arch/sh/math-emu/math.c

   1 /*
   2  * arch/sh/math-emu/math.c
   3  *
   4  * Copyright (C) 2006 Takashi YOSHII <takasi-y@ops.dti.ne.jp>
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/types.h>
  13 #include <linux/sched.h>
  14 #include <linux/signal.h>
  15 #include <linux/perf_event.h>
  16
  17 #include <asm/system.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/processor.h>
  20 #include <asm/io.h>
  21
  22 #include "sfp-util.h"
  23 #include <math-emu/soft-fp.h>
  24 #include <math-emu/single.h>
  25 #include <math-emu/double.h>
  26
  27 #define FPUL            (fregs->fpul)
  28 #define FPSCR           (fregs->fpscr)
  29 #define FPSCR_RM        (FPSCR&3)
  30 #define FPSCR_DN        ((FPSCR>>18)&1)
  31 #define FPSCR_PR        ((FPSCR>>19)&1)
  32 #define FPSCR_SZ        ((FPSCR>>20)&1)
  33 #define FPSCR_FR        ((FPSCR>>21)&1)
  34 #define FPSCR_MASK      0x003fffffUL
  35
  36 #define BANK(n) (n^(FPSCR_FR?16:0))
  37 #define FR      ((unsigned long*)(fregs->fp_regs))
  38 #define FR0     (FR[BANK(0)])
  39 #define FRn     (FR[BANK(n)])
  40 #define FRm     (FR[BANK(m)])
  41 #define DR      ((unsigned long long*)(fregs->fp_regs))
  42 #define DRn     (DR[BANK(n)/2])
  43 #define DRm     (DR[BANK(m)/2])
  44
  45 #define XREG(n) (n^16)
  46 #define XFn     (FR[BANK(XREG(n))])
  47 #define XFm     (FR[BANK(XREG(m))])
  48 #define XDn     (DR[BANK(XREG(n))/2])
  49 #define XDm     (DR[BANK(XREG(m))/2])
  50
  51 #define R0      (regs->regs[0])
  52 #define Rn      (regs->regs[n])
  53 #define Rm      (regs->regs[m])
  54
  55 #define WRITE(d,a)      ({if(put_user(d, (typeof (d)*)a)) return -EFAULT;})
  56 #define READ(d,a)       ({if(get_user(d, (typeof (d)*)a)) return -EFAULT;})
  57
  58 #define PACK_S(r,f)     FP_PACK_SP(&r,f)
  59 #define UNPACK_S(f,r)   FP_UNPACK_SP(f,&r)
  60 #define PACK_D(r,f) \
  61         {u32 t[2]; FP_PACK_DP(t,f); ((u32*)&r)[0]=t[1]; ((u32*)&r)[1]=t[0];}
  62 #define UNPACK_D(f,r) \
  63         {u32 t[2]; t[0]=((u32*)&r)[1]; t[1]=((u32*)&r)[0]; FP_UNPACK_DP(f,t);}
  64
  65 // 2 args instructions.
  66 #define BOTH_PRmn(op,x) \
  67         FP_DECL_EX; if(FPSCR_PR) op(D,x,DRm,DRn); else op(S,x,FRm,FRn);
  68
  69 #define CMP_X(SZ,R,M,N) do{ \
  70         FP_DECL_##SZ(Fm); FP_DECL_##SZ(Fn); \
  71         UNPACK_##SZ(Fm, M); UNPACK_##SZ(Fn, N); \
  72         FP_CMP_##SZ(R, Fn, Fm, 2); }while(0)
  73 #define EQ_X(SZ,R,M,N) do{ \
  74         FP_DECL_##SZ(Fm); FP_DECL_##SZ(Fn); \
  75         UNPACK_##SZ(Fm, M); UNPACK_##SZ(Fn, N); \
  76         FP_CMP_EQ_##SZ(R, Fn, Fm); }while(0)
  77 #define CMP(OP) ({ int r; BOTH_PRmn(OP##_X,r); r; })
  78
  79 static int
  80 fcmp_gt(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
  81 {
  82         if (CMP(CMP) > 0)
  83                 regs->sr |= 1;
  84         else
  85                 regs->sr &= ~1;
  86
  87         return 0;
  88 }
  89
  90 static int
  91 fcmp_eq(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
  92 {
  93         if (CMP(CMP /*EQ*/) == 0)
  94                 regs->sr |= 1;
  95         else
  96                 regs->sr &= ~1;
  97         return 0;
  98 }
  99
 100 #define ARITH_X(SZ,OP,M,N) do{ \
 101         FP_DECL_##SZ(Fm); FP_DECL_##SZ(Fn); FP_DECL_##SZ(Fr); \
 102         UNPACK_##SZ(Fm, M); UNPACK_##SZ(Fn, N); \
 103         FP_##OP##_##SZ(Fr, Fn, Fm); \
 104         PACK_##SZ(N, Fr); }while(0)
 105
 106 static int
 107 fadd(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 108 {
 109         BOTH_PRmn(ARITH_X, ADD);
 110         return 0;
 111 }
 112
 113 static int
 114 fsub(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 115 {
 116         BOTH_PRmn(ARITH_X, SUB);
 117         return 0;
 118 }
 119
 120 static int
 121 fmul(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 122 {
 123         BOTH_PRmn(ARITH_X, MUL);
 124         return 0;
 125 }
 126
 127 static int
 128 fdiv(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 129 {
 130         BOTH_PRmn(ARITH_X, DIV);
 131         return 0;
 132 }
 133
 134 static int
 135 fmac(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 136 {
 137         FP_DECL_EX;
 138         FP_DECL_S(Fr);
 139         FP_DECL_S(Ft);
 140         FP_DECL_S(F0);
 141         FP_DECL_S(Fm);
 142         FP_DECL_S(Fn);
 143         UNPACK_S(F0, FR0);
 144         UNPACK_S(Fm, FRm);
 145         UNPACK_S(Fn, FRn);
 146         FP_MUL_S(Ft, Fm, F0);
 147         FP_ADD_S(Fr, Fn, Ft);
 148         PACK_S(FRn, Fr);
 149         return 0;
 150 }
 151
 152 // to process fmov's extension (odd n for DR access XD).
 153 #define FMOV_EXT(x) if(x&1) x+=16-1
 154
 155 static int
 156 fmov_idx_reg(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 157              int n)
 158 {
 159         if (FPSCR_SZ) {
 160                 FMOV_EXT(n);
 161                 READ(FRn, Rm + R0 + 4);
 162                 n++;
 163                 READ(FRn, Rm + R0);
 164         } else {
 165                 READ(FRn, Rm + R0);
 166         }
 167
 168         return 0;
 169 }
 170
 171 static int
 172 fmov_mem_reg(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 173              int n)
 174 {
 175         if (FPSCR_SZ) {
 176                 FMOV_EXT(n);
 177                 READ(FRn, Rm + 4);
 178                 n++;
 179                 READ(FRn, Rm);
 180         } else {
 181                 READ(FRn, Rm);
 182         }
 183
 184         return 0;
 185 }
 186
 187 static int
 188 fmov_inc_reg(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 189              int n)
 190 {
 191         if (FPSCR_SZ) {
 192                 FMOV_EXT(n);
 193                 READ(FRn, Rm + 4);
 194                 n++;
 195                 READ(FRn, Rm);
 196                 Rm += 8;
 197         } else {
 198                 READ(FRn, Rm);
 199                 Rm += 4;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static int
 206 fmov_reg_idx(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 207              int n)
 208 {
 209         if (FPSCR_SZ) {
 210                 FMOV_EXT(m);
 211                 WRITE(FRm, Rn + R0 + 4);
 212                 m++;
 213                 WRITE(FRm, Rn + R0);
 214         } else {
 215                 WRITE(FRm, Rn + R0);
 216         }
 217
 218         return 0;
 219 }
 220
 221 static int
 222 fmov_reg_mem(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 223              int n)
 224 {
 225         if (FPSCR_SZ) {
 226                 FMOV_EXT(m);
 227                 WRITE(FRm, Rn + 4);
 228                 m++;
 229                 WRITE(FRm, Rn);
 230         } else {
 231                 WRITE(FRm, Rn);
 232         }
 233
 234         return 0;
 235 }
 236
 237 static int
 238 fmov_reg_dec(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 239              int n)
 240 {
 241         if (FPSCR_SZ) {
 242                 FMOV_EXT(m);
 243                 Rn -= 8;
 244                 WRITE(FRm, Rn + 4);
 245                 m++;
 246                 WRITE(FRm, Rn);
 247         } else {
 248                 Rn -= 4;
 249                 WRITE(FRm, Rn);
 250         }
 251
 252         return 0;
 253 }
 254
 255 static int
 256 fmov_reg_reg(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m,
 257              int n)
 258 {
 259         if (FPSCR_SZ) {
 260                 FMOV_EXT(m);
 261                 FMOV_EXT(n);
 262                 DRn = DRm;
 263         } else {
 264                 FRn = FRm;
 265         }
 266
 267         return 0;
 268 }
 269
 270 static int
 271 fnop_mn(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int m, int n)
 272 {
 273         return -EINVAL;
 274 }
 275
 276 // 1 arg instructions.
 277 #define NOTYETn(i) static int i(struct sh_fpu_soft_struct *fregs, int n) \
 278         { printk( #i " not yet done.\n"); return 0; }
 279
 280 NOTYETn(ftrv)
 281 NOTYETn(fsqrt)
 282 NOTYETn(fipr)
 283 NOTYETn(fsca)
 284 NOTYETn(fsrra)
 285
 286 #define EMU_FLOAT_X(SZ,N) do { \
 287         FP_DECL_##SZ(Fn); \
 288         FP_FROM_INT_##SZ(Fn, FPUL, 32, int); \
 289         PACK_##SZ(N, Fn); }while(0)
 290 static int ffloat(struct sh_fpu_soft_struct *fregs, int n)
 291 {
 292         FP_DECL_EX;
 293
 294         if (FPSCR_PR)
 295                 EMU_FLOAT_X(D, DRn);
 296         else
 297                 EMU_FLOAT_X(S, FRn);
 298
 299         return 0;
 300 }
 301
 302 #define EMU_FTRC_X(SZ,N) do { \
 303         FP_DECL_##SZ(Fn); \
 304         UNPACK_##SZ(Fn, N); \
 305         FP_TO_INT_##SZ(FPUL, Fn, 32, 1); }while(0)
 306 static int ftrc(struct sh_fpu_soft_struct *fregs, int n)
 307 {
 308         FP_DECL_EX;
 309
 310         if (FPSCR_PR)
 311                 EMU_FTRC_X(D, DRn);
 312         else
 313                 EMU_FTRC_X(S, FRn);
 314
 315         return 0;
 316 }
 317
 318 static int fcnvsd(struct sh_fpu_soft_struct *fregs, int n)
 319 {
 320         FP_DECL_EX;
 321         FP_DECL_S(Fn);
 322         FP_DECL_D(Fr);
 323         UNPACK_S(Fn, FPUL);
 324         FP_CONV(D, S, 2, 1, Fr, Fn);
 325         PACK_D(DRn, Fr);
 326         return 0;
 327 }
 328
 329 static int fcnvds(struct sh_fpu_soft_struct *fregs, int n)
 330 {
 331         FP_DECL_EX;
 332         FP_DECL_D(Fn);
 333         FP_DECL_S(Fr);
 334         UNPACK_D(Fn, DRn);
 335         FP_CONV(S, D, 1, 2, Fr, Fn);
 336         PACK_S(FPUL, Fr);
 337         return 0;
 338 }
 339
 340 static int fxchg(struct sh_fpu_soft_struct *fregs, int flag)
 341 {
 342         FPSCR ^= flag;
 343         return 0;
 344 }
 345
 346 static int fsts(struct sh_fpu_soft_struct *fregs, int n)
 347 {
 348         FRn = FPUL;
 349         return 0;
 350 }
 351
 352 static int flds(struct sh_fpu_soft_struct *fregs, int n)
 353 {
 354         FPUL = FRn;
 355         return 0;
 356 }
 357
 358 static int fneg(struct sh_fpu_soft_struct *fregs, int n)
 359 {
 360         FRn ^= (1 << (_FP_W_TYPE_SIZE - 1));
 361         return 0;
 362 }
 363
 364 static int fabs(struct sh_fpu_soft_struct *fregs, int n)
 365 {
 366         FRn &= ~(1 << (_FP_W_TYPE_SIZE - 1));
 367         return 0;
 368 }
 369
 370 static int fld0(struct sh_fpu_soft_struct *fregs, int n)
 371 {
 372         FRn = 0;
 373         return 0;
 374 }
 375
 376 static int fld1(struct sh_fpu_soft_struct *fregs, int n)
 377 {
 378         FRn = (_FP_EXPBIAS_S << (_FP_FRACBITS_S - 1));
 379         return 0;
 380 }
 381
 382 static int fnop_n(struct sh_fpu_soft_struct *fregs, int n)
 383 {
 384         return -EINVAL;
 385 }
 386
 387 /// Instruction decoders.
 388
 389 static int id_fxfd(struct sh_fpu_soft_struct *, int);
 390 static int id_fnxd(struct sh_fpu_soft_struct *, struct pt_regs *, int, int);
 391
 392 static int (*fnxd[])(struct sh_fpu_soft_struct *, int) = {
 393         fsts, flds, ffloat, ftrc, fneg, fabs, fsqrt, fsrra,
 394         fld0, fld1, fcnvsd, fcnvds, fnop_n, fnop_n, fipr, id_fxfd
 395 };
 396
 397 static int (*fnmx[])(struct sh_fpu_soft_struct *, struct pt_regs *, int, int) = {
 398         fadd, fsub, fmul, fdiv, fcmp_eq, fcmp_gt, fmov_idx_reg, fmov_reg_idx,
 399         fmov_mem_reg, fmov_inc_reg, fmov_reg_mem, fmov_reg_dec,
 400         fmov_reg_reg, id_fnxd, fmac, fnop_mn};
 401
 402 static int id_fxfd(struct sh_fpu_soft_struct *fregs, int x)
 403 {
 404         const int flag[] = { FPSCR_SZ, FPSCR_PR, FPSCR_FR, 0 };
 405         switch (x & 3) {
 406         case 3:
 407                 fxchg(fregs, flag[x >> 2]);
 408                 break;
 409         case 1:
 410                 ftrv(fregs, x - 1);
 411                 break;
 412         default:
 413                 fsca(fregs, x);
 414         }
 415         return 0;
 416 }
 417
 418 static int
 419 id_fnxd(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, int x, int n)
 420 {
 421         return (fnxd[x])(fregs, n);
 422 }
 423
 424 static int
 425 id_fnmx(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, u16 code)
 426 {
 427         int n = (code >> 8) & 0xf, m = (code >> 4) & 0xf, x = code & 0xf;
 428         return (fnmx[x])(fregs, regs, m, n);
 429 }
 430
 431 static int
 432 id_sys(struct sh_fpu_soft_struct *fregs, struct pt_regs *regs, u16 code)
 433 {
 434         int n = ((code >> 8) & 0xf);
 435         unsigned long *reg = (code & 0x0010) ? &FPUL : &FPSCR;
 436
 437         switch (code & 0xf0ff) {
 438         case 0x005a:
 439         case 0x006a:
 440                 Rn = *reg;
 441                 break;
 442         case 0x405a:
 443         case 0x406a:
 444                 *reg = Rn;
 445                 break;
 446         case 0x4052:
 447         case 0x4062:
 448                 Rn -= 4;
 449                 WRITE(*reg, Rn);
 450                 break;
 451         case 0x4056:
 452         case 0x4066:
 453                 READ(*reg, Rn);
 454                 Rn += 4;
 455                 break;
 456         default:
 457                 return -EINVAL;
 458         }
 459
 460         return 0;
 461 }
 462
 463 static int fpu_emulate(u16 code, struct sh_fpu_soft_struct *fregs, struct pt_regs *regs)
 464 {
 465         if ((code & 0xf000) == 0xf000)
 466                 return id_fnmx(fregs, regs, code);
 467         else
 468                 return id_sys(fregs, regs, code);
 469 }
 470
 471 /**
 472  *      denormal_to_double - Given denormalized float number,
 473  *                           store double float
 474  *
 475  *      @fpu: Pointer to sh_fpu_soft structure
 476  *      @n: Index to FP register
 477  */
 478 static void denormal_to_double(struct sh_fpu_soft_struct *fpu, int n)
 479 {
 480         unsigned long du, dl;
 481         unsigned long x = fpu->fpul;
 482         int exp = 1023 - 126;
 483
 484         if (x != 0 && (x & 0x7f800000) == 0) {
 485                 du = (x & 0x80000000);
 486                 while ((x & 0x00800000) == 0) {
 487                         x <<= 1;
 488                         exp--;
 489                 }
 490                 x &= 0x007fffff;
 491                 du |= (exp << 20) | (x >> 3);
 492                 dl = x << 29;
 493
 494                 fpu->fp_regs[n] = du;
 495                 fpu->fp_regs[n+1] = dl;
 496         }
 497 }
 498
 499 /**
 500  *      ieee_fpe_handler - Handle denormalized number exception
 501  *
 502  *      @regs: Pointer to register structure
 503  *
 504  *      Returns 1 when it's handled (should not cause exception).
 505  */
 506 static int ieee_fpe_handler(struct pt_regs *regs)
 507 {
 508         unsigned short insn = *(unsigned short *)regs->pc;
 509         unsigned short finsn;
 510         unsigned long nextpc;
 511         siginfo_t info;
 512         int nib[4] = {
 513                 (insn >> 12) & 0xf,
 514                 (insn >> 8) & 0xf,
 515                 (insn >> 4) & 0xf,
 516                 insn & 0xf};
 517
 518         if (nib[0] == 0xb ||
 519             (nib[0] == 0x4 && nib[2] == 0x0 && nib[3] == 0xb)) /* bsr & jsr */
 520                 regs->pr = regs->pc + 4;
 521
 522         if (nib[0] == 0xa || nib[0] == 0xb) { /* bra & bsr */
 523                 nextpc = regs->pc + 4 + ((short) ((insn & 0xfff) << 4) >> 3);
 524                 finsn = *(unsigned short *) (regs->pc + 2);
 525         } else if (nib[0] == 0x8 && nib[1] == 0xd) { /* bt/s */
 526                 if (regs->sr & 1)
 527                         nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1);
 528                 else
 529                         nextpc = regs->pc + 4;
 530                 finsn = *(unsigned short *) (regs->pc + 2);
 531         } else if (nib[0] == 0x8 && nib[1] == 0xf) { /* bf/s */
 532                 if (regs->sr & 1)
 533                         nextpc = regs->pc + 4;
 534                 else
 535                         nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1);
 536                 finsn = *(unsigned short *) (regs->pc + 2);
 537         } else if (nib[0] == 0x4 && nib[3] == 0xb &&
 538                  (nib[2] == 0x0 || nib[2] == 0x2)) { /* jmp & jsr */
 539                 nextpc = regs->regs[nib[1]];
 540                 finsn = *(unsigned short *) (regs->pc + 2);
 541         } else if (nib[0] == 0x0 && nib[3] == 0x3 &&
 542                  (nib[2] == 0x0 || nib[2] == 0x2)) { /* braf & bsrf */
 543                 nextpc = regs->pc + 4 + regs->regs[nib[1]];
 544                 finsn = *(unsigned short *) (regs->pc + 2);
 545         } else if (insn == 0x000b) { /* rts */
 546                 nextpc = regs->pr;
 547                 finsn = *(unsigned short *) (regs->pc + 2);
 548         } else {
 549                 nextpc = regs->pc + 2;
 550                 finsn = insn;
 551         }
 552
 553         if ((finsn & 0xf1ff) == 0xf0ad) { /* fcnvsd */
 554                 struct task_struct *tsk = current;
 555
 556                 if ((tsk->thread.xstate->softfpu.fpscr & (1 << 17))) {
 557                         /* FPU error */
 558                         denormal_to_double (&tsk->thread.xstate->softfpu,
 559                                             (finsn >> 8) & 0xf);
 560                         tsk->thread.xstate->softfpu.fpscr &=
 561                                 ~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK);
 562                         task_thread_info(tsk)->status |= TS_USEDFPU;
 563                 } else {
 564                         info.si_signo = SIGFPE;
 565                         info.si_errno = 0;
 566                         info.si_code = FPE_FLTINV;
 567                         info.si_addr = (void __user *)regs->pc;
 568                         force_sig_info(SIGFPE, &info, tsk);
 569                 }
 570
 571                 regs->pc = nextpc;
 572                 return 1;
 573         }
 574
 575         return 0;
 576 }
 577
 578 asmlinkage void do_fpu_error(unsigned long r4, unsigned long r5,
 579                              unsigned long r6, unsigned long r7,
 580                              struct pt_regs regs)
 581 {
 582         struct task_struct *tsk = current;
 583         siginfo_t info;
 584
 585         if (ieee_fpe_handler (&regs))
 586                 return;
 587
 588         regs.pc += 2;
 589         info.si_signo = SIGFPE;
 590         info.si_errno = 0;
 591         info.si_code = FPE_FLTINV;
 592         info.si_addr = (void __user *)regs.pc;
 593         force_sig_info(SIGFPE, &info, tsk);
 594 }
 595
 596 /**
 597  * fpu_init - Initialize FPU registers
 598  * @fpu: Pointer to software emulated FPU registers.
 599  */
 600 static void fpu_init(struct sh_fpu_soft_struct *fpu)
 601 {
 602         int i;
 603
 604         fpu->fpscr = FPSCR_INIT;
 605         fpu->fpul = 0;
 606
 607         for (i = 0; i < 16; i++) {
 608                 fpu->fp_regs[i] = 0;
 609                 fpu->xfp_regs[i]= 0;
 610         }
 611 }
 612
 613 /**
 614  * do_fpu_inst - Handle reserved instructions for FPU emulation
 615  * @inst: instruction code.
 616  * @regs: registers on stack.
 617  */
 618 int do_fpu_inst(unsigned short inst, struct pt_regs *regs)
 619 {
 620         struct task_struct *tsk = current;
 621         struct sh_fpu_soft_struct *fpu = &(tsk->thread.xstate->softfpu);
 622
 623         perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
 624
 625         if (!(task_thread_info(tsk)->status & TS_USEDFPU)) {
 626                 /* initialize once. */
 627                 fpu_init(fpu);
 628                 task_thread_info(tsk)->status |= TS_USEDFPU;
 629         }
 630
 631         return fpu_emulate(inst, fpu, regs);
 632 }