arch/arm64/kernel/traps.c

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