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 #include <sys/lwp.h> 46 47 #include <machine/trap.h> 48 #include <machine/md_var.h> 49 #include <machine/segments.h> 50 #include <machine/cpu.h> 51 #include <machine/smp.h> 52 53 #include <err.h> 54 #include <signal.h> 55 #include <stdio.h> 56 #include <unistd.h> 57 58 int _ucodesel = GSEL(GUCODE_SEL, SEL_UPL); 59 int _udatasel = GSEL(GUDATA_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 * WARNING: Signals are not physically disabled here so we have to enter 71 * our critical section before bumping gd_intr_nesting_level or another 72 * interrupt can come along and get really confused. 73 */ 74 static 75 void 76 ipisig(int nada, siginfo_t *info, void *ctxp) 77 { 78 globaldata_t gd = mycpu; 79 thread_t td = gd->gd_curthread; 80 int save; 81 82 save = errno; 83 if (td->td_critcount == 0) { 84 ++td->td_critcount; 85 ++gd->gd_cnt.v_ipi; 86 ++gd->gd_intr_nesting_level; 87 atomic_swap_int(&gd->gd_npoll, 0); 88 lwkt_process_ipiq(); 89 --gd->gd_intr_nesting_level; 90 --td->td_critcount; 91 } else { 92 need_ipiq(); 93 } 94 errno = save; 95 } 96 97 /* 98 * Unconditionally stop or restart a cpu. 99 * 100 * Note: cpu_mask_all_signals() masks all signals except SIGXCPU itself. 101 * SIGXCPU itself is blocked on entry to stopsig() by the signal handler 102 * itself. 103 * 104 * WARNING: Signals are not physically disabled here so we have to enter 105 * our critical section before bumping gd_intr_nesting_level or another 106 * interrupt can come along and get really confused. 107 */ 108 static 109 void 110 stopsig(int nada, siginfo_t *info, void *ctxp) 111 { 112 globaldata_t gd = mycpu; 113 thread_t td = gd->gd_curthread; 114 sigset_t ss; 115 int save; 116 117 save = errno; 118 sigemptyset(&ss); 119 sigaddset(&ss, SIGALRM); 120 sigaddset(&ss, SIGIO); 121 sigaddset(&ss, SIGURG); 122 sigaddset(&ss, SIGQUIT); 123 sigaddset(&ss, SIGUSR1); 124 sigaddset(&ss, SIGUSR2); 125 sigaddset(&ss, SIGTERM); 126 sigaddset(&ss, SIGWINCH); 127 128 ++td->td_critcount; 129 ++gd->gd_intr_nesting_level; 130 while (CPUMASK_TESTMASK(stopped_cpus, gd->gd_cpumask)) { 131 sigsuspend(&ss); 132 } 133 --gd->gd_intr_nesting_level; 134 --td->td_critcount; 135 136 errno = save; 137 } 138 139 /* 140 * SIGIO is used by cothreads to signal back into the virtual kernel. 141 */ 142 static 143 void 144 kqueuesig(int nada, siginfo_t *info, void *ctxp) 145 { 146 globaldata_t gd = mycpu; 147 thread_t td = gd->gd_curthread; 148 int save; 149 150 save = errno; 151 if (td->td_critcount == 0) { 152 ++td->td_critcount; 153 ++gd->gd_intr_nesting_level; 154 kqueue_intr(NULL); 155 --gd->gd_intr_nesting_level; 156 --td->td_critcount; 157 } else { 158 need_kqueue(); 159 } 160 errno = save; 161 } 162 163 static 164 void 165 timersig(int nada, siginfo_t *info, void *ctxp) 166 { 167 globaldata_t gd = mycpu; 168 thread_t td = gd->gd_curthread; 169 int save; 170 171 save = errno; 172 if (td->td_critcount == 0) { 173 ++td->td_critcount; 174 ++gd->gd_intr_nesting_level; 175 vktimer_intr(NULL); 176 --gd->gd_intr_nesting_level; 177 --td->td_critcount; 178 } else { 179 need_timer(); 180 } 181 errno = save; 182 } 183 184 static 185 void 186 cosig(int nada, siginfo_t *info, void *ctxp) 187 { 188 int save; 189 190 save = errno; 191 /* handles critical section checks */ 192 signalintr(1); 193 errno = save; 194 } 195 196 static 197 void 198 infosig(int nada, siginfo_t *info, void *ctxp) 199 { 200 ucontext_t *ctx = ctxp; 201 char buf[256]; 202 int save; 203 204 save = errno; 205 snprintf(buf, sizeof(buf), "lwp %d pc=%p sp=%p\n", 206 (lwpid_t)lwp_gettid(), 207 (void *)(intptr_t)ctx->uc_mcontext.mc_rip, 208 (void *)(intptr_t)ctx->uc_mcontext.mc_rsp); 209 write(2, buf, strlen(buf)); 210 errno = save; 211 } 212 213 void 214 init_exceptions(void) 215 { 216 struct sigaction sa; 217 218 bzero(&sa, sizeof(sa)); 219 sa.sa_sigaction = exc_segfault; 220 sa.sa_flags |= SA_SIGINFO | SA_NODEFER; 221 sigemptyset(&sa.sa_mask); 222 sigaction(SIGBUS, &sa, NULL); 223 sigaction(SIGSEGV, &sa, NULL); 224 sigaction(SIGTRAP, &sa, NULL); 225 sigaction(SIGFPE, &sa, NULL); 226 227 sa.sa_flags &= ~SA_NODEFER; 228 229 #ifdef DDB 230 sa.sa_sigaction = exc_debugger; 231 sigaction(SIGQUIT, &sa, NULL); 232 #endif 233 sa.sa_sigaction = ipisig; 234 sigaction(SIGUSR1, &sa, NULL); 235 236 sa.sa_sigaction = stopsig; 237 sigaction(SIGXCPU, &sa, NULL); 238 239 sa.sa_sigaction = kqueuesig; 240 sigaction(SIGIO, &sa, NULL); 241 242 sa.sa_sigaction = timersig; 243 sigaction(SIGURG, &sa, NULL); 244 245 sa.sa_sigaction = cosig; 246 sigaction(SIGALRM, &sa, NULL); 247 248 sa.sa_sigaction = infosig; 249 sigaction(SIGINFO, &sa, NULL); 250 } 251 252 /* 253 * This function handles a segmentation fault. 254 * 255 * XXX We assume that trapframe is a subset of ucontext. It is as of 256 * this writing. 257 */ 258 static void 259 exc_segfault(int signo, siginfo_t *info, void *ctxp) 260 { 261 ucontext_t *ctx = ctxp; 262 int save; 263 264 save = errno; 265 #if 0 266 kprintf("CAUGHT SIG %d RIP %08lx ERR %08lx TRAPNO %ld " 267 "err %ld addr %08lx\n", 268 signo, 269 ctx->uc_mcontext.mc_rip, 270 ctx->uc_mcontext.mc_err, 271 ctx->uc_mcontext.mc_trapno & 0xFFFF, 272 ctx->uc_mcontext.mc_trapno >> 16, 273 ctx->uc_mcontext.mc_addr); 274 #endif 275 kern_trap((struct trapframe *)&ctx->uc_mcontext.mc_rdi); 276 splz(); 277 errno = save; 278 } 279 280 #ifdef DDB 281 282 static void 283 exc_debugger(int signo, siginfo_t *info, void *ctxp) 284 { 285 ucontext_t *ctx = ctxp; 286 int save; 287 288 save = errno; 289 kprintf("CAUGHT SIG %d RIP %08lx RSP %08lx TD %p\n", 290 signo, 291 ctx->uc_mcontext.mc_rip, 292 ctx->uc_mcontext.mc_rsp, 293 curthread); 294 Debugger("interrupt from console"); 295 errno = save; 296 } 297 298 #endif 299