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("$FreeBSD$"); 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 10 104 105 static int gdb_trapper(u_int, u_int, struct trapframe *, int); 106 107 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS]; 108 109 110 void * 111 install_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 } 124 125 void 126 install_coproc_handler_static(int coproc, struct undefined_handler *uh) 127 { 128 129 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link); 130 } 131 132 void 133 remove_coproc_handler(void *cookie) 134 { 135 struct undefined_handler *uh = cookie; 136 137 LIST_REMOVE(uh, uh_link); 138 free(uh, M_TEMP); 139 } 140 141 142 static int 143 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code) 144 { 145 struct thread *td; 146 ksiginfo_t ksi; 147 int error; 148 149 td = (curthread == NULL) ? &thread0 : curthread; 150 151 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) { 152 if (code == FAULT_USER) { 153 ksiginfo_init_trap(&ksi); 154 ksi.ksi_signo = SIGTRAP; 155 ksi.ksi_code = TRAP_BRKPT; 156 ksi.ksi_addr = (u_int32_t *)addr; 157 trapsignal(td, &ksi); 158 return 0; 159 } 160 #if 0 161 #ifdef KGDB 162 return !kgdb_trap(T_BREAKPOINT, frame); 163 #endif 164 #endif 165 } 166 167 if (code == FAULT_USER) { 168 /* TODO: No support for ptrace from Thumb-2 */ 169 if ((frame->tf_spsr & PSR_T) == 0 && 170 insn == PTRACE_BREAKPOINT) { 171 PROC_LOCK(td->td_proc); 172 _PHOLD(td->td_proc); 173 error = ptrace_clear_single_step(td); 174 _PRELE(td->td_proc); 175 PROC_UNLOCK(td->td_proc); 176 if (error == 0) { 177 ksiginfo_init_trap(&ksi); 178 ksi.ksi_signo = SIGTRAP; 179 ksi.ksi_code = TRAP_TRACE; 180 ksi.ksi_addr = (u_int32_t *)addr; 181 trapsignal(td, &ksi); 182 return (0); 183 } 184 } 185 } 186 187 return 1; 188 } 189 190 static struct undefined_handler gdb_uh; 191 192 void 193 undefined_init(void) 194 { 195 int loop; 196 197 /* Not actually necessary -- the initialiser is just NULL */ 198 for (loop = 0; loop < MAX_COPROCS; ++loop) 199 LIST_INIT(&undefined_handlers[loop]); 200 201 /* Install handler for GDB breakpoints */ 202 gdb_uh.uh_handler = gdb_trapper; 203 install_coproc_handler_static(0, &gdb_uh); 204 } 205 206 207 void 208 undefinedinstruction(struct trapframe *frame) 209 { 210 struct thread *td; 211 u_int fault_pc; 212 int fault_instruction; 213 int fault_code; 214 int coprocessor; 215 struct undefined_handler *uh; 216 #ifdef VERBOSE_ARM32 217 int s; 218 #endif 219 ksiginfo_t ksi; 220 221 /* Enable interrupts if they were enabled before the exception. */ 222 if (__predict_true(frame->tf_spsr & PSR_I) == 0) 223 enable_interrupts(PSR_I); 224 if (__predict_true(frame->tf_spsr & PSR_F) == 0) 225 enable_interrupts(PSR_F); 226 227 VM_CNT_INC(v_trap); 228 229 fault_pc = frame->tf_pc; 230 231 /* 232 * Get the current thread/proc structure or thread0/proc0 if there is 233 * none. 234 */ 235 td = curthread == NULL ? &thread0 : curthread; 236 237 coprocessor = 0; 238 if ((frame->tf_spsr & PSR_T) == 0) { 239 /* 240 * Make sure the program counter is correctly aligned so we 241 * don't take an alignment fault trying to read the opcode. 242 */ 243 if (__predict_false((fault_pc & 3) != 0)) { 244 ksiginfo_init_trap(&ksi); 245 ksi.ksi_signo = SIGILL; 246 ksi.ksi_code = ILL_ILLADR; 247 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 248 trapsignal(td, &ksi); 249 userret(td, frame); 250 return; 251 } 252 253 /* 254 * Should use fuword() here .. but in the interests of 255 * squeezing every bit of speed we will just use ReadWord(). 256 * We know the instruction can be read as was just executed 257 * so this will never fail unless the kernel is screwed up 258 * in which case it does not really matter does it ? 259 */ 260 261 fault_instruction = *(u_int32_t *)fault_pc; 262 263 /* Check for coprocessor instruction */ 264 265 /* 266 * According to the datasheets you only need to look at bit 267 * 27 of the instruction to tell the difference between and 268 * undefined instruction and a coprocessor instruction 269 * following an undefined instruction trap. 270 */ 271 272 if (ARM_COPROC_INSN(fault_instruction)) 273 coprocessor = ARM_COPROC(fault_instruction); 274 else { /* check for special instructions */ 275 if (ARM_VFP_INSN(fault_instruction)) 276 coprocessor = COPROC_VFP; /* vfp / simd */ 277 } 278 } else { 279 #if __ARM_ARCH >= 7 280 fault_instruction = *(uint16_t *)fault_pc; 281 if (THUMB_32BIT_INSN(fault_instruction)) { 282 fault_instruction <<= 16; 283 fault_instruction |= *(uint16_t *)(fault_pc + 2); 284 285 /* 286 * Is it a Coprocessor, Advanced SIMD, or 287 * Floating-point instruction. 288 */ 289 if (THUMB_COPROC_INSN(fault_instruction)) { 290 if (THUMB_COPROC_UNDEFINED(fault_instruction)) { 291 /* undefined insn */ 292 } else if (THUMB_VFP_INSN(fault_instruction)) 293 coprocessor = COPROC_VFP; 294 else 295 coprocessor = 296 THUMB_COPROC(fault_instruction); 297 } 298 } 299 #else 300 /* 301 * No support for Thumb-2 on this cpu 302 */ 303 ksiginfo_init_trap(&ksi); 304 ksi.ksi_signo = SIGILL; 305 ksi.ksi_code = ILL_ILLADR; 306 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 307 trapsignal(td, &ksi); 308 userret(td, frame); 309 return; 310 #endif 311 } 312 313 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) { 314 /* 315 * Modify the fault_code to reflect the USR/SVC state at 316 * time of fault. 317 */ 318 fault_code = FAULT_USER; 319 td->td_frame = frame; 320 } else 321 fault_code = 0; 322 323 /* OK this is were we do something about the instruction. */ 324 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link) 325 if (uh->uh_handler(fault_pc, fault_instruction, frame, 326 fault_code) == 0) 327 break; 328 329 if (uh == NULL && (fault_code & FAULT_USER)) { 330 /* Fault has not been handled */ 331 ksiginfo_init_trap(&ksi); 332 ksi.ksi_signo = SIGILL; 333 ksi.ksi_code = ILL_ILLOPC; 334 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 335 trapsignal(td, &ksi); 336 } 337 338 if ((fault_code & FAULT_USER) == 0) { 339 if (fault_instruction == KERNEL_BREAKPOINT) { 340 #ifdef KDB 341 kdb_trap(T_BREAKPOINT, 0, frame); 342 #else 343 printf("No debugger in kernel.\n"); 344 #endif 345 return; 346 } 347 else 348 panic("Undefined instruction in kernel.\n"); 349 } 350 351 userret(td, frame); 352 } 353