subr_trap.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
    1 /*-
    2  * SPDX-License-Identifier: BSD-4-Clause
    3  *
    4  * Copyright (C) 1994, David Greenman
    5  * Copyright (c) 1990, 1993
    6  *      The Regents of the University of California.  All rights reserved.
    7  * Copyright (c) 2007 The FreeBSD Foundation
    8  *
    9  * This code is derived from software contributed to Berkeley by
   10  * the University of Utah, and William Jolitz.
   11  *
   12  * Portions of this software were developed by A. Joseph Koshy under
   13  * sponsorship from the FreeBSD Foundation and Google, Inc.
   14  *
   15  * Redistribution and use in source and binary forms, with or without
   16  * modification, are permitted provided that the following conditions
   17  * are met:
   18  * 1. Redistributions of source code must retain the above copyright
   19  *    notice, this list of conditions and the following disclaimer.
   20  * 2. Redistributions in binary form must reproduce the above copyright
   21  *    notice, this list of conditions and the following disclaimer in the
   22  *    documentation and/or other materials provided with the distribution.
   23  * 3. All advertising materials mentioning features or use of this software
   24  *    must display the following acknowledgement:
   25  *      This product includes software developed by the University of
   26  *      California, Berkeley and its contributors.
   27  * 4. Neither the name of the University nor the names of its contributors
   28  *    may be used to endorse or promote products derived from this software
   29  *    without specific prior written permission.
   30  *
   31  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   41  * SUCH DAMAGE.
   42  *
   43  *      from: @(#)trap.c        7.4 (Berkeley) 5/13/91
   44  */
   45 
   46 #include <sys/cdefs.h>
   47 __FBSDID("$FreeBSD$");
   48 
   49 #include "opt_hwpmc_hooks.h"
   50 #include "opt_ktrace.h"
   51 #include "opt_sched.h"
   52 
   53 #include <sys/param.h>
   54 #include <sys/bus.h>
   55 #include <sys/capsicum.h>
   56 #include <sys/event.h>
   57 #include <sys/kernel.h>
   58 #include <sys/lock.h>
   59 #include <sys/mutex.h>
   60 #include <sys/pmckern.h>
   61 #include <sys/proc.h>
   62 #include <sys/ktr.h>
   63 #include <sys/ptrace.h>
   64 #include <sys/racct.h>
   65 #include <sys/resourcevar.h>
   66 #include <sys/sched.h>
   67 #include <sys/signalvar.h>
   68 #include <sys/syscall.h>
   69 #include <sys/syscallsubr.h>
   70 #include <sys/sysent.h>
   71 #include <sys/systm.h>
   72 #include <sys/vmmeter.h>
   73 #ifdef KTRACE
   74 #include <sys/uio.h>
   75 #include <sys/ktrace.h>
   76 #endif
   77 #include <security/audit/audit.h>
   78 
   79 #include <machine/cpu.h>
   80 
   81 #ifdef VIMAGE
   82 #include <net/vnet.h>
   83 #endif
   84 
   85 #ifdef  HWPMC_HOOKS
   86 #include <sys/pmckern.h>
   87 #endif
   88 
   89 #include <security/mac/mac_framework.h>
   90 
   91 void (*softdep_ast_cleanup)(struct thread *);
   92 
   93 /*
   94  * Define the code needed before returning to user mode, for trap and
   95  * syscall.
   96  */
   97 void
   98 userret(struct thread *td, struct trapframe *frame)
   99 {
  100         struct proc *p = td->td_proc;
  101 
  102         CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
  103             td->td_name);
  104         KASSERT((p->p_flag & P_WEXIT) == 0,
  105             ("Exiting process returns to usermode"));
  106 #ifdef DIAGNOSTIC
  107         /*
  108          * Check that we called signotify() enough.  For
  109          * multi-threaded processes, where signal distribution might
  110          * change due to other threads changing sigmask, the check is
  111          * racy and cannot be performed reliably.
  112          * If current process is vfork child, indicated by P_PPWAIT, then
  113          * issignal() ignores stops, so we block the check to avoid
  114          * classifying pending signals.
  115          */
  116         if (p->p_numthreads == 1) {
  117                 PROC_LOCK(p);
  118                 thread_lock(td);
  119                 if ((p->p_flag & P_PPWAIT) == 0 &&
  120                     (td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
  121                         if (SIGPENDING(td) && (td->td_flags &
  122                             (TDF_NEEDSIGCHK | TDF_ASTPENDING)) !=
  123                             (TDF_NEEDSIGCHK | TDF_ASTPENDING)) {
  124                                 thread_unlock(td);
  125                                 panic(
  126         "failed to set signal flags for ast p %p td %p fl %x",
  127                                     p, td, td->td_flags);
  128                         }
  129                 }
  130                 thread_unlock(td);
  131                 PROC_UNLOCK(p);
  132         }
  133 #endif
  134 
  135         /*
  136          * Charge system time if profiling.
  137          */
  138         if (__predict_false(p->p_flag & P_PROFIL))
  139                 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
  140 
  141 #ifdef HWPMC_HOOKS
  142         if (PMC_THREAD_HAS_SAMPLES(td))
  143                 PMC_CALL_HOOK(td, PMC_FN_THR_USERRET, NULL);
  144 #endif
  145 #ifdef TCPHPTS
  146         /*
  147          * @gallatin is adament that this needs to go here, I
  148          * am not so sure. Running hpts is a lot like
  149          * a lro_flush() that happens while a user process
  150          * is running. But he may know best so I will go
  151          * with his view of accounting. :-)
  152          */
  153         tcp_run_hpts();
  154 #endif
  155         /*
  156          * Let the scheduler adjust our priority etc.
  157          */
  158         sched_userret(td);
  159 
  160         /*
  161          * Check for misbehavior.
  162          *
  163          * In case there is a callchain tracing ongoing because of
  164          * hwpmc(4), skip the scheduler pinning check.
  165          * hwpmc(4) subsystem, infact, will collect callchain informations
  166          * at ast() checkpoint, which is past userret().
  167          */
  168         WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
  169         KASSERT(td->td_critnest == 0,
  170             ("userret: Returning in a critical section"));
  171         KASSERT(td->td_locks == 0,
  172             ("userret: Returning with %d locks held", td->td_locks));
  173         KASSERT(td->td_rw_rlocks == 0,
  174             ("userret: Returning with %d rwlocks held in read mode",
  175             td->td_rw_rlocks));
  176         KASSERT(td->td_sx_slocks == 0,
  177             ("userret: Returning with %d sx locks held in shared mode",
  178             td->td_sx_slocks));
  179         KASSERT(td->td_lk_slocks == 0,
  180             ("userret: Returning with %d lockmanager locks held in shared mode",
  181             td->td_lk_slocks));
  182         KASSERT((td->td_pflags & TDP_NOFAULTING) == 0,
  183             ("userret: Returning with pagefaults disabled"));
  184         if (__predict_false(!THREAD_CAN_SLEEP())) {
  185 #ifdef EPOCH_TRACE
  186                 epoch_trace_list(curthread);
  187 #endif
  188                 KASSERT(0, ("userret: Returning with sleep disabled"));
  189         }
  190         KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
  191             ("userret: Returning with with pinned thread"));
  192         KASSERT(td->td_vp_reserved == NULL,
  193             ("userret: Returning with preallocated vnode"));
  194         KASSERT((td->td_flags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0,
  195             ("userret: Returning with stop signals deferred"));
  196         KASSERT(td->td_vslock_sz == 0,
  197             ("userret: Returning with vslock-wired space"));
  198 #ifdef VIMAGE
  199         /* Unfortunately td_vnet_lpush needs VNET_DEBUG. */
  200         VNET_ASSERT(curvnet == NULL,
  201             ("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s",
  202             __func__, td, p->p_pid, td->td_name, curvnet,
  203             (td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A"));
  204 #endif
  205 }
  206 
  207 /*
  208  * Process an asynchronous software trap.
  209  * This is relatively easy.
  210  * This function will return with preemption disabled.
  211  */
  212 void
  213 ast(struct trapframe *framep)
  214 {
  215         struct thread *td;
  216         struct proc *p;
  217         int flags, old_boundary, sig;
  218         bool resched_sigs;
  219 
  220         td = curthread;
  221         p = td->td_proc;
  222 
  223         CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
  224             p->p_comm);
  225         KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
  226         WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
  227         mtx_assert(&Giant, MA_NOTOWNED);
  228         THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
  229         td->td_frame = framep;
  230         td->td_pticks = 0;
  231 
  232         /*
  233          * This updates the td_flag's for the checks below in one
  234          * "atomic" operation with turning off the astpending flag.
  235          * If another AST is triggered while we are handling the
  236          * AST's saved in flags, the astpending flag will be set and
  237          * ast() will be called again.
  238          */
  239         thread_lock(td);
  240         flags = td->td_flags;
  241         td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
  242             TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND |
  243             TDF_KQTICKLED);
  244         thread_unlock(td);
  245         VM_CNT_INC(v_trap);
  246 
  247         if (td->td_cowgen != p->p_cowgen)
  248                 thread_cow_update(td);
  249         if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
  250                 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
  251                 td->td_profil_ticks = 0;
  252                 td->td_pflags &= ~TDP_OWEUPC;
  253         }
  254 #ifdef HWPMC_HOOKS
  255         /* Handle Software PMC callchain capture. */
  256         if (PMC_IS_PENDING_CALLCHAIN(td))
  257                 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN_SOFT, (void *) framep);
  258 #endif
  259         if (flags & TDF_ALRMPEND) {
  260                 PROC_LOCK(p);
  261                 kern_psignal(p, SIGVTALRM);
  262                 PROC_UNLOCK(p);
  263         }
  264         if (flags & TDF_PROFPEND) {
  265                 PROC_LOCK(p);
  266                 kern_psignal(p, SIGPROF);
  267                 PROC_UNLOCK(p);
  268         }
  269 #ifdef MAC
  270         if (flags & TDF_MACPEND)
  271                 mac_thread_userret(td);
  272 #endif
  273         if (flags & TDF_NEEDRESCHED) {
  274 #ifdef KTRACE
  275                 if (KTRPOINT(td, KTR_CSW))
  276                         ktrcsw(1, 1, __func__);
  277 #endif
  278                 thread_lock(td);
  279                 sched_prio(td, td->td_user_pri);
  280                 mi_switch(SW_INVOL | SWT_NEEDRESCHED);
  281 #ifdef KTRACE
  282                 if (KTRPOINT(td, KTR_CSW))
  283                         ktrcsw(0, 1, __func__);
  284 #endif
  285         }
  286 
  287         td_softdep_cleanup(td);
  288         MPASS(td->td_su == NULL);
  289 
  290         /*
  291          * If this thread tickled GEOM, we need to wait for the giggling to
  292          * stop before we return to userland
  293          */
  294         if (__predict_false(td->td_pflags & TDP_GEOM))
  295                 g_waitidle();
  296 
  297 #ifdef DIAGNOSTIC
  298         if (p->p_numthreads == 1 && (flags & TDF_NEEDSIGCHK) == 0) {
  299                 PROC_LOCK(p);
  300                 thread_lock(td);
  301                 /*
  302                  * Note that TDF_NEEDSIGCHK should be re-read from
  303                  * td_flags, since signal might have been delivered
  304                  * after we cleared td_flags above.  This is one of
  305                  * the reason for looping check for AST condition.
  306                  * See comment in userret() about P_PPWAIT.
  307                  */
  308                 if ((p->p_flag & P_PPWAIT) == 0 &&
  309                     (td->td_pflags & TDP_SIGFASTBLOCK) == 0) {
  310                         if (SIGPENDING(td) && (td->td_flags &
  311                             (TDF_NEEDSIGCHK | TDF_ASTPENDING)) !=
  312                             (TDF_NEEDSIGCHK | TDF_ASTPENDING)) {
  313                                 thread_unlock(td); /* fix dumps */
  314                                 panic(
  315         "failed2 to set signal flags for ast p %p td %p fl %x %x",
  316                                     p, td, flags, td->td_flags);
  317                         }
  318                 }
  319                 thread_unlock(td);
  320                 PROC_UNLOCK(p);
  321         }
  322 #endif
  323 
  324         /*
  325          * Check for signals. Unlocked reads of p_pendingcnt or
  326          * p_siglist might cause process-directed signal to be handled
  327          * later.
  328          */
  329         if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 ||
  330             !SIGISEMPTY(p->p_siglist)) {
  331                 sigfastblock_fetch(td);
  332                 PROC_LOCK(p);
  333                 old_boundary = ~TDB_BOUNDARY | (td->td_dbgflags & TDB_BOUNDARY);
  334                 td->td_dbgflags |= TDB_BOUNDARY;
  335                 mtx_lock(&p->p_sigacts->ps_mtx);
  336                 while ((sig = cursig(td)) != 0) {
  337                         KASSERT(sig >= 0, ("sig %d", sig));
  338                         postsig(sig);
  339                 }
  340                 mtx_unlock(&p->p_sigacts->ps_mtx);
  341                 td->td_dbgflags &= old_boundary;
  342                 PROC_UNLOCK(p);
  343                 resched_sigs = true;
  344         } else {
  345                 resched_sigs = false;
  346         }
  347 
  348         if ((flags & TDF_KQTICKLED) != 0)
  349                 kqueue_drain_schedtask();
  350 
  351         /*
  352          * Handle deferred update of the fast sigblock value, after
  353          * the postsig() loop was performed.
  354          */
  355         sigfastblock_setpend(td, resched_sigs);
  356 
  357 #ifdef KTRACE
  358         KTRUSERRET(td);
  359 #endif
  360 
  361         /*
  362          * We need to check to see if we have to exit or wait due to a
  363          * single threading requirement or some other STOP condition.
  364          */
  365         if (flags & TDF_NEEDSUSPCHK) {
  366                 PROC_LOCK(p);
  367                 thread_suspend_check(0);
  368                 PROC_UNLOCK(p);
  369         }
  370 
  371         if (td->td_pflags & TDP_OLDMASK) {
  372                 td->td_pflags &= ~TDP_OLDMASK;
  373                 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
  374         }
  375 
  376 #ifdef RACCT
  377         if (__predict_false(racct_enable && p->p_throttled != 0))
  378                 racct_proc_throttled(p);
  379 #endif
  380 
  381         userret(td, framep);
  382 }
  383 
  384 const char *
  385 syscallname(struct proc *p, u_int code)
  386 {
  387         static const char unknown[] = "unknown";
  388         struct sysentvec *sv;
  389 
  390         sv = p->p_sysent;
  391         if (sv->sv_syscallnames == NULL || code >= sv->sv_size)
  392                 return (unknown);
  393         return (sv->sv_syscallnames[code]);
  394 }
Cache object: 63bb4725e49cf4032233b9aa51aea80b
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.
FreeBSD/Linux Kernel Cross Reference sys/kern/subr_trap.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_trap.c
