1 /* $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $ */ 2 3 /*- 4 * Copyright (c) 2001 Ben Harris. 5 * Copyright (c) 1995 Mark Brinicombe. 6 * Copyright (c) 1995 Brini. 7 * All rights reserved. 8 * 9 * This code is derived from software written for Brini by Mark Brinicombe 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by Brini. 22 * 4. The name of the company nor the name of the author may be used to 23 * endorse or promote products derived from this software without specific 24 * prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 27 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 28 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 30 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 31 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 32 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * RiscBSD kernel project 39 * 40 * undefined.c 41 * 42 * Fault handler 43 * 44 * Created : 06/01/95 45 */ 46 47 48 #include "opt_ddb.h" 49 50 #include <sys/cdefs.h> 51 __FBSDID("$FreeBSD$"); 52 53 #include <sys/param.h> 54 #include <sys/malloc.h> 55 #include <sys/queue.h> 56 #include <sys/signal.h> 57 #include <sys/systm.h> 58 #include <sys/proc.h> 59 #include <sys/syslog.h> 60 #include <sys/vmmeter.h> 61 #include <sys/lock.h> 62 #include <sys/mutex.h> 63 #include <sys/signalvar.h> 64 #include <sys/ptrace.h> 65 #ifdef KDB 66 #include <sys/kdb.h> 67 #endif 68 #ifdef FAST_FPE 69 #include <sys/acct.h> 70 #endif 71 72 #include <vm/vm.h> 73 #include <vm/vm_extern.h> 74 75 #include <machine/asm.h> 76 #include <machine/cpu.h> 77 #include <machine/frame.h> 78 #include <machine/undefined.h> 79 #include <machine/trap.h> 80 81 #include <machine/disassem.h> 82 83 #ifdef DDB 84 #include <ddb/db_output.h> 85 #endif 86 87 #ifdef KDB 88 #include <machine/db_machdep.h> 89 #endif 90 91 static int gdb_trapper(u_int, u_int, struct trapframe *, int); 92 #ifdef FAST_FPE 93 extern int want_resched; 94 #endif 95 96 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS]; 97 98 99 void * 100 install_coproc_handler(int coproc, undef_handler_t handler) 101 { 102 struct undefined_handler *uh; 103 104 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc")); 105 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */ 106 107 /* XXX: M_TEMP??? */ 108 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK); 109 uh->uh_handler = handler; 110 install_coproc_handler_static(coproc, uh); 111 return uh; 112 } 113 114 void 115 install_coproc_handler_static(int coproc, struct undefined_handler *uh) 116 { 117 118 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 119 } 120 121 void 122 remove_coproc_handler(void *cookie) 123 { 124 struct undefined_handler *uh = cookie; 125 126 LIST_REMOVE(uh, uh_link); 127 free(uh, M_TEMP); 128 } 129 130 131 static int 132 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 133 { 134 struct thread *td; 135 ksiginfo_t ksi; 136 137 td = (curthread == NULL) ? &thread0 : curthread; 138 139 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 140 if (code == FAULT_USER) { 141 ksiginfo_init_trap(&ksi); 142 ksi.ksi_signo = SIGTRAP; 143 ksi.ksi_code = TRAP_BRKPT; 144 ksi.ksi_addr = (u_int32_t *)addr; 145 trapsignal(td, &ksi); 146 return 0; 147 } 148 #if 0 149 #ifdef KGDB 150 return !kgdb_trap(T_BREAKPOINT, frame); 151 #endif 152 #endif 153 } 154 return 1; 155 } 156 157 static struct undefined_handler gdb_uh; 158 159 void 160 undefined_init() 161 { 162 int loop; 163 164 /* Not actually necessary -- the initialiser is just NULL */ 165 for (loop = 0; loop < MAX_COPROCS; ++loop) 166 LIST_INIT(&undefined_handlers[loop]); 167 168 /* Install handler for GDB breakpoints */ 169 gdb_uh.uh_handler = gdb_trapper; 170 install_coproc_handler_static(0, &gdb_uh); 171 } 172 173 174 void 175 undefinedinstruction(trapframe_t *frame) 176 { 177 struct thread *td; 178 u_int fault_pc; 179 int fault_instruction; 180 int fault_code; 181 int coprocessor; 182 struct undefined_handler *uh; 183 #ifdef VERBOSE_ARM32 184 int s; 185 #endif 186 ksiginfo_t ksi; 187 188 /* Enable interrupts if they were enabled before the exception. */ 189 if (!(frame->tf_spsr & I32_bit)) 190 enable_interrupts(I32_bit|F32_bit); 191 192 frame->tf_pc -= INSN_SIZE; 193 PCPU_INC(cnt.v_trap); 194 195 fault_pc = frame->tf_pc; 196 197 /* 198 * Get the current thread/proc structure or thread0/proc0 if there is 199 * none. 200 */ 201 td = curthread == NULL ? &thread0 : curthread; 202 203 /* 204 * Make sure the program counter is correctly aligned so we 205 * don't take an alignment fault trying to read the opcode. 206 */ 207 if (__predict_false((fault_pc & 3) != 0)) { 208 ksiginfo_init_trap(&ksi); 209 ksi.ksi_signo = SIGILL; 210 ksi.ksi_code = ILL_ILLADR; 211 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 212 trapsignal(td, &ksi); 213 userret(td, frame); 214 return; 215 } 216 217 /* 218 * Should use fuword() here .. but in the interests of squeezing every 219 * bit of speed we will just use ReadWord(). We know the instruction 220 * can be read as was just executed so this will never fail unless the 221 * kernel is screwed up in which case it does not really matter does 222 * it ? 223 */ 224 225 fault_instruction = *(u_int32_t *)fault_pc; 226 227 /* Update vmmeter statistics */ 228 #if 0 229 uvmexp.traps++; 230 #endif 231 /* Check for coprocessor instruction */ 232 233 /* 234 * According to the datasheets you only need to look at bit 27 of the 235 * instruction to tell the difference between and undefined 236 * instruction and a coprocessor instruction following an undefined 237 * instruction trap. 238 */ 239 240 if ((fault_instruction & (1 << 27)) != 0) 241 coprocessor = (fault_instruction >> 8) & 0x0f; 242 else 243 coprocessor = 0; 244 245 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 246 /* 247 * Modify the fault_code to reflect the USR/SVC state at 248 * time of fault. 249 */ 250 fault_code = FAULT_USER; 251 td->td_frame = frame; 252 } else 253 fault_code = 0; 254 255 /* OK this is were we do something about the instruction. */ 256 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 257 if (uh->uh_handler(fault_pc, fault_instruction, frame, 258 fault_code) == 0) 259 break; 260 261 if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) { 262 PROC_LOCK(td->td_proc); 263 _PHOLD(td->td_proc); 264 ptrace_clear_single_step(td); 265 _PRELE(td->td_proc); 266 PROC_UNLOCK(td->td_proc); 267 return; 268 } 269 270 if (uh == NULL && (fault_code & FAULT_USER)) { 271 /* Fault has not been handled */ 272 ksiginfo_init_trap(&ksi); 273 ksi.ksi_signo = SIGILL; 274 ksi.ksi_code = ILL_ILLOPC; 275 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 276 trapsignal(td, &ksi); 277 } 278 279 if ((fault_code & FAULT_USER) == 0) { 280 if (fault_instruction == KERNEL_BREAKPOINT) { 281 #ifdef KDB 282 kdb_trap(T_BREAKPOINT, 0, frame); 283 #else 284 printf("No debugger in kernel.\n"); 285 #endif 286 return; 287 } else 288 panic("Undefined instruction in kernel.\n"); 289 } 290 291 #ifdef FAST_FPE 292 /* Optimised exit code */ 293 { 294 295 /* 296 * Check for reschedule request, at the moment there is only 297 * 1 ast so this code should always be run 298 */ 299 300 if (want_resched) { 301 /* 302 * We are being preempted. 303 */ 304 preempt(0); 305 } 306 307 /* Invoke MI userret code */ 308 mi_userret(td); 309 310 #if 0 311 l->l_priority = l->l_usrpri; 312 313 curcpu()->ci_schedstate.spc_curpriority = l->l_priority; 314 #endif 315 } 316 317 #else 318 userret(td, frame); 319 #endif 320 } 321