1 /*-
2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/cpuset.h>
33 #include <sys/kthread.h>
34 #include <sys/lock.h>
35 #include <sys/mutex.h>
36 #include <sys/proc.h>
37 #include <sys/resourcevar.h>
38 #include <sys/rwlock.h>
39 #include <sys/signalvar.h>
40 #include <sys/sx.h>
41 #include <sys/umtx.h>
42 #include <sys/unistd.h>
43 #include <sys/wait.h>
44 #include <sys/sched.h>
45 #include <vm/vm.h>
46 #include <vm/vm_extern.h>
47
48 #include <machine/stdarg.h>
49
50 /*
51 * Start a kernel process. This is called after a fork() call in
52 * mi_startup() in the file kern/init_main.c.
53 *
54 * This function is used to start "internal" daemons and intended
55 * to be called from SYSINIT().
56 */
57 void
kproc_start(udata)58 kproc_start(udata)
59 const void *udata;
60 {
61 const struct kproc_desc *kp = udata;
62 int error;
63
64 error = kproc_create((void (*)(void *))kp->func, NULL,
65 kp->global_procpp, 0, 0, "%s", kp->arg0);
66 if (error)
67 panic("kproc_start: %s: error %d", kp->arg0, error);
68 }
69
70 /*
71 * Create a kernel process/thread/whatever. It shares its address space
72 * with proc0 - ie: kernel only.
73 *
74 * func is the function to start.
75 * arg is the parameter to pass to function on first startup.
76 * newpp is the return value pointing to the thread's struct proc.
77 * flags are flags to fork1 (in unistd.h)
78 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
79 */
80 int
kproc_create(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * fmt,...)81 kproc_create(void (*func)(void *), void *arg,
82 struct proc **newpp, int flags, int pages, const char *fmt, ...)
83 {
84 int error;
85 va_list ap;
86 struct thread *td;
87 struct proc *p2;
88
89 if (!proc0.p_stats)
90 panic("kproc_create called too soon");
91
92 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
93 pages, &p2, NULL, 0);
94 if (error)
95 return error;
96
97 /* save a global descriptor, if desired */
98 if (newpp != NULL)
99 *newpp = p2;
100
101 /* this is a non-swapped system process */
102 PROC_LOCK(p2);
103 td = FIRST_THREAD_IN_PROC(p2);
104 p2->p_flag |= P_SYSTEM | P_KTHREAD;
105 td->td_pflags |= TDP_KTHREAD;
106 mtx_lock(&p2->p_sigacts->ps_mtx);
107 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
108 mtx_unlock(&p2->p_sigacts->ps_mtx);
109 PROC_UNLOCK(p2);
110
111 /* set up arg0 for 'ps', et al */
112 va_start(ap, fmt);
113 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
114 va_end(ap);
115 /* set up arg0 for 'ps', et al */
116 va_start(ap, fmt);
117 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
118 va_end(ap);
119 #ifdef KTR
120 sched_clear_tdname(td);
121 #endif
122
123 /* call the processes' main()... */
124 cpu_set_fork_handler(td, func, arg);
125
126 /* Avoid inheriting affinity from a random parent. */
127 cpuset_setthread(td->td_tid, cpuset_root);
128 thread_lock(td);
129 TD_SET_CAN_RUN(td);
130 sched_prio(td, PVM);
131 sched_user_prio(td, PUSER);
132
133 /* Delay putting it on the run queue until now. */
134 if (!(flags & RFSTOPPED))
135 sched_add(td, SRQ_BORING);
136 thread_unlock(td);
137
138 return 0;
139 }
140
141 void
kproc_exit(int ecode)142 kproc_exit(int ecode)
143 {
144 struct thread *td;
145 struct proc *p;
146
147 td = curthread;
148 p = td->td_proc;
149
150 /*
151 * Reparent curthread from proc0 to init so that the zombie
152 * is harvested.
153 */
154 sx_xlock(&proctree_lock);
155 PROC_LOCK(p);
156 proc_reparent(p, initproc);
157 PROC_UNLOCK(p);
158 sx_xunlock(&proctree_lock);
159
160 /*
161 * Wakeup anyone waiting for us to exit.
162 */
163 wakeup(p);
164
165 /* Buh-bye! */
166 exit1(td, W_EXITCODE(ecode, 0));
167 }
168
169 /*
170 * Advise a kernel process to suspend (or resume) in its main loop.
171 * Participation is voluntary.
172 */
173 int
kproc_suspend(struct proc * p,int timo)174 kproc_suspend(struct proc *p, int timo)
175 {
176 /*
177 * Make sure this is indeed a system process and we can safely
178 * use the p_siglist field.
179 */
180 PROC_LOCK(p);
181 if ((p->p_flag & P_KTHREAD) == 0) {
182 PROC_UNLOCK(p);
183 return (EINVAL);
184 }
185 SIGADDSET(p->p_siglist, SIGSTOP);
186 wakeup(p);
187 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
188 }
189
190 int
kproc_resume(struct proc * p)191 kproc_resume(struct proc *p)
192 {
193 /*
194 * Make sure this is indeed a system process and we can safely
195 * use the p_siglist field.
196 */
197 PROC_LOCK(p);
198 if ((p->p_flag & P_KTHREAD) == 0) {
199 PROC_UNLOCK(p);
200 return (EINVAL);
201 }
202 SIGDELSET(p->p_siglist, SIGSTOP);
203 PROC_UNLOCK(p);
204 wakeup(&p->p_siglist);
205 return (0);
206 }
207
208 void
kproc_suspend_check(struct proc * p)209 kproc_suspend_check(struct proc *p)
210 {
211 PROC_LOCK(p);
212 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
213 wakeup(&p->p_siglist);
214 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
215 }
216 PROC_UNLOCK(p);
217 }
218
219
220 /*
221 * Start a kernel thread.
222 *
223 * This function is used to start "internal" daemons and intended
224 * to be called from SYSINIT().
225 */
226
227 void
kthread_start(udata)228 kthread_start(udata)
229 const void *udata;
230 {
231 const struct kthread_desc *kp = udata;
232 int error;
233
234 error = kthread_add((void (*)(void *))kp->func, NULL,
235 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
236 if (error)
237 panic("kthread_start: %s: error %d", kp->arg0, error);
238 }
239
240 /*
241 * Create a kernel thread. It shares its address space
242 * with proc0 - ie: kernel only.
243 *
244 * func is the function to start.
245 * arg is the parameter to pass to function on first startup.
246 * newtdp is the return value pointing to the thread's struct thread.
247 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
248 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
249 */
250 int
kthread_add(void (* func)(void *),void * arg,struct proc * p,struct thread ** newtdp,int flags,int pages,const char * fmt,...)251 kthread_add(void (*func)(void *), void *arg, struct proc *p,
252 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
253 {
254 va_list ap;
255 struct thread *newtd, *oldtd;
256
257 if (!proc0.p_stats)
258 panic("kthread_add called too soon");
259
260 /* If no process supplied, put it on proc0 */
261 if (p == NULL)
262 p = &proc0;
263
264 /* Initialize our new td */
265 newtd = thread_alloc(pages);
266 if (newtd == NULL)
267 return (ENOMEM);
268
269 PROC_LOCK(p);
270 oldtd = FIRST_THREAD_IN_PROC(p);
271
272 bzero(&newtd->td_startzero,
273 __rangeof(struct thread, td_startzero, td_endzero));
274 newtd->td_su = NULL;
275 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
276 __rangeof(struct thread, td_startcopy, td_endcopy));
277
278 /* set up arg0 for 'ps', et al */
279 va_start(ap, fmt);
280 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
281 va_end(ap);
282
283 newtd->td_proc = p; /* needed for cpu_set_upcall */
284
285 /* XXX optimise this probably? */
286 /* On x86 (and probably the others too) it is way too full of junk */
287 /* Needs a better name */
288 cpu_set_upcall(newtd, oldtd);
289 /* put the designated function(arg) as the resume context */
290 cpu_set_fork_handler(newtd, func, arg);
291
292 newtd->td_pflags |= TDP_KTHREAD;
293 newtd->td_ucred = crhold(p->p_ucred);
294
295 /* this code almost the same as create_thread() in kern_thr.c */
296 p->p_flag |= P_HADTHREADS;
297 thread_link(newtd, p);
298 thread_lock(oldtd);
299 /* let the scheduler know about these things. */
300 sched_fork_thread(oldtd, newtd);
301 TD_SET_CAN_RUN(newtd);
302 thread_unlock(oldtd);
303 PROC_UNLOCK(p);
304
305 tidhash_add(newtd);
306
307 /* Avoid inheriting affinity from a random parent. */
308 cpuset_setthread(newtd->td_tid, cpuset_root);
309
310 /* Delay putting it on the run queue until now. */
311 if (!(flags & RFSTOPPED)) {
312 thread_lock(newtd);
313 sched_add(newtd, SRQ_BORING);
314 thread_unlock(newtd);
315 }
316 if (newtdp)
317 *newtdp = newtd;
318 return 0;
319 }
320
321 void
kthread_exit(void)322 kthread_exit(void)
323 {
324 struct proc *p;
325
326 p = curthread->td_proc;
327
328 /* A module may be waiting for us to exit. */
329 wakeup(curthread);
330
331 /*
332 * The last exiting thread in a kernel process must tear down
333 * the whole process.
334 */
335 rw_wlock(&tidhash_lock);
336 PROC_LOCK(p);
337 if (p->p_numthreads == 1) {
338 PROC_UNLOCK(p);
339 rw_wunlock(&tidhash_lock);
340 kproc_exit(0);
341 }
342 LIST_REMOVE(curthread, td_hash);
343 rw_wunlock(&tidhash_lock);
344 umtx_thread_exit(curthread);
345 PROC_SLOCK(p);
346 thread_exit();
347 }
348
349 /*
350 * Advise a kernel process to suspend (or resume) in its main loop.
351 * Participation is voluntary.
352 */
353 int
kthread_suspend(struct thread * td,int timo)354 kthread_suspend(struct thread *td, int timo)
355 {
356 struct proc *p;
357
358 p = td->td_proc;
359
360 /*
361 * td_pflags should not be read by any thread other than
362 * curthread, but as long as this flag is invariant during the
363 * thread's lifetime, it is OK to check its state.
364 */
365 if ((td->td_pflags & TDP_KTHREAD) == 0)
366 return (EINVAL);
367
368 /*
369 * The caller of the primitive should have already checked that the
370 * thread is up and running, thus not being blocked by other
371 * conditions.
372 */
373 PROC_LOCK(p);
374 thread_lock(td);
375 td->td_flags |= TDF_KTH_SUSP;
376 thread_unlock(td);
377 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
378 timo));
379 }
380
381 /*
382 * Resume a thread previously put asleep with kthread_suspend().
383 */
384 int
kthread_resume(struct thread * td)385 kthread_resume(struct thread *td)
386 {
387 struct proc *p;
388
389 p = td->td_proc;
390
391 /*
392 * td_pflags should not be read by any thread other than
393 * curthread, but as long as this flag is invariant during the
394 * thread's lifetime, it is OK to check its state.
395 */
396 if ((td->td_pflags & TDP_KTHREAD) == 0)
397 return (EINVAL);
398
399 PROC_LOCK(p);
400 thread_lock(td);
401 td->td_flags &= ~TDF_KTH_SUSP;
402 thread_unlock(td);
403 wakeup(&td->td_flags);
404 PROC_UNLOCK(p);
405 return (0);
406 }
407
408 /*
409 * Used by the thread to poll as to whether it should yield/sleep
410 * and notify the caller that is has happened.
411 */
412 void
kthread_suspend_check()413 kthread_suspend_check()
414 {
415 struct proc *p;
416 struct thread *td;
417
418 td = curthread;
419 p = td->td_proc;
420
421 if ((td->td_pflags & TDP_KTHREAD) == 0)
422 panic("%s: curthread is not a valid kthread", __func__);
423
424 /*
425 * As long as the double-lock protection is used when accessing the
426 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex
427 * is fine.
428 */
429 PROC_LOCK(p);
430 while (td->td_flags & TDF_KTH_SUSP) {
431 wakeup(&td->td_flags);
432 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
433 }
434 PROC_UNLOCK(p);
435 }
436
437 int
kproc_kthread_add(void (* func)(void *),void * arg,struct proc ** procptr,struct thread ** tdptr,int flags,int pages,const char * procname,const char * fmt,...)438 kproc_kthread_add(void (*func)(void *), void *arg,
439 struct proc **procptr, struct thread **tdptr,
440 int flags, int pages, const char *procname, const char *fmt, ...)
441 {
442 int error;
443 va_list ap;
444 char buf[100];
445 struct thread *td;
446
447 if (*procptr == 0) {
448 error = kproc_create(func, arg,
449 procptr, flags, pages, "%s", procname);
450 if (error)
451 return (error);
452 td = FIRST_THREAD_IN_PROC(*procptr);
453 if (tdptr)
454 *tdptr = td;
455 va_start(ap, fmt);
456 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
457 va_end(ap);
458 #ifdef KTR
459 sched_clear_tdname(td);
460 #endif
461 return (0);
462 }
463 va_start(ap, fmt);
464 vsnprintf(buf, sizeof(buf), fmt, ap);
465 va_end(ap);
466 error = kthread_add(func, arg, *procptr,
467 tdptr, flags, pages, "%s", buf);
468 return (error);
469 }
470