoqi return (EINVAL); 17473911Sjhb } 175104306Sjmallett SIGADDSET(p->p_siglist, SIGSTOP); 17688160Speter wakeup(p); 177173004Sjulian return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo); 17855539Sluoqi} 17955539Sluoqi 18055539Sluoqiint 181172836Sjuliankproc_resume(struct proc *p) 18255539Sluoqi{ 18355539Sluoqi /* 18455539Sluoqi * Make sure this is indeed a system process and we can safely 18555539Sluoqi * use the p_siglist field. 18655539Sluoqi */ 18773911Sjhb PROC_LOCK(p); 18873911Sjhb if ((p->p_flag & P_KTHREAD) == 0) { 18973911Sjhb PROC_UNLOCK(p); 19055539Sluoqi return (EINVAL); 19173911Sjhb } 192104306Sjmallett SIGDELSET(p->p_siglist, SIGSTOP); 19373911Sjhb PROC_UNLOCK(p); 194104306Sjmallett wakeup(&p->p_siglist); 19555539Sluoqi return (0); 19655539Sluoqi} 19755539Sluoqi 19855539Sluoqivoid 199172836Sjuliankproc_suspend_check(struct proc *p) 20055539Sluoqi{ 20173911Sjhb PROC_LOCK(p); 202104306Sjmallett while (SIGISMEMBER(p->p_siglist, SIGSTOP)) { 203104306Sjmallett wakeup(&p->p_siglist); 204173004Sjulian msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0); 20555539Sluoqi } 20673911Sjhb PROC_UNLOCK(p); 20755539Sluoqi} 208173004Sjulian 209173004Sjulian 210173004Sjulian/* 211173004Sjulian * Start a kernel thread. 212173004Sjulian * 213173004Sjulian * This function is used to start "internal" daemons and intended 214173004Sjulian * to be called from SYSINIT(). 215173004Sjulian */ 216173004Sjulian 217173004Sjulianvoid 218173004Sjuliankthread_start(udata) 219173004Sjulian const void *udata; 220173004Sjulian{ 221173004Sjulian const struct kthread_desc *kp = udata; 222173004Sjulian int error; 223173004Sjulian 224173004Sjulian error = kthread_add((void (*)(void *))kp->func, NULL, 225173004Sjulian NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0); 226173004Sjulian if (error) 227173004Sjulian panic("kthread_start: %s: error %d", kp->arg0, error); 228173004Sjulian} 229173004Sjulian 230173004Sjulian/* 231173004Sjulian * Create a kernel thread. It shares its address space 232173004Sjulian * with proc0 - ie: kernel only. 233173004Sjulian * 234173004Sjulian * func is the function to start. 235173004Sjulian * arg is the parameter to pass to function on first startup. 236173004Sjulian * newtdp is the return value pointing to the thread's struct thread. 237173004Sjulian * ** XXX fix this --> flags are flags to fork1 (in unistd.h) 238173004Sjulian * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.). 239173004Sjulian */ 240173004Sjulianint 241173004Sjuliankthread_add(void (*func)(void *), void *arg, struct proc *p, 242173004Sjulian struct thread **newtdp, int flags, int pages, const char *fmt, ...) 243173004Sjulian{ 244173004Sjulian va_list ap; 245173004Sjulian struct thread *newtd, *oldtd; 246173004Sjulian 247173004Sjulian if (!proc0.p_stats) 248173004Sjulian panic("kthread_add called too soon"); 249173004Sjulian 250173052Sjulian /* If no process supplied, put it on proc0 */ 251173004Sjulian if (p == NULL) { 252173004Sjulian p = &proc0; 253173004Sjulian oldtd = &thread0; 254173004Sjulian } else { 255173052Sjulian oldtd = FIRST_THREAD_IN_PROC(p); 256173004Sjulian } 257173004Sjulian 258173052Sjulian /* Initialize our new td */ 259196730Skib newtd = thread_alloc(pages); 260173004Sjulian if (newtd == NULL) 261173004Sjulian return (ENOMEM); 262173004Sjulian 263173004Sjulian bzero(&newtd->td_startzero, 264173004Sjulian __rangeof(struct thread, td_startzero, td_endzero)); 265173004Sjulian/* XXX check if we should zero. */ 266173004Sjulian bcopy(&oldtd->td_startcopy, &newtd->td_startcopy, 267173004Sjulian __rangeof(struct thread, td_startcopy, td_endcopy)); 268173004Sjulian 269173004Sjulian /* set up arg0 for 'ps', et al */ 270173004Sjulian va_start(ap, fmt); 271173004Sjulian vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap); 272173004Sjulian va_end(ap); 273173004Sjulian 274173004Sjulian newtd->td_proc = p; /* needed for cpu_set_upcall */ 275173004Sjulian 276173004Sjulian /* XXX optimise this probably? */ 277173004Sjulian /* On x86 (and probably the others too) it is way too full of junk */ 278173004Sjulian /* Needs a better name */ 279173004Sjulian cpu_set_upcall(newtd, oldtd); 280173004Sjulian /* put the designated function(arg) as the resume context */ 281173004Sjulian cpu_set_fork_handler(newtd, func, arg); 282173004Sjulian 283173004Sjulian newtd->td_pflags |= TDP_KTHREAD; 284173004Sjulian newtd->td_ucred = crhold(p->p_ucred); 285173004Sjulian 286173004Sjulian /* this code almost the same as create_thread() in kern_thr.c */ 287173004Sjulian PROC_LOCK(p); 288173004Sjulian p->p_flag |= P_HADTHREADS; 289173004Sjulian newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */ 290173004Sjulian thread_link(newtd, p); 291173004Sjulian thread_lock(oldtd); 292173004Sjulian /* let the scheduler know about these things. */ 293173004Sjulian sched_fork_thread(oldtd, newtd); 294173004Sjulian TD_SET_CAN_RUN(newtd); 295173004Sjulian thread_unlock(oldtd); 296173004Sjulian PROC_UNLOCK(p); 297173004Sjulian 298173004Sjulian 299173004Sjulian /* Delay putting it on the run queue until now. */ 300173004Sjulian if (!(flags & RFSTOPPED)) { 301173004Sjulian thread_lock(newtd); 302173004Sjulian sched_add(newtd, SRQ_BORING); 303173004Sjulian thread_unlock(newtd); 304173004Sjulian } 305173004Sjulian if (newtdp) 306173004Sjulian *newtdp = newtd; 307173004Sjulian return 0; 308173004Sjulian} 309173004Sjulian 310173004Sjulianvoid 311173031Sjuliankthread_exit(void) 312173004Sjulian{ 313173658Sjhb struct proc *p; 314173658Sjhb 315204087Sattilio p = curthread->td_proc; 316204087Sattilio 317173658Sjhb /* A module may be waiting for us to exit. */ 318173052Sjulian wakeup(curthread); 319204087Sattilio PROC_LOCK(p); 320204089Sattilio if (p->p_numthreads == 1) { 321204087Sattilio PROC_UNLOCK(p); 322204087Sattilio kproc_exit(0); 323173658Sjhb 324204087Sattilio /* NOTREACHED. */ 325204087Sattilio } 326173658Sjhb PROC_SLOCK(p); 327173004Sjulian thread_exit(); 328173004Sjulian} 329173004Sjulian 330173004Sjulian/* 331173004Sjulian * Advise a kernel process to suspend (or resume) in its main loop. 332173004Sjulian * Participation is voluntary. 333173004Sjulian */ 334173004Sjulianint 335173004Sjuliankthread_suspend(struct thread *td, int timo) 336173004Sjulian{ 337202933Sattilio struct proc *p; 338202933Sattilio 339202933Sattilio p = td->td_proc; 340202933Sattilio 341202933Sattilio /* 342204088Sattilio * td_pflags should not be read by any thread other than 343202933Sattilio * curthread, but as long as this flag is invariant during the 344204088Sattilio * thread's lifetime, it is OK to check its state. 345202933Sattilio */ 346202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 347173004Sjulian return (EINVAL); 348202933Sattilio 349202933Sattilio /* 350202933Sattilio * The caller of the primitive should have already checked that the 351202933Sattilio * thread is up and running, thus not being blocked by other 352202933Sattilio * conditions. 353202933Sattilio */ 354202933Sattilio PROC_LOCK(p); 355173004Sjulian thread_lock(td); 356173004Sjulian td->td_flags |= TDF_KTH_SUSP; 357173004Sjulian thread_unlock(td); 358202933Sattilio return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt", 359202933Sattilio timo)); 360173004Sjulian} 361173004Sjulian 362173004Sjulian/* 363202933Sattilio * Resume a thread previously put asleep with kthread_suspend(). 364173004Sjulian */ 365173004Sjulianint 366173004Sjuliankthread_resume(struct thread *td) 367173004Sjulian{ 368202933Sattilio struct proc *p; 369202933Sattilio 370202933Sattilio p = td->td_proc; 371202933Sattilio 372202933Sattilio /* 373204088Sattilio * td_pflags should not be read by any thread other than 374202933Sattilio * curthread, but as long as this flag is invariant during the 375204088Sattilio * thread's lifetime, it is OK to check its state. 376202933Sattilio */ 377202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 378173004Sjulian return (EINVAL); 379202933Sattilio 380202933Sattilio PROC_LOCK(p); 381173004Sjulian thread_lock(td); 382173004Sjulian td->td_flags &= ~TDF_KTH_SUSP; 383173004Sjulian thread_unlock(td); 384202933Sattilio wakeup(&td->td_flags); 385202933Sattilio PROC_UNLOCK(p); 386173004Sjulian return (0); 387173004Sjulian} 388173004Sjulian 389173004Sjulian/* 390173004Sjulian * Used by the thread to poll as to whether it should yield/sleep 391173004Sjulian * and notify the caller that is has happened. 392173004Sjulian */ 393173004Sjulianvoid 394202933Sattiliokthread_suspend_check() 395173004Sjulian{ 396202933Sattilio struct proc *p; 397202933Sattilio struct thread *td; 398202933Sattilio 399202933Sattilio td = curthread; 400202933Sattilio p = td->td_proc; 401202933Sattilio 402202933Sattilio if ((td->td_pflags & TDP_KTHREAD) == 0) 403202933Sattilio panic("%s: curthread is not a valid kthread", __func__); 404202933Sattilio 405202933Sattilio /* 406202933Sattilio * As long as the double-lock protection is used when accessing the 407202933Sattilio * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex 408202933Sattilio * is fine. 409202933Sattilio */ 410202933Sattilio PROC_LOCK(p); 411173004Sjulian while (td->td_flags & TDF_KTH_SUSP) { 412173004Sjulian wakeup(&td->td_flags); 413202933Sattilio msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0); 414173004Sjulian } 415202933Sattilio PROC_UNLOCK(p); 416173004Sjulian} 417173004Sjulian 418173004Sjulianint 419173004Sjuliankproc_kthread_add(void (*func)(void *), void *arg, 420173004Sjulian struct proc **procptr, struct thread **tdptr, 421173004Sjulian int flags, int pages, char * procname, const char *fmt, ...) 422173004Sjulian{ 423173004Sjulian int error; 424173004Sjulian va_list ap; 425173004Sjulian char buf[100]; 426173004Sjulian struct thread *td; 427173004Sjulian 428173004Sjulian if (*procptr == 0) { 429173004Sjulian error = kproc_create(func, arg, 430173004Sjulian procptr, flags, pages, "%s", procname); 431173004Sjulian if (error) 432173004Sjulian return (error); 433173004Sjulian td = FIRST_THREAD_IN_PROC(*procptr); 434178682Sjulian if (tdptr) 435178682Sjulian *tdptr = td; 436173004Sjulian va_start(ap, fmt); 437173004Sjulian vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap); 438173004Sjulian va_end(ap); 439173004Sjulian return (0); 440173004Sjulian } 441173004Sjulian va_start(ap, fmt); 442173004Sjulian vsnprintf(buf, sizeof(buf), fmt, ap); 443173004Sjulian va_end(ap); 444173004Sjulian error = kthread_add(func, arg, *procptr, 445173004Sjulian tdptr, flags, pages, "%s", buf); 446173004Sjulian return (error); 447173004Sjulian} 448