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