1 /* 2 * Based on arch/arm/kernel/traps.c 3 * 4 * Copyright (C) 1995-2009 Russell King 5 * Copyright (C) 2012 ARM Ltd. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/signal.h> 21 #include <linux/personality.h> 22 #include <linux/kallsyms.h> 23 #include <linux/spinlock.h> 24 #include <linux/uaccess.h> 25 #include <linux/hardirq.h> 26 #include <linux/kdebug.h> 27 #include <linux/module.h> 28 #include <linux/kexec.h> 29 #include <linux/delay.h> 30 #include <linux/init.h> 31 #include <linux/sched.h> 32 #include <linux/syscalls.h> 33 34 #include <asm/atomic.h> 35 #include <asm/debug-monitors.h> 36 #include <asm/traps.h> 37 #include <asm/stacktrace.h> 38 #include <asm/exception.h> 39 #include <asm/system_misc.h> 40 41 static const char *handler[]= { 42 "Synchronous Abort", 43 "IRQ", 44 "FIQ", 45 "Error" 46 }; 47 48 int show_unhandled_signals = 1; 49 50 /* 51 * Dump out the contents of some memory nicely... 52 */ 53 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 54 unsigned long top) 55 { 56 unsigned long first; 57 mm_segment_t fs; 58 int i; 59 60 /* 61 * We need to switch to kernel mode so that we can use __get_user 62 * to safely read from kernel space. Note that we now dump the 63 * code first, just in case the backtrace kills us. 64 */ 65 fs = get_fs(); 66 set_fs(KERNEL_DS); 67 68 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); 69 70 for (first = bottom & ~31; first < top; first += 32) { 71 unsigned long p; 72 char str[sizeof(" 12345678") * 8 + 1]; 73 74 memset(str, ' ', sizeof(str)); 75 str[sizeof(str) - 1] = '\0'; 76 77 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 78 if (p >= bottom && p < top) { 79 unsigned int val; 80 if (__get_user(val, (unsigned int *)p) == 0) 81 sprintf(str + i * 9, " %08x", val); 82 else 83 sprintf(str + i * 9, " ????????"); 84 } 85 } 86 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 87 } 88 89 set_fs(fs); 90 } 91 92 static void dump_backtrace_entry(unsigned long where, unsigned long stack) 93 { 94 print_ip_sym(where); 95 if (in_exception_text(where)) 96 dump_mem("", "Exception stack", stack, 97 stack + sizeof(struct pt_regs)); 98 } 99 100 static void dump_instr(const char *lvl, struct pt_regs *regs) 101 { 102 unsigned long addr = instruction_pointer(regs); 103 mm_segment_t fs; 104 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 105 int i; 106 107 /* 108 * We need to switch to kernel mode so that we can use __get_user 109 * to safely read from kernel space. Note that we now dump the 110 * code first, just in case the backtrace kills us. 111 */ 112 fs = get_fs(); 113 set_fs(KERNEL_DS); 114 115 for (i = -4; i < 1; i++) { 116 unsigned int val, bad; 117 118 bad = __get_user(val, &((u32 *)addr)[i]); 119 120 if (!bad) 121 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); 122 else { 123 p += sprintf(p, "bad PC value"); 124 break; 125 } 126 } 127 printk("%sCode: %s\n", lvl, str); 128 129 set_fs(fs); 130 } 131 132 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 133 { 134 struct stackframe frame; 135 136 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); 137 138 if (!tsk) 139 tsk = current; 140 141 if (regs) { 142 frame.fp = regs->regs[29]; 143 frame.sp = regs->sp; 144 frame.pc = regs->pc; 145 } else if (tsk == current) { 146 frame.fp = (unsigned long)__builtin_frame_address(0); 147 frame.sp = current_stack_pointer; 148 frame.pc = (unsigned long)dump_backtrace; 149 } else { 150 /* 151 * task blocked in __switch_to 152 */ 153 frame.fp = thread_saved_fp(tsk); 154 frame.sp = thread_saved_sp(tsk); 155 frame.pc = thread_saved_pc(tsk); 156 } 157 158 pr_emerg("Call trace:\n"); 159 while (1) { 160 unsigned long where = frame.pc; 161 int ret; 162 163 ret = unwind_frame(&frame); 164 if (ret < 0) 165 break; 166 dump_backtrace_entry(where, frame.sp); 167 } 168 } 169 170 void show_stack(struct task_struct *tsk, unsigned long *sp) 171 { 172 dump_backtrace(NULL, tsk); 173 barrier(); 174 } 175 176 #ifdef CONFIG_PREEMPT 177 #define S_PREEMPT " PREEMPT" 178 #else 179 #define S_PREEMPT "" 180 #endif 181 #ifdef CONFIG_SMP 182 #define S_SMP " SMP" 183 #else 184 #define S_SMP "" 185 #endif 186 187 static int __die(const char *str, int err, struct thread_info *thread, 188 struct pt_regs *regs) 189 { 190 struct task_struct *tsk = thread->task; 191 static int die_counter; 192 int ret; 193 194 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", 195 str, err, ++die_counter); 196 197 /* trap and error numbers are mostly meaningless on ARM */ 198 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV); 199 if (ret == NOTIFY_STOP) 200 return ret; 201 202 print_modules(); 203 __show_regs(regs); 204 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", 205 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); 206 207 if (!user_mode(regs) || in_interrupt()) { 208 dump_mem(KERN_EMERG, "Stack: ", regs->sp, 209 THREAD_SIZE + (unsigned long)task_stack_page(tsk)); 210 dump_backtrace(regs, tsk); 211 dump_instr(KERN_EMERG, regs); 212 } 213 214 return ret; 215 } 216 217 static DEFINE_RAW_SPINLOCK(die_lock); 218 219 /* 220 * This function is protected against re-entrancy. 221 */ 222 void die(const char *str, struct pt_regs *regs, int err) 223 { 224 struct thread_info *thread = current_thread_info(); 225 int ret; 226 227 oops_enter(); 228 229 raw_spin_lock_irq(&die_lock); 230 console_verbose(); 231 bust_spinlocks(1); 232 ret = __die(str, err, thread, regs); 233 234 if (regs && kexec_should_crash(thread->task)) 235 crash_kexec(regs); 236 237 bust_spinlocks(0); 238 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 239 raw_spin_unlock_irq(&die_lock); 240 oops_exit(); 241 242 if (in_interrupt()) 243 panic("Fatal exception in interrupt"); 244 if (panic_on_oops) 245 panic("Fatal exception"); 246 if (ret != NOTIFY_STOP) 247 do_exit(SIGSEGV); 248 } 249 250 void arm64_notify_die(const char *str, struct pt_regs *regs, 251 struct siginfo *info, int err) 252 { 253 if (user_mode(regs)) { 254 current->thread.fault_address = 0; 255 current->thread.fault_code = err; 256 force_sig_info(info->si_signo, info, current); 257 } else { 258 die(str, regs, err); 259 } 260 } 261 262 static LIST_HEAD(undef_hook); 263 static DEFINE_RAW_SPINLOCK(undef_lock); 264 265 void register_undef_hook(struct undef_hook *hook) 266 { 267 unsigned long flags; 268 269 raw_spin_lock_irqsave(&undef_lock, flags); 270 list_add(&hook->node, &undef_hook); 271 raw_spin_unlock_irqrestore(&undef_lock, flags); 272 } 273 274 void unregister_undef_hook(struct undef_hook *hook) 275 { 276 unsigned long flags; 277 278 raw_spin_lock_irqsave(&undef_lock, flags); 279 list_del(&hook->node); 280 raw_spin_unlock_irqrestore(&undef_lock, flags); 281 } 282 283 static int call_undef_hook(struct pt_regs *regs) 284 { 285 struct undef_hook *hook; 286 unsigned long flags; 287 u32 instr; 288 int (*fn)(struct pt_regs *regs, u32 instr) = NULL; 289 void __user *pc = (void __user *)instruction_pointer(regs); 290 291 if (!user_mode(regs)) 292 return 1; 293 294 if (compat_thumb_mode(regs)) { 295 /* 16-bit Thumb instruction */ 296 if (get_user(instr, (u16 __user *)pc)) 297 goto exit; 298 instr = le16_to_cpu(instr); 299 if (aarch32_insn_is_wide(instr)) { 300 u32 instr2; 301 302 if (get_user(instr2, (u16 __user *)(pc + 2))) 303 goto exit; 304 instr2 = le16_to_cpu(instr2); 305 instr = (instr << 16) | instr2; 306 } 307 } else { 308 /* 32-bit ARM instruction */ 309 if (get_user(instr, (u32 __user *)pc)) 310 goto exit; 311 instr = le32_to_cpu(instr); 312 } 313 314 raw_spin_lock_irqsave(&undef_lock, flags); 315 list_for_each_entry(hook, &undef_hook, node) 316 if ((instr & hook->instr_mask) == hook->instr_val && 317 (regs->pstate & hook->pstate_mask) == hook->pstate_val) 318 fn = hook->fn; 319 320 raw_spin_unlock_irqrestore(&undef_lock, flags); 321 exit: 322 return fn ? fn(regs, instr) : 1; 323 } 324 325 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 326 { 327 siginfo_t info; 328 void __user *pc = (void __user *)instruction_pointer(regs); 329 330 /* check for AArch32 breakpoint instructions */ 331 if (!aarch32_break_handler(regs)) 332 return; 333 334 if (call_undef_hook(regs) == 0) 335 return; 336 337 if (show_unhandled_signals && unhandled_signal(current, SIGILL) && 338 printk_ratelimit()) { 339 pr_info("%s[%d]: undefined instruction: pc=%p\n", 340 current->comm, task_pid_nr(current), pc); 341 dump_instr(KERN_INFO, regs); 342 } 343 344 info.si_signo = SIGILL; 345 info.si_errno = 0; 346 info.si_code = ILL_ILLOPC; 347 info.si_addr = pc; 348 349 arm64_notify_die("Oops - undefined instruction", regs, &info, 0); 350 } 351 352 long compat_arm_syscall(struct pt_regs *regs); 353 354 asmlinkage long do_ni_syscall(struct pt_regs *regs) 355 { 356 #ifdef CONFIG_COMPAT 357 long ret; 358 if (is_compat_task()) { 359 ret = compat_arm_syscall(regs); 360 if (ret != -ENOSYS) 361 return ret; 362 } 363 #endif 364 365 if (show_unhandled_signals && printk_ratelimit()) { 366 pr_info("%s[%d]: syscall %d\n", current->comm, 367 task_pid_nr(current), (int)regs->syscallno); 368 dump_instr("", regs); 369 if (user_mode(regs)) 370 __show_regs(regs); 371 } 372 373 return sys_ni_syscall(); 374 } 375 376 /* 377 * bad_mode handles the impossible case in the exception vector. 378 */ 379 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) 380 { 381 siginfo_t info; 382 void __user *pc = (void __user *)instruction_pointer(regs); 383 console_verbose(); 384 385 pr_crit("Bad mode in %s handler detected, code 0x%08x\n", 386 handler[reason], esr); 387 __show_regs(regs); 388 389 info.si_signo = SIGILL; 390 info.si_errno = 0; 391 info.si_code = ILL_ILLOPC; 392 info.si_addr = pc; 393 394 arm64_notify_die("Oops - bad mode", regs, &info, 0); 395 } 396 397 void __pte_error(const char *file, int line, unsigned long val) 398 { 399 pr_crit("%s:%d: bad pte %016lx.\n", file, line, val); 400 } 401 402 void __pmd_error(const char *file, int line, unsigned long val) 403 { 404 pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val); 405 } 406 407 void __pud_error(const char *file, int line, unsigned long val) 408 { 409 pr_crit("%s:%d: bad pud %016lx.\n", file, line, val); 410 } 411 412 void __pgd_error(const char *file, int line, unsigned long val) 413 { 414 pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val); 415 } 416 417 void __init trap_init(void) 418 { 419 return; 420 } 421