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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/kexec.h>
  25 #include <linux/limits.h>
  26 #include <asm/system.h>
  27 #include <asm/uaccess.h>
  28
  29 #ifdef CONFIG_SH_KGDB
  30 #include <asm/kgdb.h>
  31 #define CHK_REMOTE_DEBUG(regs)                  \
  32 {                                               \
  33         if (kgdb_debug_hook && !user_mode(regs))\
  34                 (*kgdb_debug_hook)(regs);       \
  35 }
  36 #else
  37 #define CHK_REMOTE_DEBUG(regs)
  38 #endif
  39
  40 #ifdef CONFIG_CPU_SH2
  41 # define TRAP_RESERVED_INST     4
  42 # define TRAP_ILLEGAL_SLOT_INST 6
  43 # define TRAP_ADDRESS_ERROR     9
  44 # ifdef CONFIG_CPU_SH2A
  45 #  define TRAP_DIVZERO_ERROR    17
  46 #  define TRAP_DIVOVF_ERROR     18
  47 # endif
  48 #else
  49 #define TRAP_RESERVED_INST      12
  50 #define TRAP_ILLEGAL_SLOT_INST  13
  51 #endif
  52
  53 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  54 {
  55         unsigned long p;
  56         int i;
  57
  58         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  59
  60         for (p = bottom & ~31; p < top; ) {
  61                 printk("%04lx: ", p & 0xffff);
  62
  63                 for (i = 0; i < 8; i++, p += 4) {
  64                         unsigned int val;
  65
  66                         if (p < bottom || p >= top)
  67                                 printk("         ");
  68                         else {
  69                                 if (__get_user(val, (unsigned int __user *)p)) {
  70                                         printk("\n");
  71                                         return;
  72                                 }
  73                                 printk("%08x ", val);
  74                         }
  75                 }
  76                 printk("\n");
  77         }
  78 }
  79
  80 static DEFINE_SPINLOCK(die_lock);
  81
  82 void die(const char * str, struct pt_regs * regs, long err)
  83 {
  84         static int die_counter;
  85
  86         oops_enter();
  87
  88         console_verbose();
  89         spin_lock_irq(&die_lock);
  90         bust_spinlocks(1);
  91
  92         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
  93
  94         CHK_REMOTE_DEBUG(regs);
  95         print_modules();
  96         show_regs(regs);
  97
  98         printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
  99                         task_pid_nr(current), task_stack_page(current) + 1);
 100
 101         if (!user_mode(regs) || in_interrupt())
 102                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
 103                          (unsigned long)task_stack_page(current));
 104
 105         bust_spinlocks(0);
 106         add_taint(TAINT_DIE);
 107         spin_unlock_irq(&die_lock);
 108
 109         if (kexec_should_crash(current))
 110                 crash_kexec(regs);
 111
 112         if (in_interrupt())
 113                 panic("Fatal exception in interrupt");
 114
 115         if (panic_on_oops)
 116                 panic("Fatal exception");
 117
 118         oops_exit();
 119         do_exit(SIGSEGV);
 120 }
 121
 122 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 123                                  long err)
 124 {
 125         if (!user_mode(regs))
 126                 die(str, regs, err);
 127 }
 128
 129 /*
 130  * try and fix up kernelspace address errors
 131  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 132  * - kernel/userspace interfaces cause a jump to an appropriate handler
 133  * - other kernel errors are bad
 134  * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
 135  */
 136 static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 137 {
 138         if (!user_mode(regs)) {
 139                 const struct exception_table_entry *fixup;
 140                 fixup = search_exception_tables(regs->pc);
 141                 if (fixup) {
 142                         regs->pc = fixup->fixup;
 143                         return 0;
 144                 }
 145                 die(str, regs, err);
 146         }
 147         return -EFAULT;
 148 }
 149
 150 /*
 151  * handle an instruction that does an unaligned memory access by emulating the
 152  * desired behaviour
 153  * - note that PC _may not_ point to the faulting instruction
 154  *   (if that instruction is in a branch delay slot)
 155  * - return 0 if emulation okay, -EFAULT on existential error
 156  */
 157 static int handle_unaligned_ins(u16 instruction, struct pt_regs *regs)
 158 {
 159         int ret, index, count;
 160         unsigned long *rm, *rn;
 161         unsigned char *src, *dst;
 162
 163         index = (instruction>>8)&15;    /* 0x0F00 */
 164         rn = &regs->regs[index];
 165
 166         index = (instruction>>4)&15;    /* 0x00F0 */
 167         rm = &regs->regs[index];
 168
 169         count = 1<<(instruction&3);
 170
 171         ret = -EFAULT;
 172         switch (instruction>>12) {
 173         case 0: /* mov.[bwl] to/from memory via r0+rn */
 174                 if (instruction & 8) {
 175                         /* from memory */
 176                         src = (unsigned char*) *rm;
 177                         src += regs->regs[0];
 178                         dst = (unsigned char*) rn;
 179                         *(unsigned long*)dst = 0;
 180
 181 #ifdef __LITTLE_ENDIAN__
 182                         if (copy_from_user(dst, src, count))
 183                                 goto fetch_fault;
 184
 185                         if ((count == 2) && dst[1] & 0x80) {
 186                                 dst[2] = 0xff;
 187                                 dst[3] = 0xff;
 188                         }
 189 #else
 190                         dst += 4-count;
 191
 192                         if (__copy_user(dst, src, count))
 193                                 goto fetch_fault;
 194
 195                         if ((count == 2) && dst[2] & 0x80) {
 196                                 dst[0] = 0xff;
 197                                 dst[1] = 0xff;
 198                         }
 199 #endif
 200                 } else {
 201                         /* to memory */
 202                         src = (unsigned char*) rm;
 203 #if !defined(__LITTLE_ENDIAN__)
 204                         src += 4-count;
 205 #endif
 206                         dst = (unsigned char*) *rn;
 207                         dst += regs->regs[0];
 208
 209                         if (copy_to_user(dst, src, count))
 210                                 goto fetch_fault;
 211                 }
 212                 ret = 0;
 213                 break;
 214
 215         case 1: /* mov.l Rm,@(disp,Rn) */
 216                 src = (unsigned char*) rm;
 217                 dst = (unsigned char*) *rn;
 218                 dst += (instruction&0x000F)<<2;
 219
 220                 if (copy_to_user(dst,src,4))
 221                         goto fetch_fault;
 222                 ret = 0;
 223                 break;
 224
 225         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 226                 if (instruction & 4)
 227                         *rn -= count;
 228                 src = (unsigned char*) rm;
 229                 dst = (unsigned char*) *rn;
 230 #if !defined(__LITTLE_ENDIAN__)
 231                 src += 4-count;
 232 #endif
 233                 if (copy_to_user(dst, src, count))
 234                         goto fetch_fault;
 235                 ret = 0;
 236                 break;
 237
 238         case 5: /* mov.l @(disp,Rm),Rn */
 239                 src = (unsigned char*) *rm;
 240                 src += (instruction&0x000F)<<2;
 241                 dst = (unsigned char*) rn;
 242                 *(unsigned long*)dst = 0;
 243
 244                 if (copy_from_user(dst,src,4))
 245                         goto fetch_fault;
 246                 ret = 0;
 247                 break;
 248
 249         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 250                 src = (unsigned char*) *rm;
 251                 if (instruction & 4)
 252                         *rm += count;
 253                 dst = (unsigned char*) rn;
 254                 *(unsigned long*)dst = 0;
 255
 256 #ifdef __LITTLE_ENDIAN__
 257                 if (copy_from_user(dst, src, count))
 258                         goto fetch_fault;
 259
 260                 if ((count == 2) && dst[1] & 0x80) {
 261                         dst[2] = 0xff;
 262                         dst[3] = 0xff;
 263                 }
 264 #else
 265                 dst += 4-count;
 266
 267                 if (copy_from_user(dst, src, count))
 268                         goto fetch_fault;
 269
 270                 if ((count == 2) && dst[2] & 0x80) {
 271                         dst[0] = 0xff;
 272                         dst[1] = 0xff;
 273                 }
 274 #endif
 275                 ret = 0;
 276                 break;
 277
 278         case 8:
 279                 switch ((instruction&0xFF00)>>8) {
 280                 case 0x81: /* mov.w R0,@(disp,Rn) */
 281                         src = (unsigned char*) &regs->regs[0];
 282 #if !defined(__LITTLE_ENDIAN__)
 283                         src += 2;
 284 #endif
 285                         dst = (unsigned char*) *rm; /* called Rn in the spec */
 286                         dst += (instruction&0x000F)<<1;
 287
 288                         if (copy_to_user(dst, src, 2))
 289                                 goto fetch_fault;
 290                         ret = 0;
 291                         break;
 292
 293                 case 0x85: /* mov.w @(disp,Rm),R0 */
 294                         src = (unsigned char*) *rm;
 295                         src += (instruction&0x000F)<<1;
 296                         dst = (unsigned char*) &regs->regs[0];
 297                         *(unsigned long*)dst = 0;
 298
 299 #if !defined(__LITTLE_ENDIAN__)
 300                         dst += 2;
 301 #endif
 302
 303                         if (copy_from_user(dst, src, 2))
 304                                 goto fetch_fault;
 305
 306 #ifdef __LITTLE_ENDIAN__
 307                         if (dst[1] & 0x80) {
 308                                 dst[2] = 0xff;
 309                                 dst[3] = 0xff;
 310                         }
 311 #else
 312                         if (dst[2] & 0x80) {
 313                                 dst[0] = 0xff;
 314                                 dst[1] = 0xff;
 315                         }
 316 #endif
 317                         ret = 0;
 318                         break;
 319                 }
 320                 break;
 321         }
 322         return ret;
 323
 324  fetch_fault:
 325         /* Argh. Address not only misaligned but also non-existent.
 326          * Raise an EFAULT and see if it's trapped
 327          */
 328         return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 329 }
 330
 331 /*
 332  * emulate the instruction in the delay slot
 333  * - fetches the instruction from PC+2
 334  */
 335 static inline int handle_unaligned_delayslot(struct pt_regs *regs)
 336 {
 337         u16 instruction;
 338
 339         if (copy_from_user(&instruction, (u16 *)(regs->pc+2), 2)) {
 340                 /* the instruction-fetch faulted */
 341                 if (user_mode(regs))
 342                         return -EFAULT;
 343
 344                 /* kernel */
 345                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 346                     regs, 0);
 347         }
 348
 349         return handle_unaligned_ins(instruction,regs);
 350 }
 351
 352 /*
 353  * handle an instruction that does an unaligned memory access
 354  * - have to be careful of branch delay-slot instructions that fault
 355  *  SH3:
 356  *   - if the branch would be taken PC points to the branch
 357  *   - if the branch would not be taken, PC points to delay-slot
 358  *  SH4:
 359  *   - PC always points to delayed branch
 360  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 361  */
 362
 363 /* Macros to determine offset from current PC for branch instructions */
 364 /* Explicit type coercion is used to force sign extension where needed */
 365 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 366 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 367
 368 /*
 369  * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
 370  * opcodes..
 371  */
 372 #ifndef CONFIG_CPU_SH2A
 373 static int handle_unaligned_notify_count = 10;
 374
 375 static int handle_unaligned_access(u16 instruction, struct pt_regs *regs)
 376 {
 377         u_int rm;
 378         int ret, index;
 379
 380         index = (instruction>>8)&15;    /* 0x0F00 */
 381         rm = regs->regs[index];
 382
 383         /* shout about the first ten userspace fixups */
 384         if (user_mode(regs) && handle_unaligned_notify_count>0) {
 385                 handle_unaligned_notify_count--;
 386
 387                 printk(KERN_NOTICE "Fixing up unaligned userspace access "
 388                        "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 389                        current->comm, task_pid_nr(current),
 390                        (u16 *)regs->pc, instruction);
 391         }
 392
 393         ret = -EFAULT;
 394         switch (instruction&0xF000) {
 395         case 0x0000:
 396                 if (instruction==0x000B) {
 397                         /* rts */
 398                         ret = handle_unaligned_delayslot(regs);
 399                         if (ret==0)
 400                                 regs->pc = regs->pr;
 401                 }
 402                 else if ((instruction&0x00FF)==0x0023) {
 403                         /* braf @Rm */
 404                         ret = handle_unaligned_delayslot(regs);
 405                         if (ret==0)
 406                                 regs->pc += rm + 4;
 407                 }
 408                 else if ((instruction&0x00FF)==0x0003) {
 409                         /* bsrf @Rm */
 410                         ret = handle_unaligned_delayslot(regs);
 411                         if (ret==0) {
 412                                 regs->pr = regs->pc + 4;
 413                                 regs->pc += rm + 4;
 414                         }
 415                 }
 416                 else {
 417                         /* mov.[bwl] to/from memory via r0+rn */
 418                         goto simple;
 419                 }
 420                 break;
 421
 422         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 423                 goto simple;
 424
 425         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 426                 goto simple;
 427
 428         case 0x4000:
 429                 if ((instruction&0x00FF)==0x002B) {
 430                         /* jmp @Rm */
 431                         ret = handle_unaligned_delayslot(regs);
 432                         if (ret==0)
 433                                 regs->pc = rm;
 434                 }
 435                 else if ((instruction&0x00FF)==0x000B) {
 436                         /* jsr @Rm */
 437                         ret = handle_unaligned_delayslot(regs);
 438                         if (ret==0) {
 439                                 regs->pr = regs->pc + 4;
 440                                 regs->pc = rm;
 441                         }
 442                 }
 443                 else {
 444                         /* mov.[bwl] to/from memory via r0+rn */
 445                         goto simple;
 446                 }
 447                 break;
 448
 449         case 0x5000: /* mov.l @(disp,Rm),Rn */
 450                 goto simple;
 451
 452         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 453                 goto simple;
 454
 455         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 456                 switch (instruction&0x0F00) {
 457                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 458                         goto simple;
 459                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 460                         goto simple;
 461                 case 0x0B00: /* bf   lab - no delayslot*/
 462                         break;
 463                 case 0x0F00: /* bf/s lab */
 464                         ret = handle_unaligned_delayslot(regs);
 465                         if (ret==0) {
 466 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 467                                 if ((regs->sr & 0x00000001) != 0)
 468                                         regs->pc += 4; /* next after slot */
 469                                 else
 470 #endif
 471                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 472                         }
 473                         break;
 474                 case 0x0900: /* bt   lab - no delayslot */
 475                         break;
 476                 case 0x0D00: /* bt/s lab */
 477                         ret = handle_unaligned_delayslot(regs);
 478                         if (ret==0) {
 479 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 480                                 if ((regs->sr & 0x00000001) == 0)
 481                                         regs->pc += 4; /* next after slot */
 482                                 else
 483 #endif
 484                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 485                         }
 486                         break;
 487                 }
 488                 break;
 489
 490         case 0xA000: /* bra label */
 491                 ret = handle_unaligned_delayslot(regs);
 492                 if (ret==0)
 493                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 494                 break;
 495
 496         case 0xB000: /* bsr label */
 497                 ret = handle_unaligned_delayslot(regs);
 498                 if (ret==0) {
 499                         regs->pr = regs->pc + 4;
 500                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 501                 }
 502                 break;
 503         }
 504         return ret;
 505
 506         /* handle non-delay-slot instruction */
 507  simple:
 508         ret = handle_unaligned_ins(instruction,regs);
 509         if (ret==0)
 510                 regs->pc += instruction_size(instruction);
 511         return ret;
 512 }
 513 #endif /* CONFIG_CPU_SH2A */
 514
 515 #ifdef CONFIG_CPU_HAS_SR_RB
 516 #define lookup_exception_vector(x)      \
 517         __asm__ __volatile__ ("stc r2_bank, %0\n\t" : "=r" ((x)))
 518 #else
 519 #define lookup_exception_vector(x)      \
 520         __asm__ __volatile__ ("mov r4, %0\n\t" : "=r" ((x)))
 521 #endif
 522
 523 /*
 524  * Handle various address error exceptions:
 525  *  - instruction address error:
 526  *       misaligned PC
 527  *       PC >= 0x80000000 in user mode
 528  *  - data address error (read and write)
 529  *       misaligned data access
 530  *       access to >= 0x80000000 is user mode
 531  * Unfortuntaly we can't distinguish between instruction address error
 532  * and data address errors caused by read accesses.
 533  */
 534 asmlinkage void do_address_error(struct pt_regs *regs,
 535                                  unsigned long writeaccess,
 536                                  unsigned long address)
 537 {
 538         unsigned long error_code = 0;
 539         mm_segment_t oldfs;
 540         siginfo_t info;
 541 #ifndef CONFIG_CPU_SH2A
 542         u16 instruction;
 543         int tmp;
 544 #endif
 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 #ifndef CONFIG_CPU_SH2A
 565                 set_fs(USER_DS);
 566                 if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
 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                 set_fs(oldfs);
 576
 577                 if (tmp==0)
 578                         return; /* sorted */
 579 #endif
 580
 581 uspace_segv:
 582                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 583                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 584                        regs->pr);
 585
 586                 info.si_signo = SIGBUS;
 587                 info.si_errno = 0;
 588                 info.si_code = si_code;
 589                 info.si_addr = (void __user *)address;
 590                 force_sig_info(SIGBUS, &info, current);
 591         } else {
 592                 if (regs->pc & 1)
 593                         die("unaligned program counter", regs, error_code);
 594
 595 #ifndef CONFIG_CPU_SH2A
 596                 set_fs(KERNEL_DS);
 597                 if (copy_from_user(&instruction, (u16 *)(regs->pc), 2)) {
 598                         /* Argh. Fault on the instruction itself.
 599                            This should never happen non-SMP
 600                         */
 601                         set_fs(oldfs);
 602                         die("insn faulting in do_address_error", regs, 0);
 603                 }
 604
 605                 handle_unaligned_access(instruction, regs);
 606                 set_fs(oldfs);
 607 #else
 608                 printk(KERN_NOTICE "Killing process \"%s\" due to unaligned "
 609                        "access\n", current->comm);
 610
 611                 force_sig(SIGSEGV, current);
 612 #endif
 613         }
 614 }
 615
 616 #ifdef CONFIG_SH_DSP
 617 /*
 618  *      SH-DSP support gerg@snapgear.com.
 619  */
 620 int is_dsp_inst(struct pt_regs *regs)
 621 {
 622         unsigned short inst = 0;
 623
 624         /*
 625          * Safe guard if DSP mode is already enabled or we're lacking
 626          * the DSP altogether.
 627          */
 628         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 629                 return 0;
 630
 631         get_user(inst, ((unsigned short *) regs->pc));
 632
 633         inst &= 0xf000;
 634
 635         /* Check for any type of DSP or support instruction */
 636         if ((inst == 0xf000) || (inst == 0x4000))
 637                 return 1;
 638
 639         return 0;
 640 }
 641 #else
 642 #define is_dsp_inst(regs)       (0)
 643 #endif /* CONFIG_SH_DSP */
 644
 645 #ifdef CONFIG_CPU_SH2A
 646 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 647                                 unsigned long r6, unsigned long r7,
 648                                 struct pt_regs __regs)
 649 {
 650         siginfo_t info;
 651
 652         switch (r4) {
 653         case TRAP_DIVZERO_ERROR:
 654                 info.si_code = FPE_INTDIV;
 655                 break;
 656         case TRAP_DIVOVF_ERROR:
 657                 info.si_code = FPE_INTOVF;
 658                 break;
 659         }
 660
 661         force_sig_info(SIGFPE, &info, current);
 662 }
 663 #endif
 664
 665 /* arch/sh/kernel/cpu/sh4/fpu.c */
 666 extern int do_fpu_inst(unsigned short, struct pt_regs *);
 667 extern asmlinkage void do_fpu_state_restore(unsigned long r4, unsigned long r5,
 668                 unsigned long r6, unsigned long r7, struct pt_regs __regs);
 669
 670 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 671                                 unsigned long r6, unsigned long r7,
 672                                 struct pt_regs __regs)
 673 {
 674         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 675         unsigned long error_code;
 676         struct task_struct *tsk = current;
 677
 678 #ifdef CONFIG_SH_FPU_EMU
 679         unsigned short inst = 0;
 680         int err;
 681
 682         get_user(inst, (unsigned short*)regs->pc);
 683
 684         err = do_fpu_inst(inst, regs);
 685         if (!err) {
 686                 regs->pc += instruction_size(inst);
 687                 return;
 688         }
 689         /* not a FPU inst. */
 690 #endif
 691
 692 #ifdef CONFIG_SH_DSP
 693         /* Check if it's a DSP instruction */
 694         if (is_dsp_inst(regs)) {
 695                 /* Enable DSP mode, and restart instruction. */
 696                 regs->sr |= SR_DSP;
 697                 return;
 698         }
 699 #endif
 700
 701         lookup_exception_vector(error_code);
 702
 703         local_irq_enable();
 704         CHK_REMOTE_DEBUG(regs);
 705         force_sig(SIGILL, tsk);
 706         die_if_no_fixup("reserved instruction", regs, error_code);
 707 }
 708
 709 #ifdef CONFIG_SH_FPU_EMU
 710 static int emulate_branch(unsigned short inst, struct pt_regs* regs)
 711 {
 712         /*
 713          * bfs: 8fxx: PC+=d*2+4;
 714          * bts: 8dxx: PC+=d*2+4;
 715          * bra: axxx: PC+=D*2+4;
 716          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 717          * braf:0x23: PC+=Rn*2+4;
 718          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 719          * jmp: 4x2b: PC=Rn;
 720          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 721          * rts: 000b: PC=PR;
 722          */
 723         if ((inst & 0xfd00) == 0x8d00) {
 724                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 725                 return 0;
 726         }
 727
 728         if ((inst & 0xe000) == 0xa000) {
 729                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 730                 return 0;
 731         }
 732
 733         if ((inst & 0xf0df) == 0x0003) {
 734                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 735                 return 0;
 736         }
 737
 738         if ((inst & 0xf0df) == 0x400b) {
 739                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 740                 return 0;
 741         }
 742
 743         if ((inst & 0xffff) == 0x000b) {
 744                 regs->pc = regs->pr;
 745                 return 0;
 746         }
 747
 748         return 1;
 749 }
 750 #endif
 751
 752 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 753                                 unsigned long r6, unsigned long r7,
 754                                 struct pt_regs __regs)
 755 {
 756         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 757         unsigned long error_code;
 758         struct task_struct *tsk = current;
 759 #ifdef CONFIG_SH_FPU_EMU
 760         unsigned short inst = 0;
 761
 762         get_user(inst, (unsigned short *)regs->pc + 1);
 763         if (!do_fpu_inst(inst, regs)) {
 764                 get_user(inst, (unsigned short *)regs->pc);
 765                 if (!emulate_branch(inst, regs))
 766                         return;
 767                 /* fault in branch.*/
 768         }
 769         /* not a FPU inst. */
 770 #endif
 771
 772         lookup_exception_vector(error_code);
 773
 774         local_irq_enable();
 775         CHK_REMOTE_DEBUG(regs);
 776         force_sig(SIGILL, tsk);
 777         die_if_no_fixup("illegal slot instruction", regs, error_code);
 778 }
 779
 780 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
 781                                    unsigned long r6, unsigned long r7,
 782                                    struct pt_regs __regs)
 783 {
 784         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 785         long ex;
 786
 787         lookup_exception_vector(ex);
 788         die_if_kernel("exception", regs, ex);
 789 }
 790
 791 #if defined(CONFIG_SH_STANDARD_BIOS)
 792 void *gdb_vbr_vector;
 793
 794 static inline void __init gdb_vbr_init(void)
 795 {
 796         register unsigned long vbr;
 797
 798         /*
 799          * Read the old value of the VBR register to initialise
 800          * the vector through which debug and BIOS traps are
 801          * delegated by the Linux trap handler.
 802          */
 803         asm volatile("stc vbr, %0" : "=r" (vbr));
 804
 805         gdb_vbr_vector = (void *)(vbr + 0x100);
 806         printk("Setting GDB trap vector to 0x%08lx\n",
 807                (unsigned long)gdb_vbr_vector);
 808 }
 809 #endif
 810
 811 void __cpuinit per_cpu_trap_init(void)
 812 {
 813         extern void *vbr_base;
 814
 815 #ifdef CONFIG_SH_STANDARD_BIOS
 816         if (raw_smp_processor_id() == 0)
 817                 gdb_vbr_init();
 818 #endif
 819
 820         /* NOTE: The VBR value should be at P1
 821            (or P2, virtural "fixed" address space).
 822            It's definitely should not in physical address.  */
 823
 824         asm volatile("ldc       %0, vbr"
 825                      : /* no output */
 826                      : "r" (&vbr_base)
 827                      : "memory");
 828 }
 829
 830 void *set_exception_table_vec(unsigned int vec, void *handler)
 831 {
 832         extern void *exception_handling_table[];
 833         void *old_handler;
 834
 835         old_handler = exception_handling_table[vec];
 836         exception_handling_table[vec] = handler;
 837         return old_handler;
 838 }
 839
 840 extern asmlinkage void address_error_handler(unsigned long r4, unsigned long r5,
 841                                              unsigned long r6, unsigned long r7,
 842                                              struct pt_regs __regs);
 843
 844 void __init trap_init(void)
 845 {
 846         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 847         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 848
 849 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 850     defined(CONFIG_SH_FPU_EMU)
 851         /*
 852          * For SH-4 lacking an FPU, treat floating point instructions as
 853          * reserved. They'll be handled in the math-emu case, or faulted on
 854          * otherwise.
 855          */
 856         set_exception_table_evt(0x800, do_reserved_inst);
 857         set_exception_table_evt(0x820, do_illegal_slot_inst);
 858 #elif defined(CONFIG_SH_FPU)
 859 #ifdef CONFIG_CPU_SUBTYPE_SHX3
 860         set_exception_table_evt(0xd80, do_fpu_state_restore);
 861         set_exception_table_evt(0xda0, do_fpu_state_restore);
 862 #else
 863         set_exception_table_evt(0x800, do_fpu_state_restore);
 864         set_exception_table_evt(0x820, do_fpu_state_restore);
 865 #endif
 866 #endif
 867
 868 #ifdef CONFIG_CPU_SH2
 869         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_handler);
 870 #endif
 871 #ifdef CONFIG_CPU_SH2A
 872         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 873         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 874 #endif
 875
 876         /* Setup VBR for boot cpu */
 877         per_cpu_trap_init();
 878 }
 879
 880 #ifdef CONFIG_BUG
 881 void handle_BUG(struct pt_regs *regs)
 882 {
 883         enum bug_trap_type tt;
 884         tt = report_bug(regs->pc, regs);
 885         if (tt == BUG_TRAP_TYPE_WARN) {
 886                 regs->pc += 2;
 887                 return;
 888         }
 889
 890         die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
 891 }
 892
 893 int is_valid_bugaddr(unsigned long addr)
 894 {
 895         return addr >= PAGE_OFFSET;
 896 }
 897 #endif
 898
 899 void show_trace(struct task_struct *tsk, unsigned long *sp,
 900                 struct pt_regs *regs)
 901 {
 902         unsigned long addr;
 903
 904         if (regs && user_mode(regs))
 905                 return;
 906
 907         printk("\nCall trace: ");
 908 #ifdef CONFIG_KALLSYMS
 909         printk("\n");
 910 #endif
 911
 912         while (!kstack_end(sp)) {
 913                 addr = *sp++;
 914                 if (kernel_text_address(addr))
 915                         print_ip_sym(addr);
 916         }
 917
 918         printk("\n");
 919
 920         if (!tsk)
 921                 tsk = current;
 922
 923         debug_show_held_locks(tsk);
 924 }
 925
 926 void show_stack(struct task_struct *tsk, unsigned long *sp)
 927 {
 928         unsigned long stack;
 929
 930         if (!tsk)
 931                 tsk = current;
 932         if (tsk == current)
 933                 sp = (unsigned long *)current_stack_pointer;
 934         else
 935                 sp = (unsigned long *)tsk->thread.sp;
 936
 937         stack = (unsigned long)sp;
 938         dump_mem("Stack: ", stack, THREAD_SIZE +
 939                  (unsigned long)task_stack_page(tsk));
 940         show_trace(tsk, sp, NULL);
 941 }
 942
 943 void dump_stack(void)
 944 {
 945         show_stack(NULL, NULL);
 946 }
 947 EXPORT_SYMBOL(dump_stack);