sys/kern/subr_trap.c

   1 /*-
   2  * Copyright (C) 1994, David Greenman
   3  * Copyright (c) 1990, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  * Copyright (c) 2007 The FreeBSD Foundation
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * the University of Utah, and William Jolitz.
   9  *
  10  * Portions of this software were developed by A. Joseph Koshy under
  11  * sponsorship from the FreeBSD Foundation and Google, Inc.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgement:
  23  *      This product includes software developed by the University of
  24  *      California, Berkeley and its contributors.
  25  * 4. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  *
  41  *      from: @(#)trap.c        7.4 (Berkeley) 5/13/91
  42  */
  43
  44 #include <sys/cdefs.h>
  45 __FBSDID("$FreeBSD$");
  46
  47 #include "opt_hwpmc_hooks.h"
  48 #include "opt_ktrace.h"
  49 #include "opt_mac.h"
  50 #ifdef __i386__
  51 #include "opt_npx.h"
  52 #endif
  53 #include "opt_sched.h"
  54
  55 #include <sys/param.h>
  56 #include <sys/bus.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/resourcevar.h>
  64 #include <sys/sched.h>
  65 #include <sys/signalvar.h>
  66 #include <sys/systm.h>
  67 #include <sys/vmmeter.h>
  68 #ifdef KTRACE
  69 #include <sys/uio.h>
  70 #include <sys/ktrace.h>
  71 #endif
  72
  73 #include <machine/cpu.h>
  74 #include <machine/pcb.h>
  75
  76 #include <security/mac/mac_framework.h>
  77
  78 /*
  79  * Define the code needed before returning to user mode, for trap and
  80  * syscall.
  81  */
  82 void
  83 userret(struct thread *td, struct trapframe *frame)
  84 {
  85         struct proc *p = td->td_proc;
  86
  87         CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
  88             td->td_name);
  89 #ifdef DIAGNOSTIC
  90         /* Check that we called signotify() enough. */
  91         PROC_LOCK(p);
  92         thread_lock(td);
  93         if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
  94             (td->td_flags & TDF_ASTPENDING) == 0))
  95                 printf("failed to set signal flags properly for ast()\n");
  96         thread_unlock(td);
  97         PROC_UNLOCK(p);
  98 #endif
  99 #ifdef KTRACE
 100         KTRUSERRET(td);
 101 #endif
 102         /*
 103          * If this thread tickled GEOM, we need to wait for the giggling to
 104          * stop before we return to userland
 105          */
 106         if (td->td_pflags & TDP_GEOM)
 107                 g_waitidle();
 108
 109         /*
 110          * Charge system time if profiling.
 111          */
 112         if (p->p_flag & P_PROFIL) {
 113                 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
 114         }
 115         /*
 116          * Let the scheduler adjust our priority etc.
 117          */
 118         sched_userret(td);
 119         KASSERT(td->td_locks == 0,
 120             ("userret: Returning with %d locks held.", td->td_locks));
 121 }
 122
 123 /*
 124  * Process an asynchronous software trap.
 125  * This is relatively easy.
 126  * This function will return with preemption disabled.
 127  */
 128 void
 129 ast(struct trapframe *framep)
 130 {
 131         struct thread *td;
 132         struct proc *p;
 133         int flags;
 134         int sig;
 135 #if defined(DEV_NPX) && !defined(SMP)
 136         int ucode;
 137         ksiginfo_t ksi;
 138 #endif
 139
 140         td = curthread;
 141         p = td->td_proc;
 142
 143         CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
 144             p->p_comm);
 145         KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
 146         WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
 147         mtx_assert(&Giant, MA_NOTOWNED);
 148         THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
 149         td->td_frame = framep;
 150         td->td_pticks = 0;
 151
 152         /*
 153          * This updates the td_flag's for the checks below in one
 154          * "atomic" operation with turning off the astpending flag.
 155          * If another AST is triggered while we are handling the
 156          * AST's saved in flags, the astpending flag will be set and
 157          * ast() will be called again.
 158          */
 159         thread_lock(td);
 160         flags = td->td_flags;
 161         td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
 162             TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
 163         thread_unlock(td);
 164         PCPU_INC(cnt.v_trap);
 165
 166         if (td->td_ucred != p->p_ucred)
 167                 cred_update_thread(td);
 168         if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
 169                 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
 170                 td->td_profil_ticks = 0;
 171                 td->td_pflags &= ~TDP_OWEUPC;
 172         }
 173 #if defined(HWPMC_HOOKS)
 174         if (td->td_pflags & TDP_CALLCHAIN) {
 175                 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN,
 176                     (void *) framep);
 177                 td->td_pflags &= ~TDP_CALLCHAIN;
 178         }
 179 #endif
 180         if (flags & TDF_ALRMPEND) {
 181                 PROC_LOCK(p);
 182                 psignal(p, SIGVTALRM);
 183                 PROC_UNLOCK(p);
 184         }
 185 #if defined(DEV_NPX) && !defined(SMP)
 186         if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
 187                 atomic_clear_int(&PCPU_GET(curpcb)->pcb_flags,
 188                     PCB_NPXTRAP);
 189                 ucode = npxtrap();
 190                 if (ucode != -1) {
 191                         ksiginfo_init_trap(&ksi);
 192                         ksi.ksi_signo = SIGFPE;
 193                         ksi.ksi_code = ucode;
 194                         trapsignal(td, &ksi);
 195                 }
 196         }
 197 #endif
 198         if (flags & TDF_PROFPEND) {
 199                 PROC_LOCK(p);
 200                 psignal(p, SIGPROF);
 201                 PROC_UNLOCK(p);
 202         }
 203 #ifdef MAC
 204         if (flags & TDF_MACPEND)
 205                 mac_thread_userret(td);
 206 #endif
 207         if (flags & TDF_NEEDRESCHED) {
 208 #ifdef KTRACE
 209                 if (KTRPOINT(td, KTR_CSW))
 210                         ktrcsw(1, 1);
 211 #endif
 212                 thread_lock(td);
 213                 sched_prio(td, td->td_user_pri);
 214                 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL);
 215                 thread_unlock(td);
 216 #ifdef KTRACE
 217                 if (KTRPOINT(td, KTR_CSW))
 218                         ktrcsw(0, 1);
 219 #endif
 220         }
 221         if (flags & TDF_NEEDSIGCHK) {
 222                 PROC_LOCK(p);
 223                 mtx_lock(&p->p_sigacts->ps_mtx);
 224                 while ((sig = cursig(td)) != 0)
 225                         postsig(sig);
 226                 mtx_unlock(&p->p_sigacts->ps_mtx);
 227                 PROC_UNLOCK(p);
 228         }
 229         /*
 230          * We need to check to see if we have to exit or wait due to a
 231          * single threading requirement or some other STOP condition.
 232          */
 233         if (flags & TDF_NEEDSUSPCHK) {
 234                 PROC_LOCK(p);
 235                 thread_suspend_check(0);
 236                 PROC_UNLOCK(p);
 237         }
 238
 239         userret(td, framep);
 240         mtx_assert(&Giant, MA_NOTOWNED);
 241 }