9197ce2ee5
This flag gets set whenever the thread posts an event on the GEOM event queue, and if the flag is set when the thread is prepared to return to userland from the kernel, g_waitidle() will be called to make sure that the posted events have completed. This can replace an insufficient number of g_waitidle() calls in various other places, and has the advantage of being failsafe: Any system call which does a VOP_OPEN()/VOP_CLOSE will now correctly wait for any geom events it posted as part of spoils or tastes. Assert that topology and Giant is not held in g_waitidle().
272 lines
7.4 KiB
C
272 lines
7.4 KiB
C
/*-
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* Copyright (C) 1994, David Greenman
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* the University of Utah, and William Jolitz.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ktrace.h"
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#include "opt_mac.h"
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#ifdef __i386__
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#include "opt_npx.h"
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#endif
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mac.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/ktr.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/signalvar.h>
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#include <sys/systm.h>
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#include <sys/vmmeter.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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#include <machine/cpu.h>
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#include <machine/pcb.h>
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/*
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* Define the code needed before returning to user mode, for
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* trap and syscall.
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*
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* MPSAFE
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*/
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void
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userret(td, frame, oticks)
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struct thread *td;
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struct trapframe *frame;
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u_int oticks;
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{
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struct proc *p = td->td_proc;
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CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
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p->p_comm);
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#ifdef DIAGNOSTIC
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/* Check that we called signotify() enough. */
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
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(td->td_flags & TDF_ASTPENDING) == 0))
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printf("failed to set signal flags properly for ast()\n");
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mtx_unlock_spin(&sched_lock);
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PROC_UNLOCK(p);
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#endif
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/*
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* If this thread tickled GEOM, we need to wait for the giggling to
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* stop before we return to userland
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*/
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if (td->td_pflags & TDP_GEOM)
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g_waitidle();
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/*
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* Let the scheduler adjust our priority etc.
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*/
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sched_userret(td);
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/*
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* We need to check to see if we have to exit or wait due to a
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* single threading requirement or some other STOP condition.
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* Don't bother doing all the work if the stop bits are not set
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* at this time.. If we miss it, we miss it.. no big deal.
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*/
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if (P_SHOULDSTOP(p)) {
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PROC_LOCK(p);
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thread_suspend_check(0); /* Can suspend or kill */
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PROC_UNLOCK(p);
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}
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/*
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* Do special thread processing, e.g. upcall tweaking and such.
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*/
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if (p->p_flag & P_SA)
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thread_userret(td, frame);
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/*
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* Charge system time if profiling.
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*/
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if (p->p_flag & P_PROFIL) {
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quad_t ticks;
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ticks = td->td_sticks - oticks;
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addupc_task(td, TRAPF_PC(frame), (u_int)ticks * psratio);
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}
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}
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/*
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* Process an asynchronous software trap.
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* This is relatively easy.
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* This function will return with preemption disabled.
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*/
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void
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ast(struct trapframe *framep)
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{
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struct thread *td;
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struct proc *p;
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struct ksegrp *kg;
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struct rlimit rlim;
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u_int sticks;
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int sflag;
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int flags;
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int sig;
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#if defined(DEV_NPX) && !defined(SMP)
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int ucode;
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#endif
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td = curthread;
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p = td->td_proc;
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kg = td->td_ksegrp;
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CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
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p->p_comm);
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KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
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WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
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mtx_assert(&Giant, MA_NOTOWNED);
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mtx_assert(&sched_lock, MA_NOTOWNED);
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td->td_frame = framep;
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sticks = td->td_sticks;
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if ((p->p_flag & P_SA) && (td->td_mailbox == NULL))
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thread_user_enter(td);
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/*
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* This updates the p_sflag's for the checks below in one
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* "atomic" operation with turning off the astpending flag.
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* If another AST is triggered while we are handling the
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* AST's saved in sflag, the astpending flag will be set and
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* ast() will be called again.
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*/
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mtx_lock_spin(&sched_lock);
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flags = td->td_flags;
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sflag = p->p_sflag;
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p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
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#ifdef MAC
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p->p_sflag &= ~PS_MACPEND;
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#endif
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td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
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TDF_NEEDRESCHED | TDF_INTERRUPT);
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cnt.v_soft++;
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mtx_unlock_spin(&sched_lock);
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/*
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* XXXKSE While the fact that we owe a user profiling
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* tick is stored per KSE in this code, the statistics
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* themselves are still stored per process.
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* This should probably change, by which I mean that
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* possibly the location of both might change.
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*/
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if (td->td_ucred != p->p_ucred)
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cred_update_thread(td);
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if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
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addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
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td->td_profil_ticks = 0;
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td->td_pflags &= ~TDP_OWEUPC;
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}
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if (sflag & PS_ALRMPEND) {
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PROC_LOCK(p);
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psignal(p, SIGVTALRM);
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PROC_UNLOCK(p);
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}
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#if defined(DEV_NPX) && !defined(SMP)
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if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
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atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
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PCB_NPXTRAP);
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ucode = npxtrap();
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if (ucode != -1) {
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trapsignal(td, SIGFPE, ucode);
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}
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}
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#endif
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if (sflag & PS_PROFPEND) {
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PROC_LOCK(p);
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psignal(p, SIGPROF);
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PROC_UNLOCK(p);
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}
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if (sflag & PS_XCPU) {
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PROC_LOCK(p);
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lim_rlimit(p, RLIMIT_CPU, &rlim);
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mtx_lock_spin(&sched_lock);
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if (p->p_rux.rux_runtime.sec >= rlim.rlim_max) {
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mtx_unlock_spin(&sched_lock);
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killproc(p, "exceeded maximum CPU limit");
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} else {
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if (p->p_cpulimit < rlim.rlim_max)
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p->p_cpulimit += 5;
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mtx_unlock_spin(&sched_lock);
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psignal(p, SIGXCPU);
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}
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PROC_UNLOCK(p);
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}
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#ifdef MAC
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if (sflag & PS_MACPEND)
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mac_thread_userret(td);
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#endif
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if (flags & TDF_NEEDRESCHED) {
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(1, 1);
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#endif
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mtx_lock_spin(&sched_lock);
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sched_prio(td, kg->kg_user_pri);
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mi_switch(SW_INVOL, NULL);
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mtx_unlock_spin(&sched_lock);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_CSW))
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ktrcsw(0, 1);
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#endif
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}
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if (flags & TDF_NEEDSIGCHK) {
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PROC_LOCK(p);
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mtx_lock(&p->p_sigacts->ps_mtx);
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while ((sig = cursig(td)) != 0)
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postsig(sig);
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mtx_unlock(&p->p_sigacts->ps_mtx);
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PROC_UNLOCK(p);
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}
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userret(td, framep, sticks);
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mtx_assert(&Giant, MA_NOTOWNED);
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}
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