468 lines
11 KiB
C
468 lines
11 KiB
C
/*-
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* Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/cpuset.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/rwlock.h>
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#include <sys/signalvar.h>
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#include <sys/sx.h>
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#include <sys/umtx.h>
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#include <sys/unistd.h>
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#include <sys/wait.h>
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#include <sys/sched.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <machine/stdarg.h>
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/*
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* Start a kernel process. This is called after a fork() call in
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* mi_startup() in the file kern/init_main.c.
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*
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* This function is used to start "internal" daemons and intended
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* to be called from SYSINIT().
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*/
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void
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kproc_start(const void *udata)
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{
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const struct kproc_desc *kp = udata;
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int error;
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error = kproc_create((void (*)(void *))kp->func, NULL,
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kp->global_procpp, 0, 0, "%s", kp->arg0);
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if (error)
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panic("kproc_start: %s: error %d", kp->arg0, error);
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}
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/*
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* Create a kernel process/thread/whatever. It shares its address space
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* with proc0 - ie: kernel only.
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*
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* func is the function to start.
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* arg is the parameter to pass to function on first startup.
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* newpp is the return value pointing to the thread's struct proc.
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* flags are flags to fork1 (in unistd.h)
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* fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
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*/
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int
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kproc_create(void (*func)(void *), void *arg,
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struct proc **newpp, int flags, int pages, const char *fmt, ...)
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{
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struct fork_req fr;
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int error;
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va_list ap;
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struct thread *td;
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struct proc *p2;
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if (!proc0.p_stats)
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panic("kproc_create called too soon");
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bzero(&fr, sizeof(fr));
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fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags;
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fr.fr_pages = pages;
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fr.fr_procp = &p2;
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error = fork1(&thread0, &fr);
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if (error)
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return error;
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/* save a global descriptor, if desired */
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if (newpp != NULL)
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*newpp = p2;
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/* this is a non-swapped system process */
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PROC_LOCK(p2);
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td = FIRST_THREAD_IN_PROC(p2);
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p2->p_flag |= P_SYSTEM | P_KPROC;
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td->td_pflags |= TDP_KTHREAD;
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mtx_lock(&p2->p_sigacts->ps_mtx);
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p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
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mtx_unlock(&p2->p_sigacts->ps_mtx);
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PROC_UNLOCK(p2);
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/* set up arg0 for 'ps', et al */
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va_start(ap, fmt);
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vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
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va_end(ap);
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/* set up arg0 for 'ps', et al */
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va_start(ap, fmt);
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vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
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va_end(ap);
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#ifdef KTR
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sched_clear_tdname(td);
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#endif
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/* call the processes' main()... */
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cpu_fork_kthread_handler(td, func, arg);
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/* Avoid inheriting affinity from a random parent. */
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cpuset_setthread(td->td_tid, cpuset_root);
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thread_lock(td);
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TD_SET_CAN_RUN(td);
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sched_prio(td, PVM);
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sched_user_prio(td, PUSER);
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/* Delay putting it on the run queue until now. */
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if (!(flags & RFSTOPPED))
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sched_add(td, SRQ_BORING);
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thread_unlock(td);
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return 0;
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}
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void
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kproc_exit(int ecode)
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{
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struct thread *td;
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struct proc *p;
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td = curthread;
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p = td->td_proc;
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/*
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* Reparent curthread from proc0 to init so that the zombie
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* is harvested.
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*/
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sx_xlock(&proctree_lock);
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PROC_LOCK(p);
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proc_reparent(p, initproc);
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PROC_UNLOCK(p);
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sx_xunlock(&proctree_lock);
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/*
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* Wakeup anyone waiting for us to exit.
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*/
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wakeup(p);
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/* Buh-bye! */
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exit1(td, ecode, 0);
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}
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/*
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* Advise a kernel process to suspend (or resume) in its main loop.
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* Participation is voluntary.
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*/
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int
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kproc_suspend(struct proc *p, int timo)
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{
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/*
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* Make sure this is indeed a system process and we can safely
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* use the p_siglist field.
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*/
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PROC_LOCK(p);
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if ((p->p_flag & P_KPROC) == 0) {
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PROC_UNLOCK(p);
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return (EINVAL);
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}
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SIGADDSET(p->p_siglist, SIGSTOP);
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wakeup(p);
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return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
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}
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int
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kproc_resume(struct proc *p)
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{
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/*
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* Make sure this is indeed a system process and we can safely
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* use the p_siglist field.
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*/
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PROC_LOCK(p);
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if ((p->p_flag & P_KPROC) == 0) {
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PROC_UNLOCK(p);
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return (EINVAL);
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}
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SIGDELSET(p->p_siglist, SIGSTOP);
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PROC_UNLOCK(p);
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wakeup(&p->p_siglist);
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return (0);
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}
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void
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kproc_suspend_check(struct proc *p)
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{
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PROC_LOCK(p);
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while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
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wakeup(&p->p_siglist);
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msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
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}
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PROC_UNLOCK(p);
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}
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/*
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* Start a kernel thread.
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*
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* This function is used to start "internal" daemons and intended
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* to be called from SYSINIT().
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*/
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void
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kthread_start(const void *udata)
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{
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const struct kthread_desc *kp = udata;
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int error;
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error = kthread_add((void (*)(void *))kp->func, NULL,
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NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
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if (error)
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panic("kthread_start: %s: error %d", kp->arg0, error);
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}
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/*
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* Create a kernel thread. It shares its address space
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* with proc0 - ie: kernel only.
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*
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* func is the function to start.
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* arg is the parameter to pass to function on first startup.
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* newtdp is the return value pointing to the thread's struct thread.
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* ** XXX fix this --> flags are flags to fork1 (in unistd.h)
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* fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
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*/
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int
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kthread_add(void (*func)(void *), void *arg, struct proc *p,
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struct thread **newtdp, int flags, int pages, const char *fmt, ...)
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{
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va_list ap;
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struct thread *newtd, *oldtd;
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if (!proc0.p_stats)
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panic("kthread_add called too soon");
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/* If no process supplied, put it on proc0 */
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if (p == NULL)
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p = &proc0;
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/* Initialize our new td */
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newtd = thread_alloc(pages);
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if (newtd == NULL)
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return (ENOMEM);
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PROC_LOCK(p);
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oldtd = FIRST_THREAD_IN_PROC(p);
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bzero(&newtd->td_startzero,
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__rangeof(struct thread, td_startzero, td_endzero));
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bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
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__rangeof(struct thread, td_startcopy, td_endcopy));
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/* set up arg0 for 'ps', et al */
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va_start(ap, fmt);
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vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
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va_end(ap);
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newtd->td_proc = p; /* needed for cpu_copy_thread */
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/* might be further optimized for kthread */
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cpu_copy_thread(newtd, oldtd);
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/* put the designated function(arg) as the resume context */
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cpu_fork_kthread_handler(newtd, func, arg);
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newtd->td_pflags |= TDP_KTHREAD;
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thread_cow_get_proc(newtd, p);
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/* this code almost the same as create_thread() in kern_thr.c */
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p->p_flag |= P_HADTHREADS;
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thread_link(newtd, p);
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thread_lock(oldtd);
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/* let the scheduler know about these things. */
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sched_fork_thread(oldtd, newtd);
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TD_SET_CAN_RUN(newtd);
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thread_unlock(oldtd);
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PROC_UNLOCK(p);
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tidhash_add(newtd);
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/* Avoid inheriting affinity from a random parent. */
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cpuset_setthread(newtd->td_tid, cpuset_root);
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/* Delay putting it on the run queue until now. */
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if (!(flags & RFSTOPPED)) {
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thread_lock(newtd);
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sched_add(newtd, SRQ_BORING);
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thread_unlock(newtd);
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}
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if (newtdp)
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*newtdp = newtd;
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return 0;
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}
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void
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kthread_exit(void)
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{
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struct proc *p;
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p = curthread->td_proc;
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/* A module may be waiting for us to exit. */
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wakeup(curthread);
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/*
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* The last exiting thread in a kernel process must tear down
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* the whole process.
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*/
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rw_wlock(&tidhash_lock);
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PROC_LOCK(p);
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if (p->p_numthreads == 1) {
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PROC_UNLOCK(p);
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rw_wunlock(&tidhash_lock);
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kproc_exit(0);
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}
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LIST_REMOVE(curthread, td_hash);
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rw_wunlock(&tidhash_lock);
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umtx_thread_exit(curthread);
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PROC_SLOCK(p);
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thread_exit();
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}
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/*
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* Advise a kernel process to suspend (or resume) in its main loop.
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* Participation is voluntary.
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*/
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int
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kthread_suspend(struct thread *td, int timo)
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{
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struct proc *p;
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p = td->td_proc;
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/*
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* td_pflags should not be read by any thread other than
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* curthread, but as long as this flag is invariant during the
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* thread's lifetime, it is OK to check its state.
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*/
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if ((td->td_pflags & TDP_KTHREAD) == 0)
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return (EINVAL);
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/*
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* The caller of the primitive should have already checked that the
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* thread is up and running, thus not being blocked by other
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* conditions.
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*/
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PROC_LOCK(p);
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thread_lock(td);
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td->td_flags |= TDF_KTH_SUSP;
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thread_unlock(td);
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return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
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timo));
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}
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/*
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* Resume a thread previously put asleep with kthread_suspend().
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*/
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int
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kthread_resume(struct thread *td)
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{
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struct proc *p;
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p = td->td_proc;
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/*
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* td_pflags should not be read by any thread other than
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* curthread, but as long as this flag is invariant during the
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* thread's lifetime, it is OK to check its state.
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*/
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if ((td->td_pflags & TDP_KTHREAD) == 0)
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return (EINVAL);
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PROC_LOCK(p);
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thread_lock(td);
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td->td_flags &= ~TDF_KTH_SUSP;
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thread_unlock(td);
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wakeup(&td->td_flags);
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PROC_UNLOCK(p);
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return (0);
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}
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/*
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* Used by the thread to poll as to whether it should yield/sleep
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* and notify the caller that is has happened.
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*/
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void
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kthread_suspend_check(void)
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{
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struct proc *p;
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struct thread *td;
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td = curthread;
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p = td->td_proc;
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if ((td->td_pflags & TDP_KTHREAD) == 0)
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panic("%s: curthread is not a valid kthread", __func__);
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/*
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* As long as the double-lock protection is used when accessing the
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* TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex
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* is fine.
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*/
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PROC_LOCK(p);
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while (td->td_flags & TDF_KTH_SUSP) {
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wakeup(&td->td_flags);
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msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
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}
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PROC_UNLOCK(p);
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}
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int
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kproc_kthread_add(void (*func)(void *), void *arg,
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struct proc **procptr, struct thread **tdptr,
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int flags, int pages, const char *procname, const char *fmt, ...)
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{
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int error;
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va_list ap;
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char buf[100];
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struct thread *td;
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if (*procptr == NULL) {
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error = kproc_create(func, arg,
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procptr, flags, pages, "%s", procname);
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if (error)
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return (error);
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td = FIRST_THREAD_IN_PROC(*procptr);
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if (tdptr)
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*tdptr = td;
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va_start(ap, fmt);
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vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
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va_end(ap);
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#ifdef KTR
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sched_clear_tdname(td);
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#endif
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return (0);
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}
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va_start(ap, fmt);
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vsnprintf(buf, sizeof(buf), fmt, ap);
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va_end(ap);
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error = kthread_add(func, arg, *procptr,
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tdptr, flags, pages, "%s", buf);
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return (error);
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}
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