arch/sparc/lib/copy_user.S

   1 /* copy_user.S: Sparc optimized copy_from_user and copy_to_user code.
   2  *
   3  *  Copyright(C) 1995 Linus Torvalds
   4  *  Copyright(C) 1996 David S. Miller
   5  *  Copyright(C) 1996 Eddie C. Dost
   6  *  Copyright(C) 1996,1998 Jakub Jelinek
   7  *
   8  * derived from:
   9  *      e-mail between David and Eddie.
  10  *
  11  * Returns 0 if successful, otherwise count of bytes not copied yet
  12  */
  13
  14 #include <asm/ptrace.h>
  15 #include <asm/asmmacro.h>
  16 #include <asm/page.h>
  17
  18 /* Work around cpp -rob */
  19 #define ALLOC #alloc
  20 #define EXECINSTR #execinstr
  21 #define EX(x,y,a,b)                             \
  22 98:     x,y;                                    \
  23         .section .fixup,ALLOC,EXECINSTR;        \
  24         .align  4;                              \
  25 99:     ba fixupretl;                           \
  26          a, b, %g3;                             \
  27         .section __ex_table,ALLOC;              \
  28         .align  4;                              \
  29         .word   98b, 99b;                       \
  30         .text;                                  \
  31         .align  4
  32
  33 #define EX2(x,y,c,d,e,a,b)                      \
  34 98:     x,y;                                    \
  35         .section .fixup,ALLOC,EXECINSTR;        \
  36         .align  4;                              \
  37 99:     c, d, e;                                \
  38         ba fixupretl;                           \
  39          a, b, %g3;                             \
  40         .section __ex_table,ALLOC;              \
  41         .align  4;                              \
  42         .word   98b, 99b;                       \
  43         .text;                                  \
  44         .align  4
  45
  46 #define EXO2(x,y)                               \
  47 98:     x, y;                                   \
  48         .section __ex_table,ALLOC;              \
  49         .align  4;                              \
  50         .word   98b, 97f;                       \
  51         .text;                                  \
  52         .align  4
  53
  54 #define EXT(start,end,handler)                  \
  55         .section __ex_table,ALLOC;              \
  56         .align  4;                              \
  57         .word   start, 0, end, handler;         \
  58         .text;                                  \
  59         .align  4
  60
  61 /* Please do not change following macros unless you change logic used
  62  * in .fixup at the end of this file as well
  63  */
  64
  65 /* Both these macros have to start with exactly the same insn */
  66 #define MOVE_BIGCHUNK(src, dst, offset, t0, t1, t2, t3, t4, t5, t6, t7) \
  67         ldd     [%src + (offset) + 0x00], %t0; \
  68         ldd     [%src + (offset) + 0x08], %t2; \
  69         ldd     [%src + (offset) + 0x10], %t4; \
  70         ldd     [%src + (offset) + 0x18], %t6; \
  71         st      %t0, [%dst + (offset) + 0x00]; \
  72         st      %t1, [%dst + (offset) + 0x04]; \
  73         st      %t2, [%dst + (offset) + 0x08]; \
  74         st      %t3, [%dst + (offset) + 0x0c]; \
  75         st      %t4, [%dst + (offset) + 0x10]; \
  76         st      %t5, [%dst + (offset) + 0x14]; \
  77         st      %t6, [%dst + (offset) + 0x18]; \
  78         st      %t7, [%dst + (offset) + 0x1c];
  79
  80 #define MOVE_BIGALIGNCHUNK(src, dst, offset, t0, t1, t2, t3, t4, t5, t6, t7) \
  81         ldd     [%src + (offset) + 0x00], %t0; \
  82         ldd     [%src + (offset) + 0x08], %t2; \
  83         ldd     [%src + (offset) + 0x10], %t4; \
  84         ldd     [%src + (offset) + 0x18], %t6; \
  85         std     %t0, [%dst + (offset) + 0x00]; \
  86         std     %t2, [%dst + (offset) + 0x08]; \
  87         std     %t4, [%dst + (offset) + 0x10]; \
  88         std     %t6, [%dst + (offset) + 0x18];
  89
  90 #define MOVE_LASTCHUNK(src, dst, offset, t0, t1, t2, t3) \
  91         ldd     [%src - (offset) - 0x10], %t0; \
  92         ldd     [%src - (offset) - 0x08], %t2; \
  93         st      %t0, [%dst - (offset) - 0x10]; \
  94         st      %t1, [%dst - (offset) - 0x0c]; \
  95         st      %t2, [%dst - (offset) - 0x08]; \
  96         st      %t3, [%dst - (offset) - 0x04];
  97
  98 #define MOVE_HALFCHUNK(src, dst, offset, t0, t1, t2, t3) \
  99         lduh    [%src + (offset) + 0x00], %t0; \
 100         lduh    [%src + (offset) + 0x02], %t1; \
 101         lduh    [%src + (offset) + 0x04], %t2; \
 102         lduh    [%src + (offset) + 0x06], %t3; \
 103         sth     %t0, [%dst + (offset) + 0x00]; \
 104         sth     %t1, [%dst + (offset) + 0x02]; \
 105         sth     %t2, [%dst + (offset) + 0x04]; \
 106         sth     %t3, [%dst + (offset) + 0x06];
 107
 108 #define MOVE_SHORTCHUNK(src, dst, offset, t0, t1) \
 109         ldub    [%src - (offset) - 0x02], %t0; \
 110         ldub    [%src - (offset) - 0x01], %t1; \
 111         stb     %t0, [%dst - (offset) - 0x02]; \
 112         stb     %t1, [%dst - (offset) - 0x01];
 113
 114         .text
 115         .align  4
 116
 117         .globl  __copy_user_begin
 118 __copy_user_begin:
 119
 120         .globl  __copy_user
 121 dword_align:
 122         andcc   %o1, 1, %g0
 123         be      4f
 124          andcc  %o1, 2, %g0
 125
 126         EXO2(ldub [%o1], %g2)
 127         add     %o1, 1, %o1
 128         EXO2(stb %g2, [%o0])
 129         sub     %o2, 1, %o2
 130         bne     3f
 131          add    %o0, 1, %o0
 132
 133         EXO2(lduh [%o1], %g2)
 134         add     %o1, 2, %o1
 135         EXO2(sth %g2, [%o0])
 136         sub     %o2, 2, %o2
 137         b       3f
 138          add    %o0, 2, %o0
 139 4:
 140         EXO2(lduh [%o1], %g2)
 141         add     %o1, 2, %o1
 142         EXO2(sth %g2, [%o0])
 143         sub     %o2, 2, %o2
 144         b       3f
 145          add    %o0, 2, %o0
 146
 147 __copy_user:    /* %o0=dst %o1=src %o2=len */
 148         xor     %o0, %o1, %o4
 149 1:
 150         andcc   %o4, 3, %o5
 151 2:
 152         bne     cannot_optimize
 153          cmp    %o2, 15
 154
 155         bleu    short_aligned_end
 156          andcc  %o1, 3, %g0
 157
 158         bne     dword_align
 159 3:
 160          andcc  %o1, 4, %g0
 161
 162         be      2f
 163          mov    %o2, %g1
 164
 165         EXO2(ld [%o1], %o4)
 166         sub     %g1, 4, %g1
 167         EXO2(st %o4, [%o0])
 168         add     %o1, 4, %o1
 169         add     %o0, 4, %o0
 170 2:
 171         andcc   %g1, 0xffffff80, %g7
 172         be      3f
 173          andcc  %o0, 4, %g0
 174
 175         be      ldd_std + 4
 176 5:
 177         MOVE_BIGCHUNK(o1, o0, 0x00, o2, o3, o4, o5, g2, g3, g4, g5)
 178         MOVE_BIGCHUNK(o1, o0, 0x20, o2, o3, o4, o5, g2, g3, g4, g5)
 179         MOVE_BIGCHUNK(o1, o0, 0x40, o2, o3, o4, o5, g2, g3, g4, g5)
 180         MOVE_BIGCHUNK(o1, o0, 0x60, o2, o3, o4, o5, g2, g3, g4, g5)
 181 80:
 182         EXT(5b, 80b, 50f)
 183         subcc   %g7, 128, %g7
 184         add     %o1, 128, %o1
 185         bne     5b
 186          add    %o0, 128, %o0
 187 3:
 188         andcc   %g1, 0x70, %g7
 189         be      copy_user_table_end
 190          andcc  %g1, 8, %g0
 191
 192         sethi   %hi(copy_user_table_end), %o5
 193         srl     %g7, 1, %o4
 194         add     %g7, %o4, %o4
 195         add     %o1, %g7, %o1
 196         sub     %o5, %o4, %o5
 197         jmpl    %o5 + %lo(copy_user_table_end), %g0
 198          add    %o0, %g7, %o0
 199
 200 copy_user_table:
 201         MOVE_LASTCHUNK(o1, o0, 0x60, g2, g3, g4, g5)
 202         MOVE_LASTCHUNK(o1, o0, 0x50, g2, g3, g4, g5)
 203         MOVE_LASTCHUNK(o1, o0, 0x40, g2, g3, g4, g5)
 204         MOVE_LASTCHUNK(o1, o0, 0x30, g2, g3, g4, g5)
 205         MOVE_LASTCHUNK(o1, o0, 0x20, g2, g3, g4, g5)
 206         MOVE_LASTCHUNK(o1, o0, 0x10, g2, g3, g4, g5)
 207         MOVE_LASTCHUNK(o1, o0, 0x00, g2, g3, g4, g5)
 208 copy_user_table_end:
 209         EXT(copy_user_table, copy_user_table_end, 51f)
 210         be      copy_user_last7
 211          andcc  %g1, 4, %g0
 212
 213         EX(ldd  [%o1], %g2, and %g1, 0xf)
 214         add     %o0, 8, %o0
 215         add     %o1, 8, %o1
 216         EX(st   %g2, [%o0 - 0x08], and %g1, 0xf)
 217         EX2(st  %g3, [%o0 - 0x04], and %g1, 0xf, %g1, sub %g1, 4)
 218 copy_user_last7:
 219         be      1f
 220          andcc  %g1, 2, %g0
 221
 222         EX(ld   [%o1], %g2, and %g1, 7)
 223         add     %o1, 4, %o1
 224         EX(st   %g2, [%o0], and %g1, 7)
 225         add     %o0, 4, %o0
 226 1:
 227         be      1f
 228          andcc  %g1, 1, %g0
 229
 230         EX(lduh [%o1], %g2, and %g1, 3)
 231         add     %o1, 2, %o1
 232         EX(sth  %g2, [%o0], and %g1, 3)
 233         add     %o0, 2, %o0
 234 1:
 235         be      1f
 236          nop
 237
 238         EX(ldub [%o1], %g2, add %g0, 1)
 239         EX(stb  %g2, [%o0], add %g0, 1)
 240 1:
 241         retl
 242          clr    %o0
 243
 244 ldd_std:
 245         MOVE_BIGALIGNCHUNK(o1, o0, 0x00, o2, o3, o4, o5, g2, g3, g4, g5)
 246         MOVE_BIGALIGNCHUNK(o1, o0, 0x20, o2, o3, o4, o5, g2, g3, g4, g5)
 247         MOVE_BIGALIGNCHUNK(o1, o0, 0x40, o2, o3, o4, o5, g2, g3, g4, g5)
 248         MOVE_BIGALIGNCHUNK(o1, o0, 0x60, o2, o3, o4, o5, g2, g3, g4, g5)
 249 81:
 250         EXT(ldd_std, 81b, 52f)
 251         subcc   %g7, 128, %g7
 252         add     %o1, 128, %o1
 253         bne     ldd_std
 254          add    %o0, 128, %o0
 255
 256         andcc   %g1, 0x70, %g7
 257         be      copy_user_table_end
 258          andcc  %g1, 8, %g0
 259
 260         sethi   %hi(copy_user_table_end), %o5
 261         srl     %g7, 1, %o4
 262         add     %g7, %o4, %o4
 263         add     %o1, %g7, %o1
 264         sub     %o5, %o4, %o5
 265         jmpl    %o5 + %lo(copy_user_table_end), %g0
 266          add    %o0, %g7, %o0
 267
 268 cannot_optimize:
 269         bleu    short_end
 270          cmp    %o5, 2
 271
 272         bne     byte_chunk
 273          and    %o2, 0xfffffff0, %o3
 274
 275         andcc   %o1, 1, %g0
 276         be      10f
 277          nop
 278
 279         EXO2(ldub [%o1], %g2)
 280         add     %o1, 1, %o1
 281         EXO2(stb %g2, [%o0])
 282         sub     %o2, 1, %o2
 283         andcc   %o2, 0xfffffff0, %o3
 284         be      short_end
 285          add    %o0, 1, %o0
 286 10:
 287         MOVE_HALFCHUNK(o1, o0, 0x00, g2, g3, g4, g5)
 288         MOVE_HALFCHUNK(o1, o0, 0x08, g2, g3, g4, g5)
 289 82:
 290         EXT(10b, 82b, 53f)
 291         subcc   %o3, 0x10, %o3
 292         add     %o1, 0x10, %o1
 293         bne     10b
 294          add    %o0, 0x10, %o0
 295         b       2f
 296          and    %o2, 0xe, %o3
 297
 298 byte_chunk:
 299         MOVE_SHORTCHUNK(o1, o0, -0x02, g2, g3)
 300         MOVE_SHORTCHUNK(o1, o0, -0x04, g2, g3)
 301         MOVE_SHORTCHUNK(o1, o0, -0x06, g2, g3)
 302         MOVE_SHORTCHUNK(o1, o0, -0x08, g2, g3)
 303         MOVE_SHORTCHUNK(o1, o0, -0x0a, g2, g3)
 304         MOVE_SHORTCHUNK(o1, o0, -0x0c, g2, g3)
 305         MOVE_SHORTCHUNK(o1, o0, -0x0e, g2, g3)
 306         MOVE_SHORTCHUNK(o1, o0, -0x10, g2, g3)
 307 83:
 308         EXT(byte_chunk, 83b, 54f)
 309         subcc   %o3, 0x10, %o3
 310         add     %o1, 0x10, %o1
 311         bne     byte_chunk
 312          add    %o0, 0x10, %o0
 313
 314 short_end:
 315         and     %o2, 0xe, %o3
 316 2:
 317         sethi   %hi(short_table_end), %o5
 318         sll     %o3, 3, %o4
 319         add     %o0, %o3, %o0
 320         sub     %o5, %o4, %o5
 321         add     %o1, %o3, %o1
 322         jmpl    %o5 + %lo(short_table_end), %g0
 323          andcc  %o2, 1, %g0
 324 84:
 325         MOVE_SHORTCHUNK(o1, o0, 0x0c, g2, g3)
 326         MOVE_SHORTCHUNK(o1, o0, 0x0a, g2, g3)
 327         MOVE_SHORTCHUNK(o1, o0, 0x08, g2, g3)
 328         MOVE_SHORTCHUNK(o1, o0, 0x06, g2, g3)
 329         MOVE_SHORTCHUNK(o1, o0, 0x04, g2, g3)
 330         MOVE_SHORTCHUNK(o1, o0, 0x02, g2, g3)
 331         MOVE_SHORTCHUNK(o1, o0, 0x00, g2, g3)
 332 short_table_end:
 333         EXT(84b, short_table_end, 55f)
 334         be      1f
 335          nop
 336         EX(ldub [%o1], %g2, add %g0, 1)
 337         EX(stb  %g2, [%o0], add %g0, 1)
 338 1:
 339         retl
 340          clr    %o0
 341
 342 short_aligned_end:
 343         bne     short_end
 344          andcc  %o2, 8, %g0
 345
 346         be      1f
 347          andcc  %o2, 4, %g0
 348
 349         EXO2(ld [%o1 + 0x00], %g2)
 350         EXO2(ld [%o1 + 0x04], %g3)
 351         add     %o1, 8, %o1
 352         EXO2(st %g2, [%o0 + 0x00])
 353         EX(st   %g3, [%o0 + 0x04], sub %o2, 4)
 354         add     %o0, 8, %o0
 355 1:
 356         b       copy_user_last7
 357          mov    %o2, %g1
 358
 359         .section .fixup,#alloc,#execinstr
 360         .align  4
 361 97:
 362         mov     %o2, %g3
 363 fixupretl:
 364         sethi   %hi(PAGE_OFFSET), %g1
 365         cmp     %o0, %g1
 366         blu     1f
 367          cmp    %o1, %g1
 368         bgeu    1f
 369          nop
 370         save    %sp, -64, %sp
 371         mov     %i0, %o0
 372         call    __bzero
 373          mov    %g3, %o1
 374         restore
 375 1:      retl
 376          mov    %g3, %o0
 377
 378 /* exception routine sets %g2 to (broken_insn - first_insn)>>2 */
 379 50:
 380 /* This magic counts how many bytes are left when crash in MOVE_BIGCHUNK
 381  * happens. This is derived from the amount ldd reads, st stores, etc.
 382  * x = g2 % 12;
 383  * g3 = g1 + g7 - ((g2 / 12) * 32 + (x < 4) ? 0 : (x - 4) * 4);
 384  * o0 += (g2 / 12) * 32;
 385  */
 386         cmp     %g2, 12
 387         add     %o0, %g7, %o0
 388         bcs     1f
 389          cmp    %g2, 24
 390         bcs     2f
 391          cmp    %g2, 36
 392         bcs     3f
 393          nop
 394         sub     %g2, 12, %g2
 395         sub     %g7, 32, %g7
 396 3:      sub     %g2, 12, %g2
 397         sub     %g7, 32, %g7
 398 2:      sub     %g2, 12, %g2
 399         sub     %g7, 32, %g7
 400 1:      cmp     %g2, 4
 401         bcs,a   60f
 402          clr    %g2
 403         sub     %g2, 4, %g2
 404         sll     %g2, 2, %g2
 405 60:     and     %g1, 0x7f, %g3
 406         sub     %o0, %g7, %o0
 407         add     %g3, %g7, %g3
 408         ba      fixupretl
 409          sub    %g3, %g2, %g3
 410 51:
 411 /* i = 41 - g2; j = i % 6;
 412  * g3 = (g1 & 15) + (i / 6) * 16 + (j < 4) ? (j + 1) * 4 : 16;
 413  * o0 -= (i / 6) * 16 + 16;
 414  */
 415         neg     %g2
 416         and     %g1, 0xf, %g1
 417         add     %g2, 41, %g2
 418         add     %o0, %g1, %o0
 419 1:      cmp     %g2, 6
 420         bcs,a   2f
 421          cmp    %g2, 4
 422         add     %g1, 16, %g1
 423         b       1b
 424          sub    %g2, 6, %g2
 425 2:      bcc,a   2f
 426          mov    16, %g2
 427         inc     %g2
 428         sll     %g2, 2, %g2
 429 2:      add     %g1, %g2, %g3
 430         ba      fixupretl
 431          sub    %o0, %g3, %o0
 432 52:
 433 /* g3 = g1 + g7 - (g2 / 8) * 32 + (g2 & 4) ? (g2 & 3) * 8 : 0;
 434    o0 += (g2 / 8) * 32 */
 435         andn    %g2, 7, %g4
 436         add     %o0, %g7, %o0
 437         andcc   %g2, 4, %g0
 438         and     %g2, 3, %g2
 439         sll     %g4, 2, %g4
 440         sll     %g2, 3, %g2
 441         bne     60b
 442          sub    %g7, %g4, %g7
 443         ba      60b
 444          clr    %g2
 445 53:
 446 /* g3 = o3 + (o2 & 15) - (g2 & 8) - (g2 & 4) ? (g2 & 3) * 2 : 0;
 447    o0 += (g2 & 8) */
 448         and     %g2, 3, %g4
 449         andcc   %g2, 4, %g0
 450         and     %g2, 8, %g2
 451         sll     %g4, 1, %g4
 452         be      1f
 453          add    %o0, %g2, %o0
 454         add     %g2, %g4, %g2
 455 1:      and     %o2, 0xf, %g3
 456         add     %g3, %o3, %g3
 457         ba      fixupretl
 458          sub    %g3, %g2, %g3
 459 54:
 460 /* g3 = o3 + (o2 & 15) - (g2 / 4) * 2 - (g2 & 2) ? (g2 & 1) : 0;
 461    o0 += (g2 / 4) * 2 */
 462         srl     %g2, 2, %o4
 463         and     %g2, 1, %o5
 464         srl     %g2, 1, %g2
 465         add     %o4, %o4, %o4
 466         and     %o5, %g2, %o5
 467         and     %o2, 0xf, %o2
 468         add     %o0, %o4, %o0
 469         sub     %o3, %o5, %o3
 470         sub     %o2, %o4, %o2
 471         ba      fixupretl
 472          add    %o2, %o3, %g3
 473 55:
 474 /* i = 27 - g2;
 475    g3 = (o2 & 1) + i / 4 * 2 + !(i & 3);
 476    o0 -= i / 4 * 2 + 1 */
 477         neg     %g2
 478         and     %o2, 1, %o2
 479         add     %g2, 27, %g2
 480         srl     %g2, 2, %o5
 481         andcc   %g2, 3, %g0
 482         mov     1, %g2
 483         add     %o5, %o5, %o5
 484         be,a    1f
 485          clr    %g2
 486 1:      add     %g2, %o5, %g3
 487         sub     %o0, %g3, %o0
 488         ba      fixupretl
 489          add    %g3, %o2, %g3
 490
 491         .globl  __copy_user_end
 492 __copy_user_end: