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 1.7 2007/07/01 02:51:43 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 #include <machine/cpu.h>
  53
  54 #include <err.h>
  55 #include <signal.h>
  56 #include <unistd.h>
  57
  58 int _ucodesel = LSEL(LUCODE_SEL, SEL_UPL);
  59 int _udatasel = LSEL(LUDATA_SEL, SEL_UPL);
  60
  61 static void exc_segfault(int signo, siginfo_t *info, void *ctx);
  62 #ifdef DDB
  63 static void exc_debugger(int signo, siginfo_t *info, void *ctx);
  64 #endif
  65
  66 /*
  67  * IPIs are 'fast' interrupts, so we deal with them directly from our
  68  * signal handler.
  69  */
  70 static
  71 void
  72 ipi(int nada, siginfo_t *info, void *ctxp)
  73 {
  74         ++mycpu->gd_intr_nesting_level;
  75         if (curthread->td_pri < TDPRI_CRIT) {
  76                 curthread->td_pri += TDPRI_CRIT;
  77                 lwkt_process_ipiq();
  78                 curthread->td_pri -= TDPRI_CRIT;
  79         } else {
  80                 need_ipiq();
  81         }
  82         --mycpu->gd_intr_nesting_level;
  83 }
  84
  85 void
  86 init_exceptions(void)
  87 {
  88         struct sigaction sa;
  89
  90         bzero(&sa, sizeof(sa));
  91         sa.sa_sigaction = exc_segfault;
  92         sa.sa_flags |= SA_SIGINFO;
  93         sigemptyset(&sa.sa_mask);
  94         sigaction(SIGSEGV, &sa, NULL);
  95         sigaction(SIGTRAP, &sa, NULL);
  96
  97 #ifdef DDB
  98         sa.sa_sigaction = exc_debugger;
  99         sigaction(SIGQUIT, &sa, NULL);
 100 #endif
 101
 102         sa.sa_sigaction = ipi;
 103         if (sigaction(SIGUSR1, &sa, NULL) != 0)
 104         {
 105                 warn("ipi handler setup failed");
 106                 panic("IPI setup failed");
 107         }
 108 }
 109
 110 /*
 111  * This function handles a segmentation fault.
 112  *
 113  * XXX We assume that trapframe is a subset of ucontext.  It is as of
 114  *     this writing.
 115  */
 116 static void
 117 exc_segfault(int signo, siginfo_t *info, void *ctxp)
 118 {
 119         ucontext_t *ctx = ctxp;
 120
 121 #if 0
 122         kprintf("CAUGHT SEGFAULT EIP %08x ERR %08x TRAPNO %d err %d\n",
 123                 ctx->uc_mcontext.mc_eip,
 124                 ctx->uc_mcontext.mc_err,
 125                 ctx->uc_mcontext.mc_trapno & 0xFFFF,
 126                 ctx->uc_mcontext.mc_trapno >> 16);
 127 #endif
 128         kern_trap((struct trapframe *)&ctx->uc_mcontext.mc_gs);
 129         splz();
 130 }
 131
 132 #ifdef DDB
 133
 134 static void
 135 exc_debugger(int signo, siginfo_t *info, void *ctx)
 136 {
 137         Debugger("interrupt from console");
 138 }
 139
 140 #endif