300d4098cf
system calls now enter without Giant held, and then in some cases, acquire Giant explicitly. Remove a number of other MPSAFE annotations in the credential code and tweak one or two other adjacent comments.
279 lines
7.6 KiB
C
279 lines
7.6 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/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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#include <security/mac/mac_framework.h>
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/*
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* Define the code needed before returning to user mode, for trap and
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* syscall.
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*/
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void
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userret(struct thread *td, struct trapframe *frame)
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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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#ifdef KTRACE
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KTRUSERRET(td);
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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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* 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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#ifdef KSE
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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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#endif
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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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addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
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}
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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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KASSERT(td->td_locks == 0,
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("userret: Returning with %d locks held.", td->td_locks));
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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 rlimit rlim;
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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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ksiginfo_t ksi;
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#endif
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td = curthread;
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p = td->td_proc;
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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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td->td_pticks = 0;
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#ifdef KSE
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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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#endif
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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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if (p->p_sflag & (PS_ALRMPEND | PS_PROFPEND | PS_XCPU))
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p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
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#ifdef MAC
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if (p->p_sflag & PS_MACPEND)
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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_trap++;
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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 thread 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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ksiginfo_init_trap(&ksi);
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ksi.ksi_signo = SIGFPE;
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ksi.ksi_code = ucode;
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trapsignal(td, &ksi);
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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 >= rlim.rlim_max * cpu_tickrate()) {
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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, td->td_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);
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mtx_assert(&Giant, MA_NOTOWNED);
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}
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