1 /* $NetBSD: undefined.c,v 1.32 2007/11/05 20:43:02 ad 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 #define FAST_FPE 48 49 #include "opt_ddb.h" 50 #include "opt_kgdb.h" 51 52 #include <sys/param.h> 53 #ifdef KGDB 54 #include <sys/kgdb.h> 55 #endif 56 57 __KERNEL_RCSID(0, "$NetBSD: undefined.c,v 1.32 2007/11/05 20:43:02 ad Exp $"); 58 59 #include <sys/malloc.h> 60 #include <sys/queue.h> 61 #include <sys/signal.h> 62 #include <sys/systm.h> 63 #include <sys/proc.h> 64 #include <sys/user.h> 65 #include <sys/syslog.h> 66 #include <sys/vmmeter.h> 67 #ifdef FAST_FPE 68 #include <sys/acct.h> 69 #endif 70 #include <sys/userret.h> 71 72 #include <uvm/uvm_extern.h> 73 74 #include <machine/cpu.h> 75 #include <machine/frame.h> 76 #include <arm/undefined.h> 77 #include <machine/trap.h> 78 79 #include <arch/arm/arm/disassem.h> 80 81 #ifdef DDB 82 #include <ddb/db_output.h> 83 #include <machine/db_machdep.h> 84 #endif 85 86 #ifdef acorn26 87 #include <machine/machdep.h> 88 #endif 89 90 static int gdb_trapper(u_int, u_int, struct trapframe *, int); 91 92 LIST_HEAD(, undefined_handler) undefined_handlers[NUM_UNKNOWN_HANDLERS]; 93 94 95 void * 96 install_coproc_handler(int coproc, undef_handler_t handler) 97 { 98 struct undefined_handler *uh; 99 100 KASSERT(coproc >= 0 && coproc < NUM_UNKNOWN_HANDLERS); 101 KASSERT(handler != NULL); /* Used to be legal. */ 102 103 /* XXX: M_TEMP??? */ 104 MALLOC(uh, struct undefined_handler *, sizeof(*uh), M_TEMP, M_WAITOK); 105 uh->uh_handler = handler; 106 install_coproc_handler_static(coproc, uh); 107 return uh; 108 } 109 110 void 111 install_coproc_handler_static(int coproc, struct undefined_handler *uh) 112 { 113 114 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 115 } 116 117 void 118 remove_coproc_handler(void *cookie) 119 { 120 struct undefined_handler *uh = cookie; 121 122 LIST_REMOVE(uh, uh_link); 123 FREE(uh, M_TEMP); 124 } 125 126 127 static int 128 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 129 { 130 struct lwp *l; 131 l = (curlwp == NULL) ? &lwp0 : curlwp; 132 133 #ifdef THUMB_CODE 134 if (frame->tf_spsr & PSR_T_bit) { 135 if (insn == GDB_THUMB_BREAKPOINT) 136 goto bkpt; 137 } 138 else 139 #endif 140 { 141 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 142 #ifdef THUMB_CODE 143 bkpt: 144 #endif 145 if (code == FAULT_USER) { 146 ksiginfo_t ksi; 147 148 KSI_INIT_TRAP(&ksi); 149 ksi.ksi_signo = SIGTRAP; 150 ksi.ksi_code = TRAP_BRKPT; 151 ksi.ksi_addr = (u_int32_t *)addr; 152 ksi.ksi_trap = 0; 153 KERNEL_LOCK(1, l); 154 trapsignal(l, &ksi); 155 KERNEL_UNLOCK_LAST(l); 156 return 0; 157 } 158 #ifdef KGDB 159 return !kgdb_trap(T_BREAKPOINT, frame); 160 #endif 161 } 162 } 163 return 1; 164 } 165 166 static struct undefined_handler gdb_uh; 167 #ifdef THUMB_CODE 168 static struct undefined_handler gdb_uh_thumb; 169 #endif 170 171 void 172 undefined_init() 173 { 174 int loop; 175 176 /* Not actually necessary -- the initialiser is just NULL */ 177 for (loop = 0; loop < NUM_UNKNOWN_HANDLERS; ++loop) 178 LIST_INIT(&undefined_handlers[loop]); 179 180 /* Install handler for GDB breakpoints */ 181 gdb_uh.uh_handler = gdb_trapper; 182 install_coproc_handler_static(CORE_UNKNOWN_HANDLER, &gdb_uh); 183 #ifdef THUMB_CODE 184 gdb_uh_thumb.uh_handler = gdb_trapper; 185 install_coproc_handler_static(THUMB_UNKNOWN_HANDLER, &gdb_uh_thumb); 186 #endif 187 } 188 189 void 190 undefinedinstruction(trapframe_t *frame) 191 { 192 struct lwp *l; 193 u_int fault_pc; 194 int fault_instruction; 195 int fault_code; 196 int coprocessor; 197 int user; 198 struct undefined_handler *uh; 199 #ifdef VERBOSE_ARM32 200 int s; 201 #endif 202 203 /* Enable interrupts if they were enabled before the exception. */ 204 #ifdef acorn26 205 if ((frame->tf_r15 & R15_IRQ_DISABLE) == 0) 206 int_on(); 207 #else 208 if (!(frame->tf_spsr & I32_bit)) 209 enable_interrupts(I32_bit); 210 #endif 211 212 #ifndef acorn26 213 #ifdef THUMB_CODE 214 if (frame->tf_spsr & PSR_T_bit) 215 frame->tf_pc -= THUMB_INSN_SIZE; 216 else 217 #endif 218 { 219 frame->tf_pc -= INSN_SIZE; 220 } 221 #endif 222 223 #ifdef __PROG26 224 fault_pc = frame->tf_r15 & R15_PC; 225 #else 226 fault_pc = frame->tf_pc; 227 #endif 228 229 /* Get the current lwp/proc structure or lwp0/proc0 if there is none. */ 230 l = curlwp == NULL ? &lwp0 : curlwp; 231 232 #ifdef __PROG26 233 if ((frame->tf_r15 & R15_MODE) == R15_MODE_USR) { 234 #else 235 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 236 #endif 237 user = 1; 238 LWP_CACHE_CREDS(l, l->l_proc); 239 } else 240 user = 0; 241 242 243 #ifdef THUMB_CODE 244 if (frame->tf_spsr & PSR_T_bit) { 245 fault_instruction = fusword((void *)(fault_pc & ~1)); 246 } 247 else 248 #endif 249 { 250 /* 251 * Make sure the program counter is correctly aligned so we 252 * don't take an alignment fault trying to read the opcode. 253 */ 254 if (__predict_false((fault_pc & 3) != 0)) { 255 ksiginfo_t ksi; 256 /* Give the user an illegal instruction signal. */ 257 KSI_INIT_TRAP(&ksi); 258 ksi.ksi_signo = SIGILL; 259 ksi.ksi_code = ILL_ILLOPC; 260 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 261 KERNEL_LOCK(1, l); 262 trapsignal(l, &ksi); 263 KERNEL_UNLOCK_LAST(l); 264 userret(l); 265 return; 266 } 267 /* 268 * Should use fuword() here .. but in the interests of 269 * squeezing every bit of speed we will just use 270 * ReadWord(). We know the instruction can be read 271 * as was just executed so this will never fail unless 272 * the kernel is screwed up in which case it does 273 * not really matter does it ? 274 */ 275 276 fault_instruction = *(u_int32_t *)fault_pc; 277 } 278 279 /* Update vmmeter statistics */ 280 uvmexp.traps++; 281 282 #ifdef THUMB_CODE 283 if (frame->tf_spsr & PSR_T_bit) { 284 coprocessor = THUMB_UNKNOWN_HANDLER; 285 } 286 else 287 #endif 288 { 289 /* Check for coprocessor instruction */ 290 291 /* 292 * According to the datasheets you only need to look at 293 * bit 27 of the instruction to tell the difference 294 * between and undefined instruction and a coprocessor 295 * instruction following an undefined instruction trap. 296 * 297 * ARMv5 adds undefined instructions in the NV space, 298 * even when bit 27 is set. 299 */ 300 301 if ((fault_instruction & (1 << 27)) != 0 302 && (fault_instruction & 0xf0000000) != 0xf0000000) 303 coprocessor = (fault_instruction >> 8) & 0x0f; 304 else 305 coprocessor = CORE_UNKNOWN_HANDLER; 306 } 307 308 if (user) { 309 /* 310 * Modify the fault_code to reflect the USR/SVC state at 311 * time of fault. 312 */ 313 fault_code = FAULT_USER; 314 l->l_addr->u_pcb.pcb_tf = frame; 315 } else 316 fault_code = 0; 317 318 /* OK this is were we do something about the instruction. */ 319 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 320 if (uh->uh_handler(fault_pc, fault_instruction, frame, 321 fault_code) == 0) 322 break; 323 324 if (uh == NULL) { 325 /* Fault has not been handled */ 326 ksiginfo_t ksi; 327 328 #ifdef VERBOSE_ARM32 329 s = spltty(); 330 331 if ((fault_instruction & 0x0f000010) == 0x0e000000) { 332 printf("CDP\n"); 333 disassemble(fault_pc); 334 } else if ((fault_instruction & 0x0e000000) == 0x0c000000) { 335 printf("LDC/STC\n"); 336 disassemble(fault_pc); 337 } else if ((fault_instruction & 0x0f000010) == 0x0e000010) { 338 printf("MRC/MCR\n"); 339 disassemble(fault_pc); 340 } else if ((fault_instruction & ~INSN_COND_MASK) 341 != (KERNEL_BREAKPOINT & ~INSN_COND_MASK)) { 342 printf("Undefined instruction\n"); 343 disassemble(fault_pc); 344 } 345 346 splx(s); 347 #endif 348 349 if ((fault_code & FAULT_USER) == 0) { 350 #ifdef DDB 351 db_printf("Undefined instruction in kernel\n"); 352 kdb_trap(T_FAULT, frame); 353 #else 354 panic("undefined instruction in kernel"); 355 #endif 356 } 357 KSI_INIT_TRAP(&ksi); 358 ksi.ksi_signo = SIGILL; 359 ksi.ksi_code = ILL_ILLOPC; 360 ksi.ksi_addr = (u_int32_t *)fault_pc; 361 ksi.ksi_trap = fault_instruction; 362 KERNEL_LOCK(1, l); 363 trapsignal(l, &ksi); 364 KERNEL_UNLOCK_LAST(l); 365 } 366 367 if ((fault_code & FAULT_USER) == 0) 368 return; 369 370 #ifdef FAST_FPE 371 /* Optimised exit code */ 372 { 373 374 /* 375 * Check for reschedule request, at the moment there is only 376 * 1 ast so this code should always be run 377 */ 378 379 if (curcpu()->ci_want_resched) { 380 /* 381 * We are being preempted. 382 */ 383 preempt(); 384 } 385 386 /* Invoke MI userret code */ 387 mi_userret(l); 388 } 389 390 #else 391 userret(l); 392 #endif 393 } 394