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/traps.h> 36 #include <asm/stacktrace.h> 37 #include <asm/exception.h> 38 #include <asm/system_misc.h> 39 40 static const char *handler[]= { 41 "Synchronous Abort", 42 "IRQ", 43 "FIQ", 44 "Error" 45 }; 46 47 int show_unhandled_signals = 1; 48 49 /* 50 * Dump out the contents of some memory nicely... 51 */ 52 static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 53 unsigned long top) 54 { 55 unsigned long first; 56 mm_segment_t fs; 57 int i; 58 59 /* 60 * We need to switch to kernel mode so that we can use __get_user 61 * to safely read from kernel space. Note that we now dump the 62 * code first, just in case the backtrace kills us. 63 */ 64 fs = get_fs(); 65 set_fs(KERNEL_DS); 66 67 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); 68 69 for (first = bottom & ~31; first < top; first += 32) { 70 unsigned long p; 71 char str[sizeof(" 12345678") * 8 + 1]; 72 73 memset(str, ' ', sizeof(str)); 74 str[sizeof(str) - 1] = '\0'; 75 76 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { 77 if (p >= bottom && p < top) { 78 unsigned int val; 79 if (__get_user(val, (unsigned int *)p) == 0) 80 sprintf(str + i * 9, " %08x", val); 81 else 82 sprintf(str + i * 9, " ????????"); 83 } 84 } 85 printk("%s%04lx:%s\n", lvl, first & 0xffff, str); 86 } 87 88 set_fs(fs); 89 } 90 91 static void dump_backtrace_entry(unsigned long where, unsigned long stack) 92 { 93 print_ip_sym(where); 94 if (in_exception_text(where)) 95 dump_mem("", "Exception stack", stack, 96 stack + sizeof(struct pt_regs)); 97 } 98 99 static void dump_instr(const char *lvl, struct pt_regs *regs) 100 { 101 unsigned long addr = instruction_pointer(regs); 102 mm_segment_t fs; 103 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; 104 int i; 105 106 /* 107 * We need to switch to kernel mode so that we can use __get_user 108 * to safely read from kernel space. Note that we now dump the 109 * code first, just in case the backtrace kills us. 110 */ 111 fs = get_fs(); 112 set_fs(KERNEL_DS); 113 114 for (i = -4; i < 1; i++) { 115 unsigned int val, bad; 116 117 bad = __get_user(val, &((u32 *)addr)[i]); 118 119 if (!bad) 120 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); 121 else { 122 p += sprintf(p, "bad PC value"); 123 break; 124 } 125 } 126 printk("%sCode: %s\n", lvl, str); 127 128 set_fs(fs); 129 } 130 131 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) 132 { 133 struct stackframe frame; 134 const register unsigned long current_sp asm ("sp"); 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_sp; 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 printk("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 force_sig_info(info->si_signo, info, current); 255 else 256 die(str, regs, err); 257 } 258 259 asmlinkage void __exception do_undefinstr(struct pt_regs *regs) 260 { 261 siginfo_t info; 262 void __user *pc = (void __user *)instruction_pointer(regs); 263 264 #ifdef CONFIG_COMPAT 265 /* check for AArch32 breakpoint instructions */ 266 if (compat_user_mode(regs) && aarch32_break_trap(regs) == 0) 267 return; 268 #endif 269 270 if (show_unhandled_signals) { 271 pr_info("%s[%d]: undefined instruction: pc=%p\n", 272 current->comm, task_pid_nr(current), pc); 273 dump_instr(KERN_INFO, regs); 274 } 275 276 info.si_signo = SIGILL; 277 info.si_errno = 0; 278 info.si_code = ILL_ILLOPC; 279 info.si_addr = pc; 280 281 arm64_notify_die("Oops - undefined instruction", regs, &info, 0); 282 } 283 284 long compat_arm_syscall(struct pt_regs *regs); 285 286 asmlinkage long do_ni_syscall(struct pt_regs *regs) 287 { 288 #ifdef CONFIG_COMPAT 289 long ret; 290 if (is_compat_task()) { 291 ret = compat_arm_syscall(regs); 292 if (ret != -ENOSYS) 293 return ret; 294 } 295 #endif 296 297 if (show_unhandled_signals) { 298 pr_info("%s[%d]: syscall %d\n", current->comm, 299 task_pid_nr(current), (int)regs->syscallno); 300 dump_instr("", regs); 301 if (user_mode(regs)) 302 __show_regs(regs); 303 } 304 305 return sys_ni_syscall(); 306 } 307 308 /* 309 * bad_mode handles the impossible case in the exception vector. 310 */ 311 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) 312 { 313 console_verbose(); 314 315 pr_crit("Bad mode in %s handler detected, code 0x%08x\n", 316 handler[reason], esr); 317 318 die("Oops - bad mode", regs, 0); 319 local_irq_disable(); 320 panic("bad mode"); 321 } 322 323 void __pte_error(const char *file, int line, unsigned long val) 324 { 325 printk("%s:%d: bad pte %016lx.\n", file, line, val); 326 } 327 328 void __pmd_error(const char *file, int line, unsigned long val) 329 { 330 printk("%s:%d: bad pmd %016lx.\n", file, line, val); 331 } 332 333 void __pgd_error(const char *file, int line, unsigned long val) 334 { 335 printk("%s:%d: bad pgd %016lx.\n", file, line, val); 336 } 337 338 void __init trap_init(void) 339 { 340 return; 341 } 342