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   1 /*
   2  * cp1emu.c: a MIPS coprocessor 1 (fpu) instruction emulator
   3  *
   4  * MIPS floating point support
   5  * Copyright (C) 1994-2000 Algorithmics Ltd.
   6  * http://www.algor.co.uk
   7  *
   8  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
   9  * Copyright (C) 2000  MIPS Technologies, Inc.
  10  *
  11  *  This program is free software; you can distribute it and/or modify it
  12  *  under the terms of the GNU General Public License (Version 2) as
  13  *  published by the Free Software Foundation.
  14  *
  15  *  This program is distributed in the hope it will be useful, but WITHOUT
  16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18  *  for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  23  *
  24  * A complete emulator for MIPS coprocessor 1 instructions.  This is
  25  * required for #float(switch) or #float(trap), where it catches all
  26  * COP1 instructions via the "CoProcessor Unusable" exception.
  27  *
  28  * More surprisingly it is also required for #float(ieee), to help out
  29  * the hardware fpu at the boundaries of the IEEE-754 representation
  30  * (denormalised values, infinities, underflow, etc).  It is made
  31  * quite nasty because emulation of some non-COP1 instructions is
  32  * required, e.g. in branch delay slots.
  33  *
  34  * Note if you know that you won't have an fpu, then you'll get much
  35  * better performance by compiling with -msoft-float!
  36  */
  37 #include <linux/sched.h>
  38
  39 #include <asm/inst.h>
  40 #include <asm/bootinfo.h>
  41 #include <asm/cpu.h>
  42 #include <asm/cpu-features.h>
  43 #include <asm/processor.h>
  44 #include <asm/ptrace.h>
  45 #include <asm/signal.h>
  46 #include <asm/mipsregs.h>
  47 #include <asm/fpu_emulator.h>
  48 #include <asm/uaccess.h>
  49 #include <asm/branch.h>
  50
  51 #include "ieee754.h"
  52 #include "dsemul.h"
  53
  54 /* Strap kernel emulator for full MIPS IV emulation */
  55
  56 #ifdef __mips
  57 #undef __mips
  58 #endif
  59 #define __mips 4
  60
  61 /* Function which emulates a floating point instruction. */
  62
  63 static int fpu_emu(struct pt_regs *, struct mips_fpu_soft_struct *,
  64         mips_instruction);
  65
  66 #if __mips >= 4 && __mips != 32
  67 static int fpux_emu(struct pt_regs *,
  68         struct mips_fpu_soft_struct *, mips_instruction);
  69 #endif
  70
  71 /* Further private data for which no space exists in mips_fpu_soft_struct */
  72
  73 struct mips_fpu_emulator_stats fpuemustats;
  74
  75 /* Control registers */
  76
  77 #define FPCREG_RID      0       /* $0  = revision id */
  78 #define FPCREG_CSR      31      /* $31 = csr */
  79
  80 /* Convert Mips rounding mode (0..3) to IEEE library modes. */
  81 static const unsigned char ieee_rm[4] = {
  82         [FPU_CSR_RN] = IEEE754_RN,
  83         [FPU_CSR_RZ] = IEEE754_RZ,
  84         [FPU_CSR_RU] = IEEE754_RU,
  85         [FPU_CSR_RD] = IEEE754_RD,
  86 };
  87 /* Convert IEEE library modes to Mips rounding mode (0..3). */
  88 static const unsigned char mips_rm[4] = {
  89         [IEEE754_RN] = FPU_CSR_RN,
  90         [IEEE754_RZ] = FPU_CSR_RZ,
  91         [IEEE754_RD] = FPU_CSR_RD,
  92         [IEEE754_RU] = FPU_CSR_RU,
  93 };
  94
  95 #if __mips >= 4
  96 /* convert condition code register number to csr bit */
  97 static const unsigned int fpucondbit[8] = {
  98         FPU_CSR_COND0,
  99         FPU_CSR_COND1,
 100         FPU_CSR_COND2,
 101         FPU_CSR_COND3,
 102         FPU_CSR_COND4,
 103         FPU_CSR_COND5,
 104         FPU_CSR_COND6,
 105         FPU_CSR_COND7
 106 };
 107 #endif
 108
 109
 110 /*
 111  * Redundant with logic already in kernel/branch.c,
 112  * embedded in compute_return_epc.  At some point,
 113  * a single subroutine should be used across both
 114  * modules.
 115  */
 116 static int isBranchInstr(mips_instruction * i)
 117 {
 118         switch (MIPSInst_OPCODE(*i)) {
 119         case spec_op:
 120                 switch (MIPSInst_FUNC(*i)) {
 121                 case jalr_op:
 122                 case jr_op:
 123                         return 1;
 124                 }
 125                 break;
 126
 127         case bcond_op:
 128                 switch (MIPSInst_RT(*i)) {
 129                 case bltz_op:
 130                 case bgez_op:
 131                 case bltzl_op:
 132                 case bgezl_op:
 133                 case bltzal_op:
 134                 case bgezal_op:
 135                 case bltzall_op:
 136                 case bgezall_op:
 137                         return 1;
 138                 }
 139                 break;
 140
 141         case j_op:
 142         case jal_op:
 143         case jalx_op:
 144         case beq_op:
 145         case bne_op:
 146         case blez_op:
 147         case bgtz_op:
 148         case beql_op:
 149         case bnel_op:
 150         case blezl_op:
 151         case bgtzl_op:
 152                 return 1;
 153
 154         case cop0_op:
 155         case cop1_op:
 156         case cop2_op:
 157         case cop1x_op:
 158                 if (MIPSInst_RS(*i) == bc_op)
 159                         return 1;
 160                 break;
 161         }
 162
 163         return 0;
 164 }
 165
 166 /*
 167  * In the Linux kernel, we support selection of FPR format on the
 168  * basis of the Status.FR bit.  This does imply that, if a full 32
 169  * FPRs are desired, there needs to be a flip-flop that can be written
 170  * to one at that bit position.  In any case, O32 MIPS ABI uses
 171  * only the even FPRs (Status.FR = 0).
 172  */
 173
 174 #define CP0_STATUS_FR_SUPPORT
 175
 176 #ifdef CP0_STATUS_FR_SUPPORT
 177 #define FR_BIT ST0_FR
 178 #else
 179 #define FR_BIT 0
 180 #endif
 181
 182 #define SIFROMREG(si,x) ((si) = \
 183                         (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
 184                         (int)ctx->fpr[x] : \
 185                         (int)(ctx->fpr[x & ~1] >> 32 ))
 186 #define SITOREG(si,x)   (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] = \
 187                         (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
 188                         ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
 189                         ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
 190
 191 #define DIFROMREG(di,x) ((di) = \
 192                         ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)])
 193 #define DITOREG(di,x)   (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] \
 194                         = (di))
 195
 196 #define SPFROMREG(sp,x) SIFROMREG((sp).bits,x)
 197 #define SPTOREG(sp,x)   SITOREG((sp).bits,x)
 198 #define DPFROMREG(dp,x) DIFROMREG((dp).bits,x)
 199 #define DPTOREG(dp,x)   DITOREG((dp).bits,x)
 200
 201 /*
 202  * Emulate the single floating point instruction pointed at by EPC.
 203  * Two instructions if the instruction is in a branch delay slot.
 204  */
 205
 206 static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx)
 207 {
 208         mips_instruction ir;
 209         void * emulpc, *contpc;
 210         unsigned int cond;
 211
 212         if (get_user(ir, (mips_instruction __user *) xcp->cp0_epc)) {
 213                 fpuemustats.errors++;
 214                 return SIGBUS;
 215         }
 216
 217         /* XXX NEC Vr54xx bug workaround */
 218         if ((xcp->cp0_cause & CAUSEF_BD) && !isBranchInstr(&ir))
 219                 xcp->cp0_cause &= ~CAUSEF_BD;
 220
 221         if (xcp->cp0_cause & CAUSEF_BD) {
 222                 /*
 223                  * The instruction to be emulated is in a branch delay slot
 224                  * which means that we have to  emulate the branch instruction
 225                  * BEFORE we do the cop1 instruction.
 226                  *
 227                  * This branch could be a COP1 branch, but in that case we
 228                  * would have had a trap for that instruction, and would not
 229                  * come through this route.
 230                  *
 231                  * Linux MIPS branch emulator operates on context, updating the
 232                  * cp0_epc.
 233                  */
 234                 emulpc = (void *) (xcp->cp0_epc + 4);   /* Snapshot emulation target */
 235
 236                 if (__compute_return_epc(xcp)) {
 237 #ifdef CP1DBG
 238                         printk("failed to emulate branch at %p\n",
 239                                 (void *) (xcp->cp0_epc));
 240 #endif
 241                         return SIGILL;
 242                 }
 243                 if (get_user(ir, (mips_instruction __user *) emulpc)) {
 244                         fpuemustats.errors++;
 245                         return SIGBUS;
 246                 }
 247                 /* __compute_return_epc() will have updated cp0_epc */
 248                 contpc = (void *)  xcp->cp0_epc;
 249                 /* In order not to confuse ptrace() et al, tweak context */
 250                 xcp->cp0_epc = (unsigned long) emulpc - 4;
 251         } else {
 252                 emulpc = (void *)  xcp->cp0_epc;
 253                 contpc = (void *) (xcp->cp0_epc + 4);
 254         }
 255
 256       emul:
 257         fpuemustats.emulated++;
 258         switch (MIPSInst_OPCODE(ir)) {
 259         case ldc1_op:{
 260                 u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
 261                         MIPSInst_SIMM(ir));
 262                 u64 val;
 263
 264                 fpuemustats.loads++;
 265                 if (get_user(val, va)) {
 266                         fpuemustats.errors++;
 267                         return SIGBUS;
 268                 }
 269                 DITOREG(val, MIPSInst_RT(ir));
 270                 break;
 271         }
 272
 273         case sdc1_op:{
 274                 u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
 275                         MIPSInst_SIMM(ir));
 276                 u64 val;
 277
 278                 fpuemustats.stores++;
 279                 DIFROMREG(val, MIPSInst_RT(ir));
 280                 if (put_user(val, va)) {
 281                         fpuemustats.errors++;
 282                         return SIGBUS;
 283                 }
 284                 break;
 285         }
 286
 287         case lwc1_op:{
 288                 u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
 289                         MIPSInst_SIMM(ir));
 290                 u32 val;
 291
 292                 fpuemustats.loads++;
 293                 if (get_user(val, va)) {
 294                         fpuemustats.errors++;
 295                         return SIGBUS;
 296                 }
 297                 SITOREG(val, MIPSInst_RT(ir));
 298                 break;
 299         }
 300
 301         case swc1_op:{
 302                 u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
 303                         MIPSInst_SIMM(ir));
 304                 u32 val;
 305
 306                 fpuemustats.stores++;
 307                 SIFROMREG(val, MIPSInst_RT(ir));
 308                 if (put_user(val, va)) {
 309                         fpuemustats.errors++;
 310                         return SIGBUS;
 311                 }
 312                 break;
 313         }
 314
 315         case cop1_op:
 316                 switch (MIPSInst_RS(ir)) {
 317
 318 #if defined(__mips64)
 319                 case dmfc_op:
 320                         /* copregister fs -> gpr[rt] */
 321                         if (MIPSInst_RT(ir) != 0) {
 322                                 DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
 323                                         MIPSInst_RD(ir));
 324                         }
 325                         break;
 326
 327                 case dmtc_op:
 328                         /* copregister fs <- rt */
 329                         DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
 330                         break;
 331 #endif
 332
 333                 case mfc_op:
 334                         /* copregister rd -> gpr[rt] */
 335                         if (MIPSInst_RT(ir) != 0) {
 336                                 SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
 337                                         MIPSInst_RD(ir));
 338                         }
 339                         break;
 340
 341                 case mtc_op:
 342                         /* copregister rd <- rt */
 343                         SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
 344                         break;
 345
 346                 case cfc_op:{
 347                         /* cop control register rd -> gpr[rt] */
 348                         u32 value;
 349
 350                         if (ir == CP1UNDEF) {
 351                                 return do_dsemulret(xcp);
 352                         }
 353                         if (MIPSInst_RD(ir) == FPCREG_CSR) {
 354                                 value = ctx->fcr31;
 355                                 value = (value & ~0x3) | mips_rm[value & 0x3];
 356 #ifdef CSRTRACE
 357                                 printk("%p gpr[%d]<-csr=%08x\n",
 358                                         (void *) (xcp->cp0_epc),
 359                                         MIPSInst_RT(ir), value);
 360 #endif
 361                         }
 362                         else if (MIPSInst_RD(ir) == FPCREG_RID)
 363                                 value = 0;
 364                         else
 365                                 value = 0;
 366                         if (MIPSInst_RT(ir))
 367                                 xcp->regs[MIPSInst_RT(ir)] = value;
 368                         break;
 369                 }
 370
 371                 case ctc_op:{
 372                         /* copregister rd <- rt */
 373                         u32 value;
 374
 375                         if (MIPSInst_RT(ir) == 0)
 376                                 value = 0;
 377                         else
 378                                 value = xcp->regs[MIPSInst_RT(ir)];
 379
 380                         /* we only have one writable control reg
 381                          */
 382                         if (MIPSInst_RD(ir) == FPCREG_CSR) {
 383 #ifdef CSRTRACE
 384                                 printk("%p gpr[%d]->csr=%08x\n",
 385                                         (void *) (xcp->cp0_epc),
 386                                         MIPSInst_RT(ir), value);
 387 #endif
 388                                 value &= (FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
 389                                 ctx->fcr31 &= ~(FPU_CSR_FLUSH | FPU_CSR_ALL_E | FPU_CSR_ALL_S | 0x03);
 390                                 /* convert to ieee library modes */
 391                                 ctx->fcr31 |= (value & ~0x3) | ieee_rm[value & 0x3];
 392                         }
 393                         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
 394                                 return SIGFPE;
 395                         }
 396                         break;
 397                 }
 398
 399                 case bc_op:{
 400                         int likely = 0;
 401
 402                         if (xcp->cp0_cause & CAUSEF_BD)
 403                                 return SIGILL;
 404
 405 #if __mips >= 4
 406                         cond = ctx->fcr31 & fpucondbit[MIPSInst_RT(ir) >> 2];
 407 #else
 408                         cond = ctx->fcr31 & FPU_CSR_COND;
 409 #endif
 410                         switch (MIPSInst_RT(ir) & 3) {
 411                         case bcfl_op:
 412                                 likely = 1;
 413                         case bcf_op:
 414                                 cond = !cond;
 415                                 break;
 416                         case bctl_op:
 417                                 likely = 1;
 418                         case bct_op:
 419                                 break;
 420                         default:
 421                                 /* thats an illegal instruction */
 422                                 return SIGILL;
 423                         }
 424
 425                         xcp->cp0_cause |= CAUSEF_BD;
 426                         if (cond) {
 427                                 /* branch taken: emulate dslot
 428                                  * instruction
 429                                  */
 430                                 xcp->cp0_epc += 4;
 431                                 contpc = (void *)
 432                                         (xcp->cp0_epc +
 433                                         (MIPSInst_SIMM(ir) << 2));
 434
 435                                 if (get_user(ir,
 436                                     (mips_instruction __user *) xcp->cp0_epc)) {
 437                                         fpuemustats.errors++;
 438                                         return SIGBUS;
 439                                 }
 440
 441                                 switch (MIPSInst_OPCODE(ir)) {
 442                                 case lwc1_op:
 443                                 case swc1_op:
 444 #if (__mips >= 2 || defined(__mips64))
 445                                 case ldc1_op:
 446                                 case sdc1_op:
 447 #endif
 448                                 case cop1_op:
 449 #if __mips >= 4 && __mips != 32
 450                                 case cop1x_op:
 451 #endif
 452                                         /* its one of ours */
 453                                         goto emul;
 454 #if __mips >= 4
 455                                 case spec_op:
 456                                         if (MIPSInst_FUNC(ir) == movc_op)
 457                                                 goto emul;
 458                                         break;
 459 #endif
 460                                 }
 461
 462                                 /*
 463                                  * Single step the non-cp1
 464                                  * instruction in the dslot
 465                                  */
 466                                 return mips_dsemul(xcp, ir, (unsigned long) contpc);
 467                         }
 468                         else {
 469                                 /* branch not taken */
 470                                 if (likely) {
 471                                         /*
 472                                          * branch likely nullifies
 473                                          * dslot if not taken
 474                                          */
 475                                         xcp->cp0_epc += 4;
 476                                         contpc += 4;
 477                                         /*
 478                                          * else continue & execute
 479                                          * dslot as normal insn
 480                                          */
 481                                 }
 482                         }
 483                         break;
 484                 }
 485
 486                 default:
 487                         if (!(MIPSInst_RS(ir) & 0x10))
 488                                 return SIGILL;
 489                         {
 490                                 int sig;
 491
 492                                 /* a real fpu computation instruction */
 493                                 if ((sig = fpu_emu(xcp, ctx, ir)))
 494                                         return sig;
 495                         }
 496                 }
 497                 break;
 498
 499 #if __mips >= 4 && __mips != 32
 500         case cop1x_op:{
 501                 int sig;
 502
 503                 if ((sig = fpux_emu(xcp, ctx, ir)))
 504                         return sig;
 505                 break;
 506         }
 507 #endif
 508
 509 #if __mips >= 4
 510         case spec_op:
 511                 if (MIPSInst_FUNC(ir) != movc_op)
 512                         return SIGILL;
 513                 cond = fpucondbit[MIPSInst_RT(ir) >> 2];
 514                 if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
 515                         xcp->regs[MIPSInst_RD(ir)] =
 516                                 xcp->regs[MIPSInst_RS(ir)];
 517                 break;
 518 #endif
 519
 520         default:
 521                 return SIGILL;
 522         }
 523
 524         /* we did it !! */
 525         xcp->cp0_epc = (unsigned long) contpc;
 526         xcp->cp0_cause &= ~CAUSEF_BD;
 527
 528         return 0;
 529 }
 530
 531 /*
 532  * Conversion table from MIPS compare ops 48-63
 533  * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
 534  */
 535 static const unsigned char cmptab[8] = {
 536         0,                      /* cmp_0 (sig) cmp_sf */
 537         IEEE754_CUN,            /* cmp_un (sig) cmp_ngle */
 538         IEEE754_CEQ,            /* cmp_eq (sig) cmp_seq */
 539         IEEE754_CEQ | IEEE754_CUN,      /* cmp_ueq (sig) cmp_ngl  */
 540         IEEE754_CLT,            /* cmp_olt (sig) cmp_lt */
 541         IEEE754_CLT | IEEE754_CUN,      /* cmp_ult (sig) cmp_nge */
 542         IEEE754_CLT | IEEE754_CEQ,      /* cmp_ole (sig) cmp_le */
 543         IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN,        /* cmp_ule (sig) cmp_ngt */
 544 };
 545
 546
 547 #if __mips >= 4 && __mips != 32
 548
 549 /*
 550  * Additional MIPS4 instructions
 551  */
 552
 553 #define DEF3OP(name, p, f1, f2, f3) \
 554 static ieee754##p fpemu_##p##_##name (ieee754##p r, ieee754##p s, \
 555     ieee754##p t) \
 556 { \
 557         struct _ieee754_csr ieee754_csr_save; \
 558         s = f1 (s, t); \
 559         ieee754_csr_save = ieee754_csr; \
 560         s = f2 (s, r); \
 561         ieee754_csr_save.cx |= ieee754_csr.cx; \
 562         ieee754_csr_save.sx |= ieee754_csr.sx; \
 563         s = f3 (s); \
 564         ieee754_csr.cx |= ieee754_csr_save.cx; \
 565         ieee754_csr.sx |= ieee754_csr_save.sx; \
 566         return s; \
 567 }
 568
 569 static ieee754dp fpemu_dp_recip(ieee754dp d)
 570 {
 571         return ieee754dp_div(ieee754dp_one(0), d);
 572 }
 573
 574 static ieee754dp fpemu_dp_rsqrt(ieee754dp d)
 575 {
 576         return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
 577 }
 578
 579 static ieee754sp fpemu_sp_recip(ieee754sp s)
 580 {
 581         return ieee754sp_div(ieee754sp_one(0), s);
 582 }
 583
 584 static ieee754sp fpemu_sp_rsqrt(ieee754sp s)
 585 {
 586         return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
 587 }
 588
 589 DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add,);
 590 DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub,);
 591 DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
 592 DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
 593 DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add,);
 594 DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub,);
 595 DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
 596 DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);
 597
 598 static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
 599         mips_instruction ir)
 600 {
 601         unsigned rcsr = 0;      /* resulting csr */
 602
 603         fpuemustats.cp1xops++;
 604
 605         switch (MIPSInst_FMA_FFMT(ir)) {
 606         case s_fmt:{            /* 0 */
 607
 608                 ieee754sp(*handler) (ieee754sp, ieee754sp, ieee754sp);
 609                 ieee754sp fd, fr, fs, ft;
 610                 u32 __user *va;
 611                 u32 val;
 612
 613                 switch (MIPSInst_FUNC(ir)) {
 614                 case lwxc1_op:
 615                         va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
 616                                 xcp->regs[MIPSInst_FT(ir)]);
 617
 618                         fpuemustats.loads++;
 619                         if (get_user(val, va)) {
 620                                 fpuemustats.errors++;
 621                                 return SIGBUS;
 622                         }
 623                         SITOREG(val, MIPSInst_FD(ir));
 624                         break;
 625
 626                 case swxc1_op:
 627                         va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
 628                                 xcp->regs[MIPSInst_FT(ir)]);
 629
 630                         fpuemustats.stores++;
 631
 632                         SIFROMREG(val, MIPSInst_FS(ir));
 633                         if (put_user(val, va)) {
 634                                 fpuemustats.errors++;
 635                                 return SIGBUS;
 636                         }
 637                         break;
 638
 639                 case madd_s_op:
 640                         handler = fpemu_sp_madd;
 641                         goto scoptop;
 642                 case msub_s_op:
 643                         handler = fpemu_sp_msub;
 644                         goto scoptop;
 645                 case nmadd_s_op:
 646                         handler = fpemu_sp_nmadd;
 647                         goto scoptop;
 648                 case nmsub_s_op:
 649                         handler = fpemu_sp_nmsub;
 650                         goto scoptop;
 651
 652                       scoptop:
 653                         SPFROMREG(fr, MIPSInst_FR(ir));
 654                         SPFROMREG(fs, MIPSInst_FS(ir));
 655                         SPFROMREG(ft, MIPSInst_FT(ir));
 656                         fd = (*handler) (fr, fs, ft);
 657                         SPTOREG(fd, MIPSInst_FD(ir));
 658
 659                       copcsr:
 660                         if (ieee754_cxtest(IEEE754_INEXACT))
 661                                 rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
 662                         if (ieee754_cxtest(IEEE754_UNDERFLOW))
 663                                 rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
 664                         if (ieee754_cxtest(IEEE754_OVERFLOW))
 665                                 rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
 666                         if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
 667                                 rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
 668
 669                         ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
 670                         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
 671                                 /*printk ("SIGFPE: fpu csr = %08x\n",
 672                                    ctx->fcr31); */
 673                                 return SIGFPE;
 674                         }
 675
 676                         break;
 677
 678                 default:
 679                         return SIGILL;
 680                 }
 681                 break;
 682         }
 683
 684         case d_fmt:{            /* 1 */
 685                 ieee754dp(*handler) (ieee754dp, ieee754dp, ieee754dp);
 686                 ieee754dp fd, fr, fs, ft;
 687                 u64 __user *va;
 688                 u64 val;
 689
 690                 switch (MIPSInst_FUNC(ir)) {
 691                 case ldxc1_op:
 692                         va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
 693                                 xcp->regs[MIPSInst_FT(ir)]);
 694
 695                         fpuemustats.loads++;
 696                         if (get_user(val, va)) {
 697                                 fpuemustats.errors++;
 698                                 return SIGBUS;
 699                         }
 700                         DITOREG(val, MIPSInst_FD(ir));
 701                         break;
 702
 703                 case sdxc1_op:
 704                         va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
 705                                 xcp->regs[MIPSInst_FT(ir)]);
 706
 707                         fpuemustats.stores++;
 708                         DIFROMREG(val, MIPSInst_FS(ir));
 709                         if (put_user(val, va)) {
 710                                 fpuemustats.errors++;
 711                                 return SIGBUS;
 712                         }
 713                         break;
 714
 715                 case madd_d_op:
 716                         handler = fpemu_dp_madd;
 717                         goto dcoptop;
 718                 case msub_d_op:
 719                         handler = fpemu_dp_msub;
 720                         goto dcoptop;
 721                 case nmadd_d_op:
 722                         handler = fpemu_dp_nmadd;
 723                         goto dcoptop;
 724                 case nmsub_d_op:
 725                         handler = fpemu_dp_nmsub;
 726                         goto dcoptop;
 727
 728                       dcoptop:
 729                         DPFROMREG(fr, MIPSInst_FR(ir));
 730                         DPFROMREG(fs, MIPSInst_FS(ir));
 731                         DPFROMREG(ft, MIPSInst_FT(ir));
 732                         fd = (*handler) (fr, fs, ft);
 733                         DPTOREG(fd, MIPSInst_FD(ir));
 734                         goto copcsr;
 735
 736                 default:
 737                         return SIGILL;
 738                 }
 739                 break;
 740         }
 741
 742         case 0x7:               /* 7 */
 743                 if (MIPSInst_FUNC(ir) != pfetch_op) {
 744                         return SIGILL;
 745                 }
 746                 /* ignore prefx operation */
 747                 break;
 748
 749         default:
 750                 return SIGILL;
 751         }
 752
 753         return 0;
 754 }
 755 #endif
 756
 757
 758
 759 /*
 760  * Emulate a single COP1 arithmetic instruction.
 761  */
 762 static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
 763         mips_instruction ir)
 764 {
 765         int rfmt;               /* resulting format */
 766         unsigned rcsr = 0;      /* resulting csr */
 767         unsigned cond;
 768         union {
 769                 ieee754dp d;
 770                 ieee754sp s;
 771                 int w;
 772 #ifdef __mips64
 773                 s64 l;
 774 #endif
 775         } rv;                   /* resulting value */
 776
 777         fpuemustats.cp1ops++;
 778         switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
 779         case s_fmt:{            /* 0 */
 780                 union {
 781                         ieee754sp(*b) (ieee754sp, ieee754sp);
 782                         ieee754sp(*u) (ieee754sp);
 783                 } handler;
 784
 785                 switch (MIPSInst_FUNC(ir)) {
 786                         /* binary ops */
 787                 case fadd_op:
 788                         handler.b = ieee754sp_add;
 789                         goto scopbop;
 790                 case fsub_op:
 791                         handler.b = ieee754sp_sub;
 792                         goto scopbop;
 793                 case fmul_op:
 794                         handler.b = ieee754sp_mul;
 795                         goto scopbop;
 796                 case fdiv_op:
 797                         handler.b = ieee754sp_div;
 798                         goto scopbop;
 799
 800                         /* unary  ops */
 801 #if __mips >= 2 || defined(__mips64)
 802                 case fsqrt_op:
 803                         handler.u = ieee754sp_sqrt;
 804                         goto scopuop;
 805 #endif
 806 #if __mips >= 4 && __mips != 32
 807                 case frsqrt_op:
 808                         handler.u = fpemu_sp_rsqrt;
 809                         goto scopuop;
 810                 case frecip_op:
 811                         handler.u = fpemu_sp_recip;
 812                         goto scopuop;
 813 #endif
 814 #if __mips >= 4
 815                 case fmovc_op:
 816                         cond = fpucondbit[MIPSInst_FT(ir) >> 2];
 817                         if (((ctx->fcr31 & cond) != 0) !=
 818                                 ((MIPSInst_FT(ir) & 1) != 0))
 819                                 return 0;
 820                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 821                         break;
 822                 case fmovz_op:
 823                         if (xcp->regs[MIPSInst_FT(ir)] != 0)
 824                                 return 0;
 825                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 826                         break;
 827                 case fmovn_op:
 828                         if (xcp->regs[MIPSInst_FT(ir)] == 0)
 829                                 return 0;
 830                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 831                         break;
 832 #endif
 833                 case fabs_op:
 834                         handler.u = ieee754sp_abs;
 835                         goto scopuop;
 836                 case fneg_op:
 837                         handler.u = ieee754sp_neg;
 838                         goto scopuop;
 839                 case fmov_op:
 840                         /* an easy one */
 841                         SPFROMREG(rv.s, MIPSInst_FS(ir));
 842                         goto copcsr;
 843
 844                         /* binary op on handler */
 845                       scopbop:
 846                         {
 847                                 ieee754sp fs, ft;
 848
 849                                 SPFROMREG(fs, MIPSInst_FS(ir));
 850                                 SPFROMREG(ft, MIPSInst_FT(ir));
 851
 852                                 rv.s = (*handler.b) (fs, ft);
 853                                 goto copcsr;
 854                         }
 855                       scopuop:
 856                         {
 857                                 ieee754sp fs;
 858
 859                                 SPFROMREG(fs, MIPSInst_FS(ir));
 860                                 rv.s = (*handler.u) (fs);
 861                                 goto copcsr;
 862                         }
 863                       copcsr:
 864                         if (ieee754_cxtest(IEEE754_INEXACT))
 865                                 rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
 866                         if (ieee754_cxtest(IEEE754_UNDERFLOW))
 867                                 rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
 868                         if (ieee754_cxtest(IEEE754_OVERFLOW))
 869                                 rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
 870                         if (ieee754_cxtest(IEEE754_ZERO_DIVIDE))
 871                                 rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
 872                         if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
 873                                 rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
 874                         break;
 875
 876                         /* unary conv ops */
 877                 case fcvts_op:
 878                         return SIGILL;  /* not defined */
 879                 case fcvtd_op:{
 880                         ieee754sp fs;
 881
 882                         SPFROMREG(fs, MIPSInst_FS(ir));
 883                         rv.d = ieee754dp_fsp(fs);
 884                         rfmt = d_fmt;
 885                         goto copcsr;
 886                 }
 887                 case fcvtw_op:{
 888                         ieee754sp fs;
 889
 890                         SPFROMREG(fs, MIPSInst_FS(ir));
 891                         rv.w = ieee754sp_tint(fs);
 892                         rfmt = w_fmt;
 893                         goto copcsr;
 894                 }
 895
 896 #if __mips >= 2 || defined(__mips64)
 897                 case fround_op:
 898                 case ftrunc_op:
 899                 case fceil_op:
 900                 case ffloor_op:{
 901                         unsigned int oldrm = ieee754_csr.rm;
 902                         ieee754sp fs;
 903
 904                         SPFROMREG(fs, MIPSInst_FS(ir));
 905                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
 906                         rv.w = ieee754sp_tint(fs);
 907                         ieee754_csr.rm = oldrm;
 908                         rfmt = w_fmt;
 909                         goto copcsr;
 910                 }
 911 #endif /* __mips >= 2 */
 912
 913 #if defined(__mips64)
 914                 case fcvtl_op:{
 915                         ieee754sp fs;
 916
 917                         SPFROMREG(fs, MIPSInst_FS(ir));
 918                         rv.l = ieee754sp_tlong(fs);
 919                         rfmt = l_fmt;
 920                         goto copcsr;
 921                 }
 922
 923                 case froundl_op:
 924                 case ftruncl_op:
 925                 case fceill_op:
 926                 case ffloorl_op:{
 927                         unsigned int oldrm = ieee754_csr.rm;
 928                         ieee754sp fs;
 929
 930                         SPFROMREG(fs, MIPSInst_FS(ir));
 931                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
 932                         rv.l = ieee754sp_tlong(fs);
 933                         ieee754_csr.rm = oldrm;
 934                         rfmt = l_fmt;
 935                         goto copcsr;
 936                 }
 937 #endif /* defined(__mips64) */
 938
 939                 default:
 940                         if (MIPSInst_FUNC(ir) >= fcmp_op) {
 941                                 unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
 942                                 ieee754sp fs, ft;
 943
 944                                 SPFROMREG(fs, MIPSInst_FS(ir));
 945                                 SPFROMREG(ft, MIPSInst_FT(ir));
 946                                 rv.w = ieee754sp_cmp(fs, ft,
 947                                         cmptab[cmpop & 0x7], cmpop & 0x8);
 948                                 rfmt = -1;
 949                                 if ((cmpop & 0x8) && ieee754_cxtest
 950                                         (IEEE754_INVALID_OPERATION))
 951                                         rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
 952                                 else
 953                                         goto copcsr;
 954
 955                         }
 956                         else {
 957                                 return SIGILL;
 958                         }
 959                         break;
 960                 }
 961                 break;
 962         }
 963
 964         case d_fmt:{
 965                 union {
 966                         ieee754dp(*b) (ieee754dp, ieee754dp);
 967                         ieee754dp(*u) (ieee754dp);
 968                 } handler;
 969
 970                 switch (MIPSInst_FUNC(ir)) {
 971                         /* binary ops */
 972                 case fadd_op:
 973                         handler.b = ieee754dp_add;
 974                         goto dcopbop;
 975                 case fsub_op:
 976                         handler.b = ieee754dp_sub;
 977                         goto dcopbop;
 978                 case fmul_op:
 979                         handler.b = ieee754dp_mul;
 980                         goto dcopbop;
 981                 case fdiv_op:
 982                         handler.b = ieee754dp_div;
 983                         goto dcopbop;
 984
 985                         /* unary  ops */
 986 #if __mips >= 2 || defined(__mips64)
 987                 case fsqrt_op:
 988                         handler.u = ieee754dp_sqrt;
 989                         goto dcopuop;
 990 #endif
 991 #if __mips >= 4 && __mips != 32
 992                 case frsqrt_op:
 993                         handler.u = fpemu_dp_rsqrt;
 994                         goto dcopuop;
 995                 case frecip_op:
 996                         handler.u = fpemu_dp_recip;
 997                         goto dcopuop;
 998 #endif
 999 #if __mips >= 4
1000                 case fmovc_op:
1001                         cond = fpucondbit[MIPSInst_FT(ir) >> 2];
1002                         if (((ctx->fcr31 & cond) != 0) !=
1003                                 ((MIPSInst_FT(ir) & 1) != 0))
1004                                 return 0;
1005                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1006                         break;
1007                 case fmovz_op:
1008                         if (xcp->regs[MIPSInst_FT(ir)] != 0)
1009                                 return 0;
1010                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1011                         break;
1012                 case fmovn_op:
1013                         if (xcp->regs[MIPSInst_FT(ir)] == 0)
1014                                 return 0;
1015                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1016                         break;
1017 #endif
1018                 case fabs_op:
1019                         handler.u = ieee754dp_abs;
1020                         goto dcopuop;
1021
1022                 case fneg_op:
1023                         handler.u = ieee754dp_neg;
1024                         goto dcopuop;
1025
1026                 case fmov_op:
1027                         /* an easy one */
1028                         DPFROMREG(rv.d, MIPSInst_FS(ir));
1029                         goto copcsr;
1030
1031                         /* binary op on handler */
1032                       dcopbop:{
1033                                 ieee754dp fs, ft;
1034
1035                                 DPFROMREG(fs, MIPSInst_FS(ir));
1036                                 DPFROMREG(ft, MIPSInst_FT(ir));
1037
1038                                 rv.d = (*handler.b) (fs, ft);
1039                                 goto copcsr;
1040                         }
1041                       dcopuop:{
1042                                 ieee754dp fs;
1043
1044                                 DPFROMREG(fs, MIPSInst_FS(ir));
1045                                 rv.d = (*handler.u) (fs);
1046                                 goto copcsr;
1047                         }
1048
1049                         /* unary conv ops */
1050                 case fcvts_op:{
1051                         ieee754dp fs;
1052
1053                         DPFROMREG(fs, MIPSInst_FS(ir));
1054                         rv.s = ieee754sp_fdp(fs);
1055                         rfmt = s_fmt;
1056                         goto copcsr;
1057                 }
1058                 case fcvtd_op:
1059                         return SIGILL;  /* not defined */
1060
1061                 case fcvtw_op:{
1062                         ieee754dp fs;
1063
1064                         DPFROMREG(fs, MIPSInst_FS(ir));
1065                         rv.w = ieee754dp_tint(fs);      /* wrong */
1066                         rfmt = w_fmt;
1067                         goto copcsr;
1068                 }
1069
1070 #if __mips >= 2 || defined(__mips64)
1071                 case fround_op:
1072                 case ftrunc_op:
1073                 case fceil_op:
1074                 case ffloor_op:{
1075                         unsigned int oldrm = ieee754_csr.rm;
1076                         ieee754dp fs;
1077
1078                         DPFROMREG(fs, MIPSInst_FS(ir));
1079                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1080                         rv.w = ieee754dp_tint(fs);
1081                         ieee754_csr.rm = oldrm;
1082                         rfmt = w_fmt;
1083                         goto copcsr;
1084                 }
1085 #endif
1086
1087 #if defined(__mips64)
1088                 case fcvtl_op:{
1089                         ieee754dp fs;
1090
1091                         DPFROMREG(fs, MIPSInst_FS(ir));
1092                         rv.l = ieee754dp_tlong(fs);
1093                         rfmt = l_fmt;
1094                         goto copcsr;
1095                 }
1096
1097                 case froundl_op:
1098                 case ftruncl_op:
1099                 case fceill_op:
1100                 case ffloorl_op:{
1101                         unsigned int oldrm = ieee754_csr.rm;
1102                         ieee754dp fs;
1103
1104                         DPFROMREG(fs, MIPSInst_FS(ir));
1105                         ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
1106                         rv.l = ieee754dp_tlong(fs);
1107                         ieee754_csr.rm = oldrm;
1108                         rfmt = l_fmt;
1109                         goto copcsr;
1110                 }
1111 #endif /* __mips >= 3 */
1112
1113                 default:
1114                         if (MIPSInst_FUNC(ir) >= fcmp_op) {
1115                                 unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
1116                                 ieee754dp fs, ft;
1117
1118                                 DPFROMREG(fs, MIPSInst_FS(ir));
1119                                 DPFROMREG(ft, MIPSInst_FT(ir));
1120                                 rv.w = ieee754dp_cmp(fs, ft,
1121                                         cmptab[cmpop & 0x7], cmpop & 0x8);
1122                                 rfmt = -1;
1123                                 if ((cmpop & 0x8)
1124                                         &&
1125                                         ieee754_cxtest
1126                                         (IEEE754_INVALID_OPERATION))
1127                                         rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
1128                                 else
1129                                         goto copcsr;
1130
1131                         }
1132                         else {
1133                                 return SIGILL;
1134                         }
1135                         break;
1136                 }
1137                 break;
1138         }
1139
1140         case w_fmt:{
1141                 ieee754sp fs;
1142
1143                 switch (MIPSInst_FUNC(ir)) {
1144                 case fcvts_op:
1145                         /* convert word to single precision real */
1146                         SPFROMREG(fs, MIPSInst_FS(ir));
1147                         rv.s = ieee754sp_fint(fs.bits);
1148                         rfmt = s_fmt;
1149                         goto copcsr;
1150                 case fcvtd_op:
1151                         /* convert word to double precision real */
1152                         SPFROMREG(fs, MIPSInst_FS(ir));
1153                         rv.d = ieee754dp_fint(fs.bits);
1154                         rfmt = d_fmt;
1155                         goto copcsr;
1156                 default:
1157                         return SIGILL;
1158                 }
1159                 break;
1160         }
1161
1162 #if defined(__mips64)
1163         case l_fmt:{
1164                 switch (MIPSInst_FUNC(ir)) {
1165                 case fcvts_op:
1166                         /* convert long to single precision real */
1167                         rv.s = ieee754sp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1168                         rfmt = s_fmt;
1169                         goto copcsr;
1170                 case fcvtd_op:
1171                         /* convert long to double precision real */
1172                         rv.d = ieee754dp_flong(ctx->fpr[MIPSInst_FS(ir)]);
1173                         rfmt = d_fmt;
1174                         goto copcsr;
1175                 default:
1176                         return SIGILL;
1177                 }
1178                 break;
1179         }
1180 #endif
1181
1182         default:
1183                 return SIGILL;
1184         }
1185
1186         /*
1187          * Update the fpu CSR register for this operation.
1188          * If an exception is required, generate a tidy SIGFPE exception,
1189          * without updating the result register.
1190          * Note: cause exception bits do not accumulate, they are rewritten
1191          * for each op; only the flag/sticky bits accumulate.
1192          */
1193         ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
1194         if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
1195                 /*printk ("SIGFPE: fpu csr = %08x\n",ctx->fcr31); */
1196                 return SIGFPE;
1197         }
1198
1199         /*
1200          * Now we can safely write the result back to the register file.
1201          */
1202         switch (rfmt) {
1203         case -1:{
1204 #if __mips >= 4
1205                 cond = fpucondbit[MIPSInst_FD(ir) >> 2];
1206 #else
1207                 cond = FPU_CSR_COND;
1208 #endif
1209                 if (rv.w)
1210                         ctx->fcr31 |= cond;
1211                 else
1212                         ctx->fcr31 &= ~cond;
1213                 break;
1214         }
1215         case d_fmt:
1216                 DPTOREG(rv.d, MIPSInst_FD(ir));
1217                 break;
1218         case s_fmt:
1219                 SPTOREG(rv.s, MIPSInst_FD(ir));
1220                 break;
1221         case w_fmt:
1222                 SITOREG(rv.w, MIPSInst_FD(ir));
1223                 break;
1224 #if defined(__mips64)
1225         case l_fmt:
1226                 DITOREG(rv.l, MIPSInst_FD(ir));
1227                 break;
1228 #endif
1229         default:
1230                 return SIGILL;
1231         }
1232
1233         return 0;
1234 }
1235
1236 int fpu_emulator_cop1Handler(struct pt_regs *xcp,
1237         struct mips_fpu_soft_struct *ctx)
1238 {
1239         unsigned long oldepc, prevepc;
1240         mips_instruction insn;
1241         int sig = 0;
1242
1243         oldepc = xcp->cp0_epc;
1244         do {
1245                 prevepc = xcp->cp0_epc;
1246
1247                 if (get_user(insn, (mips_instruction __user *) xcp->cp0_epc)) {
1248                         fpuemustats.errors++;
1249                         return SIGBUS;
1250                 }
1251                 if (insn == 0)
1252                         xcp->cp0_epc += 4;      /* skip nops */
1253                 else {
1254                         /*
1255                          * The 'ieee754_csr' is an alias of
1256                          * ctx->fcr31.  No need to copy ctx->fcr31 to
1257                          * ieee754_csr.  But ieee754_csr.rm is ieee
1258                          * library modes. (not mips rounding mode)
1259                          */
1260                         /* convert to ieee library modes */
1261                         ieee754_csr.rm = ieee_rm[ieee754_csr.rm];
1262                         sig = cop1Emulate(xcp, ctx);
1263                         /* revert to mips rounding mode */
1264                         ieee754_csr.rm = mips_rm[ieee754_csr.rm];
1265                 }
1266
1267                 if (cpu_has_fpu)
1268                         break;
1269                 if (sig)
1270                         break;
1271
1272                 cond_resched();
1273         } while (xcp->cp0_epc > prevepc);
1274
1275         /* SIGILL indicates a non-fpu instruction */
1276         if (sig == SIGILL && xcp->cp0_epc != oldepc)
1277                 /* but if epc has advanced, then ignore it */
1278                 sig = 0;
1279
1280         return sig;
1281 }