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: stable/11/sys/arm/arm/undefined.c 331722 2018-03-29 02:50:57Z eadler $"); 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#include <sys/vmmeter.h> 66#ifdef KDB 67#include <sys/kdb.h> 68#endif 69 70#include <vm/vm.h> 71#include <vm/vm_extern.h> 72 73#include <machine/armreg.h> 74#include <machine/asm.h> 75#include <machine/cpu.h> 76#include <machine/frame.h> 77#include <machine/undefined.h> 78#include <machine/trap.h> 79 80#include <machine/disassem.h> 81 82#ifdef DDB 83#include <ddb/db_output.h> 84#endif 85 86#ifdef KDB 87#include <machine/db_machdep.h> 88#endif 89 90#define ARM_COPROC_INSN(insn) (((insn) & (1 << 27)) != 0) 91#define ARM_VFP_INSN(insn) ((((insn) & 0xfe000000) == 0xf2000000) || \ 92 (((insn) & 0xff100000) == 0xf4000000)) 93#define ARM_COPROC(insn) (((insn) >> 8) & 0xf) 94 95#define THUMB_32BIT_INSN(insn) ((insn) >= 0xe800) 96#define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26)) 97#define THUMB_COPROC_UNDEFINED(insn) (((insn) & 0x3e << 20) == 0) 98#define THUMB_VFP_INSN(insn) (((insn) & (3 << 24)) == (3 << 24)) 99#define THUMB_COPROC(insn) (((insn) >> 8) & 0xf) 100 101#define COPROC_VFP 10 102 103static int gdb_trapper(u_int, u_int, struct trapframe *, int); 104 105LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS]; 106 107 108void * 109install_coproc_handler(int coproc, undef_handler_t handler) 110{ 111 struct undefined_handler *uh; 112 113 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc")); 114 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */ 115 116 /* XXX: M_TEMP??? */ 117 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK); 118 uh->uh_handler = handler; 119 install_coproc_handler_static(coproc, uh); 120 return uh; 121} 122 123void 124install_coproc_handler_static(int coproc, struct undefined_handler *uh) 125{ 126 127 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 128} 129 130void 131remove_coproc_handler(void *cookie) 132{ 133 struct undefined_handler *uh = cookie; 134 135 LIST_REMOVE(uh, uh_link); 136 free(uh, M_TEMP); 137} 138 139 140static int 141gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 142{ 143 struct thread *td; 144 ksiginfo_t ksi; 145 146 td = (curthread == NULL) ? &thread0 : curthread; 147 148 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 149 if (code == FAULT_USER) { 150 ksiginfo_init_trap(&ksi); 151 ksi.ksi_signo = SIGTRAP; 152 ksi.ksi_code = TRAP_BRKPT; 153 ksi.ksi_addr = (u_int32_t *)addr; 154 trapsignal(td, &ksi); 155 return 0; 156 } 157#if 0 158#ifdef KGDB 159 return !kgdb_trap(T_BREAKPOINT, frame); 160#endif 161#endif 162 } 163 return 1; 164} 165 166static struct undefined_handler gdb_uh; 167 168void 169undefined_init(void) 170{ 171 int loop; 172 173 /* Not actually necessary -- the initialiser is just NULL */ 174 for (loop = 0; loop < MAX_COPROCS; ++loop) 175 LIST_INIT(&undefined_handlers[loop]); 176 177 /* Install handler for GDB breakpoints */ 178 gdb_uh.uh_handler = gdb_trapper; 179 install_coproc_handler_static(0, &gdb_uh); 180} 181 182 183void 184undefinedinstruction(struct trapframe *frame) 185{ 186 struct thread *td; 187 u_int fault_pc; 188 int fault_instruction; 189 int fault_code; 190 int coprocessor; 191 struct undefined_handler *uh; 192 int error; 193#ifdef VERBOSE_ARM32 194 int s; 195#endif 196 ksiginfo_t ksi; 197 198 /* Enable interrupts if they were enabled before the exception. */ 199 if (__predict_true(frame->tf_spsr & PSR_I) == 0) 200 enable_interrupts(PSR_I); 201 if (__predict_true(frame->tf_spsr & PSR_F) == 0) 202 enable_interrupts(PSR_F); 203 204 PCPU_INC(cnt.v_trap); 205 206 fault_pc = frame->tf_pc; 207 208 /* 209 * Get the current thread/proc structure or thread0/proc0 if there is 210 * none. 211 */ 212 td = curthread == NULL ? &thread0 : curthread; 213 214 coprocessor = 0; 215 if ((frame->tf_spsr & PSR_T) == 0) { 216 /* 217 * Make sure the program counter is correctly aligned so we 218 * don't take an alignment fault trying to read the opcode. 219 */ 220 if (__predict_false((fault_pc & 3) != 0)) { 221 ksiginfo_init_trap(&ksi); 222 ksi.ksi_signo = SIGILL; 223 ksi.ksi_code = ILL_ILLADR; 224 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 225 trapsignal(td, &ksi); 226 userret(td, frame); 227 return; 228 } 229 230 /* 231 * Should use fuword() here .. but in the interests of 232 * squeezing every bit of speed we will just use ReadWord(). 233 * We know the instruction can be read as was just executed 234 * so this will never fail unless the kernel is screwed up 235 * in which case it does not really matter does it ? 236 */ 237 238 fault_instruction = *(u_int32_t *)fault_pc; 239 240 /* Check for coprocessor instruction */ 241 242 /* 243 * According to the datasheets you only need to look at bit 244 * 27 of the instruction to tell the difference between and 245 * undefined instruction and a coprocessor instruction 246 * following an undefined instruction trap. 247 */ 248 249 if (ARM_COPROC_INSN(fault_instruction)) 250 coprocessor = ARM_COPROC(fault_instruction); 251 else { /* check for special instructions */ 252 if (ARM_VFP_INSN(fault_instruction)) 253 coprocessor = COPROC_VFP; /* vfp / simd */ 254 } 255 } else { 256#if __ARM_ARCH >= 7 257 fault_instruction = *(uint16_t *)fault_pc; 258 if (THUMB_32BIT_INSN(fault_instruction)) { 259 fault_instruction <<= 16; 260 fault_instruction |= *(uint16_t *)(fault_pc + 2); 261 262 /* 263 * Is it a Coprocessor, Advanced SIMD, or 264 * Floating-point instruction. 265 */ 266 if (THUMB_COPROC_INSN(fault_instruction)) { 267 if (THUMB_COPROC_UNDEFINED(fault_instruction)) { 268 /* undefined insn */ 269 } else if (THUMB_VFP_INSN(fault_instruction)) 270 coprocessor = COPROC_VFP; 271 else 272 coprocessor = 273 THUMB_COPROC(fault_instruction); 274 } 275 } 276#else 277 /* 278 * No support for Thumb-2 on this cpu 279 */ 280 ksiginfo_init_trap(&ksi); 281 ksi.ksi_signo = SIGILL; 282 ksi.ksi_code = ILL_ILLADR; 283 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 284 trapsignal(td, &ksi); 285 userret(td, frame); 286 return; 287#endif 288 } 289 290 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 291 /* 292 * Modify the fault_code to reflect the USR/SVC state at 293 * time of fault. 294 */ 295 fault_code = FAULT_USER; 296 td->td_frame = frame; 297 } else 298 fault_code = 0; 299 300 /* OK this is were we do something about the instruction. */ 301 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 302 if (uh->uh_handler(fault_pc, fault_instruction, frame, 303 fault_code) == 0) 304 break; 305 306 if (fault_code & FAULT_USER) { 307 /* TODO: No support for ptrace from Thumb-2 */ 308 if ((frame->tf_spsr & PSR_T) == 0 && 309 fault_instruction == PTRACE_BREAKPOINT) { 310 PROC_LOCK(td->td_proc); 311 _PHOLD(td->td_proc); 312 error = ptrace_clear_single_step(td); 313 _PRELE(td->td_proc); 314 PROC_UNLOCK(td->td_proc); 315 if (error != 0) { 316 ksiginfo_init_trap(&ksi); 317 ksi.ksi_signo = SIGILL; 318 ksi.ksi_code = ILL_ILLOPC; 319 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 320 trapsignal(td, &ksi); 321 } 322 return; 323 } 324 } 325 326 if (uh == NULL && (fault_code & FAULT_USER)) { 327 /* Fault has not been handled */ 328 ksiginfo_init_trap(&ksi); 329 ksi.ksi_signo = SIGILL; 330 ksi.ksi_code = ILL_ILLOPC; 331 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 332 trapsignal(td, &ksi); 333 } 334 335 if ((fault_code & FAULT_USER) == 0) { 336 if (fault_instruction == KERNEL_BREAKPOINT) { 337#ifdef KDB 338 kdb_trap(T_BREAKPOINT, 0, frame); 339#else 340 printf("No debugger in kernel.\n"); 341#endif 342 return; 343 } 344 else 345 panic("Undefined instruction in kernel.\n"); 346 } 347 348 userret(td, frame); 349} 350