src/arch/arm/insts/static_inst.cc

   1 /*
   2  * Copyright (c) 2010-2014, 2016 ARM Limited
   3  * Copyright (c) 2013 Advanced Micro Devices, Inc.
   4  * All rights reserved
   5  *
   6  * The license below extends only to copyright in the software and shall
   7  * not be construed as granting a license to any other intellectual
   8  * property including but not limited to intellectual property relating
   9  * to a hardware implementation of the functionality of the software
  10  * licensed hereunder.  You may use the software subject to the license
  11  * terms below provided that you ensure that this notice is replicated
  12  * unmodified and in its entirety in all distributions of the software,
  13  * modified or unmodified, in source code or in binary form.
  14  *
  15  * Copyright (c) 2007-2008 The Florida State University
  16  * All rights reserved.
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions are
  20  * met: redistributions of source code must retain the above copyright
  21  * notice, this list of conditions and the following disclaimer;
  22  * redistributions in binary form must reproduce the above copyright
  23  * notice, this list of conditions and the following disclaimer in the
  24  * documentation and/or other materials provided with the distribution;
  25  * neither the name of the copyright holders nor the names of its
  26  * contributors may be used to endorse or promote products derived from
  27  * this software without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  30  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  31  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  32  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  33  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  34  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  35  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  39  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  40  *
  41  * Authors: Stephen Hines
  42  */
  43
  44 #include "arch/arm/insts/static_inst.hh"
  45
  46 #include "arch/arm/faults.hh"
  47 #include "base/condcodes.hh"
  48 #include "base/cprintf.hh"
  49 #include "base/loader/symtab.hh"
  50 #include "cpu/reg_class.hh"
  51
  52 namespace ArmISA
  53 {
  54 // Shift Rm by an immediate value
  55 int32_t
  56 ArmStaticInst::shift_rm_imm(uint32_t base, uint32_t shamt,
  57                                 uint32_t type, uint32_t cfval) const
  58 {
  59     assert(shamt < 32);
  60     ArmShiftType shiftType;
  61     shiftType = (ArmShiftType)type;
  62
  63     switch (shiftType)
  64     {
  65       case LSL:
  66         return base << shamt;
  67       case LSR:
  68         if (shamt == 0)
  69             return 0;
  70         else
  71             return base >> shamt;
  72       case ASR:
  73         if (shamt == 0)
  74             return (base >> 31) | -((base & (1 << 31)) >> 31);
  75         else
  76             return (base >> shamt) | -((base & (1 << 31)) >> shamt);
  77       case ROR:
  78         if (shamt == 0)
  79             return (cfval << 31) | (base >> 1); // RRX
  80         else
  81             return (base << (32 - shamt)) | (base >> shamt);
  82       default:
  83         ccprintf(std::cerr, "Unhandled shift type\n");
  84         exit(1);
  85         break;
  86     }
  87     return 0;
  88 }
  89
  90 int64_t
  91 ArmStaticInst::shiftReg64(uint64_t base, uint64_t shiftAmt,
  92                           ArmShiftType type, uint8_t width) const
  93 {
  94     shiftAmt = shiftAmt % width;
  95     ArmShiftType shiftType;
  96     shiftType = (ArmShiftType)type;
  97
  98     switch (shiftType)
  99     {
 100       case LSL:
 101         return base << shiftAmt;
 102       case LSR:
 103         if (shiftAmt == 0)
 104             return base;
 105         else
 106             return (base & mask(width)) >> shiftAmt;
 107       case ASR:
 108         if (shiftAmt == 0) {
 109             return base;
 110         } else {
 111             int sign_bit = bits(base, intWidth - 1);
 112             base >>= shiftAmt;
 113             base = sign_bit ? (base | ~mask(intWidth - shiftAmt)) : base;
 114             return base & mask(intWidth);
 115         }
 116       case ROR:
 117         if (shiftAmt == 0)
 118             return base;
 119         else
 120             return (base << (width - shiftAmt)) | (base >> shiftAmt);
 121       default:
 122         ccprintf(std::cerr, "Unhandled shift type\n");
 123         exit(1);
 124         break;
 125     }
 126     return 0;
 127 }
 128
 129 int64_t
 130 ArmStaticInst::extendReg64(uint64_t base, ArmExtendType type,
 131                            uint64_t shiftAmt, uint8_t width) const
 132 {
 133     bool sign_extend = false;
 134     int len = 0;
 135     switch (type) {
 136       case UXTB:
 137         len = 8;
 138         break;
 139       case UXTH:
 140         len = 16;
 141         break;
 142       case UXTW:
 143         len = 32;
 144         break;
 145       case UXTX:
 146         len = 64;
 147         break;
 148       case SXTB:
 149         len = 8;
 150         sign_extend = true;
 151         break;
 152       case SXTH:
 153         len = 16;
 154         sign_extend = true;
 155         break;
 156       case SXTW:
 157         len = 32;
 158         sign_extend = true;
 159         break;
 160       case SXTX:
 161         len = 64;
 162         sign_extend = true;
 163         break;
 164     }
 165     len = len <= width - shiftAmt ? len : width - shiftAmt;
 166     uint64_t tmp = (uint64_t) bits(base, len - 1, 0) << shiftAmt;
 167     if (sign_extend) {
 168         int sign_bit = bits(tmp, len + shiftAmt - 1);
 169         tmp = sign_bit ? (tmp | ~mask(len + shiftAmt)) : tmp;
 170     }
 171     return tmp & mask(width);
 172 }
 173
 174 // Shift Rm by Rs
 175 int32_t
 176 ArmStaticInst::shift_rm_rs(uint32_t base, uint32_t shamt,
 177                                uint32_t type, uint32_t cfval) const
 178 {
 179     enum ArmShiftType shiftType;
 180     shiftType = (enum ArmShiftType) type;
 181
 182     switch (shiftType)
 183     {
 184       case LSL:
 185         if (shamt >= 32)
 186             return 0;
 187         else
 188             return base << shamt;
 189       case LSR:
 190         if (shamt >= 32)
 191             return 0;
 192         else
 193             return base >> shamt;
 194       case ASR:
 195         if (shamt >= 32)
 196             return (base >> 31) | -((base & (1 << 31)) >> 31);
 197         else
 198             return (base >> shamt) | -((base & (1 << 31)) >> shamt);
 199       case ROR:
 200         shamt = shamt & 0x1f;
 201         if (shamt == 0)
 202             return base;
 203         else
 204             return (base << (32 - shamt)) | (base >> shamt);
 205       default:
 206         ccprintf(std::cerr, "Unhandled shift type\n");
 207         exit(1);
 208         break;
 209     }
 210     return 0;
 211 }
 212
 213
 214 // Generate C for a shift by immediate
 215 bool
 216 ArmStaticInst::shift_carry_imm(uint32_t base, uint32_t shamt,
 217                                    uint32_t type, uint32_t cfval) const
 218 {
 219     enum ArmShiftType shiftType;
 220     shiftType = (enum ArmShiftType) type;
 221
 222     switch (shiftType)
 223     {
 224       case LSL:
 225         if (shamt == 0)
 226             return cfval;
 227         else
 228             return (base >> (32 - shamt)) & 1;
 229       case LSR:
 230         if (shamt == 0)
 231             return (base >> 31);
 232         else
 233             return (base >> (shamt - 1)) & 1;
 234       case ASR:
 235         if (shamt == 0)
 236             return (base >> 31);
 237         else
 238             return (base >> (shamt - 1)) & 1;
 239       case ROR:
 240         shamt = shamt & 0x1f;
 241         if (shamt == 0)
 242             return (base & 1); // RRX
 243         else
 244             return (base >> (shamt - 1)) & 1;
 245       default:
 246         ccprintf(std::cerr, "Unhandled shift type\n");
 247         exit(1);
 248         break;
 249     }
 250     return 0;
 251 }
 252
 253
 254 // Generate C for a shift by Rs
 255 bool
 256 ArmStaticInst::shift_carry_rs(uint32_t base, uint32_t shamt,
 257                                   uint32_t type, uint32_t cfval) const
 258 {
 259     enum ArmShiftType shiftType;
 260     shiftType = (enum ArmShiftType) type;
 261
 262     if (shamt == 0)
 263         return cfval;
 264
 265     switch (shiftType)
 266     {
 267       case LSL:
 268         if (shamt > 32)
 269             return 0;
 270         else
 271             return (base >> (32 - shamt)) & 1;
 272       case LSR:
 273         if (shamt > 32)
 274             return 0;
 275         else
 276             return (base >> (shamt - 1)) & 1;
 277       case ASR:
 278         if (shamt > 32)
 279             shamt = 32;
 280         return (base >> (shamt - 1)) & 1;
 281       case ROR:
 282         shamt = shamt & 0x1f;
 283         if (shamt == 0)
 284             shamt = 32;
 285         return (base >> (shamt - 1)) & 1;
 286       default:
 287         ccprintf(std::cerr, "Unhandled shift type\n");
 288         exit(1);
 289         break;
 290     }
 291     return 0;
 292 }
 293
 294 void
 295 ArmStaticInst::printIntReg(std::ostream &os, RegIndex reg_idx) const
 296 {
 297     if (aarch64) {
 298         if (reg_idx == INTREG_UREG0)
 299             ccprintf(os, "ureg0");
 300         else if (reg_idx == INTREG_SPX)
 301             ccprintf(os, "%s%s", (intWidth == 32) ? "w" : "", "sp");
 302         else if (reg_idx == INTREG_X31)
 303             ccprintf(os, "%szr", (intWidth == 32) ? "w" : "x");
 304         else
 305             ccprintf(os, "%s%d", (intWidth == 32) ? "w" : "x", reg_idx);
 306     } else {
 307         switch (reg_idx) {
 308           case PCReg:
 309             ccprintf(os, "pc");
 310             break;
 311           case StackPointerReg:
 312             ccprintf(os, "sp");
 313             break;
 314           case FramePointerReg:
 315              ccprintf(os, "fp");
 316              break;
 317           case ReturnAddressReg:
 318              ccprintf(os, "lr");
 319              break;
 320           default:
 321              ccprintf(os, "r%d", reg_idx);
 322              break;
 323         }
 324     }
 325 }
 326
 327 void
 328 ArmStaticInst::printFloatReg(std::ostream &os, RegIndex reg_idx) const
 329 {
 330     ccprintf(os, "f%d", reg_idx);
 331 }
 332
 333 void
 334 ArmStaticInst::printVecReg(std::ostream &os, RegIndex reg_idx) const
 335 {
 336     ccprintf(os, "v%d", reg_idx);
 337 }
 338
 339 void
 340 ArmStaticInst::printCCReg(std::ostream &os, RegIndex reg_idx) const
 341 {
 342     ccprintf(os, "cc_%s", ArmISA::ccRegName[reg_idx]);
 343 }
 344
 345 void
 346 ArmStaticInst::printMiscReg(std::ostream &os, RegIndex reg_idx) const
 347 {
 348     assert(reg_idx < NUM_MISCREGS);
 349     ccprintf(os, "%s", ArmISA::miscRegName[reg_idx]);
 350 }
 351
 352 void
 353 ArmStaticInst::printMnemonic(std::ostream &os,
 354                              const std::string &suffix,
 355                              bool withPred,
 356                              bool withCond64,
 357                              ConditionCode cond64) const
 358 {
 359     os << "  " << mnemonic;
 360     if (withPred && !aarch64) {
 361         printCondition(os, machInst.condCode);
 362         os << suffix;
 363     } else if (withCond64) {
 364         os << ".";
 365         printCondition(os, cond64);
 366         os << suffix;
 367     }
 368     if (machInst.bigThumb)
 369         os << ".w";
 370     os << "   ";
 371 }
 372
 373 void
 374 ArmStaticInst::printTarget(std::ostream &os, Addr target,
 375                            const SymbolTable *symtab) const
 376 {
 377     Addr symbolAddr;
 378     std::string symbol;
 379
 380     if (symtab && symtab->findNearestSymbol(target, symbol, symbolAddr)) {
 381         ccprintf(os, "<%s", symbol);
 382         if (symbolAddr != target)
 383             ccprintf(os, "+%d>", target - symbolAddr);
 384         else
 385             ccprintf(os, ">");
 386     } else {
 387         ccprintf(os, "%#x", target);
 388     }
 389 }
 390
 391 void
 392 ArmStaticInst::printCondition(std::ostream &os,
 393                               unsigned code,
 394                               bool noImplicit) const
 395 {
 396     switch (code) {
 397       case COND_EQ:
 398         os << "eq";
 399         break;
 400       case COND_NE:
 401         os << "ne";
 402         break;
 403       case COND_CS:
 404         os << "cs";
 405         break;
 406       case COND_CC:
 407         os << "cc";
 408         break;
 409       case COND_MI:
 410         os << "mi";
 411         break;
 412       case COND_PL:
 413         os << "pl";
 414         break;
 415       case COND_VS:
 416         os << "vs";
 417         break;
 418       case COND_VC:
 419         os << "vc";
 420         break;
 421       case COND_HI:
 422         os << "hi";
 423         break;
 424       case COND_LS:
 425         os << "ls";
 426         break;
 427       case COND_GE:
 428         os << "ge";
 429         break;
 430       case COND_LT:
 431         os << "lt";
 432         break;
 433       case COND_GT:
 434         os << "gt";
 435         break;
 436       case COND_LE:
 437         os << "le";
 438         break;
 439       case COND_AL:
 440         // This one is implicit.
 441         if (noImplicit)
 442             os << "al";
 443         break;
 444       case COND_UC:
 445         // Unconditional.
 446         if (noImplicit)
 447             os << "uc";
 448         break;
 449       default:
 450         panic("Unrecognized condition code %d.\n", code);
 451     }
 452 }
 453
 454 void
 455 ArmStaticInst::printMemSymbol(std::ostream &os,
 456                               const SymbolTable *symtab,
 457                               const std::string &prefix,
 458                               const Addr addr,
 459                               const std::string &suffix) const
 460 {
 461     Addr symbolAddr;
 462     std::string symbol;
 463     if (symtab && symtab->findNearestSymbol(addr, symbol, symbolAddr)) {
 464         ccprintf(os, "%s%s", prefix, symbol);
 465         if (symbolAddr != addr)
 466             ccprintf(os, "+%d", addr - symbolAddr);
 467         ccprintf(os, suffix);
 468     }
 469 }
 470
 471 void
 472 ArmStaticInst::printShiftOperand(std::ostream &os,
 473                                      IntRegIndex rm,
 474                                      bool immShift,
 475                                      uint32_t shiftAmt,
 476                                      IntRegIndex rs,
 477                                      ArmShiftType type) const
 478 {
 479     bool firstOp = false;
 480
 481     if (rm != INTREG_ZERO) {
 482         printIntReg(os, rm);
 483     }
 484
 485     bool done = false;
 486
 487     if ((type == LSR || type == ASR) && immShift && shiftAmt == 0)
 488         shiftAmt = 32;
 489
 490     switch (type) {
 491       case LSL:
 492         if (immShift && shiftAmt == 0) {
 493             done = true;
 494             break;
 495         }
 496         if (!firstOp)
 497             os << ", ";
 498         os << "LSL";
 499         break;
 500       case LSR:
 501         if (!firstOp)
 502             os << ", ";
 503         os << "LSR";
 504         break;
 505       case ASR:
 506         if (!firstOp)
 507             os << ", ";
 508         os << "ASR";
 509         break;
 510       case ROR:
 511         if (immShift && shiftAmt == 0) {
 512             if (!firstOp)
 513                 os << ", ";
 514             os << "RRX";
 515             done = true;
 516             break;
 517         }
 518         if (!firstOp)
 519             os << ", ";
 520         os << "ROR";
 521         break;
 522       default:
 523         panic("Tried to disassemble unrecognized shift type.\n");
 524     }
 525     if (!done) {
 526         if (!firstOp)
 527             os << " ";
 528         if (immShift)
 529             os << "#" << shiftAmt;
 530         else
 531             printIntReg(os, rs);
 532     }
 533 }
 534
 535 void
 536 ArmStaticInst::printExtendOperand(bool firstOperand, std::ostream &os,
 537                                   IntRegIndex rm, ArmExtendType type,
 538                                   int64_t shiftAmt) const
 539 {
 540     if (!firstOperand)
 541         ccprintf(os, ", ");
 542     printIntReg(os, rm);
 543     if (type == UXTX && shiftAmt == 0)
 544         return;
 545     switch (type) {
 546       case UXTB: ccprintf(os, ", UXTB");
 547         break;
 548       case UXTH: ccprintf(os, ", UXTH");
 549         break;
 550       case UXTW: ccprintf(os, ", UXTW");
 551         break;
 552       case UXTX: ccprintf(os, ", LSL");
 553         break;
 554       case SXTB: ccprintf(os, ", SXTB");
 555         break;
 556       case SXTH: ccprintf(os, ", SXTH");
 557         break;
 558       case SXTW: ccprintf(os, ", SXTW");
 559         break;
 560       case SXTX: ccprintf(os, ", SXTW");
 561         break;
 562     }
 563     if (type == UXTX || shiftAmt)
 564         ccprintf(os, " #%d", shiftAmt);
 565 }
 566
 567 void
 568 ArmStaticInst::printDataInst(std::ostream &os, bool withImm,
 569         bool immShift, bool s, IntRegIndex rd, IntRegIndex rn,
 570         IntRegIndex rm, IntRegIndex rs, uint32_t shiftAmt,
 571         ArmShiftType type, uint64_t imm) const
 572 {
 573     printMnemonic(os, s ? "s" : "");
 574     bool firstOp = true;
 575
 576     // Destination
 577     if (rd != INTREG_ZERO) {
 578         firstOp = false;
 579         printIntReg(os, rd);
 580     }
 581
 582     // Source 1.
 583     if (rn != INTREG_ZERO) {
 584         if (!firstOp)
 585             os << ", ";
 586         firstOp = false;
 587         printIntReg(os, rn);
 588     }
 589
 590     if (!firstOp)
 591         os << ", ";
 592     if (withImm) {
 593         ccprintf(os, "#%ld", imm);
 594     } else {
 595         printShiftOperand(os, rm, immShift, shiftAmt, rs, type);
 596     }
 597 }
 598
 599 std::string
 600 ArmStaticInst::generateDisassembly(Addr pc,
 601                                    const SymbolTable *symtab) const
 602 {
 603     std::stringstream ss;
 604     printMnemonic(ss);
 605     return ss.str();
 606 }
 607
 608
 609 Fault
 610 ArmStaticInst::advSIMDFPAccessTrap64(ExceptionLevel el) const
 611 {
 612     switch (el) {
 613       case EL1:
 614         return std::make_shared<SupervisorTrap>(machInst, 0x1E00000,
 615                                                 EC_TRAPPED_SIMD_FP);
 616       case EL2:
 617         return std::make_shared<HypervisorTrap>(machInst, 0x1E00000,
 618                                                 EC_TRAPPED_SIMD_FP);
 619       case EL3:
 620         return std::make_shared<SecureMonitorTrap>(machInst, 0x1E00000,
 621                                                    EC_TRAPPED_SIMD_FP);
 622
 623       default:
 624         panic("Illegal EL in advSIMDFPAccessTrap64\n");
 625     }
 626 }
 627
 628
 629 Fault
 630 ArmStaticInst::checkFPAdvSIMDTrap64(ThreadContext *tc, CPSR cpsr) const
 631 {
 632     const ExceptionLevel el = (ExceptionLevel) (uint8_t)cpsr.el;
 633
 634     if (ArmSystem::haveVirtualization(tc) && el <= EL2) {
 635         HCPTR cptrEnCheck = tc->readMiscReg(MISCREG_CPTR_EL2);
 636         if (cptrEnCheck.tfp)
 637             return advSIMDFPAccessTrap64(EL2);
 638     }
 639
 640     if (ArmSystem::haveSecurity(tc)) {
 641         HCPTR cptrEnCheck = tc->readMiscReg(MISCREG_CPTR_EL3);
 642         if (cptrEnCheck.tfp)
 643             return advSIMDFPAccessTrap64(EL3);
 644     }
 645
 646     return NoFault;
 647 }
 648
 649 Fault
 650 ArmStaticInst::checkFPAdvSIMDEnabled64(ThreadContext *tc,
 651                                        CPSR cpsr, CPACR cpacr) const
 652 {
 653     const ExceptionLevel el = (ExceptionLevel) (uint8_t)cpsr.el;
 654     if ((el == EL0 && cpacr.fpen != 0x3) ||
 655         (el == EL1 && !(cpacr.fpen & 0x1)))
 656         return advSIMDFPAccessTrap64(EL1);
 657
 658     return checkFPAdvSIMDTrap64(tc, cpsr);
 659 }
 660
 661 Fault
 662 ArmStaticInst::checkAdvSIMDOrFPEnabled32(ThreadContext *tc,
 663                                          CPSR cpsr, CPACR cpacr,
 664                                          NSACR nsacr, FPEXC fpexc,
 665                                          bool fpexc_check, bool advsimd) const
 666 {
 667     const bool have_virtualization = ArmSystem::haveVirtualization(tc);
 668     const bool have_security = ArmSystem::haveSecurity(tc);
 669     const bool is_secure = inSecureState(tc);
 670     const ExceptionLevel cur_el = opModeToEL(currOpMode(tc));
 671
 672     if (cur_el == EL0 && ELIs64(tc, EL1))
 673         return checkFPAdvSIMDEnabled64(tc, cpsr, cpacr);
 674
 675     uint8_t cpacr_cp10 = cpacr.cp10;
 676     bool cpacr_asedis = cpacr.asedis;
 677
 678     if (have_security && !ELIs64(tc, EL3) && !is_secure) {
 679         if (nsacr.nsasedis)
 680             cpacr_asedis = true;
 681         if (nsacr.cp10 == 0)
 682             cpacr_cp10 = 0;
 683     }
 684
 685     if (cur_el != EL2) {
 686         if (advsimd && cpacr_asedis)
 687             return disabledFault();
 688
 689         if ((cur_el == EL0 && cpacr_cp10 != 0x3) ||
 690             (cur_el != EL0 && !(cpacr_cp10 & 0x1)))
 691             return disabledFault();
 692     }
 693
 694     if (fpexc_check && !fpexc.en)
 695         return disabledFault();
 696
 697     // -- aarch32/exceptions/traps/AArch32.CheckFPAdvSIMDTrap --
 698
 699     if (have_virtualization && !is_secure && ELIs64(tc, EL2))
 700         return checkFPAdvSIMDTrap64(tc, cpsr);
 701
 702     if (have_virtualization && !is_secure) {
 703         HCPTR hcptr = tc->readMiscReg(MISCREG_HCPTR);
 704         bool hcptr_cp10 = hcptr.tcp10;
 705         bool hcptr_tase = hcptr.tase;
 706
 707         if (have_security && !ELIs64(tc, EL3) && !is_secure) {
 708             if (nsacr.nsasedis)
 709                 hcptr_tase = true;
 710             if (nsacr.cp10)
 711                 hcptr_cp10 = true;
 712         }
 713
 714         if ((advsimd && hcptr_tase) || hcptr_cp10) {
 715             const uint32_t iss = advsimd ? (1 << 5) : 0xA;
 716             if (cur_el == EL2) {
 717                 return std::make_shared<UndefinedInstruction>(
 718                     machInst, iss,
 719                     EC_TRAPPED_HCPTR, mnemonic);
 720             } else {
 721                 return std::make_shared<HypervisorTrap>(
 722                     machInst, iss,
 723                     EC_TRAPPED_HCPTR);
 724             }
 725
 726         }
 727     }
 728
 729     if (have_security && ELIs64(tc, EL3)) {
 730         HCPTR cptrEnCheck = tc->readMiscReg(MISCREG_CPTR_EL3);
 731         if (cptrEnCheck.tfp)
 732             return advSIMDFPAccessTrap64(EL3);
 733     }
 734
 735     return NoFault;
 736 }
 737
 738
 739 static uint8_t
 740 getRestoredITBits(ThreadContext *tc, CPSR spsr)
 741 {
 742     // See: shared/functions/system/RestoredITBits in the ARM ARM
 743
 744     const ExceptionLevel el = opModeToEL((OperatingMode) (uint8_t)spsr.mode);
 745     const uint8_t it = itState(spsr);
 746
 747     if (!spsr.t || spsr.il)
 748         return 0;
 749
 750     // The IT bits are forced to zero when they are set to a reserved
 751     // value.
 752     if (bits(it, 7, 4) != 0 && bits(it, 3, 0) == 0)
 753         return 0;
 754
 755     const bool itd = el == EL2 ?
 756         ((SCTLR)tc->readMiscReg(MISCREG_HSCTLR)).itd :
 757         ((SCTLR)tc->readMiscReg(MISCREG_SCTLR)).itd;
 758
 759     // The IT bits are forced to zero when returning to A32 state, or
 760     // when returning to an EL with the ITD bit set to 1, and the IT
 761     // bits are describing a multi-instruction block.
 762     if (itd && bits(it, 2, 0) != 0)
 763         return 0;
 764
 765     return it;
 766 }
 767
 768 static bool
 769 illegalExceptionReturn(ThreadContext *tc, CPSR cpsr, CPSR spsr)
 770 {
 771     const OperatingMode mode = (OperatingMode) (uint8_t)spsr.mode;
 772     if (badMode(mode))
 773         return true;
 774
 775     const OperatingMode cur_mode = (OperatingMode) (uint8_t)cpsr.mode;
 776     const ExceptionLevel target_el = opModeToEL(mode);
 777     if (target_el > opModeToEL(cur_mode))
 778         return true;
 779
 780     if (target_el == EL3 && !ArmSystem::haveSecurity(tc))
 781         return true;
 782
 783     if (target_el == EL2 && !ArmSystem::haveVirtualization(tc))
 784         return true;
 785
 786     if (!spsr.width) {
 787         // aarch64
 788         if (!ArmSystem::highestELIs64(tc))
 789             return true;
 790
 791         if (spsr & 0x2)
 792             return true;
 793         if (target_el == EL0 && spsr.sp)
 794             return true;
 795         if (target_el == EL2 && !((SCR)tc->readMiscReg(MISCREG_SCR_EL3)).ns)
 796             return false;
 797     } else {
 798         return badMode32(mode);
 799     }
 800
 801     return false;
 802 }
 803
 804 CPSR
 805 ArmStaticInst::getPSTATEFromPSR(ThreadContext *tc, CPSR cpsr, CPSR spsr) const
 806 {
 807     CPSR new_cpsr = 0;
 808
 809     // gem5 doesn't implement single-stepping, so force the SS bit to
 810     // 0.
 811     new_cpsr.ss = 0;
 812
 813     if (illegalExceptionReturn(tc, cpsr, spsr)) {
 814         new_cpsr.il = 1;
 815     } else {
 816         new_cpsr.il = spsr.il;
 817         if (spsr.width && badMode32((OperatingMode)(uint8_t)spsr.mode)) {
 818             new_cpsr.il = 1;
 819         } else if (spsr.width) {
 820             new_cpsr.mode = spsr.mode;
 821         } else {
 822             new_cpsr.el = spsr.el;
 823             new_cpsr.sp = spsr.sp;
 824         }
 825     }
 826
 827     new_cpsr.nz = spsr.nz;
 828     new_cpsr.c = spsr.c;
 829     new_cpsr.v = spsr.v;
 830     if (new_cpsr.width) {
 831         // aarch32
 832         const ITSTATE it = getRestoredITBits(tc, spsr);
 833         new_cpsr.q = spsr.q;
 834         new_cpsr.ge = spsr.ge;
 835         new_cpsr.e = spsr.e;
 836         new_cpsr.aif = spsr.aif;
 837         new_cpsr.t = spsr.t;
 838         new_cpsr.it2 = it.top6;
 839         new_cpsr.it1 = it.bottom2;
 840     } else {
 841         // aarch64
 842         new_cpsr.daif = spsr.daif;
 843     }
 844
 845     return new_cpsr;
 846 }
 847
 848
 849
 850 }