git.oblomov.eu Git - linux-2.6/blob - arch/sh/kernel/traps_32.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/kdebug.h>
  24 #include <linux/kexec.h>
  25 #include <linux/limits.h>
  26 #include <asm/system.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/fpu.h>
  29 #include <asm/kprobes.h>
  30
  31 #ifdef CONFIG_SH_KGDB
  32 #include <asm/kgdb.h>
  33 #define CHK_REMOTE_DEBUG(regs)                  \
  34 {                                               \
  35         if (kgdb_debug_hook && !user_mode(regs))\
  36                 (*kgdb_debug_hook)(regs);       \
  37 }
  38 #else
  39 #define CHK_REMOTE_DEBUG(regs)
  40 #endif
  41
  42 #ifdef CONFIG_CPU_SH2
  43 # define TRAP_RESERVED_INST     4
  44 # define TRAP_ILLEGAL_SLOT_INST 6
  45 # define TRAP_ADDRESS_ERROR     9
  46 # ifdef CONFIG_CPU_SH2A
  47 #  define TRAP_FPU_ERROR        13
  48 #  define TRAP_DIVZERO_ERROR    17
  49 #  define TRAP_DIVOVF_ERROR     18
  50 # endif
  51 #else
  52 #define TRAP_RESERVED_INST      12
  53 #define TRAP_ILLEGAL_SLOT_INST  13
  54 #endif
  55
  56 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  57 {
  58         unsigned long p;
  59         int i;
  60
  61         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  62
  63         for (p = bottom & ~31; p < top; ) {
  64                 printk("%04lx: ", p & 0xffff);
  65
  66                 for (i = 0; i < 8; i++, p += 4) {
  67                         unsigned int val;
  68
  69                         if (p < bottom || p >= top)
  70                                 printk("         ");
  71                         else {
  72                                 if (__get_user(val, (unsigned int __user *)p)) {
  73                                         printk("\n");
  74                                         return;
  75                                 }
  76                                 printk("%08x ", val);
  77                         }
  78                 }
  79                 printk("\n");
  80         }
  81 }
  82
  83 static DEFINE_SPINLOCK(die_lock);
  84
  85 void die(const char * str, struct pt_regs * regs, long err)
  86 {
  87         static int die_counter;
  88
  89         oops_enter();
  90
  91         console_verbose();
  92         spin_lock_irq(&die_lock);
  93         bust_spinlocks(1);
  94
  95         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
  96
  97         CHK_REMOTE_DEBUG(regs);
  98         print_modules();
  99         show_regs(regs);
 100
 101         printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
 102                         task_pid_nr(current), task_stack_page(current) + 1);
 103
 104         if (!user_mode(regs) || in_interrupt())
 105                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
 106                          (unsigned long)task_stack_page(current));
 107
 108         bust_spinlocks(0);
 109         add_taint(TAINT_DIE);
 110         spin_unlock_irq(&die_lock);
 111
 112         if (kexec_should_crash(current))
 113                 crash_kexec(regs);
 114
 115         if (in_interrupt())
 116                 panic("Fatal exception in interrupt");
 117
 118         if (panic_on_oops)
 119                 panic("Fatal exception");
 120
 121         oops_exit();
 122         do_exit(SIGSEGV);
 123 }
 124
 125 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 126                                  long err)
 127 {
 128         if (!user_mode(regs))
 129                 die(str, regs, err);
 130 }
 131
 132 /*
 133  * try and fix up kernelspace address errors
 134  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 135  * - kernel/userspace interfaces cause a jump to an appropriate handler
 136  * - other kernel errors are bad
 137  * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
 138  */
 139 static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 140 {
 141         if (!user_mode(regs)) {
 142                 const struct exception_table_entry *fixup;
 143                 fixup = search_exception_tables(regs->pc);
 144                 if (fixup) {
 145                         regs->pc = fixup->fixup;
 146                         return 0;
 147                 }
 148                 die(str, regs, err);
 149         }
 150         return -EFAULT;
 151 }
 152
 153 static inline void sign_extend(unsigned int count, unsigned char *dst)
 154 {
 155 #ifdef __LITTLE_ENDIAN__
 156         if ((count == 1) && dst[0] & 0x80) {
 157                 dst[1] = 0xff;
 158                 dst[2] = 0xff;
 159                 dst[3] = 0xff;
 160         }
 161         if ((count == 2) && dst[1] & 0x80) {
 162                 dst[2] = 0xff;
 163                 dst[3] = 0xff;
 164         }
 165 #else
 166         if ((count == 1) && dst[3] & 0x80) {
 167                 dst[2] = 0xff;
 168                 dst[1] = 0xff;
 169                 dst[0] = 0xff;
 170         }
 171         if ((count == 2) && dst[2] & 0x80) {
 172                 dst[1] = 0xff;
 173                 dst[0] = 0xff;
 174         }
 175 #endif
 176 }
 177
 178 static struct mem_access user_mem_access = {
 179         copy_from_user,
 180         copy_to_user,
 181 };
 182
 183 /*
 184  * handle an instruction that does an unaligned memory access by emulating the
 185  * desired behaviour
 186  * - note that PC _may not_ point to the faulting instruction
 187  *   (if that instruction is in a branch delay slot)
 188  * - return 0 if emulation okay, -EFAULT on existential error
 189  */
 190 static int handle_unaligned_ins(opcode_t instruction, struct pt_regs *regs,
 191                                 struct mem_access *ma)
 192 {
 193         int ret, index, count;
 194         unsigned long *rm, *rn;
 195         unsigned char *src, *dst;
 196         unsigned char __user *srcu, *dstu;
 197
 198         index = (instruction>>8)&15;    /* 0x0F00 */
 199         rn = &regs->regs[index];
 200
 201         index = (instruction>>4)&15;    /* 0x00F0 */
 202         rm = &regs->regs[index];
 203
 204         count = 1<<(instruction&3);
 205
 206         ret = -EFAULT;
 207         switch (instruction>>12) {
 208         case 0: /* mov.[bwl] to/from memory via r0+rn */
 209                 if (instruction & 8) {
 210                         /* from memory */
 211                         srcu = (unsigned char __user *)*rm;
 212                         srcu += regs->regs[0];
 213                         dst = (unsigned char *)rn;
 214                         *(unsigned long *)dst = 0;
 215
 216 #if !defined(__LITTLE_ENDIAN__)
 217                         dst += 4-count;
 218 #endif
 219                         if (ma->from(dst, srcu, count))
 220                                 goto fetch_fault;
 221
 222                         sign_extend(count, dst);
 223                 } else {
 224                         /* to memory */
 225                         src = (unsigned char *)rm;
 226 #if !defined(__LITTLE_ENDIAN__)
 227                         src += 4-count;
 228 #endif
 229                         dstu = (unsigned char __user *)*rn;
 230                         dstu += regs->regs[0];
 231
 232                         if (ma->to(dstu, src, count))
 233                                 goto fetch_fault;
 234                 }
 235                 ret = 0;
 236                 break;
 237
 238         case 1: /* mov.l Rm,@(disp,Rn) */
 239                 src = (unsigned char*) rm;
 240                 dstu = (unsigned char __user *)*rn;
 241                 dstu += (instruction&0x000F)<<2;
 242
 243                 if (ma->to(dstu, src, 4))
 244                         goto fetch_fault;
 245                 ret = 0;
 246                 break;
 247
 248         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 249                 if (instruction & 4)
 250                         *rn -= count;
 251                 src = (unsigned char*) rm;
 252                 dstu = (unsigned char __user *)*rn;
 253 #if !defined(__LITTLE_ENDIAN__)
 254                 src += 4-count;
 255 #endif
 256                 if (ma->to(dstu, src, count))
 257                         goto fetch_fault;
 258                 ret = 0;
 259                 break;
 260
 261         case 5: /* mov.l @(disp,Rm),Rn */
 262                 srcu = (unsigned char __user *)*rm;
 263                 srcu += (instruction & 0x000F) << 2;
 264                 dst = (unsigned char *)rn;
 265                 *(unsigned long *)dst = 0;
 266
 267                 if (ma->from(dst, srcu, 4))
 268                         goto fetch_fault;
 269                 ret = 0;
 270                 break;
 271
 272         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 273                 srcu = (unsigned char __user *)*rm;
 274                 if (instruction & 4)
 275                         *rm += count;
 276                 dst = (unsigned char*) rn;
 277                 *(unsigned long*)dst = 0;
 278
 279 #if !defined(__LITTLE_ENDIAN__)
 280                 dst += 4-count;
 281 #endif
 282                 if (ma->from(dst, srcu, count))
 283                         goto fetch_fault;
 284                 sign_extend(count, dst);
 285                 ret = 0;
 286                 break;
 287
 288         case 8:
 289                 switch ((instruction&0xFF00)>>8) {
 290                 case 0x81: /* mov.w R0,@(disp,Rn) */
 291                         src = (unsigned char *) &regs->regs[0];
 292 #if !defined(__LITTLE_ENDIAN__)
 293                         src += 2;
 294 #endif
 295                         dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
 296                         dstu += (instruction & 0x000F) << 1;
 297
 298                         if (ma->to(dstu, src, 2))
 299                                 goto fetch_fault;
 300                         ret = 0;
 301                         break;
 302
 303                 case 0x85: /* mov.w @(disp,Rm),R0 */
 304                         srcu = (unsigned char __user *)*rm;
 305                         srcu += (instruction & 0x000F) << 1;
 306                         dst = (unsigned char *) &regs->regs[0];
 307                         *(unsigned long *)dst = 0;
 308
 309 #if !defined(__LITTLE_ENDIAN__)
 310                         dst += 2;
 311 #endif
 312                         if (ma->from(dst, srcu, 2))
 313                                 goto fetch_fault;
 314                         sign_extend(2, dst);
 315                         ret = 0;
 316                         break;
 317                 }
 318                 break;
 319         }
 320         return ret;
 321
 322  fetch_fault:
 323         /* Argh. Address not only misaligned but also non-existent.
 324          * Raise an EFAULT and see if it's trapped
 325          */
 326         return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 327 }
 328
 329 /*
 330  * emulate the instruction in the delay slot
 331  * - fetches the instruction from PC+2
 332  */
 333 static inline int handle_delayslot(struct pt_regs *regs,
 334                                    opcode_t old_instruction,
 335                                    struct mem_access *ma)
 336 {
 337         opcode_t instruction;
 338         void __user *addr = (void __user *)(regs->pc +
 339                 instruction_size(old_instruction));
 340
 341         if (copy_from_user(&instruction, addr, sizeof(instruction))) {
 342                 /* the instruction-fetch faulted */
 343                 if (user_mode(regs))
 344                         return -EFAULT;
 345
 346                 /* kernel */
 347                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 348                     regs, 0);
 349         }
 350
 351         return handle_unaligned_ins(instruction, regs, ma);
 352 }
 353
 354 /*
 355  * handle an instruction that does an unaligned memory access
 356  * - have to be careful of branch delay-slot instructions that fault
 357  *  SH3:
 358  *   - if the branch would be taken PC points to the branch
 359  *   - if the branch would not be taken, PC points to delay-slot
 360  *  SH4:
 361  *   - PC always points to delayed branch
 362  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 363  */
 364
 365 /* Macros to determine offset from current PC for branch instructions */
 366 /* Explicit type coercion is used to force sign extension where needed */
 367 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 368 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 369
 370 /*
 371  * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
 372  * opcodes..
 373  */
 374
 375 static int handle_unaligned_notify_count = 10;
 376
 377 int handle_unaligned_access(opcode_t instruction, struct pt_regs *regs,
 378                             struct mem_access *ma)
 379 {
 380         u_int rm;
 381         int ret, index;
 382
 383         index = (instruction>>8)&15;    /* 0x0F00 */
 384         rm = regs->regs[index];
 385
 386         /* shout about the first ten userspace fixups */
 387         if (user_mode(regs) && handle_unaligned_notify_count>0) {
 388                 handle_unaligned_notify_count--;
 389
 390                 printk(KERN_NOTICE "Fixing up unaligned userspace access "
 391                        "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 392                        current->comm, task_pid_nr(current),
 393                        (void *)regs->pc, instruction);
 394         }
 395
 396         ret = -EFAULT;
 397         switch (instruction&0xF000) {
 398         case 0x0000:
 399                 if (instruction==0x000B) {
 400                         /* rts */
 401                         ret = handle_delayslot(regs, instruction, ma);
 402                         if (ret==0)
 403                                 regs->pc = regs->pr;
 404                 }
 405                 else if ((instruction&0x00FF)==0x0023) {
 406                         /* braf @Rm */
 407                         ret = handle_delayslot(regs, instruction, ma);
 408                         if (ret==0)
 409                                 regs->pc += rm + 4;
 410                 }
 411                 else if ((instruction&0x00FF)==0x0003) {
 412                         /* bsrf @Rm */
 413                         ret = handle_delayslot(regs, instruction, ma);
 414                         if (ret==0) {
 415                                 regs->pr = regs->pc + 4;
 416                                 regs->pc += rm + 4;
 417                         }
 418                 }
 419                 else {
 420                         /* mov.[bwl] to/from memory via r0+rn */
 421                         goto simple;
 422                 }
 423                 break;
 424
 425         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 426                 goto simple;
 427
 428         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 429                 goto simple;
 430
 431         case 0x4000:
 432                 if ((instruction&0x00FF)==0x002B) {
 433                         /* jmp @Rm */
 434                         ret = handle_delayslot(regs, instruction, ma);
 435                         if (ret==0)
 436                                 regs->pc = rm;
 437                 }
 438                 else if ((instruction&0x00FF)==0x000B) {
 439                         /* jsr @Rm */
 440                         ret = handle_delayslot(regs, instruction, ma);
 441                         if (ret==0) {
 442                                 regs->pr = regs->pc + 4;
 443                                 regs->pc = rm;
 444                         }
 445                 }
 446                 else {
 447                         /* mov.[bwl] to/from memory via r0+rn */
 448                         goto simple;
 449                 }
 450                 break;
 451
 452         case 0x5000: /* mov.l @(disp,Rm),Rn */
 453                 goto simple;
 454
 455         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 456                 goto simple;
 457
 458         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 459                 switch (instruction&0x0F00) {
 460                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 461                         goto simple;
 462                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 463                         goto simple;
 464                 case 0x0B00: /* bf   lab - no delayslot*/
 465                         break;
 466                 case 0x0F00: /* bf/s lab */
 467                         ret = handle_delayslot(regs, instruction, ma);
 468                         if (ret==0) {
 469 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 470                                 if ((regs->sr & 0x00000001) != 0)
 471                                         regs->pc += 4; /* next after slot */
 472                                 else
 473 #endif
 474                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 475                         }
 476                         break;
 477                 case 0x0900: /* bt   lab - no delayslot */
 478                         break;
 479                 case 0x0D00: /* bt/s lab */
 480                         ret = handle_delayslot(regs, instruction, ma);
 481                         if (ret==0) {
 482 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 483                                 if ((regs->sr & 0x00000001) == 0)
 484                                         regs->pc += 4; /* next after slot */
 485                                 else
 486 #endif
 487                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 488                         }
 489                         break;
 490                 }
 491                 break;
 492
 493         case 0xA000: /* bra label */
 494                 ret = handle_delayslot(regs, instruction, ma);
 495                 if (ret==0)
 496                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 497                 break;
 498
 499         case 0xB000: /* bsr label */
 500                 ret = handle_delayslot(regs, instruction, ma);
 501                 if (ret==0) {
 502                         regs->pr = regs->pc + 4;
 503                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 504                 }
 505                 break;
 506         }
 507         return ret;
 508
 509         /* handle non-delay-slot instruction */
 510  simple:
 511         ret = handle_unaligned_ins(instruction, regs, ma);
 512         if (ret==0)
 513                 regs->pc += instruction_size(instruction);
 514         return ret;
 515 }
 516
 517 #ifdef CONFIG_CPU_HAS_SR_RB
 518 #define lookup_exception_vector(x)      \
 519         __asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))
 520 #else
 521 #define lookup_exception_vector(x)      \
 522         __asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))
 523 #endif
 524
 525 /*
 526  * Handle various address error exceptions:
 527  *  - instruction address error:
 528  *       misaligned PC
 529  *       PC >= 0x80000000 in user mode
 530  *  - data address error (read and write)
 531  *       misaligned data access
 532  *       access to >= 0x80000000 is user mode
 533  * Unfortuntaly we can't distinguish between instruction address error
 534  * and data address errors caused by read accesses.
 535  */
 536 asmlinkage void do_address_error(struct pt_regs *regs,
 537                                  unsigned long writeaccess,
 538                                  unsigned long address)
 539 {
 540         unsigned long error_code = 0;
 541         mm_segment_t oldfs;
 542         siginfo_t info;
 543         opcode_t instruction;
 544         int tmp;
 545
 546         /* Intentional ifdef */
 547 #ifdef CONFIG_CPU_HAS_SR_RB
 548         lookup_exception_vector(error_code);
 549 #endif
 550
 551         oldfs = get_fs();
 552
 553         if (user_mode(regs)) {
 554                 int si_code = BUS_ADRERR;
 555
 556                 local_irq_enable();
 557
 558                 /* bad PC is not something we can fix */
 559                 if (regs->pc & 1) {
 560                         si_code = BUS_ADRALN;
 561                         goto uspace_segv;
 562                 }
 563
 564                 set_fs(USER_DS);
 565                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 566                                    sizeof(instruction))) {
 567                         /* Argh. Fault on the instruction itself.
 568                            This should never happen non-SMP
 569                         */
 570                         set_fs(oldfs);
 571                         goto uspace_segv;
 572                 }
 573
 574                 tmp = handle_unaligned_access(instruction, regs,
 575                                               &user_mem_access);
 576                 set_fs(oldfs);
 577
 578                 if (tmp==0)
 579                         return; /* sorted */
 580 uspace_segv:
 581                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 582                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 583                        regs->pr);
 584
 585                 info.si_signo = SIGBUS;
 586                 info.si_errno = 0;
 587                 info.si_code = si_code;
 588                 info.si_addr = (void __user *)address;
 589                 force_sig_info(SIGBUS, &info, current);
 590         } else {
 591                 if (regs->pc & 1)
 592                         die("unaligned program counter", regs, error_code);
 593
 594                 set_fs(KERNEL_DS);
 595                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 596                                    sizeof(instruction))) {
 597                         /* Argh. Fault on the instruction itself.
 598                            This should never happen non-SMP
 599                         */
 600                         set_fs(oldfs);
 601                         die("insn faulting in do_address_error", regs, 0);
 602                 }
 603
 604                 handle_unaligned_access(instruction, regs, &user_mem_access);
 605                 set_fs(oldfs);
 606         }
 607 }
 608
 609 #ifdef CONFIG_SH_DSP
 610 /*
 611  *      SH-DSP support gerg@snapgear.com.
 612  */
 613 int is_dsp_inst(struct pt_regs *regs)
 614 {
 615         unsigned short inst = 0;
 616
 617         /*
 618          * Safe guard if DSP mode is already enabled or we're lacking
 619          * the DSP altogether.
 620          */
 621         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 622                 return 0;
 623
 624         get_user(inst, ((unsigned short *) regs->pc));
 625
 626         inst &= 0xf000;
 627
 628         /* Check for any type of DSP or support instruction */
 629         if ((inst == 0xf000) || (inst == 0x4000))
 630                 return 1;
 631
 632         return 0;
 633 }
 634 #else
 635 #define is_dsp_inst(regs)       (0)
 636 #endif /* CONFIG_SH_DSP */
 637
 638 #ifdef CONFIG_CPU_SH2A
 639 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 640                                 unsigned long r6, unsigned long r7,
 641                                 struct pt_regs __regs)
 642 {
 643         siginfo_t info;
 644
 645         switch (r4) {
 646         case TRAP_DIVZERO_ERROR:
 647                 info.si_code = FPE_INTDIV;
 648                 break;
 649         case TRAP_DIVOVF_ERROR:
 650                 info.si_code = FPE_INTOVF;
 651                 break;
 652         }
 653
 654         force_sig_info(SIGFPE, &info, current);
 655 }
 656 #endif
 657
 658 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 659                                 unsigned long r6, unsigned long r7,
 660                                 struct pt_regs __regs)
 661 {
 662         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 663         unsigned long error_code;
 664         struct task_struct *tsk = current;
 665
 666 #ifdef CONFIG_SH_FPU_EMU
 667         unsigned short inst = 0;
 668         int err;
 669
 670         get_user(inst, (unsigned short*)regs->pc);
 671
 672         err = do_fpu_inst(inst, regs);
 673         if (!err) {
 674                 regs->pc += instruction_size(inst);
 675                 return;
 676         }
 677         /* not a FPU inst. */
 678 #endif
 679
 680 #ifdef CONFIG_SH_DSP
 681         /* Check if it's a DSP instruction */
 682         if (is_dsp_inst(regs)) {
 683                 /* Enable DSP mode, and restart instruction. */
 684                 regs->sr |= SR_DSP;
 685                 return;
 686         }
 687 #endif
 688
 689         lookup_exception_vector(error_code);
 690
 691         local_irq_enable();
 692         CHK_REMOTE_DEBUG(regs);
 693         force_sig(SIGILL, tsk);
 694         die_if_no_fixup("reserved instruction", regs, error_code);
 695 }
 696
 697 #ifdef CONFIG_SH_FPU_EMU
 698 static int emulate_branch(unsigned short inst, struct pt_regs* regs)
 699 {
 700         /*
 701          * bfs: 8fxx: PC+=d*2+4;
 702          * bts: 8dxx: PC+=d*2+4;
 703          * bra: axxx: PC+=D*2+4;
 704          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 705          * braf:0x23: PC+=Rn*2+4;
 706          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 707          * jmp: 4x2b: PC=Rn;
 708          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 709          * rts: 000b: PC=PR;
 710          */
 711         if ((inst & 0xfd00) == 0x8d00) {
 712                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 713                 return 0;
 714         }
 715
 716         if ((inst & 0xe000) == 0xa000) {
 717                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 718                 return 0;
 719         }
 720
 721         if ((inst & 0xf0df) == 0x0003) {
 722                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 723                 return 0;
 724         }
 725
 726         if ((inst & 0xf0df) == 0x400b) {
 727                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 728                 return 0;
 729         }
 730
 731         if ((inst & 0xffff) == 0x000b) {
 732                 regs->pc = regs->pr;
 733                 return 0;
 734         }
 735
 736         return 1;
 737 }
 738 #endif
 739
 740 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 741                                 unsigned long r6, unsigned long r7,
 742                                 struct pt_regs __regs)
 743 {
 744         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 745         unsigned long inst;
 746         struct task_struct *tsk = current;
 747
 748         if (kprobe_handle_illslot(regs->pc) == 0)
 749                 return;
 750
 751 #ifdef CONFIG_SH_FPU_EMU
 752         get_user(inst, (unsigned short *)regs->pc + 1);
 753         if (!do_fpu_inst(inst, regs)) {
 754                 get_user(inst, (unsigned short *)regs->pc);
 755                 if (!emulate_branch(inst, regs))
 756                         return;
 757                 /* fault in branch.*/
 758         }
 759         /* not a FPU inst. */
 760 #endif
 761
 762         lookup_exception_vector(inst);
 763
 764         local_irq_enable();
 765         CHK_REMOTE_DEBUG(regs);
 766         force_sig(SIGILL, tsk);
 767         die_if_no_fixup("illegal slot instruction", regs, inst);
 768 }
 769
 770 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
 771                                    unsigned long r6, unsigned long r7,
 772                                    struct pt_regs __regs)
 773 {
 774         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 775         long ex;
 776
 777         lookup_exception_vector(ex);
 778         die_if_kernel("exception", regs, ex);
 779 }
 780
 781 #if defined(CONFIG_SH_STANDARD_BIOS)
 782 void *gdb_vbr_vector;
 783
 784 static inline void __init gdb_vbr_init(void)
 785 {
 786         register unsigned long vbr;
 787
 788         /*
 789          * Read the old value of the VBR register to initialise
 790          * the vector through which debug and BIOS traps are
 791          * delegated by the Linux trap handler.
 792          */
 793         asm volatile("stc vbr, %0" : "=r" (vbr));
 794
 795         gdb_vbr_vector = (void *)(vbr + 0x100);
 796         printk("Setting GDB trap vector to 0x%08lx\n",
 797                (unsigned long)gdb_vbr_vector);
 798 }
 799 #endif
 800
 801 void __cpuinit per_cpu_trap_init(void)
 802 {
 803         extern void *vbr_base;
 804
 805 #ifdef CONFIG_SH_STANDARD_BIOS
 806         if (raw_smp_processor_id() == 0)
 807                 gdb_vbr_init();
 808 #endif
 809
 810         /* NOTE: The VBR value should be at P1
 811            (or P2, virtural "fixed" address space).
 812            It's definitely should not in physical address.  */
 813
 814         asm volatile("ldc       %0, vbr"
 815                      : /* no output */
 816                      : "r" (&vbr_base)
 817                      : "memory");
 818 }
 819
 820 void *set_exception_table_vec(unsigned int vec, void *handler)
 821 {
 822         extern void *exception_handling_table[];
 823         void *old_handler;
 824
 825         old_handler = exception_handling_table[vec];
 826         exception_handling_table[vec] = handler;
 827         return old_handler;
 828 }
 829
 830 void __init trap_init(void)
 831 {
 832         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 833         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 834
 835 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 836     defined(CONFIG_SH_FPU_EMU)
 837         /*
 838          * For SH-4 lacking an FPU, treat floating point instructions as
 839          * reserved. They'll be handled in the math-emu case, or faulted on
 840          * otherwise.
 841          */
 842         set_exception_table_evt(0x800, do_reserved_inst);
 843         set_exception_table_evt(0x820, do_illegal_slot_inst);
 844 #elif defined(CONFIG_SH_FPU)
 845 #ifdef CONFIG_CPU_SUBTYPE_SHX3
 846         set_exception_table_evt(0xd80, fpu_state_restore_trap_handler);
 847         set_exception_table_evt(0xda0, fpu_state_restore_trap_handler);
 848 #else
 849         set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
 850         set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
 851 #endif
 852 #endif
 853
 854 #ifdef CONFIG_CPU_SH2
 855         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
 856 #endif
 857 #ifdef CONFIG_CPU_SH2A
 858         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 859         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 860 #ifdef CONFIG_SH_FPU
 861         set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
 862 #endif
 863 #endif
 864
 865         /* Setup VBR for boot cpu */
 866         per_cpu_trap_init();
 867 }
 868
 869 void show_trace(struct task_struct *tsk, unsigned long *sp,
 870                 struct pt_regs *regs)
 871 {
 872         unsigned long addr;
 873
 874         if (regs && user_mode(regs))
 875                 return;
 876
 877         printk("\nCall trace: ");
 878 #ifdef CONFIG_KALLSYMS
 879         printk("\n");
 880 #endif
 881
 882         while (!kstack_end(sp)) {
 883                 addr = *sp++;
 884                 if (kernel_text_address(addr))
 885                         print_ip_sym(addr);
 886         }
 887
 888         printk("\n");
 889
 890         if (!tsk)
 891                 tsk = current;
 892
 893         debug_show_held_locks(tsk);
 894 }
 895
 896 void show_stack(struct task_struct *tsk, unsigned long *sp)
 897 {
 898         unsigned long stack;
 899
 900         if (!tsk)
 901                 tsk = current;
 902         if (tsk == current)
 903                 sp = (unsigned long *)current_stack_pointer;
 904         else
 905                 sp = (unsigned long *)tsk->thread.sp;
 906
 907         stack = (unsigned long)sp;
 908         dump_mem("Stack: ", stack, THREAD_SIZE +
 909                  (unsigned long)task_stack_page(tsk));
 910         show_trace(tsk, sp, NULL);
 911 }
 912
 913 void dump_stack(void)
 914 {
 915         show_stack(NULL, NULL);
 916 }
 917 EXPORT_SYMBOL(dump_stack);