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 - 2007 Paul Mundt
   9  *
  10  * This file is subject to the terms and conditions of the GNU General Public
  11  * License.  See the file "COPYING" in the main directory of this archive
  12  * for more details.
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/init.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/module.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/io.h>
  21 #include <linux/bug.h>
  22 #include <linux/debug_locks.h>
  23 #include <linux/kdebug.h>
  24 #include <linux/kexec.h>
  25 #include <linux/limits.h>
  26 #include <asm/system.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/fpu.h>
  29 #include <asm/kprobes.h>
  30
  31 #ifdef CONFIG_SH_KGDB
  32 #include <asm/kgdb.h>
  33 #define CHK_REMOTE_DEBUG(regs)                  \
  34 {                                               \
  35         if (kgdb_debug_hook && !user_mode(regs))\
  36                 (*kgdb_debug_hook)(regs);       \
  37 }
  38 #else
  39 #define CHK_REMOTE_DEBUG(regs)
  40 #endif
  41
  42 #ifdef CONFIG_CPU_SH2
  43 # define TRAP_RESERVED_INST     4
  44 # define TRAP_ILLEGAL_SLOT_INST 6
  45 # define TRAP_ADDRESS_ERROR     9
  46 # ifdef CONFIG_CPU_SH2A
  47 #  define TRAP_FPU_ERROR        13
  48 #  define TRAP_DIVZERO_ERROR    17
  49 #  define TRAP_DIVOVF_ERROR     18
  50 # endif
  51 #else
  52 #define TRAP_RESERVED_INST      12
  53 #define TRAP_ILLEGAL_SLOT_INST  13
  54 #endif
  55
  56 static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
  57 {
  58         unsigned long p;
  59         int i;
  60
  61         printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
  62
  63         for (p = bottom & ~31; p < top; ) {
  64                 printk("%04lx: ", p & 0xffff);
  65
  66                 for (i = 0; i < 8; i++, p += 4) {
  67                         unsigned int val;
  68
  69                         if (p < bottom || p >= top)
  70                                 printk("         ");
  71                         else {
  72                                 if (__get_user(val, (unsigned int __user *)p)) {
  73                                         printk("\n");
  74                                         return;
  75                                 }
  76                                 printk("%08x ", val);
  77                         }
  78                 }
  79                 printk("\n");
  80         }
  81 }
  82
  83 static DEFINE_SPINLOCK(die_lock);
  84
  85 void die(const char * str, struct pt_regs * regs, long err)
  86 {
  87         static int die_counter;
  88
  89         oops_enter();
  90
  91         console_verbose();
  92         spin_lock_irq(&die_lock);
  93         bust_spinlocks(1);
  94
  95         printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
  96
  97         CHK_REMOTE_DEBUG(regs);
  98         print_modules();
  99         show_regs(regs);
 100
 101         printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
 102                         task_pid_nr(current), task_stack_page(current) + 1);
 103
 104         if (!user_mode(regs) || in_interrupt())
 105                 dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
 106                          (unsigned long)task_stack_page(current));
 107
 108         notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
 109
 110         bust_spinlocks(0);
 111         add_taint(TAINT_DIE);
 112         spin_unlock_irq(&die_lock);
 113
 114         if (kexec_should_crash(current))
 115                 crash_kexec(regs);
 116
 117         if (in_interrupt())
 118                 panic("Fatal exception in interrupt");
 119
 120         if (panic_on_oops)
 121                 panic("Fatal exception");
 122
 123         oops_exit();
 124         do_exit(SIGSEGV);
 125 }
 126
 127 static inline void die_if_kernel(const char *str, struct pt_regs *regs,
 128                                  long err)
 129 {
 130         if (!user_mode(regs))
 131                 die(str, regs, err);
 132 }
 133
 134 /*
 135  * try and fix up kernelspace address errors
 136  * - userspace errors just cause EFAULT to be returned, resulting in SEGV
 137  * - kernel/userspace interfaces cause a jump to an appropriate handler
 138  * - other kernel errors are bad
 139  * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault
 140  */
 141 static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
 142 {
 143         if (!user_mode(regs)) {
 144                 const struct exception_table_entry *fixup;
 145                 fixup = search_exception_tables(regs->pc);
 146                 if (fixup) {
 147                         regs->pc = fixup->fixup;
 148                         return 0;
 149                 }
 150                 die(str, regs, err);
 151         }
 152         return -EFAULT;
 153 }
 154
 155 static inline void sign_extend(unsigned int count, unsigned char *dst)
 156 {
 157 #ifdef __LITTLE_ENDIAN__
 158         if ((count == 1) && dst[0] & 0x80) {
 159                 dst[1] = 0xff;
 160                 dst[2] = 0xff;
 161                 dst[3] = 0xff;
 162         }
 163         if ((count == 2) && dst[1] & 0x80) {
 164                 dst[2] = 0xff;
 165                 dst[3] = 0xff;
 166         }
 167 #else
 168         if ((count == 1) && dst[3] & 0x80) {
 169                 dst[2] = 0xff;
 170                 dst[1] = 0xff;
 171                 dst[0] = 0xff;
 172         }
 173         if ((count == 2) && dst[2] & 0x80) {
 174                 dst[1] = 0xff;
 175                 dst[0] = 0xff;
 176         }
 177 #endif
 178 }
 179
 180 static struct mem_access user_mem_access = {
 181         copy_from_user,
 182         copy_to_user,
 183 };
 184
 185 /*
 186  * handle an instruction that does an unaligned memory access by emulating the
 187  * desired behaviour
 188  * - note that PC _may not_ point to the faulting instruction
 189  *   (if that instruction is in a branch delay slot)
 190  * - return 0 if emulation okay, -EFAULT on existential error
 191  */
 192 static int handle_unaligned_ins(opcode_t instruction, struct pt_regs *regs,
 193                                 struct mem_access *ma)
 194 {
 195         int ret, index, count;
 196         unsigned long *rm, *rn;
 197         unsigned char *src, *dst;
 198         unsigned char __user *srcu, *dstu;
 199
 200         index = (instruction>>8)&15;    /* 0x0F00 */
 201         rn = &regs->regs[index];
 202
 203         index = (instruction>>4)&15;    /* 0x00F0 */
 204         rm = &regs->regs[index];
 205
 206         count = 1<<(instruction&3);
 207
 208         ret = -EFAULT;
 209         switch (instruction>>12) {
 210         case 0: /* mov.[bwl] to/from memory via r0+rn */
 211                 if (instruction & 8) {
 212                         /* from memory */
 213                         srcu = (unsigned char __user *)*rm;
 214                         srcu += regs->regs[0];
 215                         dst = (unsigned char *)rn;
 216                         *(unsigned long *)dst = 0;
 217
 218 #if !defined(__LITTLE_ENDIAN__)
 219                         dst += 4-count;
 220 #endif
 221                         if (ma->from(dst, srcu, count))
 222                                 goto fetch_fault;
 223
 224                         sign_extend(count, dst);
 225                 } else {
 226                         /* to memory */
 227                         src = (unsigned char *)rm;
 228 #if !defined(__LITTLE_ENDIAN__)
 229                         src += 4-count;
 230 #endif
 231                         dstu = (unsigned char __user *)*rn;
 232                         dstu += regs->regs[0];
 233
 234                         if (ma->to(dstu, src, count))
 235                                 goto fetch_fault;
 236                 }
 237                 ret = 0;
 238                 break;
 239
 240         case 1: /* mov.l Rm,@(disp,Rn) */
 241                 src = (unsigned char*) rm;
 242                 dstu = (unsigned char __user *)*rn;
 243                 dstu += (instruction&0x000F)<<2;
 244
 245                 if (ma->to(dstu, src, 4))
 246                         goto fetch_fault;
 247                 ret = 0;
 248                 break;
 249
 250         case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
 251                 if (instruction & 4)
 252                         *rn -= count;
 253                 src = (unsigned char*) rm;
 254                 dstu = (unsigned char __user *)*rn;
 255 #if !defined(__LITTLE_ENDIAN__)
 256                 src += 4-count;
 257 #endif
 258                 if (ma->to(dstu, src, count))
 259                         goto fetch_fault;
 260                 ret = 0;
 261                 break;
 262
 263         case 5: /* mov.l @(disp,Rm),Rn */
 264                 srcu = (unsigned char __user *)*rm;
 265                 srcu += (instruction & 0x000F) << 2;
 266                 dst = (unsigned char *)rn;
 267                 *(unsigned long *)dst = 0;
 268
 269                 if (ma->from(dst, srcu, 4))
 270                         goto fetch_fault;
 271                 ret = 0;
 272                 break;
 273
 274         case 6: /* mov.[bwl] from memory, possibly with post-increment */
 275                 srcu = (unsigned char __user *)*rm;
 276                 if (instruction & 4)
 277                         *rm += count;
 278                 dst = (unsigned char*) rn;
 279                 *(unsigned long*)dst = 0;
 280
 281 #if !defined(__LITTLE_ENDIAN__)
 282                 dst += 4-count;
 283 #endif
 284                 if (ma->from(dst, srcu, count))
 285                         goto fetch_fault;
 286                 sign_extend(count, dst);
 287                 ret = 0;
 288                 break;
 289
 290         case 8:
 291                 switch ((instruction&0xFF00)>>8) {
 292                 case 0x81: /* mov.w R0,@(disp,Rn) */
 293                         src = (unsigned char *) &regs->regs[0];
 294 #if !defined(__LITTLE_ENDIAN__)
 295                         src += 2;
 296 #endif
 297                         dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
 298                         dstu += (instruction & 0x000F) << 1;
 299
 300                         if (ma->to(dstu, src, 2))
 301                                 goto fetch_fault;
 302                         ret = 0;
 303                         break;
 304
 305                 case 0x85: /* mov.w @(disp,Rm),R0 */
 306                         srcu = (unsigned char __user *)*rm;
 307                         srcu += (instruction & 0x000F) << 1;
 308                         dst = (unsigned char *) &regs->regs[0];
 309                         *(unsigned long *)dst = 0;
 310
 311 #if !defined(__LITTLE_ENDIAN__)
 312                         dst += 2;
 313 #endif
 314                         if (ma->from(dst, srcu, 2))
 315                                 goto fetch_fault;
 316                         sign_extend(2, dst);
 317                         ret = 0;
 318                         break;
 319                 }
 320                 break;
 321         }
 322         return ret;
 323
 324  fetch_fault:
 325         /* Argh. Address not only misaligned but also non-existent.
 326          * Raise an EFAULT and see if it's trapped
 327          */
 328         return die_if_no_fixup("Fault in unaligned fixup", regs, 0);
 329 }
 330
 331 /*
 332  * emulate the instruction in the delay slot
 333  * - fetches the instruction from PC+2
 334  */
 335 static inline int handle_delayslot(struct pt_regs *regs,
 336                                    opcode_t old_instruction,
 337                                    struct mem_access *ma)
 338 {
 339         opcode_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 /*
 373  * XXX: SH-2A needs this too, but it needs an overhaul thanks to mixed 32-bit
 374  * opcodes..
 375  */
 376
 377 static int handle_unaligned_notify_count = 10;
 378
 379 int handle_unaligned_access(opcode_t instruction, struct pt_regs *regs,
 380                             struct mem_access *ma)
 381 {
 382         u_int rm;
 383         int ret, index;
 384
 385         index = (instruction>>8)&15;    /* 0x0F00 */
 386         rm = regs->regs[index];
 387
 388         /* shout about the first ten userspace fixups */
 389         if (user_mode(regs) && handle_unaligned_notify_count>0) {
 390                 handle_unaligned_notify_count--;
 391
 392                 printk(KERN_NOTICE "Fixing up unaligned userspace access "
 393                        "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 394                        current->comm, task_pid_nr(current),
 395                        (void *)regs->pc, instruction);
 396         }
 397
 398         ret = -EFAULT;
 399         switch (instruction&0xF000) {
 400         case 0x0000:
 401                 if (instruction==0x000B) {
 402                         /* rts */
 403                         ret = handle_delayslot(regs, instruction, ma);
 404                         if (ret==0)
 405                                 regs->pc = regs->pr;
 406                 }
 407                 else if ((instruction&0x00FF)==0x0023) {
 408                         /* braf @Rm */
 409                         ret = handle_delayslot(regs, instruction, ma);
 410                         if (ret==0)
 411                                 regs->pc += rm + 4;
 412                 }
 413                 else if ((instruction&0x00FF)==0x0003) {
 414                         /* bsrf @Rm */
 415                         ret = handle_delayslot(regs, instruction, ma);
 416                         if (ret==0) {
 417                                 regs->pr = regs->pc + 4;
 418                                 regs->pc += rm + 4;
 419                         }
 420                 }
 421                 else {
 422                         /* mov.[bwl] to/from memory via r0+rn */
 423                         goto simple;
 424                 }
 425                 break;
 426
 427         case 0x1000: /* mov.l Rm,@(disp,Rn) */
 428                 goto simple;
 429
 430         case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
 431                 goto simple;
 432
 433         case 0x4000:
 434                 if ((instruction&0x00FF)==0x002B) {
 435                         /* jmp @Rm */
 436                         ret = handle_delayslot(regs, instruction, ma);
 437                         if (ret==0)
 438                                 regs->pc = rm;
 439                 }
 440                 else if ((instruction&0x00FF)==0x000B) {
 441                         /* jsr @Rm */
 442                         ret = handle_delayslot(regs, instruction, ma);
 443                         if (ret==0) {
 444                                 regs->pr = regs->pc + 4;
 445                                 regs->pc = rm;
 446                         }
 447                 }
 448                 else {
 449                         /* mov.[bwl] to/from memory via r0+rn */
 450                         goto simple;
 451                 }
 452                 break;
 453
 454         case 0x5000: /* mov.l @(disp,Rm),Rn */
 455                 goto simple;
 456
 457         case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
 458                 goto simple;
 459
 460         case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
 461                 switch (instruction&0x0F00) {
 462                 case 0x0100: /* mov.w R0,@(disp,Rm) */
 463                         goto simple;
 464                 case 0x0500: /* mov.w @(disp,Rm),R0 */
 465                         goto simple;
 466                 case 0x0B00: /* bf   lab - no delayslot*/
 467                         break;
 468                 case 0x0F00: /* bf/s lab */
 469                         ret = handle_delayslot(regs, instruction, ma);
 470                         if (ret==0) {
 471 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 472                                 if ((regs->sr & 0x00000001) != 0)
 473                                         regs->pc += 4; /* next after slot */
 474                                 else
 475 #endif
 476                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 477                         }
 478                         break;
 479                 case 0x0900: /* bt   lab - no delayslot */
 480                         break;
 481                 case 0x0D00: /* bt/s lab */
 482                         ret = handle_delayslot(regs, instruction, ma);
 483                         if (ret==0) {
 484 #if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
 485                                 if ((regs->sr & 0x00000001) == 0)
 486                                         regs->pc += 4; /* next after slot */
 487                                 else
 488 #endif
 489                                         regs->pc += SH_PC_8BIT_OFFSET(instruction);
 490                         }
 491                         break;
 492                 }
 493                 break;
 494
 495         case 0xA000: /* bra label */
 496                 ret = handle_delayslot(regs, instruction, ma);
 497                 if (ret==0)
 498                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 499                 break;
 500
 501         case 0xB000: /* bsr label */
 502                 ret = handle_delayslot(regs, instruction, ma);
 503                 if (ret==0) {
 504                         regs->pr = regs->pc + 4;
 505                         regs->pc += SH_PC_12BIT_OFFSET(instruction);
 506                 }
 507                 break;
 508         }
 509         return ret;
 510
 511         /* handle non-delay-slot instruction */
 512  simple:
 513         ret = handle_unaligned_ins(instruction, regs, ma);
 514         if (ret==0)
 515                 regs->pc += instruction_size(instruction);
 516         return ret;
 517 }
 518
 519 /*
 520  * Handle various address error exceptions:
 521  *  - instruction address error:
 522  *       misaligned PC
 523  *       PC >= 0x80000000 in user mode
 524  *  - data address error (read and write)
 525  *       misaligned data access
 526  *       access to >= 0x80000000 is user mode
 527  * Unfortuntaly we can't distinguish between instruction address error
 528  * and data address errors caused by read accesses.
 529  */
 530 asmlinkage void do_address_error(struct pt_regs *regs,
 531                                  unsigned long writeaccess,
 532                                  unsigned long address)
 533 {
 534         unsigned long error_code = 0;
 535         mm_segment_t oldfs;
 536         siginfo_t info;
 537         opcode_t instruction;
 538         int tmp;
 539
 540         /* Intentional ifdef */
 541 #ifdef CONFIG_CPU_HAS_SR_RB
 542         error_code = lookup_exception_vector();
 543 #endif
 544
 545         oldfs = get_fs();
 546
 547         if (user_mode(regs)) {
 548                 int si_code = BUS_ADRERR;
 549
 550                 local_irq_enable();
 551
 552                 /* bad PC is not something we can fix */
 553                 if (regs->pc & 1) {
 554                         si_code = BUS_ADRALN;
 555                         goto uspace_segv;
 556                 }
 557
 558                 set_fs(USER_DS);
 559                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 560                                    sizeof(instruction))) {
 561                         /* Argh. Fault on the instruction itself.
 562                            This should never happen non-SMP
 563                         */
 564                         set_fs(oldfs);
 565                         goto uspace_segv;
 566                 }
 567
 568                 tmp = handle_unaligned_access(instruction, regs,
 569                                               &user_mem_access);
 570                 set_fs(oldfs);
 571
 572                 if (tmp==0)
 573                         return; /* sorted */
 574 uspace_segv:
 575                 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
 576                        "access (PC %lx PR %lx)\n", current->comm, regs->pc,
 577                        regs->pr);
 578
 579                 info.si_signo = SIGBUS;
 580                 info.si_errno = 0;
 581                 info.si_code = si_code;
 582                 info.si_addr = (void __user *)address;
 583                 force_sig_info(SIGBUS, &info, current);
 584         } else {
 585                 if (regs->pc & 1)
 586                         die("unaligned program counter", regs, error_code);
 587
 588                 set_fs(KERNEL_DS);
 589                 if (copy_from_user(&instruction, (void __user *)(regs->pc),
 590                                    sizeof(instruction))) {
 591                         /* Argh. Fault on the instruction itself.
 592                            This should never happen non-SMP
 593                         */
 594                         set_fs(oldfs);
 595                         die("insn faulting in do_address_error", regs, 0);
 596                 }
 597
 598                 handle_unaligned_access(instruction, regs, &user_mem_access);
 599                 set_fs(oldfs);
 600         }
 601 }
 602
 603 #ifdef CONFIG_SH_DSP
 604 /*
 605  *      SH-DSP support gerg@snapgear.com.
 606  */
 607 int is_dsp_inst(struct pt_regs *regs)
 608 {
 609         unsigned short inst = 0;
 610
 611         /*
 612          * Safe guard if DSP mode is already enabled or we're lacking
 613          * the DSP altogether.
 614          */
 615         if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
 616                 return 0;
 617
 618         get_user(inst, ((unsigned short *) regs->pc));
 619
 620         inst &= 0xf000;
 621
 622         /* Check for any type of DSP or support instruction */
 623         if ((inst == 0xf000) || (inst == 0x4000))
 624                 return 1;
 625
 626         return 0;
 627 }
 628 #else
 629 #define is_dsp_inst(regs)       (0)
 630 #endif /* CONFIG_SH_DSP */
 631
 632 #ifdef CONFIG_CPU_SH2A
 633 asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
 634                                 unsigned long r6, unsigned long r7,
 635                                 struct pt_regs __regs)
 636 {
 637         siginfo_t info;
 638
 639         switch (r4) {
 640         case TRAP_DIVZERO_ERROR:
 641                 info.si_code = FPE_INTDIV;
 642                 break;
 643         case TRAP_DIVOVF_ERROR:
 644                 info.si_code = FPE_INTOVF;
 645                 break;
 646         }
 647
 648         force_sig_info(SIGFPE, &info, current);
 649 }
 650 #endif
 651
 652 asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
 653                                 unsigned long r6, unsigned long r7,
 654                                 struct pt_regs __regs)
 655 {
 656         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 657         unsigned long error_code;
 658         struct task_struct *tsk = current;
 659
 660 #ifdef CONFIG_SH_FPU_EMU
 661         unsigned short inst = 0;
 662         int err;
 663
 664         get_user(inst, (unsigned short*)regs->pc);
 665
 666         err = do_fpu_inst(inst, regs);
 667         if (!err) {
 668                 regs->pc += instruction_size(inst);
 669                 return;
 670         }
 671         /* not a FPU inst. */
 672 #endif
 673
 674 #ifdef CONFIG_SH_DSP
 675         /* Check if it's a DSP instruction */
 676         if (is_dsp_inst(regs)) {
 677                 /* Enable DSP mode, and restart instruction. */
 678                 regs->sr |= SR_DSP;
 679                 return;
 680         }
 681 #endif
 682
 683         error_code = lookup_exception_vector();
 684
 685         local_irq_enable();
 686         CHK_REMOTE_DEBUG(regs);
 687         force_sig(SIGILL, tsk);
 688         die_if_no_fixup("reserved instruction", regs, error_code);
 689 }
 690
 691 #ifdef CONFIG_SH_FPU_EMU
 692 static int emulate_branch(unsigned short inst, struct pt_regs* regs)
 693 {
 694         /*
 695          * bfs: 8fxx: PC+=d*2+4;
 696          * bts: 8dxx: PC+=d*2+4;
 697          * bra: axxx: PC+=D*2+4;
 698          * bsr: bxxx: PC+=D*2+4  after PR=PC+4;
 699          * braf:0x23: PC+=Rn*2+4;
 700          * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
 701          * jmp: 4x2b: PC=Rn;
 702          * jsr: 4x0b: PC=Rn      after PR=PC+4;
 703          * rts: 000b: PC=PR;
 704          */
 705         if ((inst & 0xfd00) == 0x8d00) {
 706                 regs->pc += SH_PC_8BIT_OFFSET(inst);
 707                 return 0;
 708         }
 709
 710         if ((inst & 0xe000) == 0xa000) {
 711                 regs->pc += SH_PC_12BIT_OFFSET(inst);
 712                 return 0;
 713         }
 714
 715         if ((inst & 0xf0df) == 0x0003) {
 716                 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
 717                 return 0;
 718         }
 719
 720         if ((inst & 0xf0df) == 0x400b) {
 721                 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
 722                 return 0;
 723         }
 724
 725         if ((inst & 0xffff) == 0x000b) {
 726                 regs->pc = regs->pr;
 727                 return 0;
 728         }
 729
 730         return 1;
 731 }
 732 #endif
 733
 734 asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
 735                                 unsigned long r6, unsigned long r7,
 736                                 struct pt_regs __regs)
 737 {
 738         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 739         unsigned long inst;
 740         struct task_struct *tsk = current;
 741
 742         if (kprobe_handle_illslot(regs->pc) == 0)
 743                 return;
 744
 745 #ifdef CONFIG_SH_FPU_EMU
 746         get_user(inst, (unsigned short *)regs->pc + 1);
 747         if (!do_fpu_inst(inst, regs)) {
 748                 get_user(inst, (unsigned short *)regs->pc);
 749                 if (!emulate_branch(inst, regs))
 750                         return;
 751                 /* fault in branch.*/
 752         }
 753         /* not a FPU inst. */
 754 #endif
 755
 756         inst = lookup_exception_vector();
 757
 758         local_irq_enable();
 759         CHK_REMOTE_DEBUG(regs);
 760         force_sig(SIGILL, tsk);
 761         die_if_no_fixup("illegal slot instruction", regs, inst);
 762 }
 763
 764 asmlinkage void do_exception_error(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         long ex;
 770
 771         ex = lookup_exception_vector();
 772         die_if_kernel("exception", regs, ex);
 773 }
 774
 775 #if defined(CONFIG_SH_STANDARD_BIOS)
 776 void *gdb_vbr_vector;
 777
 778 static inline void __init gdb_vbr_init(void)
 779 {
 780         register unsigned long vbr;
 781
 782         /*
 783          * Read the old value of the VBR register to initialise
 784          * the vector through which debug and BIOS traps are
 785          * delegated by the Linux trap handler.
 786          */
 787         asm volatile("stc vbr, %0" : "=r" (vbr));
 788
 789         gdb_vbr_vector = (void *)(vbr + 0x100);
 790         printk("Setting GDB trap vector to 0x%08lx\n",
 791                (unsigned long)gdb_vbr_vector);
 792 }
 793 #endif
 794
 795 void __cpuinit per_cpu_trap_init(void)
 796 {
 797         extern void *vbr_base;
 798
 799 #ifdef CONFIG_SH_STANDARD_BIOS
 800         if (raw_smp_processor_id() == 0)
 801                 gdb_vbr_init();
 802 #endif
 803
 804         /* NOTE: The VBR value should be at P1
 805            (or P2, virtural "fixed" address space).
 806            It's definitely should not in physical address.  */
 807
 808         asm volatile("ldc       %0, vbr"
 809                      : /* no output */
 810                      : "r" (&vbr_base)
 811                      : "memory");
 812 }
 813
 814 void *set_exception_table_vec(unsigned int vec, void *handler)
 815 {
 816         extern void *exception_handling_table[];
 817         void *old_handler;
 818
 819         old_handler = exception_handling_table[vec];
 820         exception_handling_table[vec] = handler;
 821         return old_handler;
 822 }
 823
 824 void __init trap_init(void)
 825 {
 826         set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
 827         set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
 828
 829 #if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
 830     defined(CONFIG_SH_FPU_EMU)
 831         /*
 832          * For SH-4 lacking an FPU, treat floating point instructions as
 833          * reserved. They'll be handled in the math-emu case, or faulted on
 834          * otherwise.
 835          */
 836         set_exception_table_evt(0x800, do_reserved_inst);
 837         set_exception_table_evt(0x820, do_illegal_slot_inst);
 838 #elif defined(CONFIG_SH_FPU)
 839 #ifdef CONFIG_CPU_SUBTYPE_SHX3
 840         set_exception_table_evt(0xd80, fpu_state_restore_trap_handler);
 841         set_exception_table_evt(0xda0, fpu_state_restore_trap_handler);
 842 #else
 843         set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
 844         set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
 845 #endif
 846 #endif
 847
 848 #ifdef CONFIG_CPU_SH2
 849         set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
 850 #endif
 851 #ifdef CONFIG_CPU_SH2A
 852         set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
 853         set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
 854 #ifdef CONFIG_SH_FPU
 855         set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
 856 #endif
 857 #endif
 858
 859         /* Setup VBR for boot cpu */
 860         per_cpu_trap_init();
 861 }
 862
 863 void show_trace(struct task_struct *tsk, unsigned long *sp,
 864                 struct pt_regs *regs)
 865 {
 866         unsigned long addr;
 867
 868         if (regs && user_mode(regs))
 869                 return;
 870
 871         printk("\nCall trace: ");
 872 #ifdef CONFIG_KALLSYMS
 873         printk("\n");
 874 #endif
 875
 876         while (!kstack_end(sp)) {
 877                 addr = *sp++;
 878                 if (kernel_text_address(addr))
 879                         print_ip_sym(addr);
 880         }
 881
 882         printk("\n");
 883
 884         if (!tsk)
 885                 tsk = current;
 886
 887         debug_show_held_locks(tsk);
 888 }
 889
 890 void show_stack(struct task_struct *tsk, unsigned long *sp)
 891 {
 892         unsigned long stack;
 893
 894         if (!tsk)
 895                 tsk = current;
 896         if (tsk == current)
 897                 sp = (unsigned long *)current_stack_pointer;
 898         else
 899                 sp = (unsigned long *)tsk->thread.sp;
 900
 901         stack = (unsigned long)sp;
 902         dump_mem("Stack: ", stack, THREAD_SIZE +
 903                  (unsigned long)task_stack_page(tsk));
 904         show_trace(tsk, sp, NULL);
 905 }
 906
 907 void dump_stack(void)
 908 {
 909         show_stack(NULL, NULL);
 910 }
 911 EXPORT_SYMBOL(dump_stack);