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 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 263 { 264 siginfo_t info; 265 void __user *pc = (void __user *)instruction_pointer(regs); 266 267 /* check for AArch32 breakpoint instructions */ 268 if (!aarch32_break_handler(regs)) 269 return; 270 271 if (show_unhandled_signals && unhandled_signal(current, SIGILL) && 272 printk_ratelimit()) { 273 pr_info("%s[%d]: undefined instruction: pc=%p\n", 274 current->comm, task_pid_nr(current), pc); 275 dump_instr(KERN_INFO, regs); 276 } 277 278 info.si_signo = SIGILL; 279 info.si_errno = 0; 280 info.si_code = ILL_ILLOPC; 281 info.si_addr = pc; 282 283 arm64_notify_die("Oops - undefined instruction", regs, &info, 0); 284 } 285 286 long compat_arm_syscall(struct pt_regs *regs); 287 288 asmlinkage long do_ni_syscall(struct pt_regs *regs) 289 { 290 #ifdef CONFIG_COMPAT 291 long ret; 292 if (is_compat_task()) { 293 ret = compat_arm_syscall(regs); 294 if (ret != -ENOSYS) 295 return ret; 296 } 297 #endif 298 299 if (show_unhandled_signals && printk_ratelimit()) { 300 pr_info("%s[%d]: syscall %d\n", current->comm, 301 task_pid_nr(current), (int)regs->syscallno); 302 dump_instr("", regs); 303 if (user_mode(regs)) 304 __show_regs(regs); 305 } 306 307 return sys_ni_syscall(); 308 } 309 310 /* 311 * bad_mode handles the impossible case in the exception vector. 312 */ 313 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) 314 { 315 siginfo_t info; 316 void __user *pc = (void __user *)instruction_pointer(regs); 317 console_verbose(); 318 319 pr_crit("Bad mode in %s handler detected, code 0x%08x\n", 320 handler[reason], esr); 321 __show_regs(regs); 322 323 info.si_signo = SIGILL; 324 info.si_errno = 0; 325 info.si_code = ILL_ILLOPC; 326 info.si_addr = pc; 327 328 arm64_notify_die("Oops - bad mode", regs, &info, 0); 329 } 330 331 void __pte_error(const char *file, int line, unsigned long val) 332 { 333 pr_crit("%s:%d: bad pte %016lx.\n", file, line, val); 334 } 335 336 void __pmd_error(const char *file, int line, unsigned long val) 337 { 338 pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val); 339 } 340 341 void __pud_error(const char *file, int line, unsigned long val) 342 { 343 pr_crit("%s:%d: bad pud %016lx.\n", file, line, val); 344 } 345 346 void __pgd_error(const char *file, int line, unsigned long val) 347 { 348 pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val); 349 } 350 351 void __init trap_init(void) 352 { 353 return; 354 } 355