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 1.11 2008/04/28 07:05:09 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 #include <machine/smp.h> 54 55 #include <err.h> 56 #include <signal.h> 57 #include <unistd.h> 58 59 int _ucodesel = GSEL(GUCODE_SEL, SEL_UPL); 60 int _udatasel = GSEL(GUDATA_SEL, SEL_UPL); 61 62 static void exc_segfault(int signo, siginfo_t *info, void *ctx); 63 #ifdef DDB 64 static void exc_debugger(int signo, siginfo_t *info, void *ctx); 65 #endif 66 67 #ifdef SMP 68 69 /* 70 * IPIs are 'fast' interrupts, so we deal with them directly from our 71 * signal handler. 72 * 73 * WARNING: Signals are not physically disabled here so we have to enter 74 * our critical section before bumping gd_intr_nesting_level or another 75 * interrupt can come along and get really confused. 76 */ 77 static 78 void 79 ipisig(int nada, siginfo_t *info, void *ctxp) 80 { 81 if (curthread->td_pri < TDPRI_CRIT) { 82 curthread->td_pri += TDPRI_CRIT; 83 ++mycpu->gd_intr_nesting_level; 84 lwkt_process_ipiq(); 85 --mycpu->gd_intr_nesting_level; 86 curthread->td_pri -= TDPRI_CRIT; 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 sigset_t ss; 108 109 sigemptyset(&ss); 110 sigaddset(&ss, SIGALRM); 111 sigaddset(&ss, SIGIO); 112 sigaddset(&ss, SIGQUIT); 113 sigaddset(&ss, SIGUSR1); 114 sigaddset(&ss, SIGUSR2); 115 sigaddset(&ss, SIGTERM); 116 sigaddset(&ss, SIGWINCH); 117 118 curthread->td_pri += TDPRI_CRIT; 119 ++mycpu->gd_intr_nesting_level; 120 while (stopped_cpus & mycpu->gd_cpumask) { 121 sigsuspend(&ss); 122 } 123 --mycpu->gd_intr_nesting_level; 124 curthread->td_pri -= TDPRI_CRIT; 125 } 126 127 #endif 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 void 144 init_exceptions(void) 145 { 146 struct sigaction sa; 147 148 bzero(&sa, sizeof(sa)); 149 sa.sa_sigaction = exc_segfault; 150 sa.sa_flags |= SA_SIGINFO | SA_NODEFER; 151 sigemptyset(&sa.sa_mask); 152 sigaction(SIGBUS, &sa, NULL); 153 sigaction(SIGSEGV, &sa, NULL); 154 sigaction(SIGTRAP, &sa, NULL); 155 sigaction(SIGFPE, &sa, NULL); 156 157 #ifdef DDB 158 sa.sa_sigaction = exc_debugger; 159 sigaction(SIGQUIT, &sa, NULL); 160 #endif 161 #ifdef SMP 162 sa.sa_sigaction = ipisig; 163 sigaction(SIGUSR1, &sa, NULL); 164 sa.sa_sigaction = stopsig; 165 sigaction(SIGXCPU, &sa, NULL); 166 #endif 167 #if 0 168 sa.sa_sigaction = iosig; 169 sigaction(SIGIO, &sa, NULL); 170 #endif 171 } 172 173 /* 174 * This function handles a segmentation fault. 175 * 176 * XXX We assume that trapframe is a subset of ucontext. It is as of 177 * this writing. 178 */ 179 static void 180 exc_segfault(int signo, siginfo_t *info, void *ctxp) 181 { 182 ucontext_t *ctx = ctxp; 183 184 #if 0 185 kprintf("CAUGHT SIG %d RIP %08lx ERR %08lx TRAPNO %ld " 186 "err %ld addr %08lx\n", 187 signo, 188 ctx->uc_mcontext.mc_rip, 189 ctx->uc_mcontext.mc_err, 190 ctx->uc_mcontext.mc_trapno & 0xFFFF, 191 ctx->uc_mcontext.mc_trapno >> 16, 192 ctx->uc_mcontext.mc_addr); 193 #endif 194 kern_trap((struct trapframe *)&ctx->uc_mcontext.mc_rdi); 195 splz(); 196 } 197 198 #ifdef DDB 199 200 static void 201 exc_debugger(int signo, siginfo_t *info, void *ctx) 202 { 203 Debugger("interrupt from console"); 204 } 205 206 #endif 207