undefined.c revision 331017
1/* $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $ */ 2 3/*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (c) 2001 Ben Harris. 7 * Copyright (c) 1995 Mark Brinicombe. 8 * Copyright (c) 1995 Brini. 9 * All rights reserved. 10 * 11 * This code is derived from software written for Brini by Mark Brinicombe 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by Brini. 24 * 4. The name of the company nor the name of the author may be used to 25 * endorse or promote products derived from this software without specific 26 * prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 29 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 30 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 32 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 33 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 34 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * RiscBSD kernel project 41 * 42 * undefined.c 43 * 44 * Fault handler 45 * 46 * Created : 06/01/95 47 */ 48 49 50#include "opt_ddb.h" 51 52#include <sys/cdefs.h> 53__FBSDID("$FreeBSD: stable/11/sys/arm/arm/undefined.c 331017 2018-03-15 19:08:33Z kevans $"); 54 55#include <sys/param.h> 56#include <sys/malloc.h> 57#include <sys/queue.h> 58#include <sys/signal.h> 59#include <sys/systm.h> 60#include <sys/proc.h> 61#include <sys/syslog.h> 62#include <sys/vmmeter.h> 63#include <sys/lock.h> 64#include <sys/mutex.h> 65#include <sys/signalvar.h> 66#include <sys/ptrace.h> 67#include <sys/vmmeter.h> 68#ifdef KDB 69#include <sys/kdb.h> 70#endif 71 72#include <vm/vm.h> 73#include <vm/vm_extern.h> 74 75#include <machine/armreg.h> 76#include <machine/asm.h> 77#include <machine/cpu.h> 78#include <machine/frame.h> 79#include <machine/undefined.h> 80#include <machine/trap.h> 81 82#include <machine/disassem.h> 83 84#ifdef DDB 85#include <ddb/db_output.h> 86#endif 87 88#ifdef KDB 89#include <machine/db_machdep.h> 90#endif 91 92#define ARM_COPROC_INSN(insn) (((insn) & (1 << 27)) != 0) 93#define ARM_VFP_INSN(insn) ((((insn) & 0xfe000000) == 0xf2000000) || \ 94 (((insn) & 0xff100000) == 0xf4000000)) 95#define ARM_COPROC(insn) (((insn) >> 8) & 0xf) 96 97#define THUMB_32BIT_INSN(insn) ((insn) >= 0xe800) 98#define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26)) 99#define THUMB_COPROC_UNDEFINED(insn) (((insn) & 0x3e << 20) == 0) 100#define THUMB_VFP_INSN(insn) (((insn) & (3 << 24)) == (3 << 24)) 101#define THUMB_COPROC(insn) (((insn) >> 8) & 0xf) 102 103#define COPROC_VFP 10 104 105static int gdb_trapper(u_int, u_int, struct trapframe *, int); 106 107LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS]; 108 109 110void * 111install_coproc_handler(int coproc, undef_handler_t handler) 112{ 113 struct undefined_handler *uh; 114 115 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc")); 116 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */ 117 118 /* XXX: M_TEMP??? */ 119 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK); 120 uh->uh_handler = handler; 121 install_coproc_handler_static(coproc, uh); 122 return uh; 123} 124 125void 126install_coproc_handler_static(int coproc, struct undefined_handler *uh) 127{ 128 129 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 130} 131 132void 133remove_coproc_handler(void *cookie) 134{ 135 struct undefined_handler *uh = cookie; 136 137 LIST_REMOVE(uh, uh_link); 138 free(uh, M_TEMP); 139} 140 141 142static int 143gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 144{ 145 struct thread *td; 146 ksiginfo_t ksi; 147 148 td = (curthread == NULL) ? &thread0 : curthread; 149 150 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 151 if (code == FAULT_USER) { 152 ksiginfo_init_trap(&ksi); 153 ksi.ksi_signo = SIGTRAP; 154 ksi.ksi_code = TRAP_BRKPT; 155 ksi.ksi_addr = (u_int32_t *)addr; 156 trapsignal(td, &ksi); 157 return 0; 158 } 159#if 0 160#ifdef KGDB 161 return !kgdb_trap(T_BREAKPOINT, frame); 162#endif 163#endif 164 } 165 return 1; 166} 167 168static struct undefined_handler gdb_uh; 169 170void 171undefined_init(void) 172{ 173 int loop; 174 175 /* Not actually necessary -- the initialiser is just NULL */ 176 for (loop = 0; loop < MAX_COPROCS; ++loop) 177 LIST_INIT(&undefined_handlers[loop]); 178 179 /* Install handler for GDB breakpoints */ 180 gdb_uh.uh_handler = gdb_trapper; 181 install_coproc_handler_static(0, &gdb_uh); 182} 183 184 185void 186undefinedinstruction(struct trapframe *frame) 187{ 188 struct thread *td; 189 u_int fault_pc; 190 int fault_instruction; 191 int fault_code; 192 int coprocessor; 193 struct undefined_handler *uh; 194 int error; 195#ifdef VERBOSE_ARM32 196 int s; 197#endif 198 ksiginfo_t ksi; 199 200 /* Enable interrupts if they were enabled before the exception. */ 201 if (__predict_true(frame->tf_spsr & PSR_I) == 0) 202 enable_interrupts(PSR_I); 203 if (__predict_true(frame->tf_spsr & PSR_F) == 0) 204 enable_interrupts(PSR_F); 205 206 PCPU_INC(cnt.v_trap); 207 208 fault_pc = frame->tf_pc; 209 210 /* 211 * Get the current thread/proc structure or thread0/proc0 if there is 212 * none. 213 */ 214 td = curthread == NULL ? &thread0 : curthread; 215 216 coprocessor = 0; 217 if ((frame->tf_spsr & PSR_T) == 0) { 218 /* 219 * Make sure the program counter is correctly aligned so we 220 * don't take an alignment fault trying to read the opcode. 221 */ 222 if (__predict_false((fault_pc & 3) != 0)) { 223 ksiginfo_init_trap(&ksi); 224 ksi.ksi_signo = SIGILL; 225 ksi.ksi_code = ILL_ILLADR; 226 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 227 trapsignal(td, &ksi); 228 userret(td, frame); 229 return; 230 } 231 232 /* 233 * Should use fuword() here .. but in the interests of 234 * squeezing every bit of speed we will just use ReadWord(). 235 * We know the instruction can be read as was just executed 236 * so this will never fail unless the kernel is screwed up 237 * in which case it does not really matter does it ? 238 */ 239 240 fault_instruction = *(u_int32_t *)fault_pc; 241 242 /* Check for coprocessor instruction */ 243 244 /* 245 * According to the datasheets you only need to look at bit 246 * 27 of the instruction to tell the difference between and 247 * undefined instruction and a coprocessor instruction 248 * following an undefined instruction trap. 249 */ 250 251 if (ARM_COPROC_INSN(fault_instruction)) 252 coprocessor = ARM_COPROC(fault_instruction); 253 else { /* check for special instructions */ 254 if (ARM_VFP_INSN(fault_instruction)) 255 coprocessor = COPROC_VFP; /* vfp / simd */ 256 } 257 } else { 258#if __ARM_ARCH >= 7 259 fault_instruction = *(uint16_t *)fault_pc; 260 if (THUMB_32BIT_INSN(fault_instruction)) { 261 fault_instruction <<= 16; 262 fault_instruction |= *(uint16_t *)(fault_pc + 2); 263 264 /* 265 * Is it a Coprocessor, Advanced SIMD, or 266 * Floating-point instruction. 267 */ 268 if (THUMB_COPROC_INSN(fault_instruction)) { 269 if (THUMB_COPROC_UNDEFINED(fault_instruction)) { 270 /* undefined insn */ 271 } else if (THUMB_VFP_INSN(fault_instruction)) 272 coprocessor = COPROC_VFP; 273 else 274 coprocessor = 275 THUMB_COPROC(fault_instruction); 276 } 277 } 278#else 279 /* 280 * No support for Thumb-2 on this cpu 281 */ 282 ksiginfo_init_trap(&ksi); 283 ksi.ksi_signo = SIGILL; 284 ksi.ksi_code = ILL_ILLADR; 285 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 286 trapsignal(td, &ksi); 287 userret(td, frame); 288 return; 289#endif 290 } 291 292 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 293 /* 294 * Modify the fault_code to reflect the USR/SVC state at 295 * time of fault. 296 */ 297 fault_code = FAULT_USER; 298 td->td_frame = frame; 299 } else 300 fault_code = 0; 301 302 /* OK this is were we do something about the instruction. */ 303 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 304 if (uh->uh_handler(fault_pc, fault_instruction, frame, 305 fault_code) == 0) 306 break; 307 308 if (fault_code & FAULT_USER) { 309 /* TODO: No support for ptrace from Thumb-2 */ 310 if ((frame->tf_spsr & PSR_T) == 0 && 311 fault_instruction == PTRACE_BREAKPOINT) { 312 PROC_LOCK(td->td_proc); 313 _PHOLD(td->td_proc); 314 error = ptrace_clear_single_step(td); 315 _PRELE(td->td_proc); 316 PROC_UNLOCK(td->td_proc); 317 if (error != 0) { 318 ksiginfo_init_trap(&ksi); 319 ksi.ksi_signo = SIGILL; 320 ksi.ksi_code = ILL_ILLOPC; 321 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 322 trapsignal(td, &ksi); 323 } 324 return; 325 } 326 } 327 328 if (uh == NULL && (fault_code & FAULT_USER)) { 329 /* Fault has not been handled */ 330 ksiginfo_init_trap(&ksi); 331 ksi.ksi_signo = SIGILL; 332 ksi.ksi_code = ILL_ILLOPC; 333 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 334 trapsignal(td, &ksi); 335 } 336 337 if ((fault_code & FAULT_USER) == 0) { 338 if (fault_instruction == KERNEL_BREAKPOINT) { 339#ifdef KDB 340 kdb_trap(T_BREAKPOINT, 0, frame); 341#else 342 printf("No debugger in kernel.\n"); 343#endif 344 return; 345 } 346 else 347 panic("Undefined instruction in kernel.\n"); 348 } 349 350 userret(td, frame); 351} 352