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/*-
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
* $FreeBSD$
*/
#ifdef __i386__
#include "opt_npx.h"
#endif
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#include <machine/cpu.h>
#include <machine/pcb.h>
/*
* Define the code needed before returning to user mode, for
* trap and syscall.
*
* MPSAFE
*/
void
userret(td, frame, oticks)
struct thread *td;
struct trapframe *frame;
u_int oticks;
{
struct proc *p = td->td_proc;
struct kse *ke = td->td_kse;
struct ksegrp *kg = td->td_ksegrp;
int sig;
mtx_lock(&Giant);
PROC_LOCK(p);
while ((sig = CURSIG(p)) != 0)
postsig(sig);
PROC_UNLOCK(p);
mtx_unlock(&Giant);
mtx_lock_spin(&sched_lock);
td->td_priority = kg->kg_user_pri;
if (ke->ke_flags & KEF_NEEDRESCHED) {
DROP_GIANT();
setrunqueue(td);
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
mtx_lock(&Giant);
PROC_LOCK(p);
while ((sig = CURSIG(p)) != 0)
postsig(sig);
mtx_unlock(&Giant);
PROC_UNLOCK(p);
mtx_lock_spin(&sched_lock);
}
/*
* Charge system time if profiling.
*/
if (p->p_sflag & PS_PROFIL) {
quad_t ticks;
ticks = ke->ke_sticks - oticks;
mtx_unlock_spin(&sched_lock);
addupc_task(ke, TRAPF_PC(frame), (u_int)ticks * psratio);
} else
mtx_unlock_spin(&sched_lock);
}
/*
* Process an asynchronous software trap.
* This is relatively easy.
* This function will return with preemption disabled.
*/
void
ast(framep)
struct trapframe *framep;
{
struct thread *td = curthread;
struct proc *p = td->td_proc;
struct kse *ke = td->td_kse;
u_int prticks, sticks;
critical_t s;
int sflag;
int flags;
#if defined(DEV_NPX) && !defined(SMP)
int ucode;
#endif
KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
#ifdef WITNESS
if (witness_list(td))
panic("Returning to user mode with mutex(s) held");
#endif
mtx_assert(&Giant, MA_NOTOWNED);
prticks = 0; /* XXX: Quiet warning. */
s = cpu_critical_enter();
while ((ke->ke_flags & (KEF_ASTPENDING | KEF_NEEDRESCHED)) != 0) {
cpu_critical_exit(s);
td->td_frame = framep;
/*
* This updates the p_sflag's for the checks below in one
* "atomic" operation with turning off the astpending flag.
* If another AST is triggered while we are handling the
* AST's saved in sflag, the astpending flag will be set and
* we will loop again.
*/
mtx_lock_spin(&sched_lock);
sticks = ke->ke_sticks;
sflag = p->p_sflag;
flags = ke->ke_flags;
p->p_sflag &= ~(PS_PROFPEND | PS_ALRMPEND);
ke->ke_flags &= ~(KEF_OWEUPC | KEF_ASTPENDING);
cnt.v_soft++;
if (flags & KEF_OWEUPC && sflag & PS_PROFIL) {
prticks = p->p_stats->p_prof.pr_ticks;
p->p_stats->p_prof.pr_ticks = 0;
}
mtx_unlock_spin(&sched_lock);
#ifdef DIAGNOSTIC
/*
* As a diagnostic tool we make sure that td->td_ucred
* is NULL while we are in user space. This is
* because theoreticaly this field is only defined
* while the thread is in the kernel. Making it NULL
* will immediatly trap invalid usage of this field.
* In practice however we keep the reference to the ucred
* because it's almost always going to be the same cred we will
* need at the next syscall, and it can be expensive
* to keep dropping and reacquiring the reference.
* We thus stash it away elsewhere until we return
* to the kernel, where we bring it back. If
* DIAGNOSTIC is not defined we don't bother with
* making it NULL, and just leave it in place.
* (don't remove this comment without removing the pointers
* to it in sys/proc.h, trap.c, kern/kern_fork.c and here.)
*/
if (td->td_ucred)
panic("ast:thread got a cred before reaching AST");
td->td_ucred = td->td_ucred_cache;
td->td_ucred_cache = NULL;
#endif /* DIAGNOSTIC */
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
if (flags & KEF_OWEUPC && sflag & PS_PROFIL)
addupc_task(ke, p->p_stats->p_prof.pr_addr, prticks);
if (sflag & PS_ALRMPEND) {
PROC_LOCK(p);
psignal(p, SIGVTALRM);
PROC_UNLOCK(p);
}
#if defined(DEV_NPX) && !defined(SMP)
if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
PCB_NPXTRAP);
ucode = npxtrap();
if (ucode != -1) {
trapsignal(p, SIGFPE, ucode);
}
}
#endif
if (sflag & PS_PROFPEND) {
PROC_LOCK(p);
psignal(p, SIGPROF);
PROC_UNLOCK(p);
}
userret(td, framep, sticks);
#ifdef DIAGNOSTIC /* see comment above */
if (td->td_ucred_cache)
panic("ast:thread already has cached ucred");
td->td_ucred_cache = td->td_ucred;
td->td_ucred = NULL;
#endif /* DIAGNOSTIC */
s = cpu_critical_enter();
}
mtx_assert(&Giant, MA_NOTOWNED);
/*
* We need to keep interrupts disabled so that if any further AST's
* come in, the interrupt they come in on will be delayed until we
* finish returning to userland. We assume that the return to userland
* will perform the equivalent of cpu_critical_exit().
*/
}
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