arch/sh/kernel/traps_32.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * 'traps.c' handles hardware traps and faults after we have saved some
   4  * state in 'entry.S'.
   5  *
   6  *  SuperH version: Copyright (C) 1999 Niibe Yutaka
   7  *                  Copyright (C) 2000 Philipp Rumpf
   8  *                  Copyright (C) 2000 David Howells
   9  *                  Copyright (C) 2002 - 2010 Paul Mundt
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/hardirq.h>
  14 #include <linux/init.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/kallsyms.h>
  17 #include <linux/io.h>
  18 #include <linux/bug.h>
  19 #include <linux/debug_locks.h>
  20 #include <linux/kdebug.h>
  21 #include <linux/limits.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/perf_event.h>
  25 #include <linux/sched/task_stack.h>
  26
  27 #include <asm/alignment.h>
  28 #include <asm/fpu.h>
  29 #include <asm/kprobes.h>
  30 #include <asm/setup.h>
  31 #include <asm/traps.h>
  32 #include <asm/bl_bit.h>
  33
  34 #ifdef CONFIG_CPU_SH2
  35 # define TRAP_RESERVED_INST     4
  36 # define TRAP_ILLEGAL_SLOT_INST 6
  37 # define TRAP_ADDRESS_ERROR     9
  38 # ifdef CONFIG_CPU_SH2A
  39 #  define TRAP_UBC              12
  40 #  define TRAP_FPU_ERROR        13
  41 #  define TRAP_DIVZERO_ERROR    17
  42 #  define TRAP_DIVOVF_ERROR     18
  43 # endif
  44 #else
  45 #define TRAP_RESERVED_INST      12
  46 #define TRAP_ILLEGAL_SLOT_INST  13
  47 #endif
  48
  49 static inline void sign_extend(unsigned int count, unsigned char *dst)
  50 {
  51 #ifdef __LITTLE_ENDIAN__
  52         if ((count == 1) && dst[0] & 0x80) {
  53                 dst[1] = 0xff;
  54                 dst[2] = 0xff;
  55                 dst[3] = 0xff;
  56         }
  57         if ((count == 2) && dst[1] & 0x80) {
  58                 dst[2] = 0xff;
  59                 dst[3] = 0xff;
  60         }
  61 #else
  62         if ((count == 1) && dst[3] & 0x80) {
  63                 dst[2] = 0xff;
  64                 dst[1] = 0xff;
  65                 dst[0] = 0xff;
  66         }
  67         if ((count == 2) && dst[2] & 0x80) {
  68                 dst[1] = 0xff;
  69                 dst[0] = 0xff;
  70         }
  71 #endif
  72 }
  73
  74 static struct mem_access user_mem_access = {
  75         copy_from_user,
  76         copy_to_user,
  77 };
  78
  79 static unsigned long copy_from_kernel_wrapper(void *dst, const void __user *src,
  80                                               unsigned long cnt)
  81 {
  82         return copy_from_kernel_nofault(dst, (const void __force *)src, cnt);
  83 }
  84
  85 static unsigned long copy_to_kernel_wrapper(void __user *dst, const void *src,
  86                                             unsigned long cnt)
  87 {
  88         return copy_to_kernel_nofault((void __force *)dst, src, cnt);
  89 }
  90
  91 static struct mem_access kernel_mem_access = {
  92         copy_from_kernel_wrapper,
  93         copy_to_kernel_wrapper,
  94 };
  95
  96 /*
  97  * handle an instruction that does an unaligned memory access by emulating the
  98  * desired behaviour
  99  * - note that PC _may not_ point to the faulting instruction
 100  *   (if that instruction is in a branch delay slot)
 101  * - return 0 if emulation okay, -EFAULT on existential error
 102  */
 103 static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
 104                                 struct mem_access *ma)
 105 {
 106         int ret, index, count;
 107         unsigned long *rm, *rn;
 108         unsigned char *src, *dst;
 109         unsigned char __user *srcu, *dstu;
 110
 111         index = (instruction>>8)&15;    /* 0x0F00 */
 112         rn = &regs->regs[index];
 113
 114         index = (instruction>>4)&15;    /* 0x00F0 */
 115         rm = &regs->regs[index];
 116
 117         count = 1<<(instruction&3);
 118
 119         switch (count) {
 120         case 1: inc_unaligned_byte_access(); break;
 121         case 2: inc_unaligned_word_access(); break;
 122         case 4: inc_unaligned_dword_access(); break;
 123         case 8: inc_unaligned_multi_access(); break;
 124         }
 125
 126         ret = -EFAULT;
 127         switch (instruction>>12) {
 128         case 0: /* mov.[bwl] to/from memory via r0+rn */
 129                 if (instruction & 8) {
 130                         /* from memory */
 131                         srcu = (unsigned char __user *)*rm;
 132                         srcu += regs->regs[0];
 133                         dst = (unsigned char *)rn;
 134                         *(unsigned long *)dst = 0;
 135
 136 #if !defined(__LITTLE_ENDIAN__)
 137                         dst += 4-count;
 138 #endif
 139                         if (ma->from(dst, srcu, count))
 140                                 goto fetch_fault;
 141
 142                         sign_extend(count, dst);
 143                 } else {
 144                         /* to memory */
 145                         src = (unsigned char *)rm;
 146 #if !defined(__LITTLE_ENDIAN__)
 147                         src += 4-count;
 148 #endif
 149                         dstu = (unsigned char __user *)*rn;
 150                         dstu += regs->regs[0];
 151
 152                         if (ma->to(dstu, src, count))
 153                                 goto fetch_fault;
 154                 }
 155                 ret = 0;
 156                 break;
 157
 158         case 1: /* mov.l Rm,@(disp,Rn) */
 159                 src = (unsigned char*) rm;
 160                 dstu = (unsigned char __user *)*rn;
 161                 dstu += (instruction&0x000F)<<2;
 162
 163                 if (ma->to(dstu, src, 4))
 164                         goto fetch_fault;
 165                 ret = 0;
 166                 break;
 167
 168         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 169                 if (instruction & 4)
 170                         *rn -= count;
 171                 src = (unsigned char*) rm;
 172                 dstu = (unsigned char __user *)*rn;
 173 #if !defined(__LITTLE_ENDIAN__)
 174                 src += 4-count;
 175 #endif
 176                 if (ma->to(dstu, src, count))
 177                         goto fetch_fault;
 178                 ret = 0;
 179                 break;
 180
 181         case 5: /* mov.l @(disp,Rm),Rn */
 182                 srcu = (unsigned char __user *)*rm;
 183                 srcu += (instruction & 0x000F) << 2;
 184                 dst = (unsigned char *)rn;
 185                 *(unsigned long *)dst = 0;
 186
 187                 if (ma->from(dst, srcu, 4))
 188                         goto fetch_fault;
 189                 ret = 0;
 190                 break;
 191
 192         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 193                 srcu = (unsigned char __user *)*rm;
 194                 if (instruction & 4)
 195                         *rm += count;
 196                 dst = (unsigned char*) rn;
 197                 *(unsigned long*)dst = 0;
 198
 199 #if !defined(__LITTLE_ENDIAN__)
 200                 dst += 4-count;
 201 #endif
 202                 if (ma->from(dst, srcu, count))
 203                         goto fetch_fault;
 204                 sign_extend(count, dst);
 205                 ret = 0;
 206                 break;
 207
 208         case 8:
 209                 switch ((instruction&0xFF00)>>8) {
 210                 case 0x81: /* mov.w R0,@(disp,Rn) */
 211                         src = (unsigned char *) &regs->regs[0];
 212 #if !defined(__LITTLE_ENDIAN__)
 213                         src += 2;
 214 #endif
 215                         dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
 216                         dstu += (instruction & 0x000F) << 1;
 217
 218                         if (ma->to(dstu, src, 2))
 219                                 goto fetch_fault;
 220                         ret = 0;
 221                         break;
 222
 223                 case 0x85: /* mov.w @(disp,Rm),R0 */
 224                         srcu = (unsigned char __user *)*rm;
 225                         srcu += (instruction & 0x000F) << 1;
 226                         dst = (unsigned char *) &regs->regs[0];
 227                         *(unsigned long *)dst = 0;
 228
 229 #if !defined(__LITTLE_ENDIAN__)
 230                         dst += 2;
 231 #endif
 232                         if (ma->from(dst, srcu, 2))
 233                                 goto fetch_fault;
 234                         sign_extend(2, dst);
 235                         ret = 0;
 236                         break;
 237                 }
 238                 break;
 239
 240         case 9: /* mov.w @(disp,PC),Rn */
 241                 srcu = (unsigned char __user *)regs->pc;
 242                 srcu += 4;
 243                 srcu += (instruction & 0x00FF) << 1;
 244                 dst = (unsigned char *)rn;
 245                 *(unsigned long *)dst = 0;
 246
 247 #if !defined(__LITTLE_ENDIAN__)
 248                 dst += 2;
 249 #endif
 250
 251                 if (ma->from(dst, srcu, 2))
 252                         goto fetch_fault;
 253                 sign_extend(2, dst);
 254                 ret = 0;
 255                 break;
 256
 257         case 0xd: /* mov.l @(disp,PC),Rn */
 258                 srcu = (unsigned char __user *)(regs->pc & ~0x3);
 259                 srcu += 4;
 260                 srcu += (instruction & 0x00FF) << 2;
 261                 dst = (unsigned char *)rn;
 262                 *(unsigned long *)dst = 0;
 263
 264                 if (ma->from(dst, srcu, 4))
 265                         goto fetch_fault;
 266                 ret = 0;
 267                 break;
 268         }
 269         return ret;
 270
 271  fetch_fault:
 272         /* Argh. Address not only misaligned but also non-existent.
 273          * Raise an EFAULT and see if it's trapped
 274          */
 275         die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 276         return -EFAULT;
 277 }
 278
 279 /*
 280  * emulate the instruction in the delay slot
 281  * - fetches the instruction from PC+2
 282  */
 283 static inline int handle_delayslot(struct pt_regs *regs,
 284                                    insn_size_t old_instruction,
 285                                    struct mem_access *ma)
 286 {
 287         insn_size_t instruction;
 288         void __user *addr = (void __user *)(regs->pc +
 289                 instruction_size(old_instruction));
 290
 291         if (copy_from_user(&instruction, addr, sizeof(instruction))) {
 292                 /* the instruction-fetch faulted */
 293                 if (user_mode(regs))
 294                         return -EFAULT;
 295
 296                 /* kernel */
 297                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 298                     regs, 0);
 299         }
 300
 301         return handle_unaligned_ins(instruction, regs, ma);
 302 }
 303
 304 /*
 305  * handle an instruction that does an unaligned memory access
 306  * - have to be careful of branch delay-slot instructions that fault
 307  *  SH3:
 308  *   - if the branch would be taken PC points to the branch
 309  *   - if the branch would not be taken, PC points to delay-slot
 310  *  SH4:
 311  *   - PC always points to delayed branch
 312  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 313  */
 314
 315 /* Macros to determine offset from current PC for branch instructions */
 316 /* Explicit type coercion is used to force sign extension where needed */
 317 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 318 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 319
 320 int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
 321                             struct mem_access *ma, int expected,
 322                             unsigned long address)
 323 {
 324         u_int rm;
 325         int ret, index;
 326
 327         /*
 328          * XXX: We can't handle mixed 16/32-bit instructions yet
 329          */
 330         if (instruction_size(instruction) != 2)
 331                 return -EINVAL;
 332
 333         index = (instruction>>8)&15;    /* 0x0F00 */
 334         rm = regs->regs[index];
 335
 336         /*
 337          * Log the unexpected fixups, and then pass them on to perf.
 338          *
 339          * We intentionally don't report the expected cases to perf as
 340          * otherwise the trapped I/O case will skew the results too much
 341          * to be useful.
 342          */
 343         if (!expected) {
 344                 unaligned_fixups_notify(current, instruction, regs);
 345                 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
 346                               regs, address);
 347         }
 348
 349         ret = -EFAULT;
 350         switch (instruction&0xF000) {
 351         case 0x0000:
 352                 if (instruction==0x000B) {
 353                         /* rts */
 354                         ret = handle_delayslot(regs, instruction, ma);
 355                         if (ret==0)
 356                                 regs->pc = regs->pr;
 357                 }
 358                 else if ((instruction&0x00FF)==0x0023) {
 359                         /* braf @Rm */
 360                         ret = handle_delayslot(regs, instruction, ma);
 361                         if (ret==0)
 362                                 regs->pc += rm + 4;
 363                 }
 364                 else if ((instruction&0x00FF)==0x0003) {
 365                         /* bsrf @Rm */
 366                         ret = handle_delayslot(regs, instruction, ma);
 367                         if (ret==0) {
 368                                 regs->pr = regs->pc + 4;
 369                                 regs->pc += rm + 4;
 370                         }
 371                 }
 372                 else {
 373                         /* mov.[bwl] to/from memory via r0+rn */
 374                         goto simple;
 375                 }
 376                 break;
 377
 378         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 379                 goto simple;
 380
 381         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 382                 goto simple;
 383
 384         case 0x4000:
 385                 if ((instruction&0x00FF)==0x002B) {
 386                         /* jmp @Rm */
 387                         ret = handle_delayslot(regs, instruction, ma);
 388                         if (ret==0)
 389                                 regs->pc = rm;
 390                 }
 391                 else if ((instruction&0x00FF)==0x000B) {
 392                         /* jsr @Rm */
 393                         ret = handle_delayslot(regs, instruction, ma);
 394                         if (ret==0) {
 395                                 regs->pr = regs->pc + 4;
 396                                 regs->pc = rm;
 397                         }
 398                 }
 399                 else {
 400                         /* mov.[bwl] to/from memory via r0+rn */
 401                         goto simple;
 402                 }
 403                 break;
 404
 405         case 0x5000: /* mov.l @(disp,Rm),Rn */
 406                 goto simple;
 407
 408         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 409                 goto simple;
 410
 411         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 412                 switch (instruction&0x0F00) {
 413                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 414                         goto simple;
 415                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 416                         goto simple;
 417                 case 0x0B00: /* bf   lab - no delayslot*/
 418                         ret = 0;
 419                         break;
 420                 case 0x0F00: /* bf/s lab */
 421                         ret = handle_delayslot(regs, instruction, ma);
 422                         if (ret==0) {
 423 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 424                                 if ((regs->sr & 0x00000001) != 0)
 425                                         regs->pc += 4; /* next after slot */
 426                                 else
 427 #endif
 428                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 429                         }
 430                         break;
 431                 case 0x0900: /* bt   lab - no delayslot */
 432                         ret = 0;
 433                         break;
 434                 case 0x0D00: /* bt/s lab */
 435                         ret = handle_delayslot(regs, instruction, ma);
 436                         if (ret==0) {
 437 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 438                                 if ((regs->sr & 0x00000001) == 0)
 439                                         regs->pc += 4; /* next after slot */
 440                                 else
 441 #endif
 442                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 443                         }
 444                         break;
 445                 }
 446                 break;
 447
 448         case 0x9000: /* mov.w @(disp,Rm),Rn */
 449                 goto simple;
 450
 451         case 0xA000: /* bra label */
 452                 ret = handle_delayslot(regs, instruction, ma);
 453                 if (ret==0)
 454                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 455                 break;
 456
 457         case 0xB000: /* bsr label */
 458                 ret = handle_delayslot(regs, instruction, ma);
 459                 if (ret==0) {
 460                         regs->pr = regs->pc + 4;
 461                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 462                 }
 463                 break;
 464
 465         case 0xD000: /* mov.l @(disp,Rm),Rn */
 466                 goto simple;
 467         }
 468         return ret;
 469
 470         /* handle non-delay-slot instruction */
 471  simple:
 472         ret = handle_unaligned_ins(instruction, regs, ma);
 473         if (ret==0)
 474                 regs->pc += instruction_size(instruction);
 475         return ret;
 476 }
 477
 478 /*
 479  * Handle various address error exceptions:
 480  *  - instruction address error:
 481  *       misaligned PC
 482  *       PC >= 0x80000000 in user mode
 483  *  - data address error (read and write)
 484  *       misaligned data access
 485  *       access to >= 0x80000000 is user mode
 486  * Unfortuntaly we can't distinguish between instruction address error
 487  * and data address errors caused by read accesses.
 488  */
 489 asmlinkage void do_address_error(struct pt_regs *regs,
 490                                  unsigned long writeaccess,
 491                                  unsigned long address)
 492 {
 493         unsigned long error_code = 0;
 494         insn_size_t instruction;
 495         int tmp;
 496
 497         /* Intentional ifdef */
 498 #ifdef CONFIG_CPU_HAS_SR_RB
 499         error_code = lookup_exception_vector();
 500 #endif
 501
 502         if (user_mode(regs)) {
 503                 int si_code = BUS_ADRERR;
 504                 unsigned int user_action;
 505
 506                 local_irq_enable();
 507                 inc_unaligned_user_access();
 508
 509                 if (copy_from_user(&instruction, (insn_size_t __user *)(regs->pc & ~1),
 510                                    sizeof(instruction))) {
 511                         goto uspace_segv;
 512                 }
 513
 514                 /* shout about userspace fixups */
 515                 unaligned_fixups_notify(current, instruction, regs);
 516
 517                 user_action = unaligned_user_action();
 518                 if (user_action & UM_FIXUP)
 519                         goto fixup;
 520                 if (user_action & UM_SIGNAL)
 521                         goto uspace_segv;
 522                 else {
 523                         /* ignore */
 524                         regs->pc += instruction_size(instruction);
 525                         return;
 526                 }
 527
 528 fixup:
 529                 /* bad PC is not something we can fix */
 530                 if (regs->pc & 1) {
 531                         si_code = BUS_ADRALN;
 532                         goto uspace_segv;
 533                 }
 534
 535                 tmp = handle_unaligned_access(instruction, regs,
 536                                               &user_mem_access, 0,
 537                                               address);
 538
 539                 if (tmp == 0)
 540                         return; /* sorted */
 541 uspace_segv:
 542                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 543                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 544                        regs->pr);
 545
 546                 force_sig_fault(SIGBUS, si_code, (void __user *)address);
 547         } else {
 548                 inc_unaligned_kernel_access();
 549
 550                 if (regs->pc & 1)
 551                         die("unaligned program counter", regs, error_code);
 552
 553                 if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
 554                                    sizeof(instruction))) {
 555                         /* Argh. Fault on the instruction itself.
 556                            This should never happen non-SMP
 557                         */
 558                         die("insn faulting in do_address_error", regs, 0);
 559                 }
 560
 561                 unaligned_fixups_notify(current, instruction, regs);
 562
 563                 handle_unaligned_access(instruction, regs, &kernel_mem_access,
 564                                         0, address);
 565         }
 566 }
 567
 568 #ifdef CONFIG_SH_DSP
 569 /*
 570  *      SH-DSP support [email protected].
 571  */
 572 static int is_dsp_inst(struct pt_regs *regs)
 573 {
 574         unsigned short inst = 0;
 575
 576         /*
 577          * Safe guard if DSP mode is already enabled or we're lacking
 578          * the DSP altogether.
 579          */
 580         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 581                 return 0;
 582
 583         get_user(inst, ((unsigned short *) regs->pc));
 584
 585         inst &= 0xf000;
 586
 587         /* Check for any type of DSP or support instruction */
 588         if ((inst == 0xf000) || (inst == 0x4000))
 589                 return 1;
 590
 591         return 0;
 592 }
 593 #else
 594 static inline int is_dsp_inst(struct pt_regs *regs) { return 0; }
 595 #endif /* CONFIG_SH_DSP */
 596
 597 #ifdef CONFIG_CPU_SH2A
 598 asmlinkage void do_divide_error(unsigned long r4)
 599 {
 600         int code;
 601
 602         switch (r4) {
 603         case TRAP_DIVZERO_ERROR:
 604                 code = FPE_INTDIV;
 605                 break;
 606         case TRAP_DIVOVF_ERROR:
 607                 code = FPE_INTOVF;
 608                 break;
 609         default:
 610                 /* Let gcc know unhandled cases don't make it past here */
 611                 return;
 612         }
 613         force_sig_fault(SIGFPE, code, NULL);
 614 }
 615 #endif
 616
 617 asmlinkage void do_reserved_inst(void)
 618 {
 619         struct pt_regs *regs = current_pt_regs();
 620         unsigned long error_code;
 621
 622 #ifdef CONFIG_SH_FPU_EMU
 623         unsigned short inst = 0;
 624         int err;
 625
 626         get_user(inst, (unsigned short __user *)regs->pc);
 627
 628         err = do_fpu_inst(inst, regs);
 629         if (!err) {
 630                 regs->pc += instruction_size(inst);
 631                 return;
 632         }
 633         /* not a FPU inst. */
 634 #endif
 635
 636 #ifdef CONFIG_SH_DSP
 637         /* Check if it's a DSP instruction */
 638         if (is_dsp_inst(regs)) {
 639                 /* Enable DSP mode, and restart instruction. */
 640                 regs->sr |= SR_DSP;
 641                 /* Save DSP mode */
 642                 current->thread.dsp_status.status |= SR_DSP;
 643                 return;
 644         }
 645 #endif
 646
 647         error_code = lookup_exception_vector();
 648
 649         local_irq_enable();
 650         force_sig(SIGILL);
 651         die_if_no_fixup("reserved instruction", regs, error_code);
 652 }
 653
 654 #ifdef CONFIG_SH_FPU_EMU
 655 static int emulate_branch(unsigned short inst, struct pt_regs *regs)
 656 {
 657         /*
 658          * bfs: 8fxx: PC+=d*2+4;
 659          * bts: 8dxx: PC+=d*2+4;
 660          * bra: axxx: PC+=D*2+4;
 661          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 662          * braf:0x23: PC+=Rn*2+4;
 663          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 664          * jmp: 4x2b: PC=Rn;
 665          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 666          * rts: 000b: PC=PR;
 667          */
 668         if (((inst & 0xf000) == 0xb000)  ||     /* bsr */
 669             ((inst & 0xf0ff) == 0x0003)  ||     /* bsrf */
 670             ((inst & 0xf0ff) == 0x400b))        /* jsr */
 671                 regs->pr = regs->pc + 4;
 672
 673         if ((inst & 0xfd00) == 0x8d00) {        /* bfs, bts */
 674                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 675                 return 0;
 676         }
 677
 678         if ((inst & 0xe000) == 0xa000) {        /* bra, bsr */
 679                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 680                 return 0;
 681         }
 682
 683         if ((inst & 0xf0df) == 0x0003) {        /* braf, bsrf */
 684                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 685                 return 0;
 686         }
 687
 688         if ((inst & 0xf0df) == 0x400b) {        /* jmp, jsr */
 689                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 690                 return 0;
 691         }
 692
 693         if ((inst & 0xffff) == 0x000b) {        /* rts */
 694                 regs->pc = regs->pr;
 695                 return 0;
 696         }
 697
 698         return 1;
 699 }
 700 #endif
 701
 702 asmlinkage void do_illegal_slot_inst(void)
 703 {
 704         struct pt_regs *regs = current_pt_regs();
 705         unsigned long inst;
 706
 707         if (kprobe_handle_illslot(regs->pc) == 0)
 708                 return;
 709
 710 #ifdef CONFIG_SH_FPU_EMU
 711         get_user(inst, (unsigned short __user *)regs->pc + 1);
 712         if (!do_fpu_inst(inst, regs)) {
 713                 get_user(inst, (unsigned short __user *)regs->pc);
 714                 if (!emulate_branch(inst, regs))
 715                         return;
 716                 /* fault in branch.*/
 717         }
 718         /* not a FPU inst. */
 719 #endif
 720
 721         inst = lookup_exception_vector();
 722
 723         local_irq_enable();
 724         force_sig(SIGILL);
 725         die_if_no_fixup("illegal slot instruction", regs, inst);
 726 }
 727
 728 asmlinkage void do_exception_error(void)
 729 {
 730         long ex;
 731
 732         ex = lookup_exception_vector();
 733         die_if_kernel("exception", current_pt_regs(), ex);
 734 }
 735
 736 void per_cpu_trap_init(void)
 737 {
 738         extern void *vbr_base;
 739
 740         /* NOTE: The VBR value should be at P1
 741            (or P2, virtural "fixed" address space).
 742            It's definitely should not in physical address.  */
 743
 744         asm volatile("ldc       %0, vbr"
 745                      : /* no output */
 746                      : "r" (&vbr_base)
 747                      : "memory");
 748
 749         /* disable exception blocking now when the vbr has been setup */
 750         clear_bl_bit();
 751 }
 752
 753 void *set_exception_table_vec(unsigned int vec, void *handler)
 754 {
 755         extern void *exception_handling_table[];
 756         void *old_handler;
 757
 758         old_handler = exception_handling_table[vec];
 759         exception_handling_table[vec] = handler;
 760         return old_handler;
 761 }
 762
 763 void __init trap_init(void)
 764 {
 765         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 766         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 767
 768 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 769     defined(CONFIG_SH_FPU_EMU)
 770         /*
 771          * For SH-4 lacking an FPU, treat floating point instructions as
 772          * reserved. They'll be handled in the math-emu case, or faulted on
 773          * otherwise.
 774          */
 775         set_exception_table_evt(0x800, do_reserved_inst);
 776         set_exception_table_evt(0x820, do_illegal_slot_inst);
 777 #elif defined(CONFIG_SH_FPU)
 778         set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
 779         set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
 780 #endif
 781
 782 #ifdef CONFIG_CPU_SH2
 783         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
 784 #endif
 785 #ifdef CONFIG_CPU_SH2A
 786         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 787         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 788 #ifdef CONFIG_SH_FPU
 789         set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
 790 #endif
 791 #endif
 792
 793 #ifdef TRAP_UBC
 794         set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
 795 #endif
 796 }