1 /* $NetBSD: undefined.c,v 1.43 2011/11/16 16:59:47 he 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 1.43 2011/11/16 16:59:47 he 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/syslog.h> 65 #include <sys/vmmeter.h> 66 #ifdef FAST_FPE 67 #include <sys/acct.h> 68 #endif 69 #include <sys/userret.h> 70 71 #include <uvm/uvm_extern.h> 72 73 #include <machine/cpu.h> 74 #include <machine/frame.h> 75 #include <arm/undefined.h> 76 #include <machine/trap.h> 77 78 #include <arch/arm/arm/disassem.h> 79 80 #ifdef DDB 81 #include <ddb/db_output.h> 82 #include <machine/db_machdep.h> 83 #endif 84 85 #ifdef acorn26 86 #include <machine/machdep.h> 87 #endif 88 89 static int gdb_trapper(u_int, u_int, struct trapframe *, int); 90 91 LIST_HEAD(, undefined_handler) undefined_handlers[NUM_UNKNOWN_HANDLERS]; 92 93 94 void * 95 install_coproc_handler(int coproc, undef_handler_t handler) 96 { 97 struct undefined_handler *uh; 98 99 KASSERT(coproc >= 0 && coproc < NUM_UNKNOWN_HANDLERS); 100 KASSERT(handler != NULL); /* Used to be legal. */ 101 102 /* XXX: M_TEMP??? */ 103 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK); 104 uh->uh_handler = handler; 105 install_coproc_handler_static(coproc, uh); 106 return uh; 107 } 108 109 void 110 install_coproc_handler_static(int coproc, struct undefined_handler *uh) 111 { 112 113 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 114 } 115 116 void 117 remove_coproc_handler(void *cookie) 118 { 119 struct undefined_handler *uh = cookie; 120 121 LIST_REMOVE(uh, uh_link); 122 free(uh, M_TEMP); 123 } 124 125 static int 126 cp15_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 127 { 128 struct lwp * const l = curlwp; 129 130 #ifdef THUMB_CODE 131 if (frame->tf_spsr & PSR_T_bit) 132 return 1; 133 #endif 134 if (code != FAULT_USER) 135 return 1; 136 137 /* 138 * Don't overwrite sp, pc, etc. 139 */ 140 const u_int regno = (insn >> 12) & 15; 141 if (regno > 12) 142 return 1; 143 144 /* 145 * Get a pointer to the register used in the instruction to be emulated. 146 */ 147 register_t * const regp = &frame->tf_r0 + regno; 148 149 /* 150 * Handle MRC p15, 0, <Rd>, c13, c0, 3 (Read User read-only thread id) 151 */ 152 if ((insn & 0xffff0fff) == 0xee1d0f70) { 153 *regp = (uintptr_t)l->l_private; 154 frame->tf_pc += INSN_SIZE; 155 return 0; 156 } 157 158 /* 159 * Handle {MRC,MCR} p15, 0, <Rd>, c13, c0, 2 (User read/write thread id) 160 */ 161 if ((insn & 0xffef0fff) == 0xee0d0f50) { 162 struct pcb * const pcb = lwp_getpcb(l); 163 if (insn & 0x00100000) 164 *regp = pcb->pcb_user_pid_rw; 165 else 166 pcb->pcb_user_pid_rw = *regp; 167 frame->tf_pc += INSN_SIZE; 168 return 0; 169 } 170 171 return 1; 172 } 173 174 static int 175 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 176 { 177 struct lwp * const l = curlwp; 178 179 #ifdef THUMB_CODE 180 if (frame->tf_spsr & PSR_T_bit) { 181 if (insn == GDB_THUMB_BREAKPOINT) 182 goto bkpt; 183 } 184 else 185 #endif 186 { 187 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 188 #ifdef THUMB_CODE 189 bkpt: 190 #endif 191 if (code == FAULT_USER) { 192 ksiginfo_t ksi; 193 194 KSI_INIT_TRAP(&ksi); 195 ksi.ksi_signo = SIGTRAP; 196 ksi.ksi_code = TRAP_BRKPT; 197 ksi.ksi_addr = (u_int32_t *)addr; 198 ksi.ksi_trap = 0; 199 trapsignal(l, &ksi); 200 return 0; 201 } 202 #ifdef KGDB 203 return !kgdb_trap(T_BREAKPOINT, frame); 204 #endif 205 } 206 } 207 return 1; 208 } 209 210 static struct undefined_handler cp15_uh; 211 static struct undefined_handler gdb_uh; 212 #ifdef THUMB_CODE 213 static struct undefined_handler gdb_uh_thumb; 214 #endif 215 216 void 217 undefined_init(void) 218 { 219 int loop; 220 221 /* Not actually necessary -- the initialiser is just NULL */ 222 for (loop = 0; loop < NUM_UNKNOWN_HANDLERS; ++loop) 223 LIST_INIT(&undefined_handlers[loop]); 224 225 /* Install handler for CP15 emulation */ 226 cp15_uh.uh_handler = cp15_trapper; 227 install_coproc_handler_static(SYSTEM_COPROC, &cp15_uh); 228 229 /* Install handler for GDB breakpoints */ 230 gdb_uh.uh_handler = gdb_trapper; 231 install_coproc_handler_static(CORE_UNKNOWN_HANDLER, &gdb_uh); 232 #ifdef THUMB_CODE 233 gdb_uh_thumb.uh_handler = gdb_trapper; 234 install_coproc_handler_static(THUMB_UNKNOWN_HANDLER, &gdb_uh_thumb); 235 #endif 236 } 237 238 void 239 undefinedinstruction(trapframe_t *frame) 240 { 241 struct lwp *l; 242 u_int fault_pc; 243 int fault_instruction; 244 int fault_code; 245 int coprocessor; 246 int user; 247 struct undefined_handler *uh; 248 #ifdef VERBOSE_ARM32 249 int s; 250 #endif 251 252 /* Enable interrupts if they were enabled before the exception. */ 253 #ifdef acorn26 254 if ((frame->tf_r15 & R15_IRQ_DISABLE) == 0) 255 int_on(); 256 #else 257 restore_interrupts(frame->tf_spsr & IF32_bits); 258 #endif 259 260 #ifndef acorn26 261 #ifdef THUMB_CODE 262 if (frame->tf_spsr & PSR_T_bit) 263 frame->tf_pc -= THUMB_INSN_SIZE; 264 else 265 #endif 266 { 267 frame->tf_pc -= INSN_SIZE; 268 } 269 #endif 270 271 #ifdef __PROG26 272 fault_pc = frame->tf_r15 & R15_PC; 273 #else 274 fault_pc = frame->tf_pc; 275 #endif 276 277 /* Get the current lwp/proc structure or lwp0/proc0 if there is none. */ 278 l = curlwp; 279 280 #ifdef __PROG26 281 if ((frame->tf_r15 & R15_MODE) == R15_MODE_USR) { 282 #else 283 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 284 #endif 285 user = 1; 286 LWP_CACHE_CREDS(l, l->l_proc); 287 } else 288 user = 0; 289 290 291 #ifdef THUMB_CODE 292 if (frame->tf_spsr & PSR_T_bit) { 293 fault_instruction = fusword((void *)(fault_pc & ~1)); 294 } 295 else 296 #endif 297 { 298 /* 299 * Make sure the program counter is correctly aligned so we 300 * don't take an alignment fault trying to read the opcode. 301 */ 302 if (__predict_false((fault_pc & 3) != 0)) { 303 ksiginfo_t ksi; 304 /* Give the user an illegal instruction signal. */ 305 KSI_INIT_TRAP(&ksi); 306 ksi.ksi_signo = SIGILL; 307 ksi.ksi_code = ILL_ILLOPC; 308 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 309 trapsignal(l, &ksi); 310 userret(l); 311 return; 312 } 313 /* 314 * Should use fuword() here .. but in the interests of 315 * squeezing every bit of speed we will just use 316 * ReadWord(). We know the instruction can be read 317 * as was just executed so this will never fail unless 318 * the kernel is screwed up in which case it does 319 * not really matter does it ? 320 */ 321 322 fault_instruction = *(u_int32_t *)fault_pc; 323 } 324 325 /* Update vmmeter statistics */ 326 curcpu()->ci_data.cpu_ntrap++; 327 328 #ifdef THUMB_CODE 329 if (frame->tf_spsr & PSR_T_bit) { 330 coprocessor = THUMB_UNKNOWN_HANDLER; 331 } 332 else 333 #endif 334 { 335 /* Check for coprocessor instruction */ 336 337 /* 338 * According to the datasheets you only need to look at 339 * bit 27 of the instruction to tell the difference 340 * between and undefined instruction and a coprocessor 341 * instruction following an undefined instruction trap. 342 * 343 * ARMv5 adds undefined instructions in the NV space, 344 * even when bit 27 is set. 345 */ 346 347 if ((fault_instruction & (1 << 27)) != 0 348 && (fault_instruction & 0xf0000000) != 0xf0000000) 349 coprocessor = (fault_instruction >> 8) & 0x0f; 350 else 351 coprocessor = CORE_UNKNOWN_HANDLER; 352 } 353 354 if (user) { 355 struct pcb *pcb = lwp_getpcb(l); 356 /* 357 * Modify the fault_code to reflect the USR/SVC state at 358 * time of fault. 359 */ 360 fault_code = FAULT_USER; 361 pcb->pcb_tf = frame; 362 } else 363 fault_code = 0; 364 365 /* OK this is were we do something about the instruction. */ 366 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 367 if (uh->uh_handler(fault_pc, fault_instruction, frame, 368 fault_code) == 0) 369 break; 370 371 if (uh == NULL) { 372 /* Fault has not been handled */ 373 ksiginfo_t ksi; 374 375 #ifdef VERBOSE_ARM32 376 s = spltty(); 377 378 if ((fault_instruction & 0x0f000010) == 0x0e000000) { 379 printf("CDP\n"); 380 disassemble(fault_pc); 381 } else if ((fault_instruction & 0x0e000000) == 0x0c000000) { 382 printf("LDC/STC\n"); 383 disassemble(fault_pc); 384 } else if ((fault_instruction & 0x0f000010) == 0x0e000010) { 385 printf("MRC/MCR\n"); 386 disassemble(fault_pc); 387 } else if ((fault_instruction & ~INSN_COND_MASK) 388 != (KERNEL_BREAKPOINT & ~INSN_COND_MASK)) { 389 printf("Undefined instruction\n"); 390 disassemble(fault_pc); 391 } 392 393 splx(s); 394 #endif 395 396 if ((fault_code & FAULT_USER) == 0) { 397 #ifdef DDB 398 db_printf("Undefined instruction in kernel\n"); 399 kdb_trap(T_FAULT, frame); 400 #else 401 panic("undefined instruction in kernel"); 402 #endif 403 } 404 KSI_INIT_TRAP(&ksi); 405 ksi.ksi_signo = SIGILL; 406 ksi.ksi_code = ILL_ILLOPC; 407 ksi.ksi_addr = (u_int32_t *)fault_pc; 408 ksi.ksi_trap = fault_instruction; 409 trapsignal(l, &ksi); 410 } 411 412 if ((fault_code & FAULT_USER) == 0) 413 return; 414 415 #ifdef FAST_FPE 416 /* Optimised exit code */ 417 { 418 /* 419 * Check for reschedule request, at the moment there is only 420 * 1 ast so this code should always be run 421 */ 422 if (curcpu()->ci_want_resched) { 423 /* 424 * We are being preempted. 425 */ 426 preempt(); 427 } 428 429 /* Invoke MI userret code */ 430 mi_userret(l); 431 } 432 #else 433 userret(l); 434 #endif 435 } 436