arch/sh/kernel/traps_64.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/kernel/traps_64.c
   4  *
   5  * Copyright (C) 2000, 2001  Paolo Alberelli
   6  * Copyright (C) 2003, 2004  Paul Mundt
   7  * Copyright (C) 2003, 2004  Richard Curnow
   8  */
   9 #include <linux/sched.h>
  10 #include <linux/sched/debug.h>
  11 #include <linux/kernel.h>
  12 #include <linux/string.h>
  13 #include <linux/errno.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/timer.h>
  16 #include <linux/mm.h>
  17 #include <linux/smp.h>
  18 #include <linux/init.h>
  19 #include <linux/delay.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/kallsyms.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/sysctl.h>
  24 #include <linux/module.h>
  25 #include <linux/perf_event.h>
  26 #include <linux/uaccess.h>
  27 #include <asm/io.h>
  28 #include <asm/alignment.h>
  29 #include <asm/processor.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/fpu.h>
  32
  33 static int read_opcode(reg_size_t pc, insn_size_t *result_opcode, int from_user_mode)
  34 {
  35         int get_user_error;
  36         unsigned long aligned_pc;
  37         insn_size_t opcode;
  38
  39         if ((pc & 3) == 1) {
  40                 /* SHmedia */
  41                 aligned_pc = pc & ~3;
  42                 if (from_user_mode) {
  43                         if (!access_ok(aligned_pc, sizeof(insn_size_t))) {
  44                                 get_user_error = -EFAULT;
  45                         } else {
  46                                 get_user_error = __get_user(opcode, (insn_size_t *)aligned_pc);
  47                                 *result_opcode = opcode;
  48                         }
  49                         return get_user_error;
  50                 } else {
  51                         /* If the fault was in the kernel, we can either read
  52                          * this directly, or if not, we fault.
  53                         */
  54                         *result_opcode = *(insn_size_t *)aligned_pc;
  55                         return 0;
  56                 }
  57         } else if ((pc & 1) == 0) {
  58                 /* SHcompact */
  59                 /* TODO : provide handling for this.  We don't really support
  60                    user-mode SHcompact yet, and for a kernel fault, this would
  61                    have to come from a module built for SHcompact.  */
  62                 return -EFAULT;
  63         } else {
  64                 /* misaligned */
  65                 return -EFAULT;
  66         }
  67 }
  68
  69 static int address_is_sign_extended(__u64 a)
  70 {
  71         __u64 b;
  72 #if (NEFF == 32)
  73         b = (__u64)(__s64)(__s32)(a & 0xffffffffUL);
  74         return (b == a) ? 1 : 0;
  75 #else
  76 #error "Sign extend check only works for NEFF==32"
  77 #endif
  78 }
  79
  80 /* return -1 for fault, 0 for OK */
  81 static int generate_and_check_address(struct pt_regs *regs,
  82                                       insn_size_t opcode,
  83                                       int displacement_not_indexed,
  84                                       int width_shift,
  85                                       __u64 *address)
  86 {
  87         __u64 base_address, addr;
  88         int basereg;
  89
  90         switch (1 << width_shift) {
  91         case 1: inc_unaligned_byte_access(); break;
  92         case 2: inc_unaligned_word_access(); break;
  93         case 4: inc_unaligned_dword_access(); break;
  94         case 8: inc_unaligned_multi_access(); break;
  95         }
  96
  97         basereg = (opcode >> 20) & 0x3f;
  98         base_address = regs->regs[basereg];
  99         if (displacement_not_indexed) {
 100                 __s64 displacement;
 101                 displacement = (opcode >> 10) & 0x3ff;
 102                 displacement = sign_extend64(displacement, 9);
 103                 addr = (__u64)((__s64)base_address + (displacement << width_shift));
 104         } else {
 105                 __u64 offset;
 106                 int offsetreg;
 107                 offsetreg = (opcode >> 10) & 0x3f;
 108                 offset = regs->regs[offsetreg];
 109                 addr = base_address + offset;
 110         }
 111
 112         /* Check sign extended */
 113         if (!address_is_sign_extended(addr))
 114                 return -1;
 115
 116         /* Check accessible.  For misaligned access in the kernel, assume the
 117            address is always accessible (and if not, just fault when the
 118            load/store gets done.) */
 119         if (user_mode(regs)) {
 120                 inc_unaligned_user_access();
 121
 122                 if (addr >= TASK_SIZE)
 123                         return -1;
 124         } else
 125                 inc_unaligned_kernel_access();
 126
 127         *address = addr;
 128
 129         perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, addr);
 130         unaligned_fixups_notify(current, opcode, regs);
 131
 132         return 0;
 133 }
 134
 135 static void misaligned_kernel_word_load(__u64 address, int do_sign_extend, __u64 *result)
 136 {
 137         unsigned short x;
 138         unsigned char *p, *q;
 139         p = (unsigned char *) (int) address;
 140         q = (unsigned char *) &x;
 141         q[0] = p[0];
 142         q[1] = p[1];
 143
 144         if (do_sign_extend) {
 145                 *result = (__u64)(__s64) *(short *) &x;
 146         } else {
 147                 *result = (__u64) x;
 148         }
 149 }
 150
 151 static void misaligned_kernel_word_store(__u64 address, __u64 value)
 152 {
 153         unsigned short x;
 154         unsigned char *p, *q;
 155         p = (unsigned char *) (int) address;
 156         q = (unsigned char *) &x;
 157
 158         x = (__u16) value;
 159         p[0] = q[0];
 160         p[1] = q[1];
 161 }
 162
 163 static int misaligned_load(struct pt_regs *regs,
 164                            insn_size_t opcode,
 165                            int displacement_not_indexed,
 166                            int width_shift,
 167                            int do_sign_extend)
 168 {
 169         /* Return -1 for a fault, 0 for OK */
 170         int error;
 171         int destreg;
 172         __u64 address;
 173
 174         error = generate_and_check_address(regs, opcode,
 175                         displacement_not_indexed, width_shift, &address);
 176         if (error < 0)
 177                 return error;
 178
 179         destreg = (opcode >> 4) & 0x3f;
 180         if (user_mode(regs)) {
 181                 __u64 buffer;
 182
 183                 if (!access_ok((unsigned long) address, 1UL<<width_shift)) {
 184                         return -1;
 185                 }
 186
 187                 if (__copy_user(&buffer, (const void *)(int)address, (1 << width_shift)) > 0) {
 188                         return -1; /* fault */
 189                 }
 190                 switch (width_shift) {
 191                 case 1:
 192                         if (do_sign_extend) {
 193                                 regs->regs[destreg] = (__u64)(__s64) *(__s16 *) &buffer;
 194                         } else {
 195                                 regs->regs[destreg] = (__u64) *(__u16 *) &buffer;
 196                         }
 197                         break;
 198                 case 2:
 199                         regs->regs[destreg] = (__u64)(__s64) *(__s32 *) &buffer;
 200                         break;
 201                 case 3:
 202                         regs->regs[destreg] = buffer;
 203                         break;
 204                 default:
 205                         printk("Unexpected width_shift %d in misaligned_load, PC=%08lx\n",
 206                                 width_shift, (unsigned long) regs->pc);
 207                         break;
 208                 }
 209         } else {
 210                 /* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
 211                 __u64 lo, hi;
 212
 213                 switch (width_shift) {
 214                 case 1:
 215                         misaligned_kernel_word_load(address, do_sign_extend, &regs->regs[destreg]);
 216                         break;
 217                 case 2:
 218                         asm ("ldlo.l %1, 0, %0" : "=r" (lo) : "r" (address));
 219                         asm ("ldhi.l %1, 3, %0" : "=r" (hi) : "r" (address));
 220                         regs->regs[destreg] = lo | hi;
 221                         break;
 222                 case 3:
 223                         asm ("ldlo.q %1, 0, %0" : "=r" (lo) : "r" (address));
 224                         asm ("ldhi.q %1, 7, %0" : "=r" (hi) : "r" (address));
 225                         regs->regs[destreg] = lo | hi;
 226                         break;
 227
 228                 default:
 229                         printk("Unexpected width_shift %d in misaligned_load, PC=%08lx\n",
 230                                 width_shift, (unsigned long) regs->pc);
 231                         break;
 232                 }
 233         }
 234
 235         return 0;
 236 }
 237
 238 static int misaligned_store(struct pt_regs *regs,
 239                             insn_size_t opcode,
 240                             int displacement_not_indexed,
 241                             int width_shift)
 242 {
 243         /* Return -1 for a fault, 0 for OK */
 244         int error;
 245         int srcreg;
 246         __u64 address;
 247
 248         error = generate_and_check_address(regs, opcode,
 249                         displacement_not_indexed, width_shift, &address);
 250         if (error < 0)
 251                 return error;
 252
 253         srcreg = (opcode >> 4) & 0x3f;
 254         if (user_mode(regs)) {
 255                 __u64 buffer;
 256
 257                 if (!access_ok((unsigned long) address, 1UL<<width_shift)) {
 258                         return -1;
 259                 }
 260
 261                 switch (width_shift) {
 262                 case 1:
 263                         *(__u16 *) &buffer = (__u16) regs->regs[srcreg];
 264                         break;
 265                 case 2:
 266                         *(__u32 *) &buffer = (__u32) regs->regs[srcreg];
 267                         break;
 268                 case 3:
 269                         buffer = regs->regs[srcreg];
 270                         break;
 271                 default:
 272                         printk("Unexpected width_shift %d in misaligned_store, PC=%08lx\n",
 273                                 width_shift, (unsigned long) regs->pc);
 274                         break;
 275                 }
 276
 277                 if (__copy_user((void *)(int)address, &buffer, (1 << width_shift)) > 0) {
 278                         return -1; /* fault */
 279                 }
 280         } else {
 281                 /* kernel mode - we can take short cuts since if we fault, it's a genuine bug */
 282                 __u64 val = regs->regs[srcreg];
 283
 284                 switch (width_shift) {
 285                 case 1:
 286                         misaligned_kernel_word_store(address, val);
 287                         break;
 288                 case 2:
 289                         asm ("stlo.l %1, 0, %0" : : "r" (val), "r" (address));
 290                         asm ("sthi.l %1, 3, %0" : : "r" (val), "r" (address));
 291                         break;
 292                 case 3:
 293                         asm ("stlo.q %1, 0, %0" : : "r" (val), "r" (address));
 294                         asm ("sthi.q %1, 7, %0" : : "r" (val), "r" (address));
 295                         break;
 296
 297                 default:
 298                         printk("Unexpected width_shift %d in misaligned_store, PC=%08lx\n",
 299                                 width_shift, (unsigned long) regs->pc);
 300                         break;
 301                 }
 302         }
 303
 304         return 0;
 305 }
 306
 307 /* Never need to fix up misaligned FPU accesses within the kernel since that's a real
 308    error. */
 309 static int misaligned_fpu_load(struct pt_regs *regs,
 310                            insn_size_t opcode,
 311                            int displacement_not_indexed,
 312                            int width_shift,
 313                            int do_paired_load)
 314 {
 315         /* Return -1 for a fault, 0 for OK */
 316         int error;
 317         int destreg;
 318         __u64 address;
 319
 320         error = generate_and_check_address(regs, opcode,
 321                         displacement_not_indexed, width_shift, &address);
 322         if (error < 0)
 323                 return error;
 324
 325         destreg = (opcode >> 4) & 0x3f;
 326         if (user_mode(regs)) {
 327                 __u64 buffer;
 328                 __u32 buflo, bufhi;
 329
 330                 if (!access_ok((unsigned long) address, 1UL<<width_shift)) {
 331                         return -1;
 332                 }
 333
 334                 if (__copy_user(&buffer, (const void *)(int)address, (1 << width_shift)) > 0) {
 335                         return -1; /* fault */
 336                 }
 337                 /* 'current' may be the current owner of the FPU state, so
 338                    context switch the registers into memory so they can be
 339                    indexed by register number. */
 340                 if (last_task_used_math == current) {
 341                         enable_fpu();
 342                         save_fpu(current);
 343                         disable_fpu();
 344                         last_task_used_math = NULL;
 345                         regs->sr |= SR_FD;
 346                 }
 347
 348                 buflo = *(__u32*) &buffer;
 349                 bufhi = *(1 + (__u32*) &buffer);
 350
 351                 switch (width_shift) {
 352                 case 2:
 353                         current->thread.xstate->hardfpu.fp_regs[destreg] = buflo;
 354                         break;
 355                 case 3:
 356                         if (do_paired_load) {
 357                                 current->thread.xstate->hardfpu.fp_regs[destreg] = buflo;
 358                                 current->thread.xstate->hardfpu.fp_regs[destreg+1] = bufhi;
 359                         } else {
 360 #if defined(CONFIG_CPU_LITTLE_ENDIAN)
 361                                 current->thread.xstate->hardfpu.fp_regs[destreg] = bufhi;
 362                                 current->thread.xstate->hardfpu.fp_regs[destreg+1] = buflo;
 363 #else
 364                                 current->thread.xstate->hardfpu.fp_regs[destreg] = buflo;
 365                                 current->thread.xstate->hardfpu.fp_regs[destreg+1] = bufhi;
 366 #endif
 367                         }
 368                         break;
 369                 default:
 370                         printk("Unexpected width_shift %d in misaligned_fpu_load, PC=%08lx\n",
 371                                 width_shift, (unsigned long) regs->pc);
 372                         break;
 373                 }
 374                 return 0;
 375         } else {
 376                 die ("Misaligned FPU load inside kernel", regs, 0);
 377                 return -1;
 378         }
 379 }
 380
 381 static int misaligned_fpu_store(struct pt_regs *regs,
 382                            insn_size_t opcode,
 383                            int displacement_not_indexed,
 384                            int width_shift,
 385                            int do_paired_load)
 386 {
 387         /* Return -1 for a fault, 0 for OK */
 388         int error;
 389         int srcreg;
 390         __u64 address;
 391
 392         error = generate_and_check_address(regs, opcode,
 393                         displacement_not_indexed, width_shift, &address);
 394         if (error < 0)
 395                 return error;
 396
 397         srcreg = (opcode >> 4) & 0x3f;
 398         if (user_mode(regs)) {
 399                 __u64 buffer;
 400                 /* Initialise these to NaNs. */
 401                 __u32 buflo=0xffffffffUL, bufhi=0xffffffffUL;
 402
 403                 if (!access_ok((unsigned long) address, 1UL<<width_shift)) {
 404                         return -1;
 405                 }
 406
 407                 /* 'current' may be the current owner of the FPU state, so
 408                    context switch the registers into memory so they can be
 409                    indexed by register number. */
 410                 if (last_task_used_math == current) {
 411                         enable_fpu();
 412                         save_fpu(current);
 413                         disable_fpu();
 414                         last_task_used_math = NULL;
 415                         regs->sr |= SR_FD;
 416                 }
 417
 418                 switch (width_shift) {
 419                 case 2:
 420                         buflo = current->thread.xstate->hardfpu.fp_regs[srcreg];
 421                         break;
 422                 case 3:
 423                         if (do_paired_load) {
 424                                 buflo = current->thread.xstate->hardfpu.fp_regs[srcreg];
 425                                 bufhi = current->thread.xstate->hardfpu.fp_regs[srcreg+1];
 426                         } else {
 427 #if defined(CONFIG_CPU_LITTLE_ENDIAN)
 428                                 bufhi = current->thread.xstate->hardfpu.fp_regs[srcreg];
 429                                 buflo = current->thread.xstate->hardfpu.fp_regs[srcreg+1];
 430 #else
 431                                 buflo = current->thread.xstate->hardfpu.fp_regs[srcreg];
 432                                 bufhi = current->thread.xstate->hardfpu.fp_regs[srcreg+1];
 433 #endif
 434                         }
 435                         break;
 436                 default:
 437                         printk("Unexpected width_shift %d in misaligned_fpu_store, PC=%08lx\n",
 438                                 width_shift, (unsigned long) regs->pc);
 439                         break;
 440                 }
 441
 442                 *(__u32*) &buffer = buflo;
 443                 *(1 + (__u32*) &buffer) = bufhi;
 444                 if (__copy_user((void *)(int)address, &buffer, (1 << width_shift)) > 0) {
 445                         return -1; /* fault */
 446                 }
 447                 return 0;
 448         } else {
 449                 die ("Misaligned FPU load inside kernel", regs, 0);
 450                 return -1;
 451         }
 452 }
 453
 454 static int misaligned_fixup(struct pt_regs *regs)
 455 {
 456         insn_size_t opcode;
 457         int error;
 458         int major, minor;
 459         unsigned int user_action;
 460
 461         user_action = unaligned_user_action();
 462         if (!(user_action & UM_FIXUP))
 463                 return -1;
 464
 465         error = read_opcode(regs->pc, &opcode, user_mode(regs));
 466         if (error < 0) {
 467                 return error;
 468         }
 469         major = (opcode >> 26) & 0x3f;
 470         minor = (opcode >> 16) & 0xf;
 471
 472         switch (major) {
 473                 case (0x84>>2): /* LD.W */
 474                         error = misaligned_load(regs, opcode, 1, 1, 1);
 475                         break;
 476                 case (0xb0>>2): /* LD.UW */
 477                         error = misaligned_load(regs, opcode, 1, 1, 0);
 478                         break;
 479                 case (0x88>>2): /* LD.L */
 480                         error = misaligned_load(regs, opcode, 1, 2, 1);
 481                         break;
 482                 case (0x8c>>2): /* LD.Q */
 483                         error = misaligned_load(regs, opcode, 1, 3, 0);
 484                         break;
 485
 486                 case (0xa4>>2): /* ST.W */
 487                         error = misaligned_store(regs, opcode, 1, 1);
 488                         break;
 489                 case (0xa8>>2): /* ST.L */
 490                         error = misaligned_store(regs, opcode, 1, 2);
 491                         break;
 492                 case (0xac>>2): /* ST.Q */
 493                         error = misaligned_store(regs, opcode, 1, 3);
 494                         break;
 495
 496                 case (0x40>>2): /* indexed loads */
 497                         switch (minor) {
 498                                 case 0x1: /* LDX.W */
 499                                         error = misaligned_load(regs, opcode, 0, 1, 1);
 500                                         break;
 501                                 case 0x5: /* LDX.UW */
 502                                         error = misaligned_load(regs, opcode, 0, 1, 0);
 503                                         break;
 504                                 case 0x2: /* LDX.L */
 505                                         error = misaligned_load(regs, opcode, 0, 2, 1);
 506                                         break;
 507                                 case 0x3: /* LDX.Q */
 508                                         error = misaligned_load(regs, opcode, 0, 3, 0);
 509                                         break;
 510                                 default:
 511                                         error = -1;
 512                                         break;
 513                         }
 514                         break;
 515
 516                 case (0x60>>2): /* indexed stores */
 517                         switch (minor) {
 518                                 case 0x1: /* STX.W */
 519                                         error = misaligned_store(regs, opcode, 0, 1);
 520                                         break;
 521                                 case 0x2: /* STX.L */
 522                                         error = misaligned_store(regs, opcode, 0, 2);
 523                                         break;
 524                                 case 0x3: /* STX.Q */
 525                                         error = misaligned_store(regs, opcode, 0, 3);
 526                                         break;
 527                                 default:
 528                                         error = -1;
 529                                         break;
 530                         }
 531                         break;
 532
 533                 case (0x94>>2): /* FLD.S */
 534                         error = misaligned_fpu_load(regs, opcode, 1, 2, 0);
 535                         break;
 536                 case (0x98>>2): /* FLD.P */
 537                         error = misaligned_fpu_load(regs, opcode, 1, 3, 1);
 538                         break;
 539                 case (0x9c>>2): /* FLD.D */
 540                         error = misaligned_fpu_load(regs, opcode, 1, 3, 0);
 541                         break;
 542                 case (0x1c>>2): /* floating indexed loads */
 543                         switch (minor) {
 544                         case 0x8: /* FLDX.S */
 545                                 error = misaligned_fpu_load(regs, opcode, 0, 2, 0);
 546                                 break;
 547                         case 0xd: /* FLDX.P */
 548                                 error = misaligned_fpu_load(regs, opcode, 0, 3, 1);
 549                                 break;
 550                         case 0x9: /* FLDX.D */
 551                                 error = misaligned_fpu_load(regs, opcode, 0, 3, 0);
 552                                 break;
 553                         default:
 554                                 error = -1;
 555                                 break;
 556                         }
 557                         break;
 558                 case (0xb4>>2): /* FLD.S */
 559                         error = misaligned_fpu_store(regs, opcode, 1, 2, 0);
 560                         break;
 561                 case (0xb8>>2): /* FLD.P */
 562                         error = misaligned_fpu_store(regs, opcode, 1, 3, 1);
 563                         break;
 564                 case (0xbc>>2): /* FLD.D */
 565                         error = misaligned_fpu_store(regs, opcode, 1, 3, 0);
 566                         break;
 567                 case (0x3c>>2): /* floating indexed stores */
 568                         switch (minor) {
 569                         case 0x8: /* FSTX.S */
 570                                 error = misaligned_fpu_store(regs, opcode, 0, 2, 0);
 571                                 break;
 572                         case 0xd: /* FSTX.P */
 573                                 error = misaligned_fpu_store(regs, opcode, 0, 3, 1);
 574                                 break;
 575                         case 0x9: /* FSTX.D */
 576                                 error = misaligned_fpu_store(regs, opcode, 0, 3, 0);
 577                                 break;
 578                         default:
 579                                 error = -1;
 580                                 break;
 581                         }
 582                         break;
 583
 584                 default:
 585                         /* Fault */
 586                         error = -1;
 587                         break;
 588         }
 589
 590         if (error < 0) {
 591                 return error;
 592         } else {
 593                 regs->pc += 4; /* Skip the instruction that's just been emulated */
 594                 return 0;
 595         }
 596 }
 597
 598 static void do_unhandled_exception(int signr, char *str, unsigned long error,
 599                                    struct pt_regs *regs)
 600 {
 601         if (user_mode(regs))
 602                 force_sig(signr);
 603
 604         die_if_no_fixup(str, regs, error);
 605 }
 606
 607 #define DO_ERROR(signr, str, name) \
 608 asmlinkage void do_##name(unsigned long error_code, struct pt_regs *regs) \
 609 { \
 610         do_unhandled_exception(signr, str, error_code, regs); \
 611 }
 612
 613 DO_ERROR(SIGILL,  "illegal slot instruction", illegal_slot_inst)
 614 DO_ERROR(SIGSEGV, "address error (exec)", address_error_exec)
 615
 616 #if defined(CONFIG_SH64_ID2815_WORKAROUND)
 617
 618 #define OPCODE_INVALID      0
 619 #define OPCODE_USER_VALID   1
 620 #define OPCODE_PRIV_VALID   2
 621
 622 /* getcon/putcon - requires checking which control register is referenced. */
 623 #define OPCODE_CTRL_REG     3
 624
 625 /* Table of valid opcodes for SHmedia mode.
 626    Form a 10-bit value by concatenating the major/minor opcodes i.e.
 627    opcode[31:26,20:16].  The 6 MSBs of this value index into the following
 628    array.  The 4 LSBs select the bit-pair in the entry (bits 1:0 correspond to
 629    LSBs==4'b0000 etc). */
 630 static unsigned long shmedia_opcode_table[64] = {
 631         0x55554044,0x54445055,0x15141514,0x14541414,0x00000000,0x10001000,0x01110055,0x04050015,
 632         0x00000444,0xc0000000,0x44545515,0x40405555,0x55550015,0x10005555,0x55555505,0x04050000,
 633         0x00000555,0x00000404,0x00040445,0x15151414,0x00000000,0x00000000,0x00000000,0x00000000,
 634         0x00000055,0x40404444,0x00000404,0xc0009495,0x00000000,0x00000000,0x00000000,0x00000000,
 635         0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
 636         0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
 637         0x80005050,0x04005055,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,0x55555555,
 638         0x81055554,0x00000404,0x55555555,0x55555555,0x00000000,0x00000000,0x00000000,0x00000000
 639 };
 640
 641 /* Workaround SH5-101 cut2 silicon defect #2815 :
 642    in some situations, inter-mode branches from SHcompact -> SHmedia
 643    which should take ITLBMISS or EXECPROT exceptions at the target
 644    falsely take RESINST at the target instead. */
 645 void do_reserved_inst(unsigned long error_code, struct pt_regs *regs)
 646 {
 647         insn_size_t opcode = 0x6ff4fff0; /* guaranteed reserved opcode */
 648         unsigned long pc, aligned_pc;
 649         unsigned long index, shift;
 650         unsigned long major, minor, combined;
 651         unsigned long reserved_field;
 652         int opcode_state;
 653         int get_user_error;
 654         int signr = SIGILL;
 655         char *exception_name = "reserved_instruction";
 656
 657         pc = regs->pc;
 658
 659         /* SHcompact is not handled */
 660         if (unlikely((pc & 3) == 0))
 661                 goto out;
 662
 663         /* SHmedia : check for defect.  This requires executable vmas
 664            to be readable too. */
 665         aligned_pc = pc & ~3;
 666         if (!access_ok(aligned_pc, sizeof(insn_size_t)))
 667                 get_user_error = -EFAULT;
 668         else
 669                 get_user_error = __get_user(opcode, (insn_size_t *)aligned_pc);
 670
 671         if (get_user_error < 0) {
 672                 /*
 673                  * Error trying to read opcode.  This typically means a
 674                  * real fault, not a RESINST any more.  So change the
 675                  * codes.
 676                  */
 677                 exception_name = "address error (exec)";
 678                 signr = SIGSEGV;
 679                 goto out;
 680         }
 681
 682         /* These bits are currently reserved as zero in all valid opcodes */
 683         reserved_field = opcode & 0xf;
 684         if (unlikely(reserved_field))
 685                 goto out;       /* invalid opcode */
 686
 687         major = (opcode >> 26) & 0x3f;
 688         minor = (opcode >> 16) & 0xf;
 689         combined = (major << 4) | minor;
 690         index = major;
 691         shift = minor << 1;
 692         opcode_state = (shmedia_opcode_table[index] >> shift) & 0x3;
 693         switch (opcode_state) {
 694         case OPCODE_INVALID:
 695                 /* Trap. */
 696                 break;
 697         case OPCODE_USER_VALID:
 698                 /*
 699                  * Restart the instruction: the branch to the instruction
 700                  * will now be from an RTE not from SHcompact so the
 701                  * silicon defect won't be triggered.
 702                  */
 703                 return;
 704         case OPCODE_PRIV_VALID:
 705                 if (!user_mode(regs)) {
 706                         /*
 707                          * Should only ever get here if a module has
 708                          * SHcompact code inside it. If so, the same fix
 709                          * up is needed.
 710                          */
 711                         return; /* same reason */
 712                 }
 713
 714                 /*
 715                  * Otherwise, user mode trying to execute a privileged
 716                  * instruction - fall through to trap.
 717                  */
 718                 break;
 719         case OPCODE_CTRL_REG:
 720                 /* If in privileged mode, return as above. */
 721                 if (!user_mode(regs))
 722                         return;
 723
 724                 /* In user mode ... */
 725                 if (combined == 0x9f) { /* GETCON */
 726                         unsigned long regno = (opcode >> 20) & 0x3f;
 727
 728                         if (regno >= 62)
 729                                 return;
 730
 731                         /* reserved/privileged control register => trap */
 732                 } else if (combined == 0x1bf) { /* PUTCON */
 733                         unsigned long regno = (opcode >> 4) & 0x3f;
 734
 735                         if (regno >= 62)
 736                                 return;
 737
 738                         /* reserved/privileged control register => trap */
 739                 }
 740
 741                 break;
 742         default:
 743                 /* Fall through to trap. */
 744                 break;
 745         }
 746
 747 out:
 748         do_unhandled_exception(signr, exception_name, error_code, regs);
 749 }
 750
 751 #else /* CONFIG_SH64_ID2815_WORKAROUND */
 752
 753 /* If the workaround isn't needed, this is just a straightforward reserved
 754    instruction */
 755 DO_ERROR(SIGILL, "reserved instruction", reserved_inst)
 756
 757 #endif /* CONFIG_SH64_ID2815_WORKAROUND */
 758
 759 /* Called with interrupts disabled */
 760 asmlinkage void do_exception_error(unsigned long ex, struct pt_regs *regs)
 761 {
 762         die_if_kernel("exception", regs, ex);
 763 }
 764
 765 asmlinkage int do_unknown_trapa(unsigned long scId, struct pt_regs *regs)
 766 {
 767         /* Syscall debug */
 768         printk("System call ID error: [0x1#args:8 #syscall:16  0x%lx]\n", scId);
 769
 770         die_if_kernel("unknown trapa", regs, scId);
 771
 772         return -ENOSYS;
 773 }
 774
 775 /* Implement misaligned load/store handling for kernel (and optionally for user
 776    mode too).  Limitation : only SHmedia mode code is handled - there is no
 777    handling at all for misaligned accesses occurring in SHcompact code yet. */
 778
 779 asmlinkage void do_address_error_load(unsigned long error_code, struct pt_regs *regs)
 780 {
 781         if (misaligned_fixup(regs) < 0)
 782                 do_unhandled_exception(SIGSEGV, "address error(load)",
 783                                        error_code, regs);
 784 }
 785
 786 asmlinkage void do_address_error_store(unsigned long error_code, struct pt_regs *regs)
 787 {
 788         if (misaligned_fixup(regs) < 0)
 789                 do_unhandled_exception(SIGSEGV, "address error(store)",
 790                                 error_code, regs);
 791 }
 792
 793 asmlinkage void do_debug_interrupt(unsigned long code, struct pt_regs *regs)
 794 {
 795         u64 peek_real_address_q(u64 addr);
 796         u64 poke_real_address_q(u64 addr, u64 val);
 797         unsigned long long DM_EXP_CAUSE_PHY = 0x0c100010;
 798         unsigned long long exp_cause;
 799         /* It's not worth ioremapping the debug module registers for the amount
 800            of access we make to them - just go direct to their physical
 801            addresses. */
 802         exp_cause = peek_real_address_q(DM_EXP_CAUSE_PHY);
 803         if (exp_cause & ~4)
 804                 printk("DM.EXP_CAUSE had unexpected bits set (=%08lx)\n",
 805                         (unsigned long)(exp_cause & 0xffffffff));
 806         show_state();
 807         /* Clear all DEBUGINT causes */
 808         poke_real_address_q(DM_EXP_CAUSE_PHY, 0x0);
 809 }
 810
 811 void per_cpu_trap_init(void)
 812 {
 813         /* Nothing to do for now, VBR initialization later. */
 814 }