git.oblomov.eu Git - linux-2.6/blob - arch/sh/kernel/traps.c

   1 /*
   2  * 'traps.c' handles hardware traps and faults after we have saved some
   3  * state in 'entry.S'.
   4  *
   5  *  SuperH version: Copyright (C) 1999 Niibe Yutaka
   6  *                  Copyright (C) 2000 Philipp Rumpf
   7  *                  Copyright (C) 2000 David Howells
   8  *                  Copyright (C) 2002 - 2007 Paul Mundt
   9  *
  10  * This file is subject to the terms and conditions of the GNU General Public
  11  * License.  See the file "COPYING" in the main directory of this archive
  12  * for more details.
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/init.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/module.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/io.h>
  21 #include <linux/bug.h>
  22 #include <linux/debug_locks.h>
  23 #include <linux/limits.h>
  24 #include <asm/system.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/kdebug.h>
  27
  28 #ifdef CONFIG_SH_KGDB
  29 #include <asm/kgdb.h>
  30 #define CHK_REMOTE_DEBUG(regs)                  \
  31 {                                               \
  32         if (kgdb_debug_hook && !user_mode(regs))\
  33                 (*kgdb_debug_hook)(regs);       \
  34 }
  35 #else
  36 #define CHK_REMOTE_DEBUG(regs)
  37 #endif
  38
  39 #ifdef CONFIG_CPU_SH2
  40 # define TRAP_RESERVED_INST     4
  41 # define TRAP_ILLEGAL_SLOT_INST 6
  42 # define TRAP_ADDRESS_ERROR     9
  43 # ifdef CONFIG_CPU_SH2A
  44 #  define TRAP_DIVZERO_ERROR    17
  45 #  define TRAP_DIVOVF_ERROR     18
  46 # endif
  47 #else
  48 #define TRAP_RESERVED_INST      12
  49 #define TRAP_ILLEGAL_SLOT_INST  13
  50 #endif
  51
  52 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  53 {
  54         unsigned long p;
  55         int i;
  56
  57         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  58
  59         for (p = bottom & ~31; p < top; ) {
  60                 printk("%04lx: ", p & 0xffff);
  61
  62                 for (i = 0; i < 8; i++, p += 4) {
  63                         unsigned int val;
  64
  65                         if (p < bottom || p >= top)
  66                                 printk("         ");
  67                         else {
  68                                 if (__get_user(val, (unsigned int __user *)p)) {
  69                                         printk("\n");
  70                                         return;
  71                                 }
  72                                 printk("%08x ", val);
  73                         }
  74                 }
  75                 printk("\n");
  76         }
  77 }
  78
  79 ATOMIC_NOTIFIER_HEAD(shdie_chain);
  80
  81 int register_die_notifier(struct notifier_block *nb)
  82 {
  83         return atomic_notifier_chain_register(&shdie_chain, nb);
  84 }
  85 EXPORT_SYMBOL(register_die_notifier);
  86
  87 int unregister_die_notifier(struct notifier_block *nb)
  88 {
  89         return atomic_notifier_chain_unregister(&shdie_chain, nb);
  90 }
  91 EXPORT_SYMBOL(unregister_die_notifier);
  92
  93 static DEFINE_SPINLOCK(die_lock);
  94
  95 void die(const char * str, struct pt_regs * regs, long err)
  96 {
  97         static int die_counter;
  98
  99         console_verbose();
 100         spin_lock_irq(&die_lock);
 101         bust_spinlocks(1);
 102
 103         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
 104
 105         CHK_REMOTE_DEBUG(regs);
 106         print_modules();
 107         show_regs(regs);
 108
 109         printk("Process: %s (pid: %d, stack limit = %p)\n",
 110                current->comm, current->pid, task_stack_page(current) + 1);
 111
 112         if (!user_mode(regs) || in_interrupt())
 113                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
 114                          (unsigned long)task_stack_page(current));
 115
 116         bust_spinlocks(0);
 117         spin_unlock_irq(&die_lock);
 118         do_exit(SIGSEGV);
 119 }
 120
 121 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 122                                  long err)
 123 {
 124         if (!user_mode(regs))
 125                 die(str, regs, err);
 126 }
 127
 128 /*
 129  * try and fix up kernelspace address errors
 130  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 131  * - kernel/userspace interfaces cause a jump to an appropriate handler
 132  * - other kernel errors are bad
 133  * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
 134  */
 135 static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 136 {
 137         if (!user_mode(regs)) {
 138                 const struct exception_table_entry *fixup;
 139                 fixup = search_exception_tables(regs->pc);
 140                 if (fixup) {
 141                         regs->pc = fixup->fixup;
 142                         return 0;
 143                 }
 144                 die(str, regs, err);
 145         }
 146         return -EFAULT;
 147 }
 148
 149 /*
 150  * handle an instruction that does an unaligned memory access by emulating the
 151  * desired behaviour
 152  * - note that PC _may not_ point to the faulting instruction
 153  *   (if that instruction is in a branch delay slot)
 154  * - return 0 if emulation okay, -EFAULT on existential error
 155  */
 156 static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs)
 157 {
 158         int ret, index, count;
 159         unsigned long *rm, *rn;
 160         unsigned char *src, *dst;
 161
 162         index = (instruction>>8)&15;    /* 0x0F00 */
 163         rn = &regs->regs[index];
 164
 165         index = (instruction>>4)&15;    /* 0x00F0 */
 166         rm = &regs->regs[index];
 167
 168         count = 1<<(instruction&3);
 169
 170         ret = -EFAULT;
 171         switch (instruction>>12) {
 172         case 0: /* mov.[bwl] to/from memory via r0+rn */
 173                 if (instruction & 8) {
 174                         /* from memory */
 175                         src = (unsigned char*) *rm;
 176                         src += regs->regs[0];
 177                         dst = (unsigned char*) rn;
 178                         *(unsigned long*)dst = 0;
 179
 180 #ifdef __LITTLE_ENDIAN__
 181                         if (copy_from_user(dst, src, count))
 182                                 goto fetch_fault;
 183
 184                         if ((count == 2) && dst[1] & 0x80) {
 185                                 dst[2] = 0xff;
 186                                 dst[3] = 0xff;
 187                         }
 188 #else
 189                         dst += 4-count;
 190
 191                         if (__copy_user(dst, src, count))
 192                                 goto fetch_fault;
 193
 194                         if ((count == 2) && dst[2] & 0x80) {
 195                                 dst[0] = 0xff;
 196                                 dst[1] = 0xff;
 197                         }
 198 #endif
 199                 } else {
 200                         /* to memory */
 201                         src = (unsigned char*) rm;
 202 #if !defined(__LITTLE_ENDIAN__)
 203                         src += 4-count;
 204 #endif
 205                         dst = (unsigned char*) *rn;
 206                         dst += regs->regs[0];
 207
 208                         if (copy_to_user(dst, src, count))
 209                                 goto fetch_fault;
 210                 }
 211                 ret = 0;
 212                 break;
 213
 214         case 1: /* mov.l Rm,@(disp,Rn) */
 215                 src = (unsigned char*) rm;
 216                 dst = (unsigned char*) *rn;
 217                 dst += (instruction&0x000F)<<2;
 218
 219                 if (copy_to_user(dst,src,4))
 220                         goto fetch_fault;
 221                 ret = 0;
 222                 break;
 223
 224         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 225                 if (instruction & 4)
 226                         *rn -= count;
 227                 src = (unsigned char*) rm;
 228                 dst = (unsigned char*) *rn;
 229 #if !defined(__LITTLE_ENDIAN__)
 230                 src += 4-count;
 231 #endif
 232                 if (copy_to_user(dst, src, count))
 233                         goto fetch_fault;
 234                 ret = 0;
 235                 break;
 236
 237         case 5: /* mov.l @(disp,Rm),Rn */
 238                 src = (unsigned char*) *rm;
 239                 src += (instruction&0x000F)<<2;
 240                 dst = (unsigned char*) rn;
 241                 *(unsigned long*)dst = 0;
 242
 243                 if (copy_from_user(dst,src,4))
 244                         goto fetch_fault;
 245                 ret = 0;
 246                 break;
 247
 248         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 249                 src = (unsigned char*) *rm;
 250                 if (instruction & 4)
 251                         *rm += count;
 252                 dst = (unsigned char*) rn;
 253                 *(unsigned long*)dst = 0;
 254
 255 #ifdef __LITTLE_ENDIAN__
 256                 if (copy_from_user(dst, src, count))
 257                         goto fetch_fault;
 258
 259                 if ((count == 2) && dst[1] & 0x80) {
 260                         dst[2] = 0xff;
 261                         dst[3] = 0xff;
 262                 }
 263 #else
 264                 dst += 4-count;
 265
 266                 if (copy_from_user(dst, src, count))
 267                         goto fetch_fault;
 268
 269                 if ((count == 2) && dst[2] & 0x80) {
 270                         dst[0] = 0xff;
 271                         dst[1] = 0xff;
 272                 }
 273 #endif
 274                 ret = 0;
 275                 break;
 276
 277         case 8:
 278                 switch ((instruction&0xFF00)>>8) {
 279                 case 0x81: /* mov.w R0,@(disp,Rn) */
 280                         src = (unsigned char*) &regs->regs[0];
 281 #if !defined(__LITTLE_ENDIAN__)
 282                         src += 2;
 283 #endif
 284                         dst = (unsigned char*) *rm; /* called Rn in the spec */
 285                         dst += (instruction&0x000F)<<1;
 286
 287                         if (copy_to_user(dst, src, 2))
 288                                 goto fetch_fault;
 289                         ret = 0;
 290                         break;
 291
 292                 case 0x85: /* mov.w @(disp,Rm),R0 */
 293                         src = (unsigned char*) *rm;
 294                         src += (instruction&0x000F)<<1;
 295                         dst = (unsigned char*) &regs->regs[0];
 296                         *(unsigned long*)dst = 0;
 297
 298 #if !defined(__LITTLE_ENDIAN__)
 299                         dst += 2;
 300 #endif
 301
 302                         if (copy_from_user(dst, src, 2))
 303                                 goto fetch_fault;
 304
 305 #ifdef __LITTLE_ENDIAN__
 306                         if (dst[1] & 0x80) {
 307                                 dst[2] = 0xff;
 308                                 dst[3] = 0xff;
 309                         }
 310 #else
 311                         if (dst[2] & 0x80) {
 312                                 dst[0] = 0xff;
 313                                 dst[1] = 0xff;
 314                         }
 315 #endif
 316                         ret = 0;
 317                         break;
 318                 }
 319                 break;
 320         }
 321         return ret;
 322
 323  fetch_fault:
 324         /* Argh. Address not only misaligned but also non-existent.
 325          * Raise an EFAULT and see if it's trapped
 326          */
 327         return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 328 }
 329
 330 /*
 331  * emulate the instruction in the delay slot
 332  * - fetches the instruction from PC+2
 333  */
 334 static inline int handle_unaligned_delayslot(struct pt_regs *regs)
 335 {
 336         u16 instruction;
 337
 338         if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) {
 339                 /* the instruction-fetch faulted */
 340                 if (user_mode(regs))
 341                         return -EFAULT;
 342
 343                 /* kernel */
 344                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 345                     regs, 0);
 346         }
 347
 348         return handle_unaligned_ins(instruction,regs);
 349 }
 350
 351 /*
 352  * handle an instruction that does an unaligned memory access
 353  * - have to be careful of branch delay-slot instructions that fault
 354  *  SH3:
 355  *   - if the branch would be taken PC points to the branch
 356  *   - if the branch would not be taken, PC points to delay-slot
 357  *  SH4:
 358  *   - PC always points to delayed branch
 359  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 360  */
 361
 362 /* Macros to determine offset from current PC for branch instructions */
 363 /* Explicit type coercion is used to force sign extension where needed */
 364 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 365 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 366
 367 /*
 368  * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
 369  * opcodes..
 370  */
 371 #ifndef CONFIG_CPU_SH2A
 372 static int handle_unaligned_notify_count = 10;
 373
 374 static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
 375 {
 376         u_int rm;
 377         int ret, index;
 378
 379         index = (instruction>>8)&15;    /* 0x0F00 */
 380         rm = regs->regs[index];
 381
 382         /* shout about the first ten userspace fixups */
 383         if (user_mode(regs) && handle_unaligned_notify_count>0) {
 384                 handle_unaligned_notify_count--;
 385
 386                 printk(KERN_NOTICE "Fixing up unaligned userspace access "
 387                        "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 388                        current->comm,current->pid,(u16*)regs->pc,instruction);
 389         }
 390
 391         ret = -EFAULT;
 392         switch (instruction&0xF000) {
 393         case 0x0000:
 394                 if (instruction==0x000B) {
 395                         /* rts */
 396                         ret = handle_unaligned_delayslot(regs);
 397                         if (ret==0)
 398                                 regs->pc = regs->pr;
 399                 }
 400                 else if ((instruction&0x00FF)==0x0023) {
 401                         /* braf @Rm */
 402                         ret = handle_unaligned_delayslot(regs);
 403                         if (ret==0)
 404                                 regs->pc += rm + 4;
 405                 }
 406                 else if ((instruction&0x00FF)==0x0003) {
 407                         /* bsrf @Rm */
 408                         ret = handle_unaligned_delayslot(regs);
 409                         if (ret==0) {
 410                                 regs->pr = regs->pc + 4;
 411                                 regs->pc += rm + 4;
 412                         }
 413                 }
 414                 else {
 415                         /* mov.[bwl] to/from memory via r0+rn */
 416                         goto simple;
 417                 }
 418                 break;
 419
 420         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 421                 goto simple;
 422
 423         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 424                 goto simple;
 425
 426         case 0x4000:
 427                 if ((instruction&0x00FF)==0x002B) {
 428                         /* jmp @Rm */
 429                         ret = handle_unaligned_delayslot(regs);
 430                         if (ret==0)
 431                                 regs->pc = rm;
 432                 }
 433                 else if ((instruction&0x00FF)==0x000B) {
 434                         /* jsr @Rm */
 435                         ret = handle_unaligned_delayslot(regs);
 436                         if (ret==0) {
 437                                 regs->pr = regs->pc + 4;
 438                                 regs->pc = rm;
 439                         }
 440                 }
 441                 else {
 442                         /* mov.[bwl] to/from memory via r0+rn */
 443                         goto simple;
 444                 }
 445                 break;
 446
 447         case 0x5000: /* mov.l @(disp,Rm),Rn */
 448                 goto simple;
 449
 450         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 451                 goto simple;
 452
 453         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 454                 switch (instruction&0x0F00) {
 455                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 456                         goto simple;
 457                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 458                         goto simple;
 459                 case 0x0B00: /* bf   lab - no delayslot*/
 460                         break;
 461                 case 0x0F00: /* bf/s lab */
 462                         ret = handle_unaligned_delayslot(regs);
 463                         if (ret==0) {
 464 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 465                                 if ((regs->sr & 0x00000001) != 0)
 466                                         regs->pc += 4; /* next after slot */
 467                                 else
 468 #endif
 469                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 470                         }
 471                         break;
 472                 case 0x0900: /* bt   lab - no delayslot */
 473                         break;
 474                 case 0x0D00: /* bt/s lab */
 475                         ret = handle_unaligned_delayslot(regs);
 476                         if (ret==0) {
 477 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 478                                 if ((regs->sr & 0x00000001) == 0)
 479                                         regs->pc += 4; /* next after slot */
 480                                 else
 481 #endif
 482                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 483                         }
 484                         break;
 485                 }
 486                 break;
 487
 488         case 0xA000: /* bra label */
 489                 ret = handle_unaligned_delayslot(regs);
 490                 if (ret==0)
 491                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 492                 break;
 493
 494         case 0xB000: /* bsr label */
 495                 ret = handle_unaligned_delayslot(regs);
 496                 if (ret==0) {
 497                         regs->pr = regs->pc + 4;
 498                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 499                 }
 500                 break;
 501         }
 502         return ret;
 503
 504         /* handle non-delay-slot instruction */
 505  simple:
 506         ret = handle_unaligned_ins(instruction,regs);
 507         if (ret==0)
 508                 regs->pc += 2;
 509         return ret;
 510 }
 511 #endif /* CONFIG_CPU_SH2A */
 512
 513 #ifdef CONFIG_CPU_HAS_SR_RB
 514 #define lookup_exception_vector(x)      \
 515         __asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))
 516 #else
 517 #define lookup_exception_vector(x)      \
 518         __asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))
 519 #endif
 520
 521 /*
 522  * Handle various address error exceptions:
 523  *  - instruction address error:
 524  *       misaligned PC
 525  *       PC >= 0x80000000 in user mode
 526  *  - data address error (read and write)
 527  *       misaligned data access
 528  *       access to >= 0x80000000 is user mode
 529  * Unfortuntaly we can't distinguish between instruction address error
 530  * and data address errors caused by read acceses.
 531  */
 532 asmlinkage void do_address_error(struct pt_regs *regs,
 533                                  unsigned long writeaccess,
 534                                  unsigned long address)
 535 {
 536         unsigned long error_code = 0;
 537         mm_segment_t oldfs;
 538         siginfo_t info;
 539 #ifndef CONFIG_CPU_SH2A
 540         u16 instruction;
 541         int tmp;
 542 #endif
 543
 544         /* Intentional ifdef */
 545 #ifdef CONFIG_CPU_HAS_SR_RB
 546         lookup_exception_vector(error_code);
 547 #endif
 548
 549         oldfs = get_fs();
 550
 551         if (user_mode(regs)) {
 552                 int si_code = BUS_ADRERR;
 553
 554                 local_irq_enable();
 555
 556                 /* bad PC is not something we can fix */
 557                 if (regs->pc & 1) {
 558                         si_code = BUS_ADRALN;
 559                         goto uspace_segv;
 560                 }
 561
 562 #ifndef CONFIG_CPU_SH2A
 563                 set_fs(USER_DS);
 564                 if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
 565                         /* Argh. Fault on the instruction itself.
 566                            This should never happen non-SMP
 567                         */
 568                         set_fs(oldfs);
 569                         goto uspace_segv;
 570                 }
 571
 572                 tmp = handle_unaligned_access(instruction, regs);
 573                 set_fs(oldfs);
 574
 575                 if (tmp==0)
 576                         return; /* sorted */
 577 #endif
 578
 579 uspace_segv:
 580                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 581                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 582                        regs->pr);
 583
 584                 info.si_signo = SIGBUS;
 585                 info.si_errno = 0;
 586                 info.si_code = si_code;
 587                 info.si_addr = (void *) address;
 588                 force_sig_info(SIGBUS, &info, current);
 589         } else {
 590                 if (regs->pc & 1)
 591                         die("unaligned program counter", regs, error_code);
 592
 593 #ifndef CONFIG_CPU_SH2A
 594                 set_fs(KERNEL_DS);
 595                 if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
 596                         /* Argh. Fault on the instruction itself.
 597                            This should never happen non-SMP
 598                         */
 599                         set_fs(oldfs);
 600                         die("insn faulting in do_address_error", regs, 0);
 601                 }
 602
 603                 handle_unaligned_access(instruction, regs);
 604                 set_fs(oldfs);
 605 #else
 606                 printk(KERN_NOTICE "Killing process \"%s\" due to unaligned "
 607                        "access\n", current->comm);
 608
 609                 force_sig(SIGSEGV, current);
 610 #endif
 611         }
 612 }
 613
 614 #ifdef CONFIG_SH_DSP
 615 /*
 616  *      SH-DSP support gerg@snapgear.com.
 617  */
 618 int is_dsp_inst(struct pt_regs *regs)
 619 {
 620         unsigned short inst;
 621
 622         /*
 623          * Safe guard if DSP mode is already enabled or we're lacking
 624          * the DSP altogether.
 625          */
 626         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 627                 return 0;
 628
 629         get_user(inst, ((unsigned short *) regs->pc));
 630
 631         inst &= 0xf000;
 632
 633         /* Check for any type of DSP or support instruction */
 634         if ((inst == 0xf000) || (inst == 0x4000))
 635                 return 1;
 636
 637         return 0;
 638 }
 639 #else
 640 #define is_dsp_inst(regs)       (0)
 641 #endif /* CONFIG_SH_DSP */
 642
 643 #ifdef CONFIG_CPU_SH2A
 644 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 645                                 unsigned long r6, unsigned long r7,
 646                                 struct pt_regs __regs)
 647 {
 648         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 649         siginfo_t info;
 650
 651         switch (r4) {
 652         case TRAP_DIVZERO_ERROR:
 653                 info.si_code = FPE_INTDIV;
 654                 break;
 655         case TRAP_DIVOVF_ERROR:
 656                 info.si_code = FPE_INTOVF;
 657                 break;
 658         }
 659
 660         force_sig_info(SIGFPE, &info, current);
 661 }
 662 #endif
 663
 664 /* arch/sh/kernel/cpu/sh4/fpu.c */
 665 extern int do_fpu_inst(unsigned short, struct pt_regs *);
 666 extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5,
 667                 unsigned long r6, unsigned long r7, struct pt_regs __regs);
 668
 669 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 670                                 unsigned long r6, unsigned long r7,
 671                                 struct pt_regs __regs)
 672 {
 673         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 674         unsigned long error_code;
 675         struct task_struct *tsk = current;
 676
 677 #ifdef CONFIG_SH_FPU_EMU
 678         unsigned short inst = 0;
 679         int err;
 680
 681         get_user(inst, (unsigned short*)regs->pc);
 682
 683         err = do_fpu_inst(inst, regs);
 684         if (!err) {
 685                 regs->pc += 2;
 686                 return;
 687         }
 688         /* not a FPU inst. */
 689 #endif
 690
 691 #ifdef CONFIG_SH_DSP
 692         /* Check if it's a DSP instruction */
 693         if (is_dsp_inst(regs)) {
 694                 /* Enable DSP mode, and restart instruction. */
 695                 regs->sr |= SR_DSP;
 696                 return;
 697         }
 698 #endif
 699
 700         lookup_exception_vector(error_code);
 701
 702         local_irq_enable();
 703         CHK_REMOTE_DEBUG(regs);
 704         force_sig(SIGILL, tsk);
 705         die_if_no_fixup("reserved instruction", regs, error_code);
 706 }
 707
 708 #ifdef CONFIG_SH_FPU_EMU
 709 static int emulate_branch(unsigned short inst, struct pt_regs* regs)
 710 {
 711         /*
 712          * bfs: 8fxx: PC+=d*2+4;
 713          * bts: 8dxx: PC+=d*2+4;
 714          * bra: axxx: PC+=D*2+4;
 715          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 716          * braf:0x23: PC+=Rn*2+4;
 717          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 718          * jmp: 4x2b: PC=Rn;
 719          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 720          * rts: 000b: PC=PR;
 721          */
 722         if ((inst & 0xfd00) == 0x8d00) {
 723                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 724                 return 0;
 725         }
 726
 727         if ((inst & 0xe000) == 0xa000) {
 728                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 729                 return 0;
 730         }
 731
 732         if ((inst & 0xf0df) == 0x0003) {
 733                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 734                 return 0;
 735         }
 736
 737         if ((inst & 0xf0df) == 0x400b) {
 738                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 739                 return 0;
 740         }
 741
 742         if ((inst & 0xffff) == 0x000b) {
 743                 regs->pc = regs->pr;
 744                 return 0;
 745         }
 746
 747         return 1;
 748 }
 749 #endif
 750
 751 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 752                                 unsigned long r6, unsigned long r7,
 753                                 struct pt_regs __regs)
 754 {
 755         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 756         unsigned long error_code;
 757         struct task_struct *tsk = current;
 758 #ifdef CONFIG_SH_FPU_EMU
 759         unsigned short inst = 0;
 760
 761         get_user(inst, (unsigned short *)regs->pc + 1);
 762         if (!do_fpu_inst(inst, regs)) {
 763                 get_user(inst, (unsigned short *)regs->pc);
 764                 if (!emulate_branch(inst, regs))
 765                         return;
 766                 /* fault in branch.*/
 767         }
 768         /* not a FPU inst. */
 769 #endif
 770
 771         lookup_exception_vector(error_code);
 772
 773         local_irq_enable();
 774         CHK_REMOTE_DEBUG(regs);
 775         force_sig(SIGILL, tsk);
 776         die_if_no_fixup("illegal slot instruction", regs, error_code);
 777 }
 778
 779 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
 780                                    unsigned long r6, unsigned long r7,
 781                                    struct pt_regs __regs)
 782 {
 783         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 784         long ex;
 785
 786         lookup_exception_vector(ex);
 787         die_if_kernel("exception", regs, ex);
 788 }
 789
 790 #if defined(CONFIG_SH_STANDARD_BIOS)
 791 void *gdb_vbr_vector;
 792
 793 static inline void __init gdb_vbr_init(void)
 794 {
 795         register unsigned long vbr;
 796
 797         /*
 798          * Read the old value of the VBR register to initialise
 799          * the vector through which debug and BIOS traps are
 800          * delegated by the Linux trap handler.
 801          */
 802         asm volatile("stc vbr, %0" : "=r" (vbr));
 803
 804         gdb_vbr_vector = (void *)(vbr + 0x100);
 805         printk("Setting GDB trap vector to 0x%08lx\n",
 806                (unsigned long)gdb_vbr_vector);
 807 }
 808 #endif
 809
 810 void __init per_cpu_trap_init(void)
 811 {
 812         extern void *vbr_base;
 813
 814 #ifdef CONFIG_SH_STANDARD_BIOS
 815         gdb_vbr_init();
 816 #endif
 817
 818         /* NOTE: The VBR value should be at P1
 819            (or P2, virtural "fixed" address space).
 820            It's definitely should not in physical address.  */
 821
 822         asm volatile("ldc       %0, vbr"
 823                      : /* no output */
 824                      : "r" (&vbr_base)
 825                      : "memory");
 826 }
 827
 828 void *set_exception_table_vec(unsigned int vec, void *handler)
 829 {
 830         extern void *exception_handling_table[];
 831         void *old_handler;
 832
 833         old_handler = exception_handling_table[vec];
 834         exception_handling_table[vec] = handler;
 835         return old_handler;
 836 }
 837
 838 extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5,
 839                                              unsigned long r6, unsigned long r7,
 840                                              struct pt_regs __regs);
 841
 842 void __init trap_init(void)
 843 {
 844         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 845         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 846
 847 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 848     defined(CONFIG_SH_FPU_EMU)
 849         /*
 850          * For SH-4 lacking an FPU, treat floating point instructions as
 851          * reserved. They'll be handled in the math-emu case, or faulted on
 852          * otherwise.
 853          */
 854         set_exception_table_evt(0x800, do_reserved_inst);
 855         set_exception_table_evt(0x820, do_illegal_slot_inst);
 856 #elif defined(CONFIG_SH_FPU)
 857         set_exception_table_evt(0x800, do_fpu_state_restore);
 858         set_exception_table_evt(0x820, do_fpu_state_restore);
 859 #endif
 860
 861 #ifdef CONFIG_CPU_SH2
 862         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler);
 863 #endif
 864 #ifdef CONFIG_CPU_SH2A
 865         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 866         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 867 #endif
 868
 869         /* Setup VBR for boot cpu */
 870         per_cpu_trap_init();
 871 }
 872
 873 #ifdef CONFIG_BUG
 874 void handle_BUG(struct pt_regs *regs)
 875 {
 876         enum bug_trap_type tt;
 877         tt = report_bug(regs->pc);
 878         if (tt == BUG_TRAP_TYPE_WARN) {
 879                 regs->pc += 2;
 880                 return;
 881         }
 882
 883         die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
 884 }
 885
 886 int is_valid_bugaddr(unsigned long addr)
 887 {
 888         return addr >= PAGE_OFFSET;
 889 }
 890 #endif
 891
 892 void show_trace(struct task_struct *tsk, unsigned long *sp,
 893                 struct pt_regs *regs)
 894 {
 895         unsigned long addr;
 896
 897         if (regs && user_mode(regs))
 898                 return;
 899
 900         printk("\nCall trace: ");
 901 #ifdef CONFIG_KALLSYMS
 902         printk("\n");
 903 #endif
 904
 905         while (!kstack_end(sp)) {
 906                 addr = *sp++;
 907                 if (kernel_text_address(addr))
 908                         print_ip_sym(addr);
 909         }
 910
 911         printk("\n");
 912
 913         if (!tsk)
 914                 tsk = current;
 915
 916         debug_show_held_locks(tsk);
 917 }
 918
 919 void show_stack(struct task_struct *tsk, unsigned long *sp)
 920 {
 921         unsigned long stack;
 922
 923         if (!tsk)
 924                 tsk = current;
 925         if (tsk == current)
 926                 sp = (unsigned long *)current_stack_pointer;
 927         else
 928                 sp = (unsigned long *)tsk->thread.sp;
 929
 930         stack = (unsigned long)sp;
 931         dump_mem("Stack: ", stack, THREAD_SIZE +
 932                  (unsigned long)task_stack_page(tsk));
 933         show_trace(tsk, sp, NULL);
 934 }
 935
 936 void dump_stack(void)
 937 {
 938         show_stack(NULL, NULL);
 939 }
 940 EXPORT_SYMBOL(dump_stack);