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 69#include <vm/vm.h> 70#include <vm/vm_extern.h> 71 72#include <machine/asm.h> 73#include <machine/cpu.h> 74#include <machine/frame.h> 75#include <machine/undefined.h> 76#include <machine/trap.h> 77 78#include <machine/disassem.h> 79 80#ifdef DDB 81#include <ddb/db_output.h> 82#endif 83 84#ifdef KDB 85#include <machine/db_machdep.h> 86#endif 87 88static int gdb_trapper(u_int, u_int, struct trapframe *, int); 89 90LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS]; 91 92 93void * 94install_coproc_handler(int coproc, undef_handler_t handler) 95{ 96 struct undefined_handler *uh; 97 98 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc")); 99 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */ 100 101 /* XXX: M_TEMP??? */ 102 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK); 103 uh->uh_handler = handler; 104 install_coproc_handler_static(coproc, uh); 105 return uh; 106} 107 108void 109install_coproc_handler_static(int coproc, struct undefined_handler *uh) 110{ 111 112 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 113} 114 115void 116remove_coproc_handler(void *cookie) 117{ 118 struct undefined_handler *uh = cookie; 119 120 LIST_REMOVE(uh, uh_link); 121 free(uh, M_TEMP); 122} 123 124 125static int 126gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 127{ 128 struct thread *td; 129 ksiginfo_t ksi; 130 131 td = (curthread == NULL) ? &thread0 : curthread; 132 133 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 134 if (code == FAULT_USER) { 135 ksiginfo_init_trap(&ksi); 136 ksi.ksi_signo = SIGTRAP; 137 ksi.ksi_code = TRAP_BRKPT; 138 ksi.ksi_addr = (u_int32_t *)addr; 139 trapsignal(td, &ksi); 140 return 0; 141 } 142#if 0 143#ifdef KGDB 144 return !kgdb_trap(T_BREAKPOINT, frame); 145#endif 146#endif 147 } 148 return 1; 149} 150 151static struct undefined_handler gdb_uh; 152 153void 154undefined_init() 155{ 156 int loop; 157 158 /* Not actually necessary -- the initialiser is just NULL */ 159 for (loop = 0; loop < MAX_COPROCS; ++loop) 160 LIST_INIT(&undefined_handlers[loop]); 161 162 /* Install handler for GDB breakpoints */ 163 gdb_uh.uh_handler = gdb_trapper; 164 install_coproc_handler_static(0, &gdb_uh); 165} 166 167 168void 169undefinedinstruction(trapframe_t *frame) 170{ 171 struct thread *td; 172 u_int fault_pc; 173 int fault_instruction; 174 int fault_code; 175 int coprocessor; 176 struct undefined_handler *uh; 177#ifdef VERBOSE_ARM32 178 int s; 179#endif 180 ksiginfo_t ksi; 181 182 /* Enable interrupts if they were enabled before the exception. */ 183 if (!(frame->tf_spsr & I32_bit)) 184 enable_interrupts(I32_bit|F32_bit); 185 186 frame->tf_pc -= INSN_SIZE; 187 PCPU_INC(cnt.v_trap); 188 189 fault_pc = frame->tf_pc; 190 191 /* 192 * Get the current thread/proc structure or thread0/proc0 if there is 193 * none. 194 */ 195 td = curthread == NULL ? &thread0 : curthread; 196 197 /* 198 * Make sure the program counter is correctly aligned so we 199 * don't take an alignment fault trying to read the opcode. 200 */ 201 if (__predict_false((fault_pc & 3) != 0)) { 202 ksiginfo_init_trap(&ksi); 203 ksi.ksi_signo = SIGILL; 204 ksi.ksi_code = ILL_ILLADR; 205 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 206 trapsignal(td, &ksi); 207 userret(td, frame); 208 return; 209 } 210 211 /* 212 * Should use fuword() here .. but in the interests of squeezing every 213 * bit of speed we will just use ReadWord(). We know the instruction 214 * can be read as was just executed so this will never fail unless the 215 * kernel is screwed up in which case it does not really matter does 216 * it ? 217 */ 218 219 fault_instruction = *(u_int32_t *)fault_pc; 220 221 /* Update vmmeter statistics */ 222#if 0 223 uvmexp.traps++; 224#endif 225 /* Check for coprocessor instruction */ 226 227 /* 228 * According to the datasheets you only need to look at bit 27 of the 229 * instruction to tell the difference between and undefined 230 * instruction and a coprocessor instruction following an undefined 231 * instruction trap. 232 */ 233 234 coprocessor = 0; 235 if ((fault_instruction & (1 << 27)) != 0) 236 coprocessor = (fault_instruction >> 8) & 0x0f; 237#ifdef VFP 238 else { /* check for special instructions */ 239 if (((fault_instruction & 0xfe000000) == 0xf2000000) || 240 ((fault_instruction & 0xff100000) == 0xf4000000)) 241 coprocessor = 10; /* vfp / simd */ 242 } 243#endif /* VFP */ 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 userret(td, frame); 292} 293