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