sys/platform/vkernel/i386/exception.c

   1
   2 /*
   3  * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to The DragonFly Project
   6  * by Matthew Dillon <dillon@backplane.com>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * $DragonFly: src/sys/platform/vkernel/i386/exception.c,v 1.6 2007/06/17 16:46:15 dillon Exp $
  36  */
  37
  38 #include "opt_ddb.h"
  39 #include <sys/types.h>
  40 #include <sys/systm.h>
  41 #include <sys/reboot.h>
  42 #include <sys/kernel.h>
  43 #include <sys/kthread.h>
  44 #include <sys/reboot.h>
  45 #include <ddb/ddb.h>
  46
  47 #include <sys/thread2.h>
  48
  49 #include <machine/trap.h>
  50 #include <machine/md_var.h>
  51 #include <machine/segments.h>
  52
  53 #include <err.h>
  54 #include <signal.h>
  55 #include <unistd.h>
  56
  57 int _ucodesel = LSEL(LUCODE_SEL, SEL_UPL);
  58 int _udatasel = LSEL(LUDATA_SEL, SEL_UPL);
  59
  60 static void exc_segfault(int signo, siginfo_t *info, void *ctx);
  61 #ifdef DDB
  62 static void exc_debugger(int signo, siginfo_t *info, void *ctx);
  63 #endif
  64
  65 /* signal shutdown thread misc. */
  66
  67 static void sigshutdown_daemon( void );
  68 static struct thread *sigshutdown_thread;
  69 static struct kproc_desc sigshut_kp = {
  70         "sigshutdown", sigshutdown_daemon, &sigshutdown_thread
  71 };
  72
  73 static
  74 void
  75 ipi(int nada, siginfo_t *info, void *ctxp)
  76 {
  77         struct globaldata *gd = mycpu;
  78
  79         kprintf("ipi\n");
  80         ++mycpu->gd_intr_nesting_level;
  81         if (IN_CRITICAL_SECT(curthread)) {
  82                 kprintf("JAT: ipi in critical section\n");
  83                 gd->gd_reqflags &= RQF_IPIQ;
  84                 lwkt_process_ipiq();
  85         } else {
  86                 kprintf("JAT: ipi NOT in critical section\n");
  87                 curthread->td_pri += TDPRI_CRIT;
  88                 lwkt_process_ipiq();
  89                 curthread->td_pri -= TDPRI_CRIT;
  90         }
  91         --mycpu->gd_intr_nesting_level;
  92 }
  93
  94
  95 void
  96 init_exceptions(void)
  97 {
  98         struct sigaction sa;
  99
 100         bzero(&sa, sizeof(sa));
 101         sa.sa_sigaction = exc_segfault;
 102         sa.sa_flags |= SA_SIGINFO;
 103         sigemptyset(&sa.sa_mask);
 104         sigaction(SIGSEGV, &sa, NULL);
 105         sigaction(SIGTRAP, &sa, NULL);
 106
 107 #ifdef DDB
 108         sa.sa_sigaction = exc_debugger;
 109         sigaction(SIGQUIT, &sa, NULL);
 110 #endif
 111
 112         sa.sa_sigaction = ipi;
 113         if (sigaction(SIGUSR1, &sa, NULL) != 0)
 114         {
 115                 warn("ipi handler setup failed");
 116                 panic("IPI setup failed");
 117         }
 118
 119         bzero(&sa, sizeof(sa));
 120         sigemptyset(&sa.sa_mask);
 121         sa.sa_flags |= SA_MAILBOX | SA_NODEFER;
 122         sa.sa_mailbox = &mdcpu->gd_shutdown;
 123         sigaction(SIGTERM, &sa, NULL);
 124 }
 125
 126 /*
 127  * This function handles a segmentation fault.
 128  *
 129  * XXX We assume that trapframe is a subset of ucontext.  It is as of
 130  *     this writing.
 131  */
 132 static void
 133 exc_segfault(int signo, siginfo_t *info, void *ctxp)
 134 {
 135         ucontext_t *ctx = ctxp;
 136
 137 #if 0
 138         kprintf("CAUGHT SEGFAULT EIP %08x ERR %08x TRAPNO %d err %d\n",
 139                 ctx->uc_mcontext.mc_eip,
 140                 ctx->uc_mcontext.mc_err,
 141                 ctx->uc_mcontext.mc_trapno & 0xFFFF,
 142                 ctx->uc_mcontext.mc_trapno >> 16);
 143 #endif
 144         kern_trap((struct trapframe *)&ctx->uc_mcontext.mc_gs);
 145         splz();
 146 }
 147
 148 /*
 149  * This function runs in a thread dedicated to external shutdown signals.
 150  *
 151  * Currently, when a vkernel recieves a SIGTERM, either the VKERNEL init(8)
 152  * is signaled with SIGUSR2, or the VKERNEL simply shuts down, preventing
 153  * fsck's when the VKERNEL is restarted.
 154  */
 155 static void
 156 sigshutdown_daemon( void )
 157 {
 158         while (mdcpu->gd_shutdown == 0) {
 159                 tsleep(&mdcpu->gd_shutdown, 0, "sswait", 0);
 160         }
 161         mdcpu->gd_shutdown = 0;
 162         kprintf("Caught SIGTERM from host system. Shutting down...\n");
 163         if (initproc != NULL) {
 164                 ksignal(initproc, SIGUSR2);
 165         }
 166         else {
 167                 reboot(RB_POWEROFF);
 168         }
 169 }
 170 SYSINIT(sigshutdown, SI_BOOT2_PROC0, SI_ORDER_ANY,
 171         kproc_start, &sigshut_kp);
 172
 173 #ifdef DDB
 174
 175 static void
 176 exc_debugger(int signo, siginfo_t *info, void *ctx)
 177 {
 178         Debugger("interrupt from console");
 179 }
 180
 181 #endif