arch/powerpc/lib/sstep.c

   1 /*
   2  * Single-step support.
   3  *
   4  * Copyright (C) 2004 Paul Mackerras <paulus@au.ibm.com>, IBM
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/kprobes.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/prefetch.h>
  15 #include <asm/sstep.h>
  16 #include <asm/processor.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/cputable.h>
  19
  20 extern char system_call_common[];
  21
  22 #ifdef CONFIG_PPC64
  23 /* Bits in SRR1 that are copied from MSR */
  24 #define MSR_MASK        0xffffffff87c0ffffUL
  25 #else
  26 #define MSR_MASK        0x87c0ffff
  27 #endif
  28
  29 /* Bits in XER */
  30 #define XER_SO          0x80000000U
  31 #define XER_OV          0x40000000U
  32 #define XER_CA          0x20000000U
  33
  34 #ifdef CONFIG_PPC_FPU
  35 /*
  36  * Functions in ldstfp.S
  37  */
  38 extern int do_lfs(int rn, unsigned long ea);
  39 extern int do_lfd(int rn, unsigned long ea);
  40 extern int do_stfs(int rn, unsigned long ea);
  41 extern int do_stfd(int rn, unsigned long ea);
  42 extern int do_lvx(int rn, unsigned long ea);
  43 extern int do_stvx(int rn, unsigned long ea);
  44 extern int do_lxvd2x(int rn, unsigned long ea);
  45 extern int do_stxvd2x(int rn, unsigned long ea);
  46 #endif
  47
  48 /*
  49  * Emulate the truncation of 64 bit values in 32-bit mode.
  50  */
  51 static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)
  52 {
  53 #ifdef __powerpc64__
  54         if ((msr & MSR_64BIT) == 0)
  55                 val &= 0xffffffffUL;
  56 #endif
  57         return val;
  58 }
  59
  60 /*
  61  * Determine whether a conditional branch instruction would branch.
  62  */
  63 static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
  64 {
  65         unsigned int bo = (instr >> 21) & 0x1f;
  66         unsigned int bi;
  67
  68         if ((bo & 4) == 0) {
  69                 /* decrement counter */
  70                 --regs->ctr;
  71                 if (((bo >> 1) & 1) ^ (regs->ctr == 0))
  72                         return 0;
  73         }
  74         if ((bo & 0x10) == 0) {
  75                 /* check bit from CR */
  76                 bi = (instr >> 16) & 0x1f;
  77                 if (((regs->ccr >> (31 - bi)) & 1) != ((bo >> 3) & 1))
  78                         return 0;
  79         }
  80         return 1;
  81 }
  82
  83
  84 static long __kprobes address_ok(struct pt_regs *regs, unsigned long ea, int nb)
  85 {
  86         if (!user_mode(regs))
  87                 return 1;
  88         return __access_ok(ea, nb, USER_DS);
  89 }
  90
  91 /*
  92  * Calculate effective address for a D-form instruction
  93  */
  94 static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs)
  95 {
  96         int ra;
  97         unsigned long ea;
  98
  99         ra = (instr >> 16) & 0x1f;
 100         ea = (signed short) instr;              /* sign-extend */
 101         if (ra) {
 102                 ea += regs->gpr[ra];
 103                 if (instr & 0x04000000) {               /* update forms */
 104                         if ((instr>>26) != 47)          /* stmw is not an update form */
 105                                 regs->gpr[ra] = ea;
 106                 }
 107         }
 108
 109         return truncate_if_32bit(regs->msr, ea);
 110 }
 111
 112 #ifdef __powerpc64__
 113 /*
 114  * Calculate effective address for a DS-form instruction
 115  */
 116 static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *regs)
 117 {
 118         int ra;
 119         unsigned long ea;
 120
 121         ra = (instr >> 16) & 0x1f;
 122         ea = (signed short) (instr & ~3);       /* sign-extend */
 123         if (ra) {
 124                 ea += regs->gpr[ra];
 125                 if ((instr & 3) == 1)           /* update forms */
 126                         regs->gpr[ra] = ea;
 127         }
 128
 129         return truncate_if_32bit(regs->msr, ea);
 130 }
 131 #endif /* __powerpc64 */
 132
 133 /*
 134  * Calculate effective address for an X-form instruction
 135  */
 136 static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs,
 137                                      int do_update)
 138 {
 139         int ra, rb;
 140         unsigned long ea;
 141
 142         ra = (instr >> 16) & 0x1f;
 143         rb = (instr >> 11) & 0x1f;
 144         ea = regs->gpr[rb];
 145         if (ra) {
 146                 ea += regs->gpr[ra];
 147                 if (do_update)          /* update forms */
 148                         regs->gpr[ra] = ea;
 149         }
 150
 151         return truncate_if_32bit(regs->msr, ea);
 152 }
 153
 154 /*
 155  * Return the largest power of 2, not greater than sizeof(unsigned long),
 156  * such that x is a multiple of it.
 157  */
 158 static inline unsigned long max_align(unsigned long x)
 159 {
 160         x |= sizeof(unsigned long);
 161         return x & -x;          /* isolates rightmost bit */
 162 }
 163
 164
 165 static inline unsigned long byterev_2(unsigned long x)
 166 {
 167         return ((x >> 8) & 0xff) | ((x & 0xff) << 8);
 168 }
 169
 170 static inline unsigned long byterev_4(unsigned long x)
 171 {
 172         return ((x >> 24) & 0xff) | ((x >> 8) & 0xff00) |
 173                 ((x & 0xff00) << 8) | ((x & 0xff) << 24);
 174 }
 175
 176 #ifdef __powerpc64__
 177 static inline unsigned long byterev_8(unsigned long x)
 178 {
 179         return (byterev_4(x) << 32) | byterev_4(x >> 32);
 180 }
 181 #endif
 182
 183 static int __kprobes read_mem_aligned(unsigned long *dest, unsigned long ea,
 184                                       int nb)
 185 {
 186         int err = 0;
 187         unsigned long x = 0;
 188
 189         switch (nb) {
 190         case 1:
 191                 err = __get_user(x, (unsigned char __user *) ea);
 192                 break;
 193         case 2:
 194                 err = __get_user(x, (unsigned short __user *) ea);
 195                 break;
 196         case 4:
 197                 err = __get_user(x, (unsigned int __user *) ea);
 198                 break;
 199 #ifdef __powerpc64__
 200         case 8:
 201                 err = __get_user(x, (unsigned long __user *) ea);
 202                 break;
 203 #endif
 204         }
 205         if (!err)
 206                 *dest = x;
 207         return err;
 208 }
 209
 210 static int __kprobes read_mem_unaligned(unsigned long *dest, unsigned long ea,
 211                                         int nb, struct pt_regs *regs)
 212 {
 213         int err;
 214         unsigned long x, b, c;
 215 #ifdef __LITTLE_ENDIAN__
 216         int len = nb; /* save a copy of the length for byte reversal */
 217 #endif
 218
 219         /* unaligned, do this in pieces */
 220         x = 0;
 221         for (; nb > 0; nb -= c) {
 222 #ifdef __LITTLE_ENDIAN__
 223                 c = 1;
 224 #endif
 225 #ifdef __BIG_ENDIAN__
 226                 c = max_align(ea);
 227 #endif
 228                 if (c > nb)
 229                         c = max_align(nb);
 230                 err = read_mem_aligned(&b, ea, c);
 231                 if (err)
 232                         return err;
 233                 x = (x << (8 * c)) + b;
 234                 ea += c;
 235         }
 236 #ifdef __LITTLE_ENDIAN__
 237         switch (len) {
 238         case 2:
 239                 *dest = byterev_2(x);
 240                 break;
 241         case 4:
 242                 *dest = byterev_4(x);
 243                 break;
 244 #ifdef __powerpc64__
 245         case 8:
 246                 *dest = byterev_8(x);
 247                 break;
 248 #endif
 249         }
 250 #endif
 251 #ifdef __BIG_ENDIAN__
 252         *dest = x;
 253 #endif
 254         return 0;
 255 }
 256
 257 /*
 258  * Read memory at address ea for nb bytes, return 0 for success
 259  * or -EFAULT if an error occurred.
 260  */
 261 static int __kprobes read_mem(unsigned long *dest, unsigned long ea, int nb,
 262                               struct pt_regs *regs)
 263 {
 264         if (!address_ok(regs, ea, nb))
 265                 return -EFAULT;
 266         if ((ea & (nb - 1)) == 0)
 267                 return read_mem_aligned(dest, ea, nb);
 268         return read_mem_unaligned(dest, ea, nb, regs);
 269 }
 270
 271 static int __kprobes write_mem_aligned(unsigned long val, unsigned long ea,
 272                                        int nb)
 273 {
 274         int err = 0;
 275
 276         switch (nb) {
 277         case 1:
 278                 err = __put_user(val, (unsigned char __user *) ea);
 279                 break;
 280         case 2:
 281                 err = __put_user(val, (unsigned short __user *) ea);
 282                 break;
 283         case 4:
 284                 err = __put_user(val, (unsigned int __user *) ea);
 285                 break;
 286 #ifdef __powerpc64__
 287         case 8:
 288                 err = __put_user(val, (unsigned long __user *) ea);
 289                 break;
 290 #endif
 291         }
 292         return err;
 293 }
 294
 295 static int __kprobes write_mem_unaligned(unsigned long val, unsigned long ea,
 296                                          int nb, struct pt_regs *regs)
 297 {
 298         int err;
 299         unsigned long c;
 300
 301 #ifdef __LITTLE_ENDIAN__
 302         switch (nb) {
 303         case 2:
 304                 val = byterev_2(val);
 305                 break;
 306         case 4:
 307                 val = byterev_4(val);
 308                 break;
 309 #ifdef __powerpc64__
 310         case 8:
 311                 val = byterev_8(val);
 312                 break;
 313 #endif
 314         }
 315 #endif
 316         /* unaligned or little-endian, do this in pieces */
 317         for (; nb > 0; nb -= c) {
 318 #ifdef __LITTLE_ENDIAN__
 319                 c = 1;
 320 #endif
 321 #ifdef __BIG_ENDIAN__
 322                 c = max_align(ea);
 323 #endif
 324                 if (c > nb)
 325                         c = max_align(nb);
 326                 err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
 327                 if (err)
 328                         return err;
 329                 ea += c;
 330         }
 331         return 0;
 332 }
 333
 334 /*
 335  * Write memory at address ea for nb bytes, return 0 for success
 336  * or -EFAULT if an error occurred.
 337  */
 338 static int __kprobes write_mem(unsigned long val, unsigned long ea, int nb,
 339                                struct pt_regs *regs)
 340 {
 341         if (!address_ok(regs, ea, nb))
 342                 return -EFAULT;
 343         if ((ea & (nb - 1)) == 0)
 344                 return write_mem_aligned(val, ea, nb);
 345         return write_mem_unaligned(val, ea, nb, regs);
 346 }
 347
 348 #ifdef CONFIG_PPC_FPU
 349 /*
 350  * Check the address and alignment, and call func to do the actual
 351  * load or store.
 352  */
 353 static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long),
 354                                 unsigned long ea, int nb,
 355                                 struct pt_regs *regs)
 356 {
 357         int err;
 358         union {
 359                 double dbl;
 360                 unsigned long ul[2];
 361                 struct {
 362 #ifdef __BIG_ENDIAN__
 363                         unsigned _pad_;
 364                         unsigned word;
 365 #endif
 366 #ifdef __LITTLE_ENDIAN__
 367                         unsigned word;
 368                         unsigned _pad_;
 369 #endif
 370                 } single;
 371         } data;
 372         unsigned long ptr;
 373
 374         if (!address_ok(regs, ea, nb))
 375                 return -EFAULT;
 376         if ((ea & 3) == 0)
 377                 return (*func)(rn, ea);
 378         ptr = (unsigned long) &data.ul;
 379         if (sizeof(unsigned long) == 8 || nb == 4) {
 380                 err = read_mem_unaligned(&data.ul[0], ea, nb, regs);
 381                 if (nb == 4)
 382                         ptr = (unsigned long)&(data.single.word);
 383         } else {
 384                 /* reading a double on 32-bit */
 385                 err = read_mem_unaligned(&data.ul[0], ea, 4, regs);
 386                 if (!err)
 387                         err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs);
 388         }
 389         if (err)
 390                 return err;
 391         return (*func)(rn, ptr);
 392 }
 393
 394 static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long),
 395                                  unsigned long ea, int nb,
 396                                  struct pt_regs *regs)
 397 {
 398         int err;
 399         union {
 400                 double dbl;
 401                 unsigned long ul[2];
 402                 struct {
 403 #ifdef __BIG_ENDIAN__
 404                         unsigned _pad_;
 405                         unsigned word;
 406 #endif
 407 #ifdef __LITTLE_ENDIAN__
 408                         unsigned word;
 409                         unsigned _pad_;
 410 #endif
 411                 } single;
 412         } data;
 413         unsigned long ptr;
 414
 415         if (!address_ok(regs, ea, nb))
 416                 return -EFAULT;
 417         if ((ea & 3) == 0)
 418                 return (*func)(rn, ea);
 419         ptr = (unsigned long) &data.ul[0];
 420         if (sizeof(unsigned long) == 8 || nb == 4) {
 421                 if (nb == 4)
 422                         ptr = (unsigned long)&(data.single.word);
 423                 err = (*func)(rn, ptr);
 424                 if (err)
 425                         return err;
 426                 err = write_mem_unaligned(data.ul[0], ea, nb, regs);
 427         } else {
 428                 /* writing a double on 32-bit */
 429                 err = (*func)(rn, ptr);
 430                 if (err)
 431                         return err;
 432                 err = write_mem_unaligned(data.ul[0], ea, 4, regs);
 433                 if (!err)
 434                         err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs);
 435         }
 436         return err;
 437 }
 438 #endif
 439
 440 #ifdef CONFIG_ALTIVEC
 441 /* For Altivec/VMX, no need to worry about alignment */
 442 static int __kprobes do_vec_load(int rn, int (*func)(int, unsigned long),
 443                                  unsigned long ea, struct pt_regs *regs)
 444 {
 445         if (!address_ok(regs, ea & ~0xfUL, 16))
 446                 return -EFAULT;
 447         return (*func)(rn, ea);
 448 }
 449
 450 static int __kprobes do_vec_store(int rn, int (*func)(int, unsigned long),
 451                                   unsigned long ea, struct pt_regs *regs)
 452 {
 453         if (!address_ok(regs, ea & ~0xfUL, 16))
 454                 return -EFAULT;
 455         return (*func)(rn, ea);
 456 }
 457 #endif /* CONFIG_ALTIVEC */
 458
 459 #ifdef CONFIG_VSX
 460 static int __kprobes do_vsx_load(int rn, int (*func)(int, unsigned long),
 461                                  unsigned long ea, struct pt_regs *regs)
 462 {
 463         int err;
 464         unsigned long val[2];
 465
 466         if (!address_ok(regs, ea, 16))
 467                 return -EFAULT;
 468         if ((ea & 3) == 0)
 469                 return (*func)(rn, ea);
 470         err = read_mem_unaligned(&val[0], ea, 8, regs);
 471         if (!err)
 472                 err = read_mem_unaligned(&val[1], ea + 8, 8, regs);
 473         if (!err)
 474                 err = (*func)(rn, (unsigned long) &val[0]);
 475         return err;
 476 }
 477
 478 static int __kprobes do_vsx_store(int rn, int (*func)(int, unsigned long),
 479                                  unsigned long ea, struct pt_regs *regs)
 480 {
 481         int err;
 482         unsigned long val[2];
 483
 484         if (!address_ok(regs, ea, 16))
 485                 return -EFAULT;
 486         if ((ea & 3) == 0)
 487                 return (*func)(rn, ea);
 488         err = (*func)(rn, (unsigned long) &val[0]);
 489         if (err)
 490                 return err;
 491         err = write_mem_unaligned(val[0], ea, 8, regs);
 492         if (!err)
 493                 err = write_mem_unaligned(val[1], ea + 8, 8, regs);
 494         return err;
 495 }
 496 #endif /* CONFIG_VSX */
 497
 498 #define __put_user_asmx(x, addr, err, op, cr)           \
 499         __asm__ __volatile__(                           \
 500                 "1:     " op " %2,0,%3\n"               \
 501                 "       mfcr    %1\n"                   \
 502                 "2:\n"                                  \
 503                 ".section .fixup,\"ax\"\n"              \
 504                 "3:     li      %0,%4\n"                \
 505                 "       b       2b\n"                   \
 506                 ".previous\n"                           \
 507                 ".section __ex_table,\"a\"\n"           \
 508                         PPC_LONG_ALIGN "\n"             \
 509                         PPC_LONG "1b,3b\n"              \
 510                 ".previous"                             \
 511                 : "=r" (err), "=r" (cr)                 \
 512                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err))
 513
 514 #define __get_user_asmx(x, addr, err, op)               \
 515         __asm__ __volatile__(                           \
 516                 "1:     "op" %1,0,%2\n"                 \
 517                 "2:\n"                                  \
 518                 ".section .fixup,\"ax\"\n"              \
 519                 "3:     li      %0,%3\n"                \
 520                 "       b       2b\n"                   \
 521                 ".previous\n"                           \
 522                 ".section __ex_table,\"a\"\n"           \
 523                         PPC_LONG_ALIGN "\n"             \
 524                         PPC_LONG "1b,3b\n"              \
 525                 ".previous"                             \
 526                 : "=r" (err), "=r" (x)                  \
 527                 : "r" (addr), "i" (-EFAULT), "0" (err))
 528
 529 #define __cacheop_user_asmx(addr, err, op)              \
 530         __asm__ __volatile__(                           \
 531                 "1:     "op" 0,%1\n"                    \
 532                 "2:\n"                                  \
 533                 ".section .fixup,\"ax\"\n"              \
 534                 "3:     li      %0,%3\n"                \
 535                 "       b       2b\n"                   \
 536                 ".previous\n"                           \
 537                 ".section __ex_table,\"a\"\n"           \
 538                         PPC_LONG_ALIGN "\n"             \
 539                         PPC_LONG "1b,3b\n"              \
 540                 ".previous"                             \
 541                 : "=r" (err)                            \
 542                 : "r" (addr), "i" (-EFAULT), "0" (err))
 543
 544 static void __kprobes set_cr0(struct pt_regs *regs, int rd)
 545 {
 546         long val = regs->gpr[rd];
 547
 548         regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);
 549 #ifdef __powerpc64__
 550         if (!(regs->msr & MSR_64BIT))
 551                 val = (int) val;
 552 #endif
 553         if (val < 0)
 554                 regs->ccr |= 0x80000000;
 555         else if (val > 0)
 556                 regs->ccr |= 0x40000000;
 557         else
 558                 regs->ccr |= 0x20000000;
 559 }
 560
 561 static void __kprobes add_with_carry(struct pt_regs *regs, int rd,
 562                                      unsigned long val1, unsigned long val2,
 563                                      unsigned long carry_in)
 564 {
 565         unsigned long val = val1 + val2;
 566
 567         if (carry_in)
 568                 ++val;
 569         regs->gpr[rd] = val;
 570 #ifdef __powerpc64__
 571         if (!(regs->msr & MSR_64BIT)) {
 572                 val = (unsigned int) val;
 573                 val1 = (unsigned int) val1;
 574         }
 575 #endif
 576         if (val < val1 || (carry_in && val == val1))
 577                 regs->xer |= XER_CA;
 578         else
 579                 regs->xer &= ~XER_CA;
 580 }
 581
 582 static void __kprobes do_cmp_signed(struct pt_regs *regs, long v1, long v2,
 583                                     int crfld)
 584 {
 585         unsigned int crval, shift;
 586
 587         crval = (regs->xer >> 31) & 1;          /* get SO bit */
 588         if (v1 < v2)
 589                 crval |= 8;
 590         else if (v1 > v2)
 591                 crval |= 4;
 592         else
 593                 crval |= 2;
 594         shift = (7 - crfld) * 4;
 595         regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
 596 }
 597
 598 static void __kprobes do_cmp_unsigned(struct pt_regs *regs, unsigned long v1,
 599                                       unsigned long v2, int crfld)
 600 {
 601         unsigned int crval, shift;
 602
 603         crval = (regs->xer >> 31) & 1;          /* get SO bit */
 604         if (v1 < v2)
 605                 crval |= 8;
 606         else if (v1 > v2)
 607                 crval |= 4;
 608         else
 609                 crval |= 2;
 610         shift = (7 - crfld) * 4;
 611         regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
 612 }
 613
 614 /*
 615  * Elements of 32-bit rotate and mask instructions.
 616  */
 617 #define MASK32(mb, me)  ((0xffffffffUL >> (mb)) + \
 618                          ((signed long)-0x80000000L >> (me)) + ((me) >= (mb)))
 619 #ifdef __powerpc64__
 620 #define MASK64_L(mb)    (~0UL >> (mb))
 621 #define MASK64_R(me)    ((signed long)-0x8000000000000000L >> (me))
 622 #define MASK64(mb, me)  (MASK64_L(mb) + MASK64_R(me) + ((me) >= (mb)))
 623 #define DATA32(x)       (((x) & 0xffffffffUL) | (((x) & 0xffffffffUL) << 32))
 624 #else
 625 #define DATA32(x)       (x)
 626 #endif
 627 #define ROTATE(x, n)    ((n) ? (((x) << (n)) | ((x) >> (8 * sizeof(long) - (n)))) : (x))
 628
 629 /*
 630  * Emulate instructions that cause a transfer of control,
 631  * loads and stores, and a few other instructions.
 632  * Returns 1 if the step was emulated, 0 if not,
 633  * or -1 if the instruction is one that should not be stepped,
 634  * such as an rfid, or a mtmsrd that would clear MSR_RI.
 635  */
 636 int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 637 {
 638         unsigned int opcode, ra, rb, rd, spr, u;
 639         unsigned long int imm;
 640         unsigned long int val, val2;
 641         unsigned long int ea;
 642         unsigned int cr, mb, me, sh;
 643         int err;
 644         unsigned long old_ra, val3;
 645         long ival;
 646
 647         opcode = instr >> 26;
 648         switch (opcode) {
 649         case 16:        /* bc */
 650                 imm = (signed short)(instr & 0xfffc);
 651                 if ((instr & 2) == 0)
 652                         imm += regs->nip;
 653                 regs->nip += 4;
 654                 regs->nip = truncate_if_32bit(regs->msr, regs->nip);
 655                 if (instr & 1)
 656                         regs->link = regs->nip;
 657                 if (branch_taken(instr, regs))
 658                         regs->nip = truncate_if_32bit(regs->msr, imm);
 659                 return 1;
 660 #ifdef CONFIG_PPC64
 661         case 17:        /* sc */
 662                 /*
 663                  * N.B. this uses knowledge about how the syscall
 664                  * entry code works.  If that is changed, this will
 665                  * need to be changed also.
 666                  */
 667                 if (regs->gpr[0] == 0x1ebe &&
 668                     cpu_has_feature(CPU_FTR_REAL_LE)) {
 669                         regs->msr ^= MSR_LE;
 670                         goto instr_done;
 671                 }
 672                 regs->gpr[9] = regs->gpr[13];
 673                 regs->gpr[10] = MSR_KERNEL;
 674                 regs->gpr[11] = regs->nip + 4;
 675                 regs->gpr[12] = regs->msr & MSR_MASK;
 676                 regs->gpr[13] = (unsigned long) get_paca();
 677                 regs->nip = (unsigned long) &system_call_common;
 678                 regs->msr = MSR_KERNEL;
 679                 return 1;
 680 #endif
 681         case 18:        /* b */
 682                 imm = instr & 0x03fffffc;
 683                 if (imm & 0x02000000)
 684                         imm -= 0x04000000;
 685                 if ((instr & 2) == 0)
 686                         imm += regs->nip;
 687                 if (instr & 1)
 688                         regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);
 689                 imm = truncate_if_32bit(regs->msr, imm);
 690                 regs->nip = imm;
 691                 return 1;
 692         case 19:
 693                 switch ((instr >> 1) & 0x3ff) {
 694                 case 16:        /* bclr */
 695                 case 528:       /* bcctr */
 696                         imm = (instr & 0x400)? regs->ctr: regs->link;
 697                         regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
 698                         imm = truncate_if_32bit(regs->msr, imm);
 699                         if (instr & 1)
 700                                 regs->link = regs->nip;
 701                         if (branch_taken(instr, regs))
 702                                 regs->nip = imm;
 703                         return 1;
 704
 705                 case 18:        /* rfid, scary */
 706                         return -1;
 707
 708                 case 150:       /* isync */
 709                         isync();
 710                         goto instr_done;
 711
 712                 case 33:        /* crnor */
 713                 case 129:       /* crandc */
 714                 case 193:       /* crxor */
 715                 case 225:       /* crnand */
 716                 case 257:       /* crand */
 717                 case 289:       /* creqv */
 718                 case 417:       /* crorc */
 719                 case 449:       /* cror */
 720                         ra = (instr >> 16) & 0x1f;
 721                         rb = (instr >> 11) & 0x1f;
 722                         rd = (instr >> 21) & 0x1f;
 723                         ra = (regs->ccr >> (31 - ra)) & 1;
 724                         rb = (regs->ccr >> (31 - rb)) & 1;
 725                         val = (instr >> (6 + ra * 2 + rb)) & 1;
 726                         regs->ccr = (regs->ccr & ~(1UL << (31 - rd))) |
 727                                 (val << (31 - rd));
 728                         goto instr_done;
 729                 }
 730                 break;
 731         case 31:
 732                 switch ((instr >> 1) & 0x3ff) {
 733                 case 598:       /* sync */
 734 #ifdef __powerpc64__
 735                         switch ((instr >> 21) & 3) {
 736                         case 1:         /* lwsync */
 737                                 asm volatile("lwsync" : : : "memory");
 738                                 goto instr_done;
 739                         case 2:         /* ptesync */
 740                                 asm volatile("ptesync" : : : "memory");
 741                                 goto instr_done;
 742                         }
 743 #endif
 744                         mb();
 745                         goto instr_done;
 746
 747                 case 854:       /* eieio */
 748                         eieio();
 749                         goto instr_done;
 750                 }
 751                 break;
 752         }
 753
 754         /* Following cases refer to regs->gpr[], so we need all regs */
 755         if (!FULL_REGS(regs))
 756                 return 0;
 757
 758         rd = (instr >> 21) & 0x1f;
 759         ra = (instr >> 16) & 0x1f;
 760         rb = (instr >> 11) & 0x1f;
 761
 762         switch (opcode) {
 763         case 7:         /* mulli */
 764                 regs->gpr[rd] = regs->gpr[ra] * (short) instr;
 765                 goto instr_done;
 766
 767         case 8:         /* subfic */
 768                 imm = (short) instr;
 769                 add_with_carry(regs, rd, ~regs->gpr[ra], imm, 1);
 770                 goto instr_done;
 771
 772         case 10:        /* cmpli */
 773                 imm = (unsigned short) instr;
 774                 val = regs->gpr[ra];
 775 #ifdef __powerpc64__
 776                 if ((rd & 1) == 0)
 777                         val = (unsigned int) val;
 778 #endif
 779                 do_cmp_unsigned(regs, val, imm, rd >> 2);
 780                 goto instr_done;
 781
 782         case 11:        /* cmpi */
 783                 imm = (short) instr;
 784                 val = regs->gpr[ra];
 785 #ifdef __powerpc64__
 786                 if ((rd & 1) == 0)
 787                         val = (int) val;
 788 #endif
 789                 do_cmp_signed(regs, val, imm, rd >> 2);
 790                 goto instr_done;
 791
 792         case 12:        /* addic */
 793                 imm = (short) instr;
 794                 add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
 795                 goto instr_done;
 796
 797         case 13:        /* addic. */
 798                 imm = (short) instr;
 799                 add_with_carry(regs, rd, regs->gpr[ra], imm, 0);
 800                 set_cr0(regs, rd);
 801                 goto instr_done;
 802
 803         case 14:        /* addi */
 804                 imm = (short) instr;
 805                 if (ra)
 806                         imm += regs->gpr[ra];
 807                 regs->gpr[rd] = imm;
 808                 goto instr_done;
 809
 810         case 15:        /* addis */
 811                 imm = ((short) instr) << 16;
 812                 if (ra)
 813                         imm += regs->gpr[ra];
 814                 regs->gpr[rd] = imm;
 815                 goto instr_done;
 816
 817         case 20:        /* rlwimi */
 818                 mb = (instr >> 6) & 0x1f;
 819                 me = (instr >> 1) & 0x1f;
 820                 val = DATA32(regs->gpr[rd]);
 821                 imm = MASK32(mb, me);
 822                 regs->gpr[ra] = (regs->gpr[ra] & ~imm) | (ROTATE(val, rb) & imm);
 823                 goto logical_done;
 824
 825         case 21:        /* rlwinm */
 826                 mb = (instr >> 6) & 0x1f;
 827                 me = (instr >> 1) & 0x1f;
 828                 val = DATA32(regs->gpr[rd]);
 829                 regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
 830                 goto logical_done;
 831
 832         case 23:        /* rlwnm */
 833                 mb = (instr >> 6) & 0x1f;
 834                 me = (instr >> 1) & 0x1f;
 835                 rb = regs->gpr[rb] & 0x1f;
 836                 val = DATA32(regs->gpr[rd]);
 837                 regs->gpr[ra] = ROTATE(val, rb) & MASK32(mb, me);
 838                 goto logical_done;
 839
 840         case 24:        /* ori */
 841                 imm = (unsigned short) instr;
 842                 regs->gpr[ra] = regs->gpr[rd] | imm;
 843                 goto instr_done;
 844
 845         case 25:        /* oris */
 846                 imm = (unsigned short) instr;
 847                 regs->gpr[ra] = regs->gpr[rd] | (imm << 16);
 848                 goto instr_done;
 849
 850         case 26:        /* xori */
 851                 imm = (unsigned short) instr;
 852                 regs->gpr[ra] = regs->gpr[rd] ^ imm;
 853                 goto instr_done;
 854
 855         case 27:        /* xoris */
 856                 imm = (unsigned short) instr;
 857                 regs->gpr[ra] = regs->gpr[rd] ^ (imm << 16);
 858                 goto instr_done;
 859
 860         case 28:        /* andi. */
 861                 imm = (unsigned short) instr;
 862                 regs->gpr[ra] = regs->gpr[rd] & imm;
 863                 set_cr0(regs, ra);
 864                 goto instr_done;
 865
 866         case 29:        /* andis. */
 867                 imm = (unsigned short) instr;
 868                 regs->gpr[ra] = regs->gpr[rd] & (imm << 16);
 869                 set_cr0(regs, ra);
 870                 goto instr_done;
 871
 872 #ifdef __powerpc64__
 873         case 30:        /* rld* */
 874                 mb = ((instr >> 6) & 0x1f) | (instr & 0x20);
 875                 val = regs->gpr[rd];
 876                 if ((instr & 0x10) == 0) {
 877                         sh = rb | ((instr & 2) << 4);
 878                         val = ROTATE(val, sh);
 879                         switch ((instr >> 2) & 3) {
 880                         case 0:         /* rldicl */
 881                                 regs->gpr[ra] = val & MASK64_L(mb);
 882                                 goto logical_done;
 883                         case 1:         /* rldicr */
 884                                 regs->gpr[ra] = val & MASK64_R(mb);
 885                                 goto logical_done;
 886                         case 2:         /* rldic */
 887                                 regs->gpr[ra] = val & MASK64(mb, 63 - sh);
 888                                 goto logical_done;
 889                         case 3:         /* rldimi */
 890                                 imm = MASK64(mb, 63 - sh);
 891                                 regs->gpr[ra] = (regs->gpr[ra] & ~imm) |
 892                                         (val & imm);
 893                                 goto logical_done;
 894                         }
 895                 } else {
 896                         sh = regs->gpr[rb] & 0x3f;
 897                         val = ROTATE(val, sh);
 898                         switch ((instr >> 1) & 7) {
 899                         case 0:         /* rldcl */
 900                                 regs->gpr[ra] = val & MASK64_L(mb);
 901                                 goto logical_done;
 902                         case 1:         /* rldcr */
 903                                 regs->gpr[ra] = val & MASK64_R(mb);
 904                                 goto logical_done;
 905                         }
 906                 }
 907 #endif
 908
 909         case 31:
 910                 switch ((instr >> 1) & 0x3ff) {
 911                 case 83:        /* mfmsr */
 912                         if (regs->msr & MSR_PR)
 913                                 break;
 914                         regs->gpr[rd] = regs->msr & MSR_MASK;
 915                         goto instr_done;
 916                 case 146:       /* mtmsr */
 917                         if (regs->msr & MSR_PR)
 918                                 break;
 919                         imm = regs->gpr[rd];
 920                         if ((imm & MSR_RI) == 0)
 921                                 /* can't step mtmsr that would clear MSR_RI */
 922                                 return -1;
 923                         regs->msr = imm;
 924                         goto instr_done;
 925 #ifdef CONFIG_PPC64
 926                 case 178:       /* mtmsrd */
 927                         /* only MSR_EE and MSR_RI get changed if bit 15 set */
 928                         /* mtmsrd doesn't change MSR_HV and MSR_ME */
 929                         if (regs->msr & MSR_PR)
 930                                 break;
 931                         imm = (instr & 0x10000)? 0x8002: 0xefffffffffffefffUL;
 932                         imm = (regs->msr & MSR_MASK & ~imm)
 933                                 | (regs->gpr[rd] & imm);
 934                         if ((imm & MSR_RI) == 0)
 935                                 /* can't step mtmsrd that would clear MSR_RI */
 936                                 return -1;
 937                         regs->msr = imm;
 938                         goto instr_done;
 939 #endif
 940                 case 19:        /* mfcr */
 941                         regs->gpr[rd] = regs->ccr;
 942                         regs->gpr[rd] &= 0xffffffffUL;
 943                         goto instr_done;
 944
 945                 case 144:       /* mtcrf */
 946                         imm = 0xf0000000UL;
 947                         val = regs->gpr[rd];
 948                         for (sh = 0; sh < 8; ++sh) {
 949                                 if (instr & (0x80000 >> sh))
 950                                         regs->ccr = (regs->ccr & ~imm) |
 951                                                 (val & imm);
 952                                 imm >>= 4;
 953                         }
 954                         goto instr_done;
 955
 956                 case 339:       /* mfspr */
 957                         spr = (instr >> 11) & 0x3ff;
 958                         switch (spr) {
 959                         case 0x20:      /* mfxer */
 960                                 regs->gpr[rd] = regs->xer;
 961                                 regs->gpr[rd] &= 0xffffffffUL;
 962                                 goto instr_done;
 963                         case 0x100:     /* mflr */
 964                                 regs->gpr[rd] = regs->link;
 965                                 goto instr_done;
 966                         case 0x120:     /* mfctr */
 967                                 regs->gpr[rd] = regs->ctr;
 968                                 goto instr_done;
 969                         }
 970                         break;
 971
 972                 case 467:       /* mtspr */
 973                         spr = (instr >> 11) & 0x3ff;
 974                         switch (spr) {
 975                         case 0x20:      /* mtxer */
 976                                 regs->xer = (regs->gpr[rd] & 0xffffffffUL);
 977                                 goto instr_done;
 978                         case 0x100:     /* mtlr */
 979                                 regs->link = regs->gpr[rd];
 980                                 goto instr_done;
 981                         case 0x120:     /* mtctr */
 982                                 regs->ctr = regs->gpr[rd];
 983                                 goto instr_done;
 984                         }
 985                         break;
 986
 987 /*
 988  * Compare instructions
 989  */
 990                 case 0: /* cmp */
 991                         val = regs->gpr[ra];
 992                         val2 = regs->gpr[rb];
 993 #ifdef __powerpc64__
 994                         if ((rd & 1) == 0) {
 995                                 /* word (32-bit) compare */
 996                                 val = (int) val;
 997                                 val2 = (int) val2;
 998                         }
 999 #endif
1000                         do_cmp_signed(regs, val, val2, rd >> 2);
1001                         goto instr_done;
1002
1003                 case 32:        /* cmpl */
1004                         val = regs->gpr[ra];
1005                         val2 = regs->gpr[rb];
1006 #ifdef __powerpc64__
1007                         if ((rd & 1) == 0) {
1008                                 /* word (32-bit) compare */
1009                                 val = (unsigned int) val;
1010                                 val2 = (unsigned int) val2;
1011                         }
1012 #endif
1013                         do_cmp_unsigned(regs, val, val2, rd >> 2);
1014                         goto instr_done;
1015
1016 /*
1017  * Arithmetic instructions
1018  */
1019                 case 8: /* subfc */
1020                         add_with_carry(regs, rd, ~regs->gpr[ra],
1021                                        regs->gpr[rb], 1);
1022                         goto arith_done;
1023 #ifdef __powerpc64__
1024                 case 9: /* mulhdu */
1025                         asm("mulhdu %0,%1,%2" : "=r" (regs->gpr[rd]) :
1026                             "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1027                         goto arith_done;
1028 #endif
1029                 case 10:        /* addc */
1030                         add_with_carry(regs, rd, regs->gpr[ra],
1031                                        regs->gpr[rb], 0);
1032                         goto arith_done;
1033
1034                 case 11:        /* mulhwu */
1035                         asm("mulhwu %0,%1,%2" : "=r" (regs->gpr[rd]) :
1036                             "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1037                         goto arith_done;
1038
1039                 case 40:        /* subf */
1040                         regs->gpr[rd] = regs->gpr[rb] - regs->gpr[ra];
1041                         goto arith_done;
1042 #ifdef __powerpc64__
1043                 case 73:        /* mulhd */
1044                         asm("mulhd %0,%1,%2" : "=r" (regs->gpr[rd]) :
1045                             "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1046                         goto arith_done;
1047 #endif
1048                 case 75:        /* mulhw */
1049                         asm("mulhw %0,%1,%2" : "=r" (regs->gpr[rd]) :
1050                             "r" (regs->gpr[ra]), "r" (regs->gpr[rb]));
1051                         goto arith_done;
1052
1053                 case 104:       /* neg */
1054                         regs->gpr[rd] = -regs->gpr[ra];
1055                         goto arith_done;
1056
1057                 case 136:       /* subfe */
1058                         add_with_carry(regs, rd, ~regs->gpr[ra], regs->gpr[rb],
1059                                        regs->xer & XER_CA);
1060                         goto arith_done;
1061
1062                 case 138:       /* adde */
1063                         add_with_carry(regs, rd, regs->gpr[ra], regs->gpr[rb],
1064                                        regs->xer & XER_CA);
1065                         goto arith_done;
1066
1067                 case 200:       /* subfze */
1068                         add_with_carry(regs, rd, ~regs->gpr[ra], 0L,
1069                                        regs->xer & XER_CA);
1070                         goto arith_done;
1071
1072                 case 202:       /* addze */
1073                         add_with_carry(regs, rd, regs->gpr[ra], 0L,
1074                                        regs->xer & XER_CA);
1075                         goto arith_done;
1076
1077                 case 232:       /* subfme */
1078                         add_with_carry(regs, rd, ~regs->gpr[ra], -1L,
1079                                        regs->xer & XER_CA);
1080                         goto arith_done;
1081 #ifdef __powerpc64__
1082                 case 233:       /* mulld */
1083                         regs->gpr[rd] = regs->gpr[ra] * regs->gpr[rb];
1084                         goto arith_done;
1085 #endif
1086                 case 234:       /* addme */
1087                         add_with_carry(regs, rd, regs->gpr[ra], -1L,
1088                                        regs->xer & XER_CA);
1089                         goto arith_done;
1090
1091                 case 235:       /* mullw */
1092                         regs->gpr[rd] = (unsigned int) regs->gpr[ra] *
1093                                 (unsigned int) regs->gpr[rb];
1094                         goto arith_done;
1095
1096                 case 266:       /* add */
1097                         regs->gpr[rd] = regs->gpr[ra] + regs->gpr[rb];
1098                         goto arith_done;
1099 #ifdef __powerpc64__
1100                 case 457:       /* divdu */
1101                         regs->gpr[rd] = regs->gpr[ra] / regs->gpr[rb];
1102                         goto arith_done;
1103 #endif
1104                 case 459:       /* divwu */
1105                         regs->gpr[rd] = (unsigned int) regs->gpr[ra] /
1106                                 (unsigned int) regs->gpr[rb];
1107                         goto arith_done;
1108 #ifdef __powerpc64__
1109                 case 489:       /* divd */
1110                         regs->gpr[rd] = (long int) regs->gpr[ra] /
1111                                 (long int) regs->gpr[rb];
1112                         goto arith_done;
1113 #endif
1114                 case 491:       /* divw */
1115                         regs->gpr[rd] = (int) regs->gpr[ra] /
1116                                 (int) regs->gpr[rb];
1117                         goto arith_done;
1118
1119
1120 /*
1121  * Logical instructions
1122  */
1123                 case 26:        /* cntlzw */
1124                         asm("cntlzw %0,%1" : "=r" (regs->gpr[ra]) :
1125                             "r" (regs->gpr[rd]));
1126                         goto logical_done;
1127 #ifdef __powerpc64__
1128                 case 58:        /* cntlzd */
1129                         asm("cntlzd %0,%1" : "=r" (regs->gpr[ra]) :
1130                             "r" (regs->gpr[rd]));
1131                         goto logical_done;
1132 #endif
1133                 case 28:        /* and */
1134                         regs->gpr[ra] = regs->gpr[rd] & regs->gpr[rb];
1135                         goto logical_done;
1136
1137                 case 60:        /* andc */
1138                         regs->gpr[ra] = regs->gpr[rd] & ~regs->gpr[rb];
1139                         goto logical_done;
1140
1141                 case 124:       /* nor */
1142                         regs->gpr[ra] = ~(regs->gpr[rd] | regs->gpr[rb]);
1143                         goto logical_done;
1144
1145                 case 284:       /* xor */
1146                         regs->gpr[ra] = ~(regs->gpr[rd] ^ regs->gpr[rb]);
1147                         goto logical_done;
1148
1149                 case 316:       /* xor */
1150                         regs->gpr[ra] = regs->gpr[rd] ^ regs->gpr[rb];
1151                         goto logical_done;
1152
1153                 case 412:       /* orc */
1154                         regs->gpr[ra] = regs->gpr[rd] | ~regs->gpr[rb];
1155                         goto logical_done;
1156
1157                 case 444:       /* or */
1158                         regs->gpr[ra] = regs->gpr[rd] | regs->gpr[rb];
1159                         goto logical_done;
1160
1161                 case 476:       /* nand */
1162                         regs->gpr[ra] = ~(regs->gpr[rd] & regs->gpr[rb]);
1163                         goto logical_done;
1164
1165                 case 922:       /* extsh */
1166                         regs->gpr[ra] = (signed short) regs->gpr[rd];
1167                         goto logical_done;
1168
1169                 case 954:       /* extsb */
1170                         regs->gpr[ra] = (signed char) regs->gpr[rd];
1171                         goto logical_done;
1172 #ifdef __powerpc64__
1173                 case 986:       /* extsw */
1174                         regs->gpr[ra] = (signed int) regs->gpr[rd];
1175                         goto logical_done;
1176 #endif
1177
1178 /*
1179  * Shift instructions
1180  */
1181                 case 24:        /* slw */
1182                         sh = regs->gpr[rb] & 0x3f;
1183                         if (sh < 32)
1184                                 regs->gpr[ra] = (regs->gpr[rd] << sh) & 0xffffffffUL;
1185                         else
1186                                 regs->gpr[ra] = 0;
1187                         goto logical_done;
1188
1189                 case 536:       /* srw */
1190                         sh = regs->gpr[rb] & 0x3f;
1191                         if (sh < 32)
1192                                 regs->gpr[ra] = (regs->gpr[rd] & 0xffffffffUL) >> sh;
1193                         else
1194                                 regs->gpr[ra] = 0;
1195                         goto logical_done;
1196
1197                 case 792:       /* sraw */
1198                         sh = regs->gpr[rb] & 0x3f;
1199                         ival = (signed int) regs->gpr[rd];
1200                         regs->gpr[ra] = ival >> (sh < 32 ? sh : 31);
1201                         if (ival < 0 && (sh >= 32 || (ival & ((1 << sh) - 1)) != 0))
1202                                 regs->xer |= XER_CA;
1203                         else
1204                                 regs->xer &= ~XER_CA;
1205                         goto logical_done;
1206
1207                 case 824:       /* srawi */
1208                         sh = rb;
1209                         ival = (signed int) regs->gpr[rd];
1210                         regs->gpr[ra] = ival >> sh;
1211                         if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
1212                                 regs->xer |= XER_CA;
1213                         else
1214                                 regs->xer &= ~XER_CA;
1215                         goto logical_done;
1216
1217 #ifdef __powerpc64__
1218                 case 27:        /* sld */
1219                         sh = regs->gpr[rd] & 0x7f;
1220                         if (sh < 64)
1221                                 regs->gpr[ra] = regs->gpr[rd] << sh;
1222                         else
1223                                 regs->gpr[ra] = 0;
1224                         goto logical_done;
1225
1226                 case 539:       /* srd */
1227                         sh = regs->gpr[rb] & 0x7f;
1228                         if (sh < 64)
1229                                 regs->gpr[ra] = regs->gpr[rd] >> sh;
1230                         else
1231                                 regs->gpr[ra] = 0;
1232                         goto logical_done;
1233
1234                 case 794:       /* srad */
1235                         sh = regs->gpr[rb] & 0x7f;
1236                         ival = (signed long int) regs->gpr[rd];
1237                         regs->gpr[ra] = ival >> (sh < 64 ? sh : 63);
1238                         if (ival < 0 && (sh >= 64 || (ival & ((1 << sh) - 1)) != 0))
1239                                 regs->xer |= XER_CA;
1240                         else
1241                                 regs->xer &= ~XER_CA;
1242                         goto logical_done;
1243
1244                 case 826:       /* sradi with sh_5 = 0 */
1245                 case 827:       /* sradi with sh_5 = 1 */
1246                         sh = rb | ((instr & 2) << 4);
1247                         ival = (signed long int) regs->gpr[rd];
1248                         regs->gpr[ra] = ival >> sh;
1249                         if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
1250                                 regs->xer |= XER_CA;
1251                         else
1252                                 regs->xer &= ~XER_CA;
1253                         goto logical_done;
1254 #endif /* __powerpc64__ */
1255
1256 /*
1257  * Cache instructions
1258  */
1259                 case 54:        /* dcbst */
1260                         ea = xform_ea(instr, regs, 0);
1261                         if (!address_ok(regs, ea, 8))
1262                                 return 0;
1263                         err = 0;
1264                         __cacheop_user_asmx(ea, err, "dcbst");
1265                         if (err)
1266                                 return 0;
1267                         goto instr_done;
1268
1269                 case 86:        /* dcbf */
1270                         ea = xform_ea(instr, regs, 0);
1271                         if (!address_ok(regs, ea, 8))
1272                                 return 0;
1273                         err = 0;
1274                         __cacheop_user_asmx(ea, err, "dcbf");
1275                         if (err)
1276                                 return 0;
1277                         goto instr_done;
1278
1279                 case 246:       /* dcbtst */
1280                         if (rd == 0) {
1281                                 ea = xform_ea(instr, regs, 0);
1282                                 prefetchw((void *) ea);
1283                         }
1284                         goto instr_done;
1285
1286                 case 278:       /* dcbt */
1287                         if (rd == 0) {
1288                                 ea = xform_ea(instr, regs, 0);
1289                                 prefetch((void *) ea);
1290                         }
1291                         goto instr_done;
1292
1293                 }
1294                 break;
1295         }
1296
1297         /*
1298          * Following cases are for loads and stores, so bail out
1299          * if we're in little-endian mode.
1300          */
1301         if (regs->msr & MSR_LE)
1302                 return 0;
1303
1304         /*
1305          * Save register RA in case it's an update form load or store
1306          * and the access faults.
1307          */
1308         old_ra = regs->gpr[ra];
1309
1310         switch (opcode) {
1311         case 31:
1312                 u = instr & 0x40;
1313                 switch ((instr >> 1) & 0x3ff) {
1314                 case 20:        /* lwarx */
1315                         ea = xform_ea(instr, regs, 0);
1316                         if (ea & 3)
1317                                 break;          /* can't handle misaligned */
1318                         err = -EFAULT;
1319                         if (!address_ok(regs, ea, 4))
1320                                 goto ldst_done;
1321                         err = 0;
1322                         __get_user_asmx(val, ea, err, "lwarx");
1323                         if (!err)
1324                                 regs->gpr[rd] = val;
1325                         goto ldst_done;
1326
1327                 case 150:       /* stwcx. */
1328                         ea = xform_ea(instr, regs, 0);
1329                         if (ea & 3)
1330                                 break;          /* can't handle misaligned */
1331                         err = -EFAULT;
1332                         if (!address_ok(regs, ea, 4))
1333                                 goto ldst_done;
1334                         err = 0;
1335                         __put_user_asmx(regs->gpr[rd], ea, err, "stwcx.", cr);
1336                         if (!err)
1337                                 regs->ccr = (regs->ccr & 0x0fffffff) |
1338                                         (cr & 0xe0000000) |
1339                                         ((regs->xer >> 3) & 0x10000000);
1340                         goto ldst_done;
1341
1342 #ifdef __powerpc64__
1343                 case 84:        /* ldarx */
1344                         ea = xform_ea(instr, regs, 0);
1345                         if (ea & 7)
1346                                 break;          /* can't handle misaligned */
1347                         err = -EFAULT;
1348                         if (!address_ok(regs, ea, 8))
1349                                 goto ldst_done;
1350                         err = 0;
1351                         __get_user_asmx(val, ea, err, "ldarx");
1352                         if (!err)
1353                                 regs->gpr[rd] = val;
1354                         goto ldst_done;
1355
1356                 case 214:       /* stdcx. */
1357                         ea = xform_ea(instr, regs, 0);
1358                         if (ea & 7)
1359                                 break;          /* can't handle misaligned */
1360                         err = -EFAULT;
1361                         if (!address_ok(regs, ea, 8))
1362                                 goto ldst_done;
1363                         err = 0;
1364                         __put_user_asmx(regs->gpr[rd], ea, err, "stdcx.", cr);
1365                         if (!err)
1366                                 regs->ccr = (regs->ccr & 0x0fffffff) |
1367                                         (cr & 0xe0000000) |
1368                                         ((regs->xer >> 3) & 0x10000000);
1369                         goto ldst_done;
1370
1371                 case 21:        /* ldx */
1372                 case 53:        /* ldux */
1373                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1374                                        8, regs);
1375                         goto ldst_done;
1376 #endif
1377
1378                 case 23:        /* lwzx */
1379                 case 55:        /* lwzux */
1380                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1381                                        4, regs);
1382                         goto ldst_done;
1383
1384                 case 87:        /* lbzx */
1385                 case 119:       /* lbzux */
1386                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1387                                        1, regs);
1388                         goto ldst_done;
1389
1390 #ifdef CONFIG_ALTIVEC
1391                 case 103:       /* lvx */
1392                 case 359:       /* lvxl */
1393                         if (!(regs->msr & MSR_VEC))
1394                                 break;
1395                         ea = xform_ea(instr, regs, 0);
1396                         err = do_vec_load(rd, do_lvx, ea, regs);
1397                         goto ldst_done;
1398
1399                 case 231:       /* stvx */
1400                 case 487:       /* stvxl */
1401                         if (!(regs->msr & MSR_VEC))
1402                                 break;
1403                         ea = xform_ea(instr, regs, 0);
1404                         err = do_vec_store(rd, do_stvx, ea, regs);
1405                         goto ldst_done;
1406 #endif /* CONFIG_ALTIVEC */
1407
1408 #ifdef __powerpc64__
1409                 case 149:       /* stdx */
1410                 case 181:       /* stdux */
1411                         val = regs->gpr[rd];
1412                         err = write_mem(val, xform_ea(instr, regs, u), 8, regs);
1413                         goto ldst_done;
1414 #endif
1415
1416                 case 151:       /* stwx */
1417                 case 183:       /* stwux */
1418                         val = regs->gpr[rd];
1419                         err = write_mem(val, xform_ea(instr, regs, u), 4, regs);
1420                         goto ldst_done;
1421
1422                 case 215:       /* stbx */
1423                 case 247:       /* stbux */
1424                         val = regs->gpr[rd];
1425                         err = write_mem(val, xform_ea(instr, regs, u), 1, regs);
1426                         goto ldst_done;
1427
1428                 case 279:       /* lhzx */
1429                 case 311:       /* lhzux */
1430                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1431                                        2, regs);
1432                         goto ldst_done;
1433
1434 #ifdef __powerpc64__
1435                 case 341:       /* lwax */
1436                 case 373:       /* lwaux */
1437                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1438                                        4, regs);
1439                         if (!err)
1440                                 regs->gpr[rd] = (signed int) regs->gpr[rd];
1441                         goto ldst_done;
1442 #endif
1443
1444                 case 343:       /* lhax */
1445                 case 375:       /* lhaux */
1446                         err = read_mem(&regs->gpr[rd], xform_ea(instr, regs, u),
1447                                        2, regs);
1448                         if (!err)
1449                                 regs->gpr[rd] = (signed short) regs->gpr[rd];
1450                         goto ldst_done;
1451
1452                 case 407:       /* sthx */
1453                 case 439:       /* sthux */
1454                         val = regs->gpr[rd];
1455                         err = write_mem(val, xform_ea(instr, regs, u), 2, regs);
1456                         goto ldst_done;
1457
1458 #ifdef __powerpc64__
1459                 case 532:       /* ldbrx */
1460                         err = read_mem(&val, xform_ea(instr, regs, 0), 8, regs);
1461                         if (!err)
1462                                 regs->gpr[rd] = byterev_8(val);
1463                         goto ldst_done;
1464
1465 #endif
1466
1467                 case 534:       /* lwbrx */
1468                         err = read_mem(&val, xform_ea(instr, regs, 0), 4, regs);
1469                         if (!err)
1470                                 regs->gpr[rd] = byterev_4(val);
1471                         goto ldst_done;
1472
1473 #ifdef CONFIG_PPC_FPU
1474                 case 535:       /* lfsx */
1475                 case 567:       /* lfsux */
1476                         if (!(regs->msr & MSR_FP))
1477                                 break;
1478                         ea = xform_ea(instr, regs, u);
1479                         err = do_fp_load(rd, do_lfs, ea, 4, regs);
1480                         goto ldst_done;
1481
1482                 case 599:       /* lfdx */
1483                 case 631:       /* lfdux */
1484                         if (!(regs->msr & MSR_FP))
1485                                 break;
1486                         ea = xform_ea(instr, regs, u);
1487                         err = do_fp_load(rd, do_lfd, ea, 8, regs);
1488                         goto ldst_done;
1489
1490                 case 663:       /* stfsx */
1491                 case 695:       /* stfsux */
1492                         if (!(regs->msr & MSR_FP))
1493                                 break;
1494                         ea = xform_ea(instr, regs, u);
1495                         err = do_fp_store(rd, do_stfs, ea, 4, regs);
1496                         goto ldst_done;
1497
1498                 case 727:       /* stfdx */
1499                 case 759:       /* stfdux */
1500                         if (!(regs->msr & MSR_FP))
1501                                 break;
1502                         ea = xform_ea(instr, regs, u);
1503                         err = do_fp_store(rd, do_stfd, ea, 8, regs);
1504                         goto ldst_done;
1505 #endif
1506
1507 #ifdef __powerpc64__
1508                 case 660:       /* stdbrx */
1509                         val = byterev_8(regs->gpr[rd]);
1510                         err = write_mem(val, xform_ea(instr, regs, 0), 8, regs);
1511                         goto ldst_done;
1512
1513 #endif
1514                 case 662:       /* stwbrx */
1515                         val = byterev_4(regs->gpr[rd]);
1516                         err = write_mem(val, xform_ea(instr, regs, 0), 4, regs);
1517                         goto ldst_done;
1518
1519                 case 790:       /* lhbrx */
1520                         err = read_mem(&val, xform_ea(instr, regs, 0), 2, regs);
1521                         if (!err)
1522                                 regs->gpr[rd] = byterev_2(val);
1523                         goto ldst_done;
1524
1525                 case 918:       /* sthbrx */
1526                         val = byterev_2(regs->gpr[rd]);
1527                         err = write_mem(val, xform_ea(instr, regs, 0), 2, regs);
1528                         goto ldst_done;
1529
1530 #ifdef CONFIG_VSX
1531                 case 844:       /* lxvd2x */
1532                 case 876:       /* lxvd2ux */
1533                         if (!(regs->msr & MSR_VSX))
1534                                 break;
1535                         rd |= (instr & 1) << 5;
1536                         ea = xform_ea(instr, regs, u);
1537                         err = do_vsx_load(rd, do_lxvd2x, ea, regs);
1538                         goto ldst_done;
1539
1540                 case 972:       /* stxvd2x */
1541                 case 1004:      /* stxvd2ux */
1542                         if (!(regs->msr & MSR_VSX))
1543                                 break;
1544                         rd |= (instr & 1) << 5;
1545                         ea = xform_ea(instr, regs, u);
1546                         err = do_vsx_store(rd, do_stxvd2x, ea, regs);
1547                         goto ldst_done;
1548
1549 #endif /* CONFIG_VSX */
1550                 }
1551                 break;
1552
1553         case 32:        /* lwz */
1554         case 33:        /* lwzu */
1555                 err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 4, regs);
1556                 goto ldst_done;
1557
1558         case 34:        /* lbz */
1559         case 35:        /* lbzu */
1560                 err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 1, regs);
1561                 goto ldst_done;
1562
1563         case 36:        /* stw */
1564                 val = regs->gpr[rd];
1565                 err = write_mem(val, dform_ea(instr, regs), 4, regs);
1566                 goto ldst_done;
1567
1568         case 37:        /* stwu */
1569                 val = regs->gpr[rd];
1570                 val3 = dform_ea(instr, regs);
1571                 /*
1572                  * For PPC32 we always use stwu to change stack point with r1. So
1573                  * this emulated store may corrupt the exception frame, now we
1574                  * have to provide the exception frame trampoline, which is pushed
1575                  * below the kprobed function stack. So we only update gpr[1] but
1576                  * don't emulate the real store operation. We will do real store
1577                  * operation safely in exception return code by checking this flag.
1578                  */
1579                 if ((ra == 1) && !(regs->msr & MSR_PR) \
1580                         && (val3 >= (regs->gpr[1] - STACK_INT_FRAME_SIZE))) {
1581 #ifdef CONFIG_PPC32
1582                         /*
1583                          * Check if we will touch kernel sack overflow
1584                          */
1585                         if (val3 - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
1586                                 printk(KERN_CRIT "Can't kprobe this since Kernel stack overflow.\n");
1587                                 err = -EINVAL;
1588                                 break;
1589                         }
1590 #endif /* CONFIG_PPC32 */
1591                         /*
1592                          * Check if we already set since that means we'll
1593                          * lose the previous value.
1594                          */
1595                         WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
1596                         set_thread_flag(TIF_EMULATE_STACK_STORE);
1597                         err = 0;
1598                 } else
1599                         err = write_mem(val, val3, 4, regs);
1600                 goto ldst_done;
1601
1602         case 38:        /* stb */
1603         case 39:        /* stbu */
1604                 val = regs->gpr[rd];
1605                 err = write_mem(val, dform_ea(instr, regs), 1, regs);
1606                 goto ldst_done;
1607
1608         case 40:        /* lhz */
1609         case 41:        /* lhzu */
1610                 err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 2, regs);
1611                 goto ldst_done;
1612
1613         case 42:        /* lha */
1614         case 43:        /* lhau */
1615                 err = read_mem(&regs->gpr[rd], dform_ea(instr, regs), 2, regs);
1616                 if (!err)
1617                         regs->gpr[rd] = (signed short) regs->gpr[rd];
1618                 goto ldst_done;
1619
1620         case 44:        /* sth */
1621         case 45:        /* sthu */
1622                 val = regs->gpr[rd];
1623                 err = write_mem(val, dform_ea(instr, regs), 2, regs);
1624                 goto ldst_done;
1625
1626         case 46:        /* lmw */
1627                 ra = (instr >> 16) & 0x1f;
1628                 if (ra >= rd)
1629                         break;          /* invalid form, ra in range to load */
1630                 ea = dform_ea(instr, regs);
1631                 do {
1632                         err = read_mem(&regs->gpr[rd], ea, 4, regs);
1633                         if (err)
1634                                 return 0;
1635                         ea += 4;
1636                 } while (++rd < 32);
1637                 goto instr_done;
1638
1639         case 47:        /* stmw */
1640                 ea = dform_ea(instr, regs);
1641                 do {
1642                         err = write_mem(regs->gpr[rd], ea, 4, regs);
1643                         if (err)
1644                                 return 0;
1645                         ea += 4;
1646                 } while (++rd < 32);
1647                 goto instr_done;
1648
1649 #ifdef CONFIG_PPC_FPU
1650         case 48:        /* lfs */
1651         case 49:        /* lfsu */
1652                 if (!(regs->msr & MSR_FP))
1653                         break;
1654                 ea = dform_ea(instr, regs);
1655                 err = do_fp_load(rd, do_lfs, ea, 4, regs);
1656                 goto ldst_done;
1657
1658         case 50:        /* lfd */
1659         case 51:        /* lfdu */
1660                 if (!(regs->msr & MSR_FP))
1661                         break;
1662                 ea = dform_ea(instr, regs);
1663                 err = do_fp_load(rd, do_lfd, ea, 8, regs);
1664                 goto ldst_done;
1665
1666         case 52:        /* stfs */
1667         case 53:        /* stfsu */
1668                 if (!(regs->msr & MSR_FP))
1669                         break;
1670                 ea = dform_ea(instr, regs);
1671                 err = do_fp_store(rd, do_stfs, ea, 4, regs);
1672                 goto ldst_done;
1673
1674         case 54:        /* stfd */
1675         case 55:        /* stfdu */
1676                 if (!(regs->msr & MSR_FP))
1677                         break;
1678                 ea = dform_ea(instr, regs);
1679                 err = do_fp_store(rd, do_stfd, ea, 8, regs);
1680                 goto ldst_done;
1681 #endif
1682
1683 #ifdef __powerpc64__
1684         case 58:        /* ld[u], lwa */
1685                 switch (instr & 3) {
1686                 case 0:         /* ld */
1687                         err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
1688                                        8, regs);
1689                         goto ldst_done;
1690                 case 1:         /* ldu */
1691                         err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
1692                                        8, regs);
1693                         goto ldst_done;
1694                 case 2:         /* lwa */
1695                         err = read_mem(&regs->gpr[rd], dsform_ea(instr, regs),
1696                                        4, regs);
1697                         if (!err)
1698                                 regs->gpr[rd] = (signed int) regs->gpr[rd];
1699                         goto ldst_done;
1700                 }
1701                 break;
1702
1703         case 62:        /* std[u] */
1704                 val = regs->gpr[rd];
1705                 switch (instr & 3) {
1706                 case 0:         /* std */
1707                         err = write_mem(val, dsform_ea(instr, regs), 8, regs);
1708                         goto ldst_done;
1709                 case 1:         /* stdu */
1710                         err = write_mem(val, dsform_ea(instr, regs), 8, regs);
1711                         goto ldst_done;
1712                 }
1713                 break;
1714 #endif /* __powerpc64__ */
1715
1716         }
1717         err = -EINVAL;
1718
1719  ldst_done:
1720         if (err) {
1721                 regs->gpr[ra] = old_ra;
1722                 return 0;       /* invoke DSI if -EFAULT? */
1723         }
1724  instr_done:
1725         regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
1726         return 1;
1727
1728  logical_done:
1729         if (instr & 1)
1730                 set_cr0(regs, ra);
1731         goto instr_done;
1732
1733  arith_done:
1734         if (instr & 1)
1735                 set_cr0(regs, rd);
1736         goto instr_done;
1737 }