/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2007 The FreeBSD Foundation
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Portions of this software were developed by A. Joseph Koshy under
* sponsorship from the FreeBSD Foundation and Google, Inc.
*
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_ktrace.h"
#include "opt_sched.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/pmckern.h>
#include <sys/proc.h>
#include <sys/ktr.h>
#include <sys/ptrace.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#include <security/audit/audit.h>
#include <machine/cpu.h>
#ifdef VIMAGE
#include <net/vnet.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#include <security/mac/mac_framework.h>
void (*softdep_ast_cleanup)(struct thread *);
/*
* Define the code needed before returning to user mode, for trap and
* syscall.
*/
void
userret(struct thread *td, struct trapframe *frame)
{
struct proc *p = td->td_proc;
CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
td->td_name);
KASSERT((p->p_flag & P_WEXIT) == 0,
("Exiting process returns to usermode"));
#ifdef DIAGNOSTIC
/*
* Check that we called signotify() enough. For
* multi-threaded processes, where signal distribution might
* change due to other threads changing sigmask, the check is
* racy and cannot be performed reliably.
* If current process is vfork child, indicated by P_PPWAIT, then
* issignal() ignores stops, so we block the check to avoid
* classifying pending signals.
*/
if (p->p_numthreads == 1) {
PROC_LOCK(p);
thread_lock(td);
if ((p->p_flag & P_PPWAIT) == 0 &&
(td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
if (SIGPENDING(td) && (td->td_flags &
(TDF_NEEDSIGCHK | TDF_ASTPENDING)) !=
(TDF_NEEDSIGCHK | TDF_ASTPENDING)) {
thread_unlock(td);
panic(
"failed to set signal flags for ast p %p td %p fl %x",
p, td, td->td_flags);
}
}
thread_unlock(td);
PROC_UNLOCK(p);
}
#endif
#ifdef KTRACE
KTRUSERRET(td);
#endif
td_softdep_cleanup(td);
MPASS(td->td_su == NULL);
/*
* If this thread tickled GEOM, we need to wait for the giggling to
* stop before we return to userland
*/
if (__predict_false(td->td_pflags & TDP_GEOM))
g_waitidle();
/*
* Charge system time if profiling.
*/
if (__predict_false(p->p_flag & P_PROFIL))
addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
#ifdef HWPMC_HOOKS
if (PMC_THREAD_HAS_SAMPLES(td))
PMC_CALL_HOOK(td, PMC_FN_THR_USERRET, NULL);
#endif
/*
* Let the scheduler adjust our priority etc.
*/
sched_userret(td);
/*
* Check for misbehavior.
*
* In case there is a callchain tracing ongoing because of
* hwpmc(4), skip the scheduler pinning check.
* hwpmc(4) subsystem, infact, will collect callchain informations
* at ast() checkpoint, which is past userret().
*/
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
KASSERT(td->td_critnest == 0,
("userret: Returning in a critical section"));
KASSERT(td->td_locks == 0,
("userret: Returning with %d locks held", td->td_locks));
KASSERT(td->td_rw_rlocks == 0,
("userret: Returning with %d rwlocks held in read mode",
td->td_rw_rlocks));
KASSERT(td->td_sx_slocks == 0,
("userret: Returning with %d sx locks held in shared mode",
td->td_sx_slocks));
KASSERT(td->td_lk_slocks == 0,
("userret: Returning with %d lockmanager locks held in shared mode",
td->td_lk_slocks));
KASSERT((td->td_pflags & TDP_NOFAULTING) == 0,
("userret: Returning with pagefaults disabled"));
if (__predict_false(!THREAD_CAN_SLEEP())) {
#ifdef EPOCH_TRACE
epoch_trace_list(curthread);
#endif
KASSERT(1, ("userret: Returning with sleep disabled"));
}
KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
("userret: Returning with with pinned thread"));
KASSERT(td->td_vp_reserved == NULL,
("userret: Returning with preallocated vnode"));
KASSERT((td->td_flags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
("userret: Returning with stop signals deferred"));
KASSERT(td->td_su == NULL,
("userret: Returning with SU cleanup request not handled"));
KASSERT(td->td_vslock_sz == 0,
("userret: Returning with vslock-wired space"));
#ifdef VIMAGE
/* Unfortunately td_vnet_lpush needs VNET_DEBUG. */
VNET_ASSERT(curvnet == NULL,
("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s",
__func__, td, p->p_pid, td->td_name, curvnet,
(td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A"));
#endif
#ifdef RACCT
if (__predict_false(racct_enable && p->p_throttled != 0))
racct_proc_throttled(p);
#endif
}
/*
* Process an asynchronous software trap.
* This is relatively easy.
* This function will return with preemption disabled.
*/
void
ast(struct trapframe *framep)
{
struct thread *td;
struct proc *p;
int flags, sig;
td = curthread;
p = td->td_proc;
CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
mtx_assert(&Giant, MA_NOTOWNED);
THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
td->td_frame = framep;
td->td_pticks = 0;
/*
* This updates the td_flag'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 flags, the astpending flag will be set and
* ast() will be called again.
*/
thread_lock(td);
flags = td->td_flags;
td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
thread_unlock(td);
VM_CNT_INC(v_trap);
if (td->td_cowgen != p->p_cowgen)
thread_cow_update(td);
if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
td->td_profil_ticks = 0;
td->td_pflags &= ~TDP_OWEUPC;
}
#ifdef HWPMC_HOOKS
/* Handle Software PMC callchain capture. */
if (PMC_IS_PENDING_CALLCHAIN(td))
PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN_SOFT, (void *) framep);
#endif
if (flags & TDF_ALRMPEND) {
PROC_LOCK(p);
kern_psignal(p, SIGVTALRM);
PROC_UNLOCK(p);
}
if (flags & TDF_PROFPEND) {
PROC_LOCK(p);
kern_psignal(p, SIGPROF);
PROC_UNLOCK(p);
}
#ifdef MAC
if (flags & TDF_MACPEND)
mac_thread_userret(td);
#endif
if (flags & TDF_NEEDRESCHED) {
#ifdef KTRACE
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 1, __func__);
#endif
thread_lock(td);
sched_prio(td, td->td_user_pri);
mi_switch(SW_INVOL | SWT_NEEDRESCHED);
#ifdef KTRACE
if (KTRPOINT(td, KTR_CSW))
ktrcsw(0, 1, __func__);
#endif
}
#ifdef DIAGNOSTIC
if (p->p_numthreads == 1 && (flags & TDF_NEEDSIGCHK) == 0) {
PROC_LOCK(p);
thread_lock(td);
/*
* Note that TDF_NEEDSIGCHK should be re-read from
* td_flags, since signal might have been delivered
* after we cleared td_flags above. This is one of
* the reason for looping check for AST condition.
* See comment in userret() about P_PPWAIT.
*/
if ((p->p_flag & P_PPWAIT) == 0 &&
(td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
if (SIGPENDING(td) && (td->td_flags &
(TDF_NEEDSIGCHK | TDF_ASTPENDING)) !=
(TDF_NEEDSIGCHK | TDF_ASTPENDING)) {
thread_unlock(td); /* fix dumps */
panic(
"failed2 to set signal flags for ast p %p td %p fl %x %x",
p, td, flags, td->td_flags);
}
}
thread_unlock(td);
PROC_UNLOCK(p);
}
#endif
/*
* Check for signals. Unlocked reads of p_pendingcnt or
* p_siglist might cause process-directed signal to be handled
* later.
*/
if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 ||
!SIGISEMPTY(p->p_siglist)) {
sigfastblock_fetch(td);
if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0 &&
td->td_sigblock_val != 0) {
sigfastblock_setpend(td, true);
} else {
PROC_LOCK(p);
mtx_lock(&p->p_sigacts->ps_mtx);
while ((sig = cursig(td)) != 0) {
KASSERT(sig >= 0, ("sig %d", sig));
postsig(sig);
}
mtx_unlock(&p->p_sigacts->ps_mtx);
PROC_UNLOCK(p);
}
}
/*
* Handle deferred update of the fast sigblock value, after
* the postsig() loop was performed.
*/
if (td->td_pflags & TDP_SIGFASTPENDING)
sigfastblock_setpend(td, false);
/*
* We need to check to see if we have to exit or wait due to a
* single threading requirement or some other STOP condition.
*/
if (flags & TDF_NEEDSUSPCHK) {
PROC_LOCK(p);
thread_suspend_check(0);
PROC_UNLOCK(p);
}
if (td->td_pflags & TDP_OLDMASK) {
td->td_pflags &= ~TDP_OLDMASK;
kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
}
userret(td, framep);
}
const char *
syscallname(struct proc *p, u_int code)
{
static const char unknown[] = "unknown";
struct sysentvec *sv;
sv = p->p_sysent;
if (sv->sv_syscallnames == NULL || code >= sv->sv_size)
return (unknown);
return (sv->sv_syscallnames[code]);
}
