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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/hardirq.h>
  17 #include <linux/init.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/module.h>
  20 #include <linux/kallsyms.h>
  21 #include <linux/io.h>
  22 #include <linux/bug.h>
  23 #include <linux/debug_locks.h>
  24 #include <linux/kdebug.h>
  25 #include <linux/kexec.h>
  26 #include <linux/limits.h>
  27 #include <asm/system.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/fpu.h>
  30 #include <asm/kprobes.h>
  31
  32 #ifdef CONFIG_CPU_SH2
  33 # define TRAP_RESERVED_INST     4
  34 # define TRAP_ILLEGAL_SLOT_INST 6
  35 # define TRAP_ADDRESS_ERROR     9
  36 # ifdef CONFIG_CPU_SH2A
  37 #  define TRAP_FPU_ERROR        13
  38 #  define TRAP_DIVZERO_ERROR    17
  39 #  define TRAP_DIVOVF_ERROR     18
  40 # endif
  41 #else
  42 #define TRAP_RESERVED_INST      12
  43 #define TRAP_ILLEGAL_SLOT_INST  13
  44 #endif
  45
  46 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  47 {
  48         unsigned long p;
  49         int i;
  50
  51         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  52
  53         for (p = bottom & ~31; p < top; ) {
  54                 printk("%04lx: ", p & 0xffff);
  55
  56                 for (i = 0; i < 8; i++, p += 4) {
  57                         unsigned int val;
  58
  59                         if (p < bottom || p >= top)
  60                                 printk("         ");
  61                         else {
  62                                 if (__get_user(val, (unsigned int __user *)p)) {
  63                                         printk("\n");
  64                                         return;
  65                                 }
  66                                 printk("%08x ", val);
  67                         }
  68                 }
  69                 printk("\n");
  70         }
  71 }
  72
  73 static DEFINE_SPINLOCK(die_lock);
  74
  75 void die(const char * str, struct pt_regs * regs, long err)
  76 {
  77         static int die_counter;
  78
  79         oops_enter();
  80
  81         console_verbose();
  82         spin_lock_irq(&die_lock);
  83         bust_spinlocks(1);
  84
  85         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
  86
  87         print_modules();
  88         show_regs(regs);
  89
  90         printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
  91                         task_pid_nr(current), task_stack_page(current) + 1);
  92
  93         if (!user_mode(regs) || in_interrupt())
  94                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
  95                          (unsigned long)task_stack_page(current));
  96
  97         notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
  98
  99         bust_spinlocks(0);
 100         add_taint(TAINT_DIE);
 101         spin_unlock_irq(&die_lock);
 102
 103         if (kexec_should_crash(current))
 104                 crash_kexec(regs);
 105
 106         if (in_interrupt())
 107                 panic("Fatal exception in interrupt");
 108
 109         if (panic_on_oops)
 110                 panic("Fatal exception");
 111
 112         oops_exit();
 113         do_exit(SIGSEGV);
 114 }
 115
 116 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 117                                  long err)
 118 {
 119         if (!user_mode(regs))
 120                 die(str, regs, err);
 121 }
 122
 123 /*
 124  * try and fix up kernelspace address errors
 125  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 126  * - kernel/userspace interfaces cause a jump to an appropriate handler
 127  * - other kernel errors are bad
 128  */
 129 static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 130 {
 131         if (!user_mode(regs)) {
 132                 const struct exception_table_entry *fixup;
 133                 fixup = search_exception_tables(regs->pc);
 134                 if (fixup) {
 135                         regs->pc = fixup->fixup;
 136                         return;
 137                 }
 138                 die(str, regs, err);
 139         }
 140 }
 141
 142 static inline void sign_extend(unsigned int count, unsigned char *dst)
 143 {
 144 #ifdef __LITTLE_ENDIAN__
 145         if ((count == 1) && dst[0] & 0x80) {
 146                 dst[1] = 0xff;
 147                 dst[2] = 0xff;
 148                 dst[3] = 0xff;
 149         }
 150         if ((count == 2) && dst[1] & 0x80) {
 151                 dst[2] = 0xff;
 152                 dst[3] = 0xff;
 153         }
 154 #else
 155         if ((count == 1) && dst[3] & 0x80) {
 156                 dst[2] = 0xff;
 157                 dst[1] = 0xff;
 158                 dst[0] = 0xff;
 159         }
 160         if ((count == 2) && dst[2] & 0x80) {
 161                 dst[1] = 0xff;
 162                 dst[0] = 0xff;
 163         }
 164 #endif
 165 }
 166
 167 static struct mem_access user_mem_access = {
 168         copy_from_user,
 169         copy_to_user,
 170 };
 171
 172 /*
 173  * handle an instruction that does an unaligned memory access by emulating the
 174  * desired behaviour
 175  * - note that PC _may not_ point to the faulting instruction
 176  *   (if that instruction is in a branch delay slot)
 177  * - return 0 if emulation okay, -EFAULT on existential error
 178  */
 179 static int handle_unaligned_ins(opcode_t instruction, struct pt_regs *regs,
 180                                 struct mem_access *ma)
 181 {
 182         int ret, index, count;
 183         unsigned long *rm, *rn;
 184         unsigned char *src, *dst;
 185         unsigned char __user *srcu, *dstu;
 186
 187         index = (instruction>>8)&15;    /* 0x0F00 */
 188         rn = &regs->regs[index];
 189
 190         index = (instruction>>4)&15;    /* 0x00F0 */
 191         rm = &regs->regs[index];
 192
 193         count = 1<<(instruction&3);
 194
 195         ret = -EFAULT;
 196         switch (instruction>>12) {
 197         case 0: /* mov.[bwl] to/from memory via r0+rn */
 198                 if (instruction & 8) {
 199                         /* from memory */
 200                         srcu = (unsigned char __user *)*rm;
 201                         srcu += regs->regs[0];
 202                         dst = (unsigned char *)rn;
 203                         *(unsigned long *)dst = 0;
 204
 205 #if !defined(__LITTLE_ENDIAN__)
 206                         dst += 4-count;
 207 #endif
 208                         if (ma->from(dst, srcu, count))
 209                                 goto fetch_fault;
 210
 211                         sign_extend(count, dst);
 212                 } else {
 213                         /* to memory */
 214                         src = (unsigned char *)rm;
 215 #if !defined(__LITTLE_ENDIAN__)
 216                         src += 4-count;
 217 #endif
 218                         dstu = (unsigned char __user *)*rn;
 219                         dstu += regs->regs[0];
 220
 221                         if (ma->to(dstu, src, count))
 222                                 goto fetch_fault;
 223                 }
 224                 ret = 0;
 225                 break;
 226
 227         case 1: /* mov.l Rm,@(disp,Rn) */
 228                 src = (unsigned char*) rm;
 229                 dstu = (unsigned char __user *)*rn;
 230                 dstu += (instruction&0x000F)<<2;
 231
 232                 if (ma->to(dstu, src, 4))
 233                         goto fetch_fault;
 234                 ret = 0;
 235                 break;
 236
 237         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 238                 if (instruction & 4)
 239                         *rn -= count;
 240                 src = (unsigned char*) rm;
 241                 dstu = (unsigned char __user *)*rn;
 242 #if !defined(__LITTLE_ENDIAN__)
 243                 src += 4-count;
 244 #endif
 245                 if (ma->to(dstu, src, count))
 246                         goto fetch_fault;
 247                 ret = 0;
 248                 break;
 249
 250         case 5: /* mov.l @(disp,Rm),Rn */
 251                 srcu = (unsigned char __user *)*rm;
 252                 srcu += (instruction & 0x000F) << 2;
 253                 dst = (unsigned char *)rn;
 254                 *(unsigned long *)dst = 0;
 255
 256                 if (ma->from(dst, srcu, 4))
 257                         goto fetch_fault;
 258                 ret = 0;
 259                 break;
 260
 261         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 262                 srcu = (unsigned char __user *)*rm;
 263                 if (instruction & 4)
 264                         *rm += count;
 265                 dst = (unsigned char*) rn;
 266                 *(unsigned long*)dst = 0;
 267
 268 #if !defined(__LITTLE_ENDIAN__)
 269                 dst += 4-count;
 270 #endif
 271                 if (ma->from(dst, srcu, count))
 272                         goto fetch_fault;
 273                 sign_extend(count, dst);
 274                 ret = 0;
 275                 break;
 276
 277         case 8:
 278                 switch ((instruction&0xFF00)>>8) {
 279                 case 0x81: /* mov.w R0,@(disp,Rn) */
 280                         src = (unsigned char *) &regs->regs[0];
 281 #if !defined(__LITTLE_ENDIAN__)
 282                         src += 2;
 283 #endif
 284                         dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
 285                         dstu += (instruction & 0x000F) << 1;
 286
 287                         if (ma->to(dstu, src, 2))
 288                                 goto fetch_fault;
 289                         ret = 0;
 290                         break;
 291
 292                 case 0x85: /* mov.w @(disp,Rm),R0 */
 293                         srcu = (unsigned char __user *)*rm;
 294                         srcu += (instruction & 0x000F) << 1;
 295                         dst = (unsigned char *) &regs->regs[0];
 296                         *(unsigned long *)dst = 0;
 297
 298 #if !defined(__LITTLE_ENDIAN__)
 299                         dst += 2;
 300 #endif
 301                         if (ma->from(dst, srcu, 2))
 302                                 goto fetch_fault;
 303                         sign_extend(2, dst);
 304                         ret = 0;
 305                         break;
 306                 }
 307                 break;
 308         }
 309         return ret;
 310
 311  fetch_fault:
 312         /* Argh. Address not only misaligned but also non-existent.
 313          * Raise an EFAULT and see if it's trapped
 314          */
 315         die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 316         return -EFAULT;
 317 }
 318
 319 /*
 320  * emulate the instruction in the delay slot
 321  * - fetches the instruction from PC+2
 322  */
 323 static inline int handle_delayslot(struct pt_regs *regs,
 324                                    opcode_t old_instruction,
 325                                    struct mem_access *ma)
 326 {
 327         opcode_t instruction;
 328         void __user *addr = (void __user *)(regs->pc +
 329                 instruction_size(old_instruction));
 330
 331         if (copy_from_user(&instruction, addr, sizeof(instruction))) {
 332                 /* the instruction-fetch faulted */
 333                 if (user_mode(regs))
 334                         return -EFAULT;
 335
 336                 /* kernel */
 337                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 338                     regs, 0);
 339         }
 340
 341         return handle_unaligned_ins(instruction, regs, ma);
 342 }
 343
 344 /*
 345  * handle an instruction that does an unaligned memory access
 346  * - have to be careful of branch delay-slot instructions that fault
 347  *  SH3:
 348  *   - if the branch would be taken PC points to the branch
 349  *   - if the branch would not be taken, PC points to delay-slot
 350  *  SH4:
 351  *   - PC always points to delayed branch
 352  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 353  */
 354
 355 /* Macros to determine offset from current PC for branch instructions */
 356 /* Explicit type coercion is used to force sign extension where needed */
 357 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 358 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 359
 360 /*
 361  * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
 362  * opcodes..
 363  */
 364
 365 static int handle_unaligned_notify_count = 10;
 366
 367 int handle_unaligned_access(opcode_t instruction, struct pt_regs *regs,
 368                             struct mem_access *ma)
 369 {
 370         u_int rm;
 371         int ret, index;
 372
 373         index = (instruction>>8)&15;    /* 0x0F00 */
 374         rm = regs->regs[index];
 375
 376         /* shout about the first ten userspace fixups */
 377         if (user_mode(regs) && handle_unaligned_notify_count>0) {
 378                 handle_unaligned_notify_count--;
 379
 380                 printk(KERN_NOTICE "Fixing up unaligned userspace access "
 381                        "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 382                        current->comm, task_pid_nr(current),
 383                        (void *)regs->pc, instruction);
 384         }
 385
 386         ret = -EFAULT;
 387         switch (instruction&0xF000) {
 388         case 0x0000:
 389                 if (instruction==0x000B) {
 390                         /* rts */
 391                         ret = handle_delayslot(regs, instruction, ma);
 392                         if (ret==0)
 393                                 regs->pc = regs->pr;
 394                 }
 395                 else if ((instruction&0x00FF)==0x0023) {
 396                         /* braf @Rm */
 397                         ret = handle_delayslot(regs, instruction, ma);
 398                         if (ret==0)
 399                                 regs->pc += rm + 4;
 400                 }
 401                 else if ((instruction&0x00FF)==0x0003) {
 402                         /* bsrf @Rm */
 403                         ret = handle_delayslot(regs, instruction, ma);
 404                         if (ret==0) {
 405                                 regs->pr = regs->pc + 4;
 406                                 regs->pc += rm + 4;
 407                         }
 408                 }
 409                 else {
 410                         /* mov.[bwl] to/from memory via r0+rn */
 411                         goto simple;
 412                 }
 413                 break;
 414
 415         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 416                 goto simple;
 417
 418         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 419                 goto simple;
 420
 421         case 0x4000:
 422                 if ((instruction&0x00FF)==0x002B) {
 423                         /* jmp @Rm */
 424                         ret = handle_delayslot(regs, instruction, ma);
 425                         if (ret==0)
 426                                 regs->pc = rm;
 427                 }
 428                 else if ((instruction&0x00FF)==0x000B) {
 429                         /* jsr @Rm */
 430                         ret = handle_delayslot(regs, instruction, ma);
 431                         if (ret==0) {
 432                                 regs->pr = regs->pc + 4;
 433                                 regs->pc = rm;
 434                         }
 435                 }
 436                 else {
 437                         /* mov.[bwl] to/from memory via r0+rn */
 438                         goto simple;
 439                 }
 440                 break;
 441
 442         case 0x5000: /* mov.l @(disp,Rm),Rn */
 443                 goto simple;
 444
 445         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 446                 goto simple;
 447
 448         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 449                 switch (instruction&0x0F00) {
 450                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 451                         goto simple;
 452                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 453                         goto simple;
 454                 case 0x0B00: /* bf   lab - no delayslot*/
 455                         break;
 456                 case 0x0F00: /* bf/s lab */
 457                         ret = handle_delayslot(regs, instruction, ma);
 458                         if (ret==0) {
 459 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 460                                 if ((regs->sr & 0x00000001) != 0)
 461                                         regs->pc += 4; /* next after slot */
 462                                 else
 463 #endif
 464                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 465                         }
 466                         break;
 467                 case 0x0900: /* bt   lab - no delayslot */
 468                         break;
 469                 case 0x0D00: /* bt/s lab */
 470                         ret = handle_delayslot(regs, instruction, ma);
 471                         if (ret==0) {
 472 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 473                                 if ((regs->sr & 0x00000001) == 0)
 474                                         regs->pc += 4; /* next after slot */
 475                                 else
 476 #endif
 477                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 478                         }
 479                         break;
 480                 }
 481                 break;
 482
 483         case 0xA000: /* bra label */
 484                 ret = handle_delayslot(regs, instruction, ma);
 485                 if (ret==0)
 486                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 487                 break;
 488
 489         case 0xB000: /* bsr label */
 490                 ret = handle_delayslot(regs, instruction, ma);
 491                 if (ret==0) {
 492                         regs->pr = regs->pc + 4;
 493                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 494                 }
 495                 break;
 496         }
 497         return ret;
 498
 499         /* handle non-delay-slot instruction */
 500  simple:
 501         ret = handle_unaligned_ins(instruction, regs, ma);
 502         if (ret==0)
 503                 regs->pc += instruction_size(instruction);
 504         return ret;
 505 }
 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         opcode_t instruction;
 526         int tmp;
 527
 528         /* Intentional ifdef */
 529 #ifdef CONFIG_CPU_HAS_SR_RB
 530         error_code = lookup_exception_vector();
 531 #endif
 532
 533         oldfs = get_fs();
 534
 535         if (user_mode(regs)) {
 536                 int si_code = BUS_ADRERR;
 537
 538                 local_irq_enable();
 539
 540                 /* bad PC is not something we can fix */
 541                 if (regs->pc & 1) {
 542                         si_code = BUS_ADRALN;
 543                         goto uspace_segv;
 544                 }
 545
 546                 set_fs(USER_DS);
 547                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 548                                    sizeof(instruction))) {
 549                         /* Argh. Fault on the instruction itself.
 550                            This should never happen non-SMP
 551                         */
 552                         set_fs(oldfs);
 553                         goto uspace_segv;
 554                 }
 555
 556                 tmp = handle_unaligned_access(instruction, regs,
 557                                               &user_mem_access);
 558                 set_fs(oldfs);
 559
 560                 if (tmp==0)
 561                         return; /* sorted */
 562 uspace_segv:
 563                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 564                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 565                        regs->pr);
 566
 567                 info.si_signo = SIGBUS;
 568                 info.si_errno = 0;
 569                 info.si_code = si_code;
 570                 info.si_addr = (void __user *)address;
 571                 force_sig_info(SIGBUS, &info, current);
 572         } else {
 573                 if (regs->pc & 1)
 574                         die("unaligned program counter", regs, error_code);
 575
 576                 set_fs(KERNEL_DS);
 577                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 578                                    sizeof(instruction))) {
 579                         /* Argh. Fault on the instruction itself.
 580                            This should never happen non-SMP
 581                         */
 582                         set_fs(oldfs);
 583                         die("insn faulting in do_address_error", regs, 0);
 584                 }
 585
 586                 handle_unaligned_access(instruction, regs, &user_mem_access);
 587                 set_fs(oldfs);
 588         }
 589 }
 590
 591 #ifdef CONFIG_SH_DSP
 592 /*
 593  *      SH-DSP support gerg@snapgear.com.
 594  */
 595 int is_dsp_inst(struct pt_regs *regs)
 596 {
 597         unsigned short inst = 0;
 598
 599         /*
 600          * Safe guard if DSP mode is already enabled or we're lacking
 601          * the DSP altogether.
 602          */
 603         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 604                 return 0;
 605
 606         get_user(inst, ((unsigned short *) regs->pc));
 607
 608         inst &= 0xf000;
 609
 610         /* Check for any type of DSP or support instruction */
 611         if ((inst == 0xf000) || (inst == 0x4000))
 612                 return 1;
 613
 614         return 0;
 615 }
 616 #else
 617 #define is_dsp_inst(regs)       (0)
 618 #endif /* CONFIG_SH_DSP */
 619
 620 #ifdef CONFIG_CPU_SH2A
 621 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 622                                 unsigned long r6, unsigned long r7,
 623                                 struct pt_regs __regs)
 624 {
 625         siginfo_t info;
 626
 627         switch (r4) {
 628         case TRAP_DIVZERO_ERROR:
 629                 info.si_code = FPE_INTDIV;
 630                 break;
 631         case TRAP_DIVOVF_ERROR:
 632                 info.si_code = FPE_INTOVF;
 633                 break;
 634         }
 635
 636         force_sig_info(SIGFPE, &info, current);
 637 }
 638 #endif
 639
 640 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 641                                 unsigned long r6, unsigned long r7,
 642                                 struct pt_regs __regs)
 643 {
 644         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 645         unsigned long error_code;
 646         struct task_struct *tsk = current;
 647
 648 #ifdef CONFIG_SH_FPU_EMU
 649         unsigned short inst = 0;
 650         int err;
 651
 652         get_user(inst, (unsigned short*)regs->pc);
 653
 654         err = do_fpu_inst(inst, regs);
 655         if (!err) {
 656                 regs->pc += instruction_size(inst);
 657                 return;
 658         }
 659         /* not a FPU inst. */
 660 #endif
 661
 662 #ifdef CONFIG_SH_DSP
 663         /* Check if it's a DSP instruction */
 664         if (is_dsp_inst(regs)) {
 665                 /* Enable DSP mode, and restart instruction. */
 666                 regs->sr |= SR_DSP;
 667                 /* Save DSP mode */
 668                 tsk->thread.dsp_status.status |= SR_DSP;
 669                 return;
 670         }
 671 #endif
 672
 673         error_code = lookup_exception_vector();
 674
 675         local_irq_enable();
 676         force_sig(SIGILL, tsk);
 677         die_if_no_fixup("reserved instruction", regs, error_code);
 678 }
 679
 680 #ifdef CONFIG_SH_FPU_EMU
 681 static int emulate_branch(unsigned short inst, struct pt_regs *regs)
 682 {
 683         /*
 684          * bfs: 8fxx: PC+=d*2+4;
 685          * bts: 8dxx: PC+=d*2+4;
 686          * bra: axxx: PC+=D*2+4;
 687          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 688          * braf:0x23: PC+=Rn*2+4;
 689          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 690          * jmp: 4x2b: PC=Rn;
 691          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 692          * rts: 000b: PC=PR;
 693          */
 694         if (((inst & 0xf000) == 0xb000)  ||     /* bsr */
 695             ((inst & 0xf0ff) == 0x0003)  ||     /* bsrf */
 696             ((inst & 0xf0ff) == 0x400b))        /* jsr */
 697                 regs->pr = regs->pc + 4;
 698
 699         if ((inst & 0xfd00) == 0x8d00) {        /* bfs, bts */
 700                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 701                 return 0;
 702         }
 703
 704         if ((inst & 0xe000) == 0xa000) {        /* bra, bsr */
 705                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 706                 return 0;
 707         }
 708
 709         if ((inst & 0xf0df) == 0x0003) {        /* braf, bsrf */
 710                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 711                 return 0;
 712         }
 713
 714         if ((inst & 0xf0df) == 0x400b) {        /* jmp, jsr */
 715                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 716                 return 0;
 717         }
 718
 719         if ((inst & 0xffff) == 0x000b) {        /* rts */
 720                 regs->pc = regs->pr;
 721                 return 0;
 722         }
 723
 724         return 1;
 725 }
 726 #endif
 727
 728 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 729                                 unsigned long r6, unsigned long r7,
 730                                 struct pt_regs __regs)
 731 {
 732         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 733         unsigned long inst;
 734         struct task_struct *tsk = current;
 735
 736         if (kprobe_handle_illslot(regs->pc) == 0)
 737                 return;
 738
 739 #ifdef CONFIG_SH_FPU_EMU
 740         get_user(inst, (unsigned short *)regs->pc + 1);
 741         if (!do_fpu_inst(inst, regs)) {
 742                 get_user(inst, (unsigned short *)regs->pc);
 743                 if (!emulate_branch(inst, regs))
 744                         return;
 745                 /* fault in branch.*/
 746         }
 747         /* not a FPU inst. */
 748 #endif
 749
 750         inst = lookup_exception_vector();
 751
 752         local_irq_enable();
 753         force_sig(SIGILL, tsk);
 754         die_if_no_fixup("illegal slot instruction", regs, inst);
 755 }
 756
 757 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
 758                                    unsigned long r6, unsigned long r7,
 759                                    struct pt_regs __regs)
 760 {
 761         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 762         long ex;
 763
 764         ex = lookup_exception_vector();
 765         die_if_kernel("exception", regs, ex);
 766 }
 767
 768 #if defined(CONFIG_SH_STANDARD_BIOS)
 769 void *gdb_vbr_vector;
 770
 771 static inline void __init gdb_vbr_init(void)
 772 {
 773         register unsigned long vbr;
 774
 775         /*
 776          * Read the old value of the VBR register to initialise
 777          * the vector through which debug and BIOS traps are
 778          * delegated by the Linux trap handler.
 779          */
 780         asm volatile("stc vbr, %0" : "=r" (vbr));
 781
 782         gdb_vbr_vector = (void *)(vbr + 0x100);
 783         printk("Setting GDB trap vector to 0x%08lx\n",
 784                (unsigned long)gdb_vbr_vector);
 785 }
 786 #endif
 787
 788 void __cpuinit per_cpu_trap_init(void)
 789 {
 790         extern void *vbr_base;
 791
 792 #ifdef CONFIG_SH_STANDARD_BIOS
 793         if (raw_smp_processor_id() == 0)
 794                 gdb_vbr_init();
 795 #endif
 796
 797         /* NOTE: The VBR value should be at P1
 798            (or P2, virtural "fixed" address space).
 799            It's definitely should not in physical address.  */
 800
 801         asm volatile("ldc       %0, vbr"
 802                      : /* no output */
 803                      : "r" (&vbr_base)
 804                      : "memory");
 805 }
 806
 807 void *set_exception_table_vec(unsigned int vec, void *handler)
 808 {
 809         extern void *exception_handling_table[];
 810         void *old_handler;
 811
 812         old_handler = exception_handling_table[vec];
 813         exception_handling_table[vec] = handler;
 814         return old_handler;
 815 }
 816
 817 void __init trap_init(void)
 818 {
 819         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 820         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 821
 822 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 823     defined(CONFIG_SH_FPU_EMU)
 824         /*
 825          * For SH-4 lacking an FPU, treat floating point instructions as
 826          * reserved. They'll be handled in the math-emu case, or faulted on
 827          * otherwise.
 828          */
 829         set_exception_table_evt(0x800, do_reserved_inst);
 830         set_exception_table_evt(0x820, do_illegal_slot_inst);
 831 #elif defined(CONFIG_SH_FPU)
 832 #ifdef CONFIG_CPU_SUBTYPE_SHX3
 833         set_exception_table_evt(0xd80, fpu_state_restore_trap_handler);
 834         set_exception_table_evt(0xda0, fpu_state_restore_trap_handler);
 835 #else
 836         set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
 837         set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
 838 #endif
 839 #endif
 840
 841 #ifdef CONFIG_CPU_SH2
 842         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
 843 #endif
 844 #ifdef CONFIG_CPU_SH2A
 845         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 846         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 847 #ifdef CONFIG_SH_FPU
 848         set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
 849 #endif
 850 #endif
 851
 852         /* Setup VBR for boot cpu */
 853         per_cpu_trap_init();
 854 }
 855
 856 void show_trace(struct task_struct *tsk, unsigned long *sp,
 857                 struct pt_regs *regs)
 858 {
 859         unsigned long addr;
 860
 861         if (regs && user_mode(regs))
 862                 return;
 863
 864         printk("\nCall trace:\n");
 865
 866         while (!kstack_end(sp)) {
 867                 addr = *sp++;
 868                 if (kernel_text_address(addr))
 869                         print_ip_sym(addr);
 870         }
 871
 872         printk("\n");
 873
 874         if (!tsk)
 875                 tsk = current;
 876
 877         debug_show_held_locks(tsk);
 878 }
 879
 880 void show_stack(struct task_struct *tsk, unsigned long *sp)
 881 {
 882         unsigned long stack;
 883
 884         if (!tsk)
 885                 tsk = current;
 886         if (tsk == current)
 887                 sp = (unsigned long *)current_stack_pointer;
 888         else
 889                 sp = (unsigned long *)tsk->thread.sp;
 890
 891         stack = (unsigned long)sp;
 892         dump_mem("Stack: ", stack, THREAD_SIZE +
 893                  (unsigned long)task_stack_page(tsk));
 894         show_trace(tsk, sp, NULL);
 895 }
 896
 897 void dump_stack(void)
 898 {
 899         show_stack(NULL, NULL);
 900 }
 901 EXPORT_SYMBOL(dump_stack);