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/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         const register unsigned long current_sp asm ("sp");
 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_sp;
 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         printk("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                 force_sig_info(info->si_signo, info, current);
 256         else
 257                 die(str, regs, err);
 258 }
 259
 260 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 261 {
 262         siginfo_t info;
 263         void __user *pc = (void __user *)instruction_pointer(regs);
 264
 265         /* check for AArch32 breakpoint instructions */
 266         if (!aarch32_break_handler(regs))
 267                 return;
 268
 269         if (show_unhandled_signals && unhandled_signal(current, SIGILL) &&
 270             printk_ratelimit()) {
 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 && printk_ratelimit()) {
 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         siginfo_t info;
 314         void __user *pc = (void __user *)instruction_pointer(regs);
 315         console_verbose();
 316
 317         pr_crit("Bad mode in %s handler detected, code 0x%08x\n",
 318                 handler[reason], esr);
 319         __show_regs(regs);
 320
 321         info.si_signo = SIGILL;
 322         info.si_errno = 0;
 323         info.si_code  = ILL_ILLOPC;
 324         info.si_addr  = pc;
 325
 326         arm64_notify_die("Oops - bad mode", regs, &info, 0);
 327 }
 328
 329 void __pte_error(const char *file, int line, unsigned long val)
 330 {
 331         printk("%s:%d: bad pte %016lx.\n", file, line, val);
 332 }
 333
 334 void __pmd_error(const char *file, int line, unsigned long val)
 335 {
 336         printk("%s:%d: bad pmd %016lx.\n", file, line, val);
 337 }
 338
 339 void __pgd_error(const char *file, int line, unsigned long val)
 340 {
 341         printk("%s:%d: bad pgd %016lx.\n", file, line, val);
 342 }
 343
 344 void __init trap_init(void)
 345 {
 346         return;
 347 }