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