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/debug-monitors.h>
  36 #include <asm/esr.h>
  37 #include <asm/traps.h>
  38 #include <asm/stacktrace.h>
  39 #include <asm/exception.h>
  40 #include <asm/system_misc.h>
  41
  42 static const char *handler[]= {
  43         "Synchronous Abort",
  44         "IRQ",
  45         "FIQ",
  46         "Error"
  47 };
  48
  49 int show_unhandled_signals = 1;
  50
  51 /*
  52  * Dump out the contents of some memory nicely...
  53  */
  54 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
  55                      unsigned long top, bool compat)
  56 {
  57         unsigned long first;
  58         mm_segment_t fs;
  59         int i;
  60         unsigned int width = compat ? 4 : 8;
  61
  62         /*
  63          * We need to switch to kernel mode so that we can use __get_user
  64          * to safely read from kernel space.  Note that we now dump the
  65          * code first, just in case the backtrace kills us.
  66          */
  67         fs = get_fs();
  68         set_fs(KERNEL_DS);
  69
  70         printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
  71
  72         for (first = bottom & ~31; first < top; first += 32) {
  73                 unsigned long p;
  74                 char str[sizeof(" 12345678") * 8 + 1];
  75
  76                 memset(str, ' ', sizeof(str));
  77                 str[sizeof(str) - 1] = '\0';
  78
  79                 for (p = first, i = 0; i < (32 / width)
  80                                         && p < top; i++, p += width) {
  81                         if (p >= bottom && p < top) {
  82                                 unsigned long val;
  83
  84                                 if (width == 8) {
  85                                         if (__get_user(val, (unsigned long *)p) == 0)
  86                                                 sprintf(str + i * 17, " %016lx", val);
  87                                         else
  88                                                 sprintf(str + i * 17, " ????????????????");
  89                                 } else {
  90                                         if (__get_user(val, (unsigned int *)p) == 0)
  91                                                 sprintf(str + i * 9, " %08lx", val);
  92                                         else
  93                                                 sprintf(str + i * 9, " ????????");
  94                                 }
  95                         }
  96                 }
  97                 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
  98         }
  99
 100         set_fs(fs);
 101 }
 102
 103 static void dump_backtrace_entry(unsigned long where, unsigned long stack)
 104 {
 105         print_ip_sym(where);
 106         if (in_exception_text(where))
 107                 dump_mem("", "Exception stack", stack,
 108                          stack + sizeof(struct pt_regs), false);
 109 }
 110
 111 static void dump_instr(const char *lvl, struct pt_regs *regs)
 112 {
 113         unsigned long addr = instruction_pointer(regs);
 114         mm_segment_t fs;
 115         char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
 116         int i;
 117
 118         /*
 119          * We need to switch to kernel mode so that we can use __get_user
 120          * to safely read from kernel space.  Note that we now dump the
 121          * code first, just in case the backtrace kills us.
 122          */
 123         fs = get_fs();
 124         set_fs(KERNEL_DS);
 125
 126         for (i = -4; i < 1; i++) {
 127                 unsigned int val, bad;
 128
 129                 bad = __get_user(val, &((u32 *)addr)[i]);
 130
 131                 if (!bad)
 132                         p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
 133                 else {
 134                         p += sprintf(p, "bad PC value");
 135                         break;
 136                 }
 137         }
 138         printk("%sCode: %s\n", lvl, str);
 139
 140         set_fs(fs);
 141 }
 142
 143 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 144 {
 145         struct stackframe frame;
 146
 147         pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 148
 149         if (!tsk)
 150                 tsk = current;
 151
 152         if (regs) {
 153                 frame.fp = regs->regs[29];
 154                 frame.sp = regs->sp;
 155                 frame.pc = regs->pc;
 156         } else if (tsk == current) {
 157                 frame.fp = (unsigned long)__builtin_frame_address(0);
 158                 frame.sp = current_stack_pointer;
 159                 frame.pc = (unsigned long)dump_backtrace;
 160         } else {
 161                 /*
 162                  * task blocked in __switch_to
 163                  */
 164                 frame.fp = thread_saved_fp(tsk);
 165                 frame.sp = thread_saved_sp(tsk);
 166                 frame.pc = thread_saved_pc(tsk);
 167         }
 168
 169         pr_emerg("Call trace:\n");
 170         while (1) {
 171                 unsigned long where = frame.pc;
 172                 int ret;
 173
 174                 ret = unwind_frame(&frame);
 175                 if (ret < 0)
 176                         break;
 177                 dump_backtrace_entry(where, frame.sp);
 178         }
 179 }
 180
 181 void show_stack(struct task_struct *tsk, unsigned long *sp)
 182 {
 183         dump_backtrace(NULL, tsk);
 184         barrier();
 185 }
 186
 187 #ifdef CONFIG_PREEMPT
 188 #define S_PREEMPT " PREEMPT"
 189 #else
 190 #define S_PREEMPT ""
 191 #endif
 192 #ifdef CONFIG_SMP
 193 #define S_SMP " SMP"
 194 #else
 195 #define S_SMP ""
 196 #endif
 197
 198 static int __die(const char *str, int err, struct thread_info *thread,
 199                  struct pt_regs *regs)
 200 {
 201         struct task_struct *tsk = thread->task;
 202         static int die_counter;
 203         int ret;
 204
 205         pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
 206                  str, err, ++die_counter);
 207
 208         /* trap and error numbers are mostly meaningless on ARM */
 209         ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
 210         if (ret == NOTIFY_STOP)
 211                 return ret;
 212
 213         print_modules();
 214         __show_regs(regs);
 215         pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
 216                  TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
 217
 218         if (!user_mode(regs) || in_interrupt()) {
 219                 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
 220                          THREAD_SIZE + (unsigned long)task_stack_page(tsk),
 221                          compat_user_mode(regs));
 222                 dump_backtrace(regs, tsk);
 223                 dump_instr(KERN_EMERG, regs);
 224         }
 225
 226         return ret;
 227 }
 228
 229 static DEFINE_RAW_SPINLOCK(die_lock);
 230
 231 /*
 232  * This function is protected against re-entrancy.
 233  */
 234 void die(const char *str, struct pt_regs *regs, int err)
 235 {
 236         struct thread_info *thread = current_thread_info();
 237         int ret;
 238
 239         oops_enter();
 240
 241         raw_spin_lock_irq(&die_lock);
 242         console_verbose();
 243         bust_spinlocks(1);
 244         ret = __die(str, err, thread, regs);
 245
 246         if (regs && kexec_should_crash(thread->task))
 247                 crash_kexec(regs);
 248
 249         bust_spinlocks(0);
 250         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 251         raw_spin_unlock_irq(&die_lock);
 252         oops_exit();
 253
 254         if (in_interrupt())
 255                 panic("Fatal exception in interrupt");
 256         if (panic_on_oops)
 257                 panic("Fatal exception");
 258         if (ret != NOTIFY_STOP)
 259                 do_exit(SIGSEGV);
 260 }
 261
 262 void arm64_notify_die(const char *str, struct pt_regs *regs,
 263                       struct siginfo *info, int err)
 264 {
 265         if (user_mode(regs)) {
 266                 current->thread.fault_address = 0;
 267                 current->thread.fault_code = err;
 268                 force_sig_info(info->si_signo, info, current);
 269         } else {
 270                 die(str, regs, err);
 271         }
 272 }
 273
 274 static LIST_HEAD(undef_hook);
 275 static DEFINE_RAW_SPINLOCK(undef_lock);
 276
 277 void register_undef_hook(struct undef_hook *hook)
 278 {
 279         unsigned long flags;
 280
 281         raw_spin_lock_irqsave(&undef_lock, flags);
 282         list_add(&hook->node, &undef_hook);
 283         raw_spin_unlock_irqrestore(&undef_lock, flags);
 284 }
 285
 286 void unregister_undef_hook(struct undef_hook *hook)
 287 {
 288         unsigned long flags;
 289
 290         raw_spin_lock_irqsave(&undef_lock, flags);
 291         list_del(&hook->node);
 292         raw_spin_unlock_irqrestore(&undef_lock, flags);
 293 }
 294
 295 static int call_undef_hook(struct pt_regs *regs)
 296 {
 297         struct undef_hook *hook;
 298         unsigned long flags;
 299         u32 instr;
 300         int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
 301         void __user *pc = (void __user *)instruction_pointer(regs);
 302
 303         if (!user_mode(regs))
 304                 return 1;
 305
 306         if (compat_thumb_mode(regs)) {
 307                 /* 16-bit Thumb instruction */
 308                 if (get_user(instr, (u16 __user *)pc))
 309                         goto exit;
 310                 instr = le16_to_cpu(instr);
 311                 if (aarch32_insn_is_wide(instr)) {
 312                         u32 instr2;
 313
 314                         if (get_user(instr2, (u16 __user *)(pc + 2)))
 315                                 goto exit;
 316                         instr2 = le16_to_cpu(instr2);
 317                         instr = (instr << 16) | instr2;
 318                 }
 319         } else {
 320                 /* 32-bit ARM instruction */
 321                 if (get_user(instr, (u32 __user *)pc))
 322                         goto exit;
 323                 instr = le32_to_cpu(instr);
 324         }
 325
 326         raw_spin_lock_irqsave(&undef_lock, flags);
 327         list_for_each_entry(hook, &undef_hook, node)
 328                 if ((instr & hook->instr_mask) == hook->instr_val &&
 329                         (regs->pstate & hook->pstate_mask) == hook->pstate_val)
 330                         fn = hook->fn;
 331
 332         raw_spin_unlock_irqrestore(&undef_lock, flags);
 333 exit:
 334         return fn ? fn(regs, instr) : 1;
 335 }
 336
 337 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 338 {
 339         siginfo_t info;
 340         void __user *pc = (void __user *)instruction_pointer(regs);
 341
 342         /* check for AArch32 breakpoint instructions */
 343         if (!aarch32_break_handler(regs))
 344                 return;
 345
 346         if (call_undef_hook(regs) == 0)
 347                 return;
 348
 349         if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {
 350                 pr_info("%s[%d]: undefined instruction: pc=%p\n",
 351                         current->comm, task_pid_nr(current), pc);
 352                 dump_instr(KERN_INFO, regs);
 353         }
 354
 355         info.si_signo = SIGILL;
 356         info.si_errno = 0;
 357         info.si_code  = ILL_ILLOPC;
 358         info.si_addr  = pc;
 359
 360         arm64_notify_die("Oops - undefined instruction", regs, &info, 0);
 361 }
 362
 363 long compat_arm_syscall(struct pt_regs *regs);
 364
 365 asmlinkage long do_ni_syscall(struct pt_regs *regs)
 366 {
 367 #ifdef CONFIG_COMPAT
 368         long ret;
 369         if (is_compat_task()) {
 370                 ret = compat_arm_syscall(regs);
 371                 if (ret != -ENOSYS)
 372                         return ret;
 373         }
 374 #endif
 375
 376         if (show_unhandled_signals_ratelimited()) {
 377                 pr_info("%s[%d]: syscall %d\n", current->comm,
 378                         task_pid_nr(current), (int)regs->syscallno);
 379                 dump_instr("", regs);
 380                 if (user_mode(regs))
 381                         __show_regs(regs);
 382         }
 383
 384         return sys_ni_syscall();
 385 }
 386
 387 static const char *esr_class_str[] = {
 388         [0 ... ESR_ELx_EC_MAX]          = "UNRECOGNIZED EC",
 389         [ESR_ELx_EC_UNKNOWN]            = "Unknown/Uncategorized",
 390         [ESR_ELx_EC_WFx]                = "WFI/WFE",
 391         [ESR_ELx_EC_CP15_32]            = "CP15 MCR/MRC",
 392         [ESR_ELx_EC_CP15_64]            = "CP15 MCRR/MRRC",
 393         [ESR_ELx_EC_CP14_MR]            = "CP14 MCR/MRC",
 394         [ESR_ELx_EC_CP14_LS]            = "CP14 LDC/STC",
 395         [ESR_ELx_EC_FP_ASIMD]           = "ASIMD",
 396         [ESR_ELx_EC_CP10_ID]            = "CP10 MRC/VMRS",
 397         [ESR_ELx_EC_CP14_64]            = "CP14 MCRR/MRRC",
 398         [ESR_ELx_EC_ILL]                = "PSTATE.IL",
 399         [ESR_ELx_EC_SVC32]              = "SVC (AArch32)",
 400         [ESR_ELx_EC_HVC32]              = "HVC (AArch32)",
 401         [ESR_ELx_EC_SMC32]              = "SMC (AArch32)",
 402         [ESR_ELx_EC_SVC64]              = "SVC (AArch64)",
 403         [ESR_ELx_EC_HVC64]              = "HVC (AArch64)",
 404         [ESR_ELx_EC_SMC64]              = "SMC (AArch64)",
 405         [ESR_ELx_EC_SYS64]              = "MSR/MRS (AArch64)",
 406         [ESR_ELx_EC_IMP_DEF]            = "EL3 IMP DEF",
 407         [ESR_ELx_EC_IABT_LOW]           = "IABT (lower EL)",
 408         [ESR_ELx_EC_IABT_CUR]           = "IABT (current EL)",
 409         [ESR_ELx_EC_PC_ALIGN]           = "PC Alignment",
 410         [ESR_ELx_EC_DABT_LOW]           = "DABT (lower EL)",
 411         [ESR_ELx_EC_DABT_CUR]           = "DABT (current EL)",
 412         [ESR_ELx_EC_SP_ALIGN]           = "SP Alignment",
 413         [ESR_ELx_EC_FP_EXC32]           = "FP (AArch32)",
 414         [ESR_ELx_EC_FP_EXC64]           = "FP (AArch64)",
 415         [ESR_ELx_EC_SERROR]             = "SError",
 416         [ESR_ELx_EC_BREAKPT_LOW]        = "Breakpoint (lower EL)",
 417         [ESR_ELx_EC_BREAKPT_CUR]        = "Breakpoint (current EL)",
 418         [ESR_ELx_EC_SOFTSTP_LOW]        = "Software Step (lower EL)",
 419         [ESR_ELx_EC_SOFTSTP_CUR]        = "Software Step (current EL)",
 420         [ESR_ELx_EC_WATCHPT_LOW]        = "Watchpoint (lower EL)",
 421         [ESR_ELx_EC_WATCHPT_CUR]        = "Watchpoint (current EL)",
 422         [ESR_ELx_EC_BKPT32]             = "BKPT (AArch32)",
 423         [ESR_ELx_EC_VECTOR32]           = "Vector catch (AArch32)",
 424         [ESR_ELx_EC_BRK64]              = "BRK (AArch64)",
 425 };
 426
 427 const char *esr_get_class_string(u32 esr)
 428 {
 429         return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
 430 }
 431
 432 /*
 433  * bad_mode handles the impossible case in the exception vector.
 434  */
 435 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 436 {
 437         siginfo_t info;
 438         void __user *pc = (void __user *)instruction_pointer(regs);
 439         console_verbose();
 440
 441         pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
 442                 handler[reason], esr, esr_get_class_string(esr));
 443         __show_regs(regs);
 444
 445         info.si_signo = SIGILL;
 446         info.si_errno = 0;
 447         info.si_code  = ILL_ILLOPC;
 448         info.si_addr  = pc;
 449
 450         arm64_notify_die("Oops - bad mode", regs, &info, 0);
 451 }
 452
 453 void __pte_error(const char *file, int line, unsigned long val)
 454 {
 455         pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
 456 }
 457
 458 void __pmd_error(const char *file, int line, unsigned long val)
 459 {
 460         pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
 461 }
 462
 463 void __pud_error(const char *file, int line, unsigned long val)
 464 {
 465         pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
 466 }
 467
 468 void __pgd_error(const char *file, int line, unsigned long val)
 469 {
 470         pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
 471 }
 472
 473 void __init trap_init(void)
 474 {
 475         return;
 476 }