arch/sh/kernel/traps_32.c

   1 /*
   2  * 'traps.c' handles hardware traps and faults after we have saved some
   3  * state in 'entry.S'.
   4  *
   5  *  SuperH version: Copyright (C) 1999 Niibe Yutaka
   6  *                  Copyright (C) 2000 Philipp Rumpf
   7  *                  Copyright (C) 2000 David Howells
   8  *                  Copyright (C) 2002 - 2010 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 <linux/sysfs.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/perf_event.h>
  30 #include <asm/system.h>
  31 #include <asm/alignment.h>
  32 #include <asm/fpu.h>
  33 #include <asm/kprobes.h>
  34
  35 #ifdef CONFIG_CPU_SH2
  36 # define TRAP_RESERVED_INST     4
  37 # define TRAP_ILLEGAL_SLOT_INST 6
  38 # define TRAP_ADDRESS_ERROR     9
  39 # ifdef CONFIG_CPU_SH2A
  40 #  define TRAP_UBC              12
  41 #  define TRAP_FPU_ERROR        13
  42 #  define TRAP_DIVZERO_ERROR    17
  43 #  define TRAP_DIVOVF_ERROR     18
  44 # endif
  45 #else
  46 #define TRAP_RESERVED_INST      12
  47 #define TRAP_ILLEGAL_SLOT_INST  13
  48 #endif
  49
  50 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  51 {
  52         unsigned long p;
  53         int i;
  54
  55         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  56
  57         for (p = bottom & ~31; p < top; ) {
  58                 printk("%04lx: ", p & 0xffff);
  59
  60                 for (i = 0; i < 8; i++, p += 4) {
  61                         unsigned int val;
  62
  63                         if (p < bottom || p >= top)
  64                                 printk("         ");
  65                         else {
  66                                 if (__get_user(val, (unsigned int __user *)p)) {
  67                                         printk("\n");
  68                                         return;
  69                                 }
  70                                 printk("%08x ", val);
  71                         }
  72                 }
  73                 printk("\n");
  74         }
  75 }
  76
  77 static DEFINE_SPINLOCK(die_lock);
  78
  79 void die(const char * str, struct pt_regs * regs, long err)
  80 {
  81         static int die_counter;
  82
  83         oops_enter();
  84
  85         spin_lock_irq(&die_lock);
  86         console_verbose();
  87         bust_spinlocks(1);
  88
  89         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
  90         sysfs_printk_last_file();
  91         print_modules();
  92         show_regs(regs);
  93
  94         printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
  95                         task_pid_nr(current), task_stack_page(current) + 1);
  96
  97         if (!user_mode(regs) || in_interrupt())
  98                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
  99                          (unsigned long)task_stack_page(current));
 100
 101         notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
 102
 103         bust_spinlocks(0);
 104         add_taint(TAINT_DIE);
 105         spin_unlock_irq(&die_lock);
 106         oops_exit();
 107
 108         if (kexec_should_crash(current))
 109                 crash_kexec(regs);
 110
 111         if (in_interrupt())
 112                 panic("Fatal exception in interrupt");
 113
 114         if (panic_on_oops)
 115                 panic("Fatal exception");
 116
 117         do_exit(SIGSEGV);
 118 }
 119
 120 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 121                                  long err)
 122 {
 123         if (!user_mode(regs))
 124                 die(str, regs, err);
 125 }
 126
 127 /*
 128  * try and fix up kernelspace address errors
 129  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 130  * - kernel/userspace interfaces cause a jump to an appropriate handler
 131  * - other kernel errors are bad
 132  */
 133 static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 134 {
 135         if (!user_mode(regs)) {
 136                 const struct exception_table_entry *fixup;
 137                 fixup = search_exception_tables(regs->pc);
 138                 if (fixup) {
 139                         regs->pc = fixup->fixup;
 140                         return;
 141                 }
 142
 143                 die(str, regs, err);
 144         }
 145 }
 146
 147 static inline void sign_extend(unsigned int count, unsigned char *dst)
 148 {
 149 #ifdef __LITTLE_ENDIAN__
 150         if ((count == 1) && dst[0] & 0x80) {
 151                 dst[1] = 0xff;
 152                 dst[2] = 0xff;
 153                 dst[3] = 0xff;
 154         }
 155         if ((count == 2) && dst[1] & 0x80) {
 156                 dst[2] = 0xff;
 157                 dst[3] = 0xff;
 158         }
 159 #else
 160         if ((count == 1) && dst[3] & 0x80) {
 161                 dst[2] = 0xff;
 162                 dst[1] = 0xff;
 163                 dst[0] = 0xff;
 164         }
 165         if ((count == 2) && dst[2] & 0x80) {
 166                 dst[1] = 0xff;
 167                 dst[0] = 0xff;
 168         }
 169 #endif
 170 }
 171
 172 static struct mem_access user_mem_access = {
 173         copy_from_user,
 174         copy_to_user,
 175 };
 176
 177 /*
 178  * handle an instruction that does an unaligned memory access by emulating the
 179  * desired behaviour
 180  * - note that PC _may not_ point to the faulting instruction
 181  *   (if that instruction is in a branch delay slot)
 182  * - return 0 if emulation okay, -EFAULT on existential error
 183  */
 184 static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
 185                                 struct mem_access *ma)
 186 {
 187         int ret, index, count;
 188         unsigned long *rm, *rn;
 189         unsigned char *src, *dst;
 190         unsigned char __user *srcu, *dstu;
 191
 192         index = (instruction>>8)&15;    /* 0x0F00 */
 193         rn = &regs->regs[index];
 194
 195         index = (instruction>>4)&15;    /* 0x00F0 */
 196         rm = &regs->regs[index];
 197
 198         count = 1<<(instruction&3);
 199
 200         switch (count) {
 201         case 1: inc_unaligned_byte_access(); break;
 202         case 2: inc_unaligned_word_access(); break;
 203         case 4: inc_unaligned_dword_access(); break;
 204         case 8: inc_unaligned_multi_access(); break;
 205         }
 206
 207         ret = -EFAULT;
 208         switch (instruction>>12) {
 209         case 0: /* mov.[bwl] to/from memory via r0+rn */
 210                 if (instruction & 8) {
 211                         /* from memory */
 212                         srcu = (unsigned char __user *)*rm;
 213                         srcu += regs->regs[0];
 214                         dst = (unsigned char *)rn;
 215                         *(unsigned long *)dst = 0;
 216
 217 #if !defined(__LITTLE_ENDIAN__)
 218                         dst += 4-count;
 219 #endif
 220                         if (ma->from(dst, srcu, count))
 221                                 goto fetch_fault;
 222
 223                         sign_extend(count, dst);
 224                 } else {
 225                         /* to memory */
 226                         src = (unsigned char *)rm;
 227 #if !defined(__LITTLE_ENDIAN__)
 228                         src += 4-count;
 229 #endif
 230                         dstu = (unsigned char __user *)*rn;
 231                         dstu += regs->regs[0];
 232
 233                         if (ma->to(dstu, src, count))
 234                                 goto fetch_fault;
 235                 }
 236                 ret = 0;
 237                 break;
 238
 239         case 1: /* mov.l Rm,@(disp,Rn) */
 240                 src = (unsigned char*) rm;
 241                 dstu = (unsigned char __user *)*rn;
 242                 dstu += (instruction&0x000F)<<2;
 243
 244                 if (ma->to(dstu, src, 4))
 245                         goto fetch_fault;
 246                 ret = 0;
 247                 break;
 248
 249         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 250                 if (instruction & 4)
 251                         *rn -= count;
 252                 src = (unsigned char*) rm;
 253                 dstu = (unsigned char __user *)*rn;
 254 #if !defined(__LITTLE_ENDIAN__)
 255                 src += 4-count;
 256 #endif
 257                 if (ma->to(dstu, src, count))
 258                         goto fetch_fault;
 259                 ret = 0;
 260                 break;
 261
 262         case 5: /* mov.l @(disp,Rm),Rn */
 263                 srcu = (unsigned char __user *)*rm;
 264                 srcu += (instruction & 0x000F) << 2;
 265                 dst = (unsigned char *)rn;
 266                 *(unsigned long *)dst = 0;
 267
 268                 if (ma->from(dst, srcu, 4))
 269                         goto fetch_fault;
 270                 ret = 0;
 271                 break;
 272
 273         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 274                 srcu = (unsigned char __user *)*rm;
 275                 if (instruction & 4)
 276                         *rm += count;
 277                 dst = (unsigned char*) rn;
 278                 *(unsigned long*)dst = 0;
 279
 280 #if !defined(__LITTLE_ENDIAN__)
 281                 dst += 4-count;
 282 #endif
 283                 if (ma->from(dst, srcu, count))
 284                         goto fetch_fault;
 285                 sign_extend(count, dst);
 286                 ret = 0;
 287                 break;
 288
 289         case 8:
 290                 switch ((instruction&0xFF00)>>8) {
 291                 case 0x81: /* mov.w R0,@(disp,Rn) */
 292                         src = (unsigned char *) &regs->regs[0];
 293 #if !defined(__LITTLE_ENDIAN__)
 294                         src += 2;
 295 #endif
 296                         dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
 297                         dstu += (instruction & 0x000F) << 1;
 298
 299                         if (ma->to(dstu, src, 2))
 300                                 goto fetch_fault;
 301                         ret = 0;
 302                         break;
 303
 304                 case 0x85: /* mov.w @(disp,Rm),R0 */
 305                         srcu = (unsigned char __user *)*rm;
 306                         srcu += (instruction & 0x000F) << 1;
 307                         dst = (unsigned char *) &regs->regs[0];
 308                         *(unsigned long *)dst = 0;
 309
 310 #if !defined(__LITTLE_ENDIAN__)
 311                         dst += 2;
 312 #endif
 313                         if (ma->from(dst, srcu, 2))
 314                                 goto fetch_fault;
 315                         sign_extend(2, dst);
 316                         ret = 0;
 317                         break;
 318                 }
 319                 break;
 320         }
 321         return ret;
 322
 323  fetch_fault:
 324         /* Argh. Address not only misaligned but also non-existent.
 325          * Raise an EFAULT and see if it's trapped
 326          */
 327         die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 328         return -EFAULT;
 329 }
 330
 331 /*
 332  * emulate the instruction in the delay slot
 333  * - fetches the instruction from PC+2
 334  */
 335 static inline int handle_delayslot(struct pt_regs *regs,
 336                                    insn_size_t old_instruction,
 337                                    struct mem_access *ma)
 338 {
 339         insn_size_t instruction;
 340         void __user *addr = (void __user *)(regs->pc +
 341                 instruction_size(old_instruction));
 342
 343         if (copy_from_user(&instruction, addr, sizeof(instruction))) {
 344                 /* the instruction-fetch faulted */
 345                 if (user_mode(regs))
 346                         return -EFAULT;
 347
 348                 /* kernel */
 349                 die("delay-slot-insn faulting in handle_unaligned_delayslot",
 350                     regs, 0);
 351         }
 352
 353         return handle_unaligned_ins(instruction, regs, ma);
 354 }
 355
 356 /*
 357  * handle an instruction that does an unaligned memory access
 358  * - have to be careful of branch delay-slot instructions that fault
 359  *  SH3:
 360  *   - if the branch would be taken PC points to the branch
 361  *   - if the branch would not be taken, PC points to delay-slot
 362  *  SH4:
 363  *   - PC always points to delayed branch
 364  * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
 365  */
 366
 367 /* Macros to determine offset from current PC for branch instructions */
 368 /* Explicit type coercion is used to force sign extension where needed */
 369 #define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
 370 #define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
 371
 372 int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
 373                             struct mem_access *ma, int expected,
 374                             unsigned long address)
 375 {
 376         u_int rm;
 377         int ret, index;
 378
 379         /*
 380          * XXX: We can't handle mixed 16/32-bit instructions yet
 381          */
 382         if (instruction_size(instruction) != 2)
 383                 return -EINVAL;
 384
 385         index = (instruction>>8)&15;    /* 0x0F00 */
 386         rm = regs->regs[index];
 387
 388         /*
 389          * Log the unexpected fixups, and then pass them on to perf.
 390          *
 391          * We intentionally don't report the expected cases to perf as
 392          * otherwise the trapped I/O case will skew the results too much
 393          * to be useful.
 394          */
 395         if (!expected) {
 396                 unaligned_fixups_notify(current, instruction, regs);
 397                 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, 0,
 398                               regs, address);
 399         }
 400
 401         ret = -EFAULT;
 402         switch (instruction&0xF000) {
 403         case 0x0000:
 404                 if (instruction==0x000B) {
 405                         /* rts */
 406                         ret = handle_delayslot(regs, instruction, ma);
 407                         if (ret==0)
 408                                 regs->pc = regs->pr;
 409                 }
 410                 else if ((instruction&0x00FF)==0x0023) {
 411                         /* braf @Rm */
 412                         ret = handle_delayslot(regs, instruction, ma);
 413                         if (ret==0)
 414                                 regs->pc += rm + 4;
 415                 }
 416                 else if ((instruction&0x00FF)==0x0003) {
 417                         /* bsrf @Rm */
 418                         ret = handle_delayslot(regs, instruction, ma);
 419                         if (ret==0) {
 420                                 regs->pr = regs->pc + 4;
 421                                 regs->pc += rm + 4;
 422                         }
 423                 }
 424                 else {
 425                         /* mov.[bwl] to/from memory via r0+rn */
 426                         goto simple;
 427                 }
 428                 break;
 429
 430         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 431                 goto simple;
 432
 433         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 434                 goto simple;
 435
 436         case 0x4000:
 437                 if ((instruction&0x00FF)==0x002B) {
 438                         /* jmp @Rm */
 439                         ret = handle_delayslot(regs, instruction, ma);
 440                         if (ret==0)
 441                                 regs->pc = rm;
 442                 }
 443                 else if ((instruction&0x00FF)==0x000B) {
 444                         /* jsr @Rm */
 445                         ret = handle_delayslot(regs, instruction, ma);
 446                         if (ret==0) {
 447                                 regs->pr = regs->pc + 4;
 448                                 regs->pc = rm;
 449                         }
 450                 }
 451                 else {
 452                         /* mov.[bwl] to/from memory via r0+rn */
 453                         goto simple;
 454                 }
 455                 break;
 456
 457         case 0x5000: /* mov.l @(disp,Rm),Rn */
 458                 goto simple;
 459
 460         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 461                 goto simple;
 462
 463         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 464                 switch (instruction&0x0F00) {
 465                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 466                         goto simple;
 467                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 468                         goto simple;
 469                 case 0x0B00: /* bf   lab - no delayslot*/
 470                         break;
 471                 case 0x0F00: /* bf/s lab */
 472                         ret = handle_delayslot(regs, instruction, ma);
 473                         if (ret==0) {
 474 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 475                                 if ((regs->sr & 0x00000001) != 0)
 476                                         regs->pc += 4; /* next after slot */
 477                                 else
 478 #endif
 479                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 480                         }
 481                         break;
 482                 case 0x0900: /* bt   lab - no delayslot */
 483                         break;
 484                 case 0x0D00: /* bt/s lab */
 485                         ret = handle_delayslot(regs, instruction, ma);
 486                         if (ret==0) {
 487 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 488                                 if ((regs->sr & 0x00000001) == 0)
 489                                         regs->pc += 4; /* next after slot */
 490                                 else
 491 #endif
 492                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 493                         }
 494                         break;
 495                 }
 496                 break;
 497
 498         case 0xA000: /* bra label */
 499                 ret = handle_delayslot(regs, instruction, ma);
 500                 if (ret==0)
 501                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 502                 break;
 503
 504         case 0xB000: /* bsr label */
 505                 ret = handle_delayslot(regs, instruction, ma);
 506                 if (ret==0) {
 507                         regs->pr = regs->pc + 4;
 508                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 509                 }
 510                 break;
 511         }
 512         return ret;
 513
 514         /* handle non-delay-slot instruction */
 515  simple:
 516         ret = handle_unaligned_ins(instruction, regs, ma);
 517         if (ret==0)
 518                 regs->pc += instruction_size(instruction);
 519         return ret;
 520 }
 521
 522 /*
 523  * Handle various address error exceptions:
 524  *  - instruction address error:
 525  *       misaligned PC
 526  *       PC >= 0x80000000 in user mode
 527  *  - data address error (read and write)
 528  *       misaligned data access
 529  *       access to >= 0x80000000 is user mode
 530  * Unfortuntaly we can't distinguish between instruction address error
 531  * and data address errors caused by read accesses.
 532  */
 533 asmlinkage void do_address_error(struct pt_regs *regs,
 534                                  unsigned long writeaccess,
 535                                  unsigned long address)
 536 {
 537         unsigned long error_code = 0;
 538         mm_segment_t oldfs;
 539         siginfo_t info;
 540         insn_size_t instruction;
 541         int tmp;
 542
 543         /* Intentional ifdef */
 544 #ifdef CONFIG_CPU_HAS_SR_RB
 545         error_code = lookup_exception_vector();
 546 #endif
 547
 548         oldfs = get_fs();
 549
 550         if (user_mode(regs)) {
 551                 int si_code = BUS_ADRERR;
 552                 unsigned int user_action;
 553
 554                 local_irq_enable();
 555                 inc_unaligned_user_access();
 556
 557                 set_fs(USER_DS);
 558                 if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
 559                                    sizeof(instruction))) {
 560                         set_fs(oldfs);
 561                         goto uspace_segv;
 562                 }
 563                 set_fs(oldfs);
 564
 565                 /* shout about userspace fixups */
 566                 unaligned_fixups_notify(current, instruction, regs);
 567
 568                 user_action = unaligned_user_action();
 569                 if (user_action & UM_FIXUP)
 570                         goto fixup;
 571                 if (user_action & UM_SIGNAL)
 572                         goto uspace_segv;
 573                 else {
 574                         /* ignore */
 575                         regs->pc += instruction_size(instruction);
 576                         return;
 577                 }
 578
 579 fixup:
 580                 /* bad PC is not something we can fix */
 581                 if (regs->pc & 1) {
 582                         si_code = BUS_ADRALN;
 583                         goto uspace_segv;
 584                 }
 585
 586                 set_fs(USER_DS);
 587                 tmp = handle_unaligned_access(instruction, regs,
 588                                               &user_mem_access, 0,
 589                                               address);
 590                 set_fs(oldfs);
 591
 592                 if (tmp == 0)
 593                         return; /* sorted */
 594 uspace_segv:
 595                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 596                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 597                        regs->pr);
 598
 599                 info.si_signo = SIGBUS;
 600                 info.si_errno = 0;
 601                 info.si_code = si_code;
 602                 info.si_addr = (void __user *)address;
 603                 force_sig_info(SIGBUS, &info, current);
 604         } else {
 605                 inc_unaligned_kernel_access();
 606
 607                 if (regs->pc & 1)
 608                         die("unaligned program counter", regs, error_code);
 609
 610                 set_fs(KERNEL_DS);
 611                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 612                                    sizeof(instruction))) {
 613                         /* Argh. Fault on the instruction itself.
 614                            This should never happen non-SMP
 615                         */
 616                         set_fs(oldfs);
 617                         die("insn faulting in do_address_error", regs, 0);
 618                 }
 619
 620                 unaligned_fixups_notify(current, instruction, regs);
 621
 622                 handle_unaligned_access(instruction, regs, &user_mem_access,
 623                                         0, address);
 624                 set_fs(oldfs);
 625         }
 626 }
 627
 628 #ifdef CONFIG_SH_DSP
 629 /*
 630  *      SH-DSP support gerg@snapgear.com.
 631  */
 632 int is_dsp_inst(struct pt_regs *regs)
 633 {
 634         unsigned short inst = 0;
 635
 636         /*
 637          * Safe guard if DSP mode is already enabled or we're lacking
 638          * the DSP altogether.
 639          */
 640         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 641                 return 0;
 642
 643         get_user(inst, ((unsigned short *) regs->pc));
 644
 645         inst &= 0xf000;
 646
 647         /* Check for any type of DSP or support instruction */
 648         if ((inst == 0xf000) || (inst == 0x4000))
 649                 return 1;
 650
 651         return 0;
 652 }
 653 #else
 654 #define is_dsp_inst(regs)       (0)
 655 #endif /* CONFIG_SH_DSP */
 656
 657 #ifdef CONFIG_CPU_SH2A
 658 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 659                                 unsigned long r6, unsigned long r7,
 660                                 struct pt_regs __regs)
 661 {
 662         siginfo_t info;
 663
 664         switch (r4) {
 665         case TRAP_DIVZERO_ERROR:
 666                 info.si_code = FPE_INTDIV;
 667                 break;
 668         case TRAP_DIVOVF_ERROR:
 669                 info.si_code = FPE_INTOVF;
 670                 break;
 671         }
 672
 673         force_sig_info(SIGFPE, &info, current);
 674 }
 675 #endif
 676
 677 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 678                                 unsigned long r6, unsigned long r7,
 679                                 struct pt_regs __regs)
 680 {
 681         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 682         unsigned long error_code;
 683         struct task_struct *tsk = current;
 684
 685 #ifdef CONFIG_SH_FPU_EMU
 686         unsigned short inst = 0;
 687         int err;
 688
 689         get_user(inst, (unsigned short*)regs->pc);
 690
 691         err = do_fpu_inst(inst, regs);
 692         if (!err) {
 693                 regs->pc += instruction_size(inst);
 694                 return;
 695         }
 696         /* not a FPU inst. */
 697 #endif
 698
 699 #ifdef CONFIG_SH_DSP
 700         /* Check if it's a DSP instruction */
 701         if (is_dsp_inst(regs)) {
 702                 /* Enable DSP mode, and restart instruction. */
 703                 regs->sr |= SR_DSP;
 704                 /* Save DSP mode */
 705                 tsk->thread.dsp_status.status |= SR_DSP;
 706                 return;
 707         }
 708 #endif
 709
 710         error_code = lookup_exception_vector();
 711
 712         local_irq_enable();
 713         force_sig(SIGILL, tsk);
 714         die_if_no_fixup("reserved instruction", regs, error_code);
 715 }
 716
 717 #ifdef CONFIG_SH_FPU_EMU
 718 static int emulate_branch(unsigned short inst, struct pt_regs *regs)
 719 {
 720         /*
 721          * bfs: 8fxx: PC+=d*2+4;
 722          * bts: 8dxx: PC+=d*2+4;
 723          * bra: axxx: PC+=D*2+4;
 724          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 725          * braf:0x23: PC+=Rn*2+4;
 726          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 727          * jmp: 4x2b: PC=Rn;
 728          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 729          * rts: 000b: PC=PR;
 730          */
 731         if (((inst & 0xf000) == 0xb000)  ||     /* bsr */
 732             ((inst & 0xf0ff) == 0x0003)  ||     /* bsrf */
 733             ((inst & 0xf0ff) == 0x400b))        /* jsr */
 734                 regs->pr = regs->pc + 4;
 735
 736         if ((inst & 0xfd00) == 0x8d00) {        /* bfs, bts */
 737                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 738                 return 0;
 739         }
 740
 741         if ((inst & 0xe000) == 0xa000) {        /* bra, bsr */
 742                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 743                 return 0;
 744         }
 745
 746         if ((inst & 0xf0df) == 0x0003) {        /* braf, bsrf */
 747                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 748                 return 0;
 749         }
 750
 751         if ((inst & 0xf0df) == 0x400b) {        /* jmp, jsr */
 752                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 753                 return 0;
 754         }
 755
 756         if ((inst & 0xffff) == 0x000b) {        /* rts */
 757                 regs->pc = regs->pr;
 758                 return 0;
 759         }
 760
 761         return 1;
 762 }
 763 #endif
 764
 765 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 766                                 unsigned long r6, unsigned long r7,
 767                                 struct pt_regs __regs)
 768 {
 769         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 770         unsigned long inst;
 771         struct task_struct *tsk = current;
 772
 773         if (kprobe_handle_illslot(regs->pc) == 0)
 774                 return;
 775
 776 #ifdef CONFIG_SH_FPU_EMU
 777         get_user(inst, (unsigned short *)regs->pc + 1);
 778         if (!do_fpu_inst(inst, regs)) {
 779                 get_user(inst, (unsigned short *)regs->pc);
 780                 if (!emulate_branch(inst, regs))
 781                         return;
 782                 /* fault in branch.*/
 783         }
 784         /* not a FPU inst. */
 785 #endif
 786
 787         inst = lookup_exception_vector();
 788
 789         local_irq_enable();
 790         force_sig(SIGILL, tsk);
 791         die_if_no_fixup("illegal slot instruction", regs, inst);
 792 }
 793
 794 asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
 795                                    unsigned long r6, unsigned long r7,
 796                                    struct pt_regs __regs)
 797 {
 798         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 799         long ex;
 800
 801         ex = lookup_exception_vector();
 802         die_if_kernel("exception", regs, ex);
 803 }
 804
 805 void __cpuinit per_cpu_trap_init(void)
 806 {
 807         extern void *vbr_base;
 808
 809         /* NOTE: The VBR value should be at P1
 810            (or P2, virtural "fixed" address space).
 811            It's definitely should not in physical address.  */
 812
 813         asm volatile("ldc       %0, vbr"
 814                      : /* no output */
 815                      : "r" (&vbr_base)
 816                      : "memory");
 817
 818         /* disable exception blocking now when the vbr has been setup */
 819         clear_bl_bit();
 820 }
 821
 822 void *set_exception_table_vec(unsigned int vec, void *handler)
 823 {
 824         extern void *exception_handling_table[];
 825         void *old_handler;
 826
 827         old_handler = exception_handling_table[vec];
 828         exception_handling_table[vec] = handler;
 829         return old_handler;
 830 }
 831
 832 void __init trap_init(void)
 833 {
 834         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 835         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 836
 837 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 838     defined(CONFIG_SH_FPU_EMU)
 839         /*
 840          * For SH-4 lacking an FPU, treat floating point instructions as
 841          * reserved. They'll be handled in the math-emu case, or faulted on
 842          * otherwise.
 843          */
 844         set_exception_table_evt(0x800, do_reserved_inst);
 845         set_exception_table_evt(0x820, do_illegal_slot_inst);
 846 #elif defined(CONFIG_SH_FPU)
 847         set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
 848         set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
 849 #endif
 850
 851 #ifdef CONFIG_CPU_SH2
 852         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
 853 #endif
 854 #ifdef CONFIG_CPU_SH2A
 855         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 856         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 857 #ifdef CONFIG_SH_FPU
 858         set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
 859 #endif
 860 #endif
 861
 862 #ifdef TRAP_UBC
 863         set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
 864 #endif
 865 }
 866
 867 void show_stack(struct task_struct *tsk, unsigned long *sp)
 868 {
 869         unsigned long stack;
 870
 871         if (!tsk)
 872                 tsk = current;
 873         if (tsk == current)
 874                 sp = (unsigned long *)current_stack_pointer;
 875         else
 876                 sp = (unsigned long *)tsk->thread.sp;
 877
 878         stack = (unsigned long)sp;
 879         dump_mem("Stack: ", stack, THREAD_SIZE +
 880                  (unsigned long)task_stack_page(tsk));
 881         show_trace(tsk, sp, NULL);
 882 }
 883
 884 void dump_stack(void)
 885 {
 886         show_stack(NULL, NULL);
 887 }
 888 EXPORT_SYMBOL(dump_stack);