arch/arm26/kernel/traps.c

   1 /*
   2  *  linux/arch/arm26/kernel/traps.c
   3  *
   4  *  Copyright (C) 1995-2002 Russell King
   5  *  Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
   6  *  Copyright (C) 2003 Ian Molton (ARM26)
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  *  'traps.c' handles hardware exceptions after we have saved some state in
  13  *  'linux/arch/arm26/lib/traps.S'.  Mostly a debugging aid, but will probably
  14  *  kill the offending process.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/config.h>
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/signal.h>
  22 #include <linux/sched.h>
  23 #include <linux/mm.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/personality.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/elf.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/init.h>
  30
  31 #include <asm/atomic.h>
  32 #include <asm/io.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/system.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/unistd.h>
  37 #include <asm/semaphore.h>
  38
  39 #include "ptrace.h"
  40
  41 extern void c_backtrace (unsigned long fp, int pmode);
  42 extern void show_pte(struct mm_struct *mm, unsigned long addr);
  43
  44 const char *processor_modes[] = { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" };
  45
  46 static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" "*bad reason*"};
  47
  48 /*
  49  * Stack pointers should always be within the kernels view of
  50  * physical memory.  If it is not there, then we can't dump
  51  * out any information relating to the stack.
  52  */
  53 static int verify_stack(unsigned long sp)
  54 {
  55         if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0))
  56                 return -EFAULT;
  57
  58         return 0;
  59 }
  60
  61 /*
  62  * Dump out the contents of some memory nicely...
  63  */
  64 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  65 {
  66         unsigned long p = bottom & ~31;
  67         mm_segment_t fs;
  68         int i;
  69
  70         /*
  71          * We need to switch to kernel mode so that we can use __get_user
  72          * to safely read from kernel space.  Note that we now dump the
  73          * code first, just in case the backtrace kills us.
  74          */
  75         fs = get_fs();
  76         set_fs(KERNEL_DS);
  77
  78         printk("%s", str);
  79         printk("(0x%08lx to 0x%08lx)\n", bottom, top);
  80
  81         for (p = bottom & ~31; p < top;) {
  82                 printk("%04lx: ", p & 0xffff);
  83
  84                 for (i = 0; i < 8; i++, p += 4) {
  85                         unsigned int val;
  86
  87                         if (p < bottom || p >= top)
  88                                 printk("         ");
  89                         else {
  90                                 __get_user(val, (unsigned long *)p);
  91                                 printk("%08x ", val);
  92                         }
  93                 }
  94                 printk ("\n");
  95         }
  96
  97         set_fs(fs);
  98 }
  99
 100 static void dump_instr(struct pt_regs *regs)
 101 {
 102         unsigned long addr = instruction_pointer(regs);
 103         const int width = 8;
 104         mm_segment_t fs;
 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         printk("Code: ");
 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                         printk(i == 0 ? "(%0*x) " : "%0*x ", width, val);
 123                 else {
 124                         printk("bad PC value.");
 125                         break;
 126                 }
 127         }
 128         printk("\n");
 129
 130         set_fs(fs);
 131 }
 132
 133 /*static*/ void __dump_stack(struct task_struct *tsk, unsigned long sp)
 134 {
 135         dump_mem("Stack: ", sp, 8192+(unsigned long)tsk->thread_info);
 136 }
 137
 138 void dump_stack(void)
 139 {
 140 #ifdef CONFIG_DEBUG_ERRORS
 141         __backtrace();
 142 #endif
 143 }
 144
 145 EXPORT_SYMBOL(dump_stack);
 146
 147 //FIXME - was a static fn
 148 void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 149 {
 150         unsigned int fp;
 151         int ok = 1;
 152
 153         printk("Backtrace: ");
 154         fp = regs->ARM_fp;
 155         if (!fp) {
 156                 printk("no frame pointer");
 157                 ok = 0;
 158         } else if (verify_stack(fp)) {
 159                 printk("invalid frame pointer 0x%08x", fp);
 160                 ok = 0;
 161         } else if (fp < (unsigned long)(tsk->thread_info + 1))
 162                 printk("frame pointer underflow");
 163         printk("\n");
 164
 165         if (ok)
 166                 c_backtrace(fp, processor_mode(regs));
 167 }
 168
 169 /* FIXME - this is probably wrong.. */
 170 void show_stack(struct task_struct *task, unsigned long *sp) {
 171         dump_mem("Stack: ", (unsigned long)sp, 8192+(unsigned long)task->thread_info);
 172 }
 173
 174 DEFINE_SPINLOCK(die_lock);
 175
 176 /*
 177  * This function is protected against re-entrancy.
 178  */
 179 NORET_TYPE void die(const char *str, struct pt_regs *regs, int err)
 180 {
 181         struct task_struct *tsk = current;
 182
 183         console_verbose();
 184         spin_lock_irq(&die_lock);
 185
 186         printk("Internal error: %s: %x\n", str, err);
 187         printk("CPU: %d\n", smp_processor_id());
 188         show_regs(regs);
 189         printk("Process %s (pid: %d, stack limit = 0x%p)\n",
 190                 current->comm, current->pid, tsk->thread_info + 1);
 191
 192         if (!user_mode(regs) || in_interrupt()) {
 193                 __dump_stack(tsk, (unsigned long)(regs + 1));
 194                 dump_backtrace(regs, tsk);
 195                 dump_instr(regs);
 196         }
 197 while(1);
 198         spin_unlock_irq(&die_lock);
 199         do_exit(SIGSEGV);
 200 }
 201
 202 void die_if_kernel(const char *str, struct pt_regs *regs, int err)
 203 {
 204         if (user_mode(regs))
 205                 return;
 206
 207         die(str, regs, err);
 208 }
 209
 210 static DECLARE_MUTEX(undef_sem);
 211 static int (*undef_hook)(struct pt_regs *);
 212
 213 int request_undef_hook(int (*fn)(struct pt_regs *))
 214 {
 215         int ret = -EBUSY;
 216
 217         down(&undef_sem);
 218         if (undef_hook == NULL) {
 219                 undef_hook = fn;
 220                 ret = 0;
 221         }
 222         up(&undef_sem);
 223
 224         return ret;
 225 }
 226
 227 int release_undef_hook(int (*fn)(struct pt_regs *))
 228 {
 229         int ret = -EINVAL;
 230
 231         down(&undef_sem);
 232         if (undef_hook == fn) {
 233                 undef_hook = NULL;
 234                 ret = 0;
 235         }
 236         up(&undef_sem);
 237
 238         return ret;
 239 }
 240
 241 static int undefined_extension(struct pt_regs *regs, unsigned int op)
 242 {
 243         switch (op) {
 244         case 1: /* 0xde01 / 0x?7f001f0 */
 245                 ptrace_break(current, regs);
 246                 return 0;
 247         }
 248         return 1;
 249 }
 250
 251 asmlinkage void do_undefinstr(struct pt_regs *regs)
 252 {
 253         siginfo_t info;
 254         void *pc;
 255
 256         regs->ARM_pc -= 4;
 257
 258         pc = (unsigned long *)instruction_pointer(regs); /* strip PSR */
 259
 260         if (user_mode(regs)) {
 261                 u32 instr;
 262
 263                 get_user(instr, (u32 *)pc);
 264
 265                 if ((instr & 0x0fff00ff) == 0x07f000f0 &&
 266                     undefined_extension(regs, (instr >> 8) & 255) == 0) {
 267                         regs->ARM_pc += 4;
 268                         return;
 269                 }
 270         } else {
 271                 if (undef_hook && undef_hook(regs) == 0) {
 272                         regs->ARM_pc += 4;
 273                         return;
 274                 }
 275         }
 276
 277 #ifdef CONFIG_DEBUG_USER
 278         printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
 279                 current->comm, current->pid, pc);
 280         dump_instr(regs);
 281 #endif
 282
 283         current->thread.error_code = 0;
 284         current->thread.trap_no = 6;
 285
 286         info.si_signo = SIGILL;
 287         info.si_errno = 0;
 288         info.si_code  = ILL_ILLOPC;
 289         info.si_addr  = pc;
 290
 291         force_sig_info(SIGILL, &info, current);
 292
 293         die_if_kernel("Oops - undefined instruction", regs, 0);
 294 }
 295
 296 asmlinkage void do_excpt(unsigned long address, struct pt_regs *regs, int mode)
 297 {
 298         siginfo_t info;
 299
 300 #ifdef CONFIG_DEBUG_USER
 301         printk(KERN_INFO "%s (%d): address exception: pc=%08lx\n",
 302                 current->comm, current->pid, instruction_pointer(regs));
 303         dump_instr(regs);
 304 #endif
 305
 306         current->thread.error_code = 0;
 307         current->thread.trap_no = 11;
 308
 309         info.si_signo = SIGBUS;
 310         info.si_errno = 0;
 311         info.si_code  = BUS_ADRERR;
 312         info.si_addr  = (void *)address;
 313
 314         force_sig_info(SIGBUS, &info, current);
 315
 316         die_if_kernel("Oops - address exception", regs, mode);
 317 }
 318
 319 asmlinkage void do_unexp_fiq (struct pt_regs *regs)
 320 {
 321 #ifndef CONFIG_IGNORE_FIQ
 322         printk("Hmm.  Unexpected FIQ received, but trying to continue\n");
 323         printk("You may have a hardware problem...\n");
 324 #endif
 325 }
 326
 327 /*
 328  * bad_mode handles the impossible case in the vectors.  If you see one of
 329  * these, then it's extremely serious, and could mean you have buggy hardware.
 330  * It never returns, and never tries to sync.  We hope that we can at least
 331  * dump out some state information...
 332  */
 333 asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
 334 {
 335         unsigned int vectors = vectors_base();
 336
 337         console_verbose();
 338
 339         printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
 340                 handler[reason<5?reason:4], processor_modes[proc_mode]);
 341
 342         /*
 343          * Dump out the vectors and stub routines.  Maybe a better solution
 344          * would be to dump them out only if we detect that they are corrupted.
 345          */
 346         dump_mem(KERN_CRIT "Vectors: ", vectors, vectors + 0x40);
 347         dump_mem(KERN_CRIT "Stubs: ", vectors + 0x200, vectors + 0x4b8);
 348
 349         die("Oops", regs, 0);
 350         local_irq_disable();
 351         panic("bad mode");
 352 }
 353
 354 static int bad_syscall(int n, struct pt_regs *regs)
 355 {
 356         struct thread_info *thread = current_thread_info();
 357         siginfo_t info;
 358
 359         if (current->personality != PER_LINUX && thread->exec_domain->handler) {
 360                 thread->exec_domain->handler(n, regs);
 361                 return regs->ARM_r0;
 362         }
 363
 364 #ifdef CONFIG_DEBUG_USER
 365         printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
 366                 current->pid, current->comm, n);
 367         dump_instr(regs);
 368 #endif
 369
 370         info.si_signo = SIGILL;
 371         info.si_errno = 0;
 372         info.si_code  = ILL_ILLTRP;
 373         info.si_addr  = (void *)instruction_pointer(regs) - 4;
 374
 375         force_sig_info(SIGILL, &info, current);
 376         die_if_kernel("Oops", regs, n);
 377         return regs->ARM_r0;
 378 }
 379
 380 static inline void
 381 do_cache_op(unsigned long start, unsigned long end, int flags)
 382 {
 383         struct vm_area_struct *vma;
 384
 385         if (end < start)
 386                 return;
 387
 388         vma = find_vma(current->active_mm, start);
 389         if (vma && vma->vm_start < end) {
 390                 if (start < vma->vm_start)
 391                         start = vma->vm_start;
 392                 if (end > vma->vm_end)
 393                         end = vma->vm_end;
 394         }
 395 }
 396
 397 /*
 398  * Handle all unrecognised system calls.
 399  *  0x9f0000 - 0x9fffff are some more esoteric system calls
 400  */
 401 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
 402 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 403 {
 404         siginfo_t info;
 405
 406         if ((no >> 16) != 0x9f)
 407                 return bad_syscall(no, regs);
 408
 409         switch (no & 0xffff) {
 410         case 0: /* branch through 0 */
 411                 info.si_signo = SIGSEGV;
 412                 info.si_errno = 0;
 413                 info.si_code  = SEGV_MAPERR;
 414                 info.si_addr  = NULL;
 415
 416                 force_sig_info(SIGSEGV, &info, current);
 417
 418                 die_if_kernel("branch through zero", regs, 0);
 419                 return 0;
 420
 421         case NR(breakpoint): /* SWI BREAK_POINT */
 422                 ptrace_break(current, regs);
 423                 return regs->ARM_r0;
 424
 425         case NR(cacheflush):
 426                 return 0;
 427
 428         case NR(usr26):
 429                 break;
 430
 431         default:
 432                 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
 433                    if not implemented, rather than raising SIGILL.  This
 434                    way the calling program can gracefully determine whether
 435                    a feature is supported.  */
 436                 if (no <= 0x7ff)
 437                         return -ENOSYS;
 438                 break;
 439         }
 440 #ifdef CONFIG_DEBUG_USER
 441         /*
 442          * experience shows that these seem to indicate that
 443          * something catastrophic has happened
 444          */
 445         printk("[%d] %s: arm syscall %d\n", current->pid, current->comm, no);
 446         dump_instr(regs);
 447         if (user_mode(regs)) {
 448                 show_regs(regs);
 449                 c_backtrace(regs->ARM_fp, processor_mode(regs));
 450         }
 451 #endif
 452         info.si_signo = SIGILL;
 453         info.si_errno = 0;
 454         info.si_code  = ILL_ILLTRP;
 455         info.si_addr  = (void *)instruction_pointer(regs) - 4;
 456
 457         force_sig_info(SIGILL, &info, current);
 458         die_if_kernel("Oops", regs, no);
 459         return 0;
 460 }
 461
 462 void __bad_xchg(volatile void *ptr, int size)
 463 {
 464         printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n",
 465                 __builtin_return_address(0), ptr, size);
 466         BUG();
 467 }
 468
 469 /*
 470  * A data abort trap was taken, but we did not handle the instruction.
 471  * Try to abort the user program, or panic if it was the kernel.
 472  */
 473 asmlinkage void
 474 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
 475 {
 476         unsigned long addr = instruction_pointer(regs);
 477         siginfo_t info;
 478
 479 #ifdef CONFIG_DEBUG_USER
 480         printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n",
 481                 current->pid, current->comm, code, instr);
 482         dump_instr(regs);
 483         show_pte(current->mm, addr);
 484 #endif
 485
 486         info.si_signo = SIGILL;
 487         info.si_errno = 0;
 488         info.si_code  = ILL_ILLOPC;
 489         info.si_addr  = (void *)addr;
 490
 491         force_sig_info(SIGILL, &info, current);
 492         die_if_kernel("unknown data abort code", regs, instr);
 493 }
 494
 495 volatile void __bug(const char *file, int line, void *data)
 496 {
 497         printk(KERN_CRIT"kernel BUG at %s:%d!", file, line);
 498         if (data)
 499                 printk(KERN_CRIT" - extra data = %p", data);
 500         printk("\n");
 501         *(int *)0 = 0;
 502 }
 503
 504 void __readwrite_bug(const char *fn)
 505 {
 506         printk("%s called, but not implemented", fn);
 507         BUG();
 508 }
 509
 510 void __pte_error(const char *file, int line, unsigned long val)
 511 {
 512         printk("%s:%d: bad pte %08lx.\n", file, line, val);
 513 }
 514
 515 void __pmd_error(const char *file, int line, unsigned long val)
 516 {
 517         printk("%s:%d: bad pmd %08lx.\n", file, line, val);
 518 }
 519
 520 void __pgd_error(const char *file, int line, unsigned long val)
 521 {
 522         printk("%s:%d: bad pgd %08lx.\n", file, line, val);
 523 }
 524
 525 asmlinkage void __div0(void)
 526 {
 527         printk("Division by zero in kernel.\n");
 528         dump_stack();
 529 }
 530
 531 void abort(void)
 532 {
 533         BUG();
 534
 535         /* if that doesn't kill us, halt */
 536         panic("Oops failed to kill thread");
 537 }
 538
 539 void __init trap_init(void)
 540 {
 541         extern void __trap_init(unsigned long);
 542         unsigned long base = vectors_base();
 543
 544         __trap_init(base);
 545         if (base != 0)
 546                 printk(KERN_DEBUG "Relocating machine vectors to 0x%08lx\n",
 547                         base);
 548 }