sys/platform/vkernel64/x86_64/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
  36 #include "opt_ddb.h"
  37 #include <sys/types.h>
  38 #include <sys/systm.h>
  39 #include <sys/reboot.h>
  40 #include <sys/kernel.h>
  41 #include <sys/kthread.h>
  42 #include <ddb/ddb.h>
  43
  44 #include <sys/thread2.h>
  45
  46 #include <machine/trap.h>
  47 #include <machine/md_var.h>
  48 #include <machine/segments.h>
  49 #include <machine/cpu.h>
  50 #include <machine/smp.h>
  51
  52 #include <err.h>
  53 #include <signal.h>
  54 #include <stdio.h>
  55 #include <unistd.h>
  56
  57 int _ucodesel = GSEL(GUCODE_SEL, SEL_UPL);
  58 int _udatasel = GSEL(GUDATA_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 /*
  66  * IPIs are 'fast' interrupts, so we deal with them directly from our
  67  * signal handler.
  68  *
  69  * WARNING: Signals are not physically disabled here so we have to enter
  70  * our critical section before bumping gd_intr_nesting_level or another
  71  * interrupt can come along and get really confused.
  72  */
  73 static
  74 void
  75 ipisig(int nada, siginfo_t *info, void *ctxp)
  76 {
  77         globaldata_t gd = mycpu;
  78         thread_t td = gd->gd_curthread;
  79
  80         if (td->td_critcount == 0) {
  81                 ++td->td_critcount;
  82                 ++gd->gd_intr_nesting_level;
  83                 atomic_swap_int(&gd->gd_npoll, 0);
  84                 lwkt_process_ipiq();
  85                 --gd->gd_intr_nesting_level;
  86                 --td->td_critcount;
  87         } else {
  88                 need_ipiq();
  89         }
  90 }
  91
  92 /*
  93  * Unconditionally stop or restart a cpu.
  94  *
  95  * Note: cpu_mask_all_signals() masks all signals except SIGXCPU itself.
  96  * SIGXCPU itself is blocked on entry to stopsig() by the signal handler
  97  * itself.
  98  *
  99  * WARNING: Signals are not physically disabled here so we have to enter
 100  * our critical section before bumping gd_intr_nesting_level or another
 101  * interrupt can come along and get really confused.
 102  */
 103 static
 104 void
 105 stopsig(int nada, siginfo_t *info, void *ctxp)
 106 {
 107         globaldata_t gd = mycpu;
 108         thread_t td = gd->gd_curthread;
 109         sigset_t ss;
 110
 111         sigemptyset(&ss);
 112         sigaddset(&ss, SIGALRM);
 113         sigaddset(&ss, SIGIO);
 114         sigaddset(&ss, SIGQUIT);
 115         sigaddset(&ss, SIGUSR1);
 116         sigaddset(&ss, SIGUSR2);
 117         sigaddset(&ss, SIGTERM);
 118         sigaddset(&ss, SIGWINCH);
 119
 120         ++td->td_critcount;
 121         ++gd->gd_intr_nesting_level;
 122         while (CPUMASK_TESTMASK(stopped_cpus, gd->gd_cpumask)) {
 123                 sigsuspend(&ss);
 124         }
 125         --gd->gd_intr_nesting_level;
 126         --td->td_critcount;
 127 }
 128
 129 #if 0
 130
 131 /*
 132  * SIGIO is used by cothreads to signal back into the virtual kernel.
 133  */
 134 static
 135 void
 136 iosig(int nada, siginfo_t *info, void *ctxp)
 137 {
 138         signalintr(4);
 139 }
 140
 141 #endif
 142
 143 static
 144 void
 145 infosig(int nada, siginfo_t *info, void *ctxp)
 146 {
 147         ucontext_t *ctx = ctxp;
 148         char buf[256];
 149
 150         snprintf(buf, sizeof(buf), "lwp %d pc=%p sp=%p\n",
 151                 (int)lwp_gettid(),
 152                 (void *)(intptr_t)ctx->uc_mcontext.mc_rip,
 153                 (void *)(intptr_t)ctx->uc_mcontext.mc_rsp);
 154         write(2, buf, strlen(buf));
 155 }
 156
 157 void
 158 init_exceptions(void)
 159 {
 160         struct sigaction sa;
 161
 162         bzero(&sa, sizeof(sa));
 163         sa.sa_sigaction = exc_segfault;
 164         sa.sa_flags |= SA_SIGINFO | SA_NODEFER;
 165         sigemptyset(&sa.sa_mask);
 166         sigaction(SIGBUS, &sa, NULL);
 167         sigaction(SIGSEGV, &sa, NULL);
 168         sigaction(SIGTRAP, &sa, NULL);
 169         sigaction(SIGFPE, &sa, NULL);
 170
 171         sa.sa_flags &= ~SA_NODEFER;
 172
 173 #ifdef DDB
 174         sa.sa_sigaction = exc_debugger;
 175         sigaction(SIGQUIT, &sa, NULL);
 176 #endif
 177         sa.sa_sigaction = ipisig;
 178         sigaction(SIGUSR1, &sa, NULL);
 179         sa.sa_sigaction = stopsig;
 180         sigaction(SIGXCPU, &sa, NULL);
 181 #if 0
 182         sa.sa_sigaction = iosig;
 183         sigaction(SIGIO, &sa, NULL);
 184 #endif
 185         sa.sa_sigaction = infosig;
 186         sigaction(SIGINFO, &sa, NULL);
 187 }
 188
 189 /*
 190  * This function handles a segmentation fault.
 191  *
 192  * XXX We assume that trapframe is a subset of ucontext.  It is as of
 193  *     this writing.
 194  */
 195 static void
 196 exc_segfault(int signo, siginfo_t *info, void *ctxp)
 197 {
 198         ucontext_t *ctx = ctxp;
 199
 200 #if 0
 201         kprintf("CAUGHT SIG %d RIP %08lx ERR %08lx TRAPNO %ld "
 202                 "err %ld addr %08lx\n",
 203                 signo,
 204                 ctx->uc_mcontext.mc_rip,
 205                 ctx->uc_mcontext.mc_err,
 206                 ctx->uc_mcontext.mc_trapno & 0xFFFF,
 207                 ctx->uc_mcontext.mc_trapno >> 16,
 208                 ctx->uc_mcontext.mc_addr);
 209 #endif
 210         kern_trap((struct trapframe *)&ctx->uc_mcontext.mc_rdi);
 211         splz();
 212 }
 213
 214 #ifdef DDB
 215
 216 static void
 217 exc_debugger(int signo, siginfo_t *info, void *ctxp)
 218 {
 219         ucontext_t *ctx = ctxp;
 220
 221         kprintf("CAUGHT SIG %d RIP %08lx RSP %08lx TD %p\n",
 222                 signo,
 223                 ctx->uc_mcontext.mc_rip,
 224                 ctx->uc_mcontext.mc_rsp,
 225                 curthread);
 226         Debugger("interrupt from console");
 227 }
 228
 229 #endif