arch/powerpc/lib/copy_32.S

   1 /*
   2  * Memory copy functions for 32-bit PowerPC.
   3  *
   4  * Copyright (C) 1996-2005 Paul Mackerras.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <asm/processor.h>
  12 #include <asm/cache.h>
  13 #include <asm/errno.h>
  14 #include <asm/ppc_asm.h>
  15 #include <asm/export.h>
  16
  17 #define COPY_16_BYTES           \
  18         lwz     r7,4(r4);       \
  19         lwz     r8,8(r4);       \
  20         lwz     r9,12(r4);      \
  21         lwzu    r10,16(r4);     \
  22         stw     r7,4(r6);       \
  23         stw     r8,8(r6);       \
  24         stw     r9,12(r6);      \
  25         stwu    r10,16(r6)
  26
  27 #define COPY_16_BYTES_WITHEX(n) \
  28 8 ## n ## 0:                    \
  29         lwz     r7,4(r4);       \
  30 8 ## n ## 1:                    \
  31         lwz     r8,8(r4);       \
  32 8 ## n ## 2:                    \
  33         lwz     r9,12(r4);      \
  34 8 ## n ## 3:                    \
  35         lwzu    r10,16(r4);     \
  36 8 ## n ## 4:                    \
  37         stw     r7,4(r6);       \
  38 8 ## n ## 5:                    \
  39         stw     r8,8(r6);       \
  40 8 ## n ## 6:                    \
  41         stw     r9,12(r6);      \
  42 8 ## n ## 7:                    \
  43         stwu    r10,16(r6)
  44
  45 #define COPY_16_BYTES_EXCODE(n)                 \
  46 9 ## n ## 0:                                    \
  47         addi    r5,r5,-(16 * n);                \
  48         b       104f;                           \
  49 9 ## n ## 1:                                    \
  50         addi    r5,r5,-(16 * n);                \
  51         b       105f;                           \
  52         EX_TABLE(8 ## n ## 0b,9 ## n ## 0b);    \
  53         EX_TABLE(8 ## n ## 1b,9 ## n ## 0b);    \
  54         EX_TABLE(8 ## n ## 2b,9 ## n ## 0b);    \
  55         EX_TABLE(8 ## n ## 3b,9 ## n ## 0b);    \
  56         EX_TABLE(8 ## n ## 4b,9 ## n ## 1b);    \
  57         EX_TABLE(8 ## n ## 5b,9 ## n ## 1b);    \
  58         EX_TABLE(8 ## n ## 6b,9 ## n ## 1b);    \
  59         EX_TABLE(8 ## n ## 7b,9 ## n ## 1b)
  60
  61         .text
  62         .stabs  "arch/powerpc/lib/",N_SO,0,0,0f
  63         .stabs  "copy_32.S",N_SO,0,0,0f
  64 0:
  65
  66 CACHELINE_BYTES = L1_CACHE_BYTES
  67 LG_CACHELINE_BYTES = L1_CACHE_SHIFT
  68 CACHELINE_MASK = (L1_CACHE_BYTES-1)
  69
  70 _GLOBAL(memset16)
  71         rlwinm. r0 ,r5, 31, 1, 31
  72         addi    r6, r3, -4
  73         beq-    2f
  74         rlwimi  r4 ,r4 ,16 ,0 ,15
  75         mtctr   r0
  76 1:      stwu    r4, 4(r6)
  77         bdnz    1b
  78 2:      andi.   r0, r5, 1
  79         beqlr
  80         sth     r4, 4(r6)
  81         blr
  82 EXPORT_SYMBOL(memset16)
  83
  84 /*
  85  * Use dcbz on the complete cache lines in the destination
  86  * to set them to zero.  This requires that the destination
  87  * area is cacheable.  -- paulus
  88  *
  89  * During early init, cache might not be active yet, so dcbz cannot be used.
  90  * We therefore skip the optimised bloc that uses dcbz. This jump is
  91  * replaced by a nop once cache is active. This is done in machine_init()
  92  */
  93 _GLOBAL(memset)
  94         cmplwi  0,r5,4
  95         blt     7f
  96
  97         rlwimi  r4,r4,8,16,23
  98         rlwimi  r4,r4,16,0,15
  99
 100         stw     r4,0(r3)
 101         beqlr
 102         andi.   r0,r3,3
 103         add     r5,r0,r5
 104         subf    r6,r0,r3
 105         cmplwi  0,r4,0
 106         /*
 107          * Skip optimised bloc until cache is enabled. Will be replaced
 108          * by 'bne' during boot to use normal procedure if r4 is not zero
 109          */
 110 _GLOBAL(memset_nocache_branch)
 111         b       2f
 112
 113         clrlwi  r7,r6,32-LG_CACHELINE_BYTES
 114         add     r8,r7,r5
 115         srwi    r9,r8,LG_CACHELINE_BYTES
 116         addic.  r9,r9,-1        /* total number of complete cachelines */
 117         ble     2f
 118         xori    r0,r7,CACHELINE_MASK & ~3
 119         srwi.   r0,r0,2
 120         beq     3f
 121         mtctr   r0
 122 4:      stwu    r4,4(r6)
 123         bdnz    4b
 124 3:      mtctr   r9
 125         li      r7,4
 126 10:     dcbz    r7,r6
 127         addi    r6,r6,CACHELINE_BYTES
 128         bdnz    10b
 129         clrlwi  r5,r8,32-LG_CACHELINE_BYTES
 130         addi    r5,r5,4
 131
 132 2:      srwi    r0,r5,2
 133         mtctr   r0
 134         bdz     6f
 135 1:      stwu    r4,4(r6)
 136         bdnz    1b
 137 6:      andi.   r5,r5,3
 138         beqlr
 139         mtctr   r5
 140         addi    r6,r6,3
 141 8:      stbu    r4,1(r6)
 142         bdnz    8b
 143         blr
 144
 145 7:      cmpwi   0,r5,0
 146         beqlr
 147         mtctr   r5
 148         addi    r6,r3,-1
 149 9:      stbu    r4,1(r6)
 150         bdnz    9b
 151         blr
 152 EXPORT_SYMBOL(memset)
 153
 154 /*
 155  * This version uses dcbz on the complete cache lines in the
 156  * destination area to reduce memory traffic.  This requires that
 157  * the destination area is cacheable.
 158  * We only use this version if the source and dest don't overlap.
 159  * -- paulus.
 160  *
 161  * During early init, cache might not be active yet, so dcbz cannot be used.
 162  * We therefore jump to generic_memcpy which doesn't use dcbz. This jump is
 163  * replaced by a nop once cache is active. This is done in machine_init()
 164  */
 165 _GLOBAL(memmove)
 166         cmplw   0,r3,r4
 167         bgt     backwards_memcpy
 168         /* fall through */
 169
 170 _GLOBAL(memcpy)
 171         b       generic_memcpy
 172         add     r7,r3,r5                /* test if the src & dst overlap */
 173         add     r8,r4,r5
 174         cmplw   0,r4,r7
 175         cmplw   1,r3,r8
 176         crand   0,0,4                   /* cr0.lt &= cr1.lt */
 177         blt     generic_memcpy          /* if regions overlap */
 178
 179         addi    r4,r4,-4
 180         addi    r6,r3,-4
 181         neg     r0,r3
 182         andi.   r0,r0,CACHELINE_MASK    /* # bytes to start of cache line */
 183         beq     58f
 184
 185         cmplw   0,r5,r0                 /* is this more than total to do? */
 186         blt     63f                     /* if not much to do */
 187         andi.   r8,r0,3                 /* get it word-aligned first */
 188         subf    r5,r0,r5
 189         mtctr   r8
 190         beq+    61f
 191 70:     lbz     r9,4(r4)                /* do some bytes */
 192         addi    r4,r4,1
 193         addi    r6,r6,1
 194         stb     r9,3(r6)
 195         bdnz    70b
 196 61:     srwi.   r0,r0,2
 197         mtctr   r0
 198         beq     58f
 199 72:     lwzu    r9,4(r4)                /* do some words */
 200         stwu    r9,4(r6)
 201         bdnz    72b
 202
 203 58:     srwi.   r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
 204         clrlwi  r5,r5,32-LG_CACHELINE_BYTES
 205         li      r11,4
 206         mtctr   r0
 207         beq     63f
 208 53:
 209         dcbz    r11,r6
 210         COPY_16_BYTES
 211 #if L1_CACHE_BYTES >= 32
 212         COPY_16_BYTES
 213 #if L1_CACHE_BYTES >= 64
 214         COPY_16_BYTES
 215         COPY_16_BYTES
 216 #if L1_CACHE_BYTES >= 128
 217         COPY_16_BYTES
 218         COPY_16_BYTES
 219         COPY_16_BYTES
 220         COPY_16_BYTES
 221 #endif
 222 #endif
 223 #endif
 224         bdnz    53b
 225
 226 63:     srwi.   r0,r5,2
 227         mtctr   r0
 228         beq     64f
 229 30:     lwzu    r0,4(r4)
 230         stwu    r0,4(r6)
 231         bdnz    30b
 232
 233 64:     andi.   r0,r5,3
 234         mtctr   r0
 235         beq+    65f
 236         addi    r4,r4,3
 237         addi    r6,r6,3
 238 40:     lbzu    r0,1(r4)
 239         stbu    r0,1(r6)
 240         bdnz    40b
 241 65:     blr
 242 EXPORT_SYMBOL(memcpy)
 243 EXPORT_SYMBOL(memmove)
 244
 245 generic_memcpy:
 246         srwi.   r7,r5,3
 247         addi    r6,r3,-4
 248         addi    r4,r4,-4
 249         beq     2f                      /* if less than 8 bytes to do */
 250         andi.   r0,r6,3                 /* get dest word aligned */
 251         mtctr   r7
 252         bne     5f
 253 1:      lwz     r7,4(r4)
 254         lwzu    r8,8(r4)
 255         stw     r7,4(r6)
 256         stwu    r8,8(r6)
 257         bdnz    1b
 258         andi.   r5,r5,7
 259 2:      cmplwi  0,r5,4
 260         blt     3f
 261         lwzu    r0,4(r4)
 262         addi    r5,r5,-4
 263         stwu    r0,4(r6)
 264 3:      cmpwi   0,r5,0
 265         beqlr
 266         mtctr   r5
 267         addi    r4,r4,3
 268         addi    r6,r6,3
 269 4:      lbzu    r0,1(r4)
 270         stbu    r0,1(r6)
 271         bdnz    4b
 272         blr
 273 5:      subfic  r0,r0,4
 274         mtctr   r0
 275 6:      lbz     r7,4(r4)
 276         addi    r4,r4,1
 277         stb     r7,4(r6)
 278         addi    r6,r6,1
 279         bdnz    6b
 280         subf    r5,r0,r5
 281         rlwinm. r7,r5,32-3,3,31
 282         beq     2b
 283         mtctr   r7
 284         b       1b
 285
 286 _GLOBAL(backwards_memcpy)
 287         rlwinm. r7,r5,32-3,3,31         /* r0 = r5 >> 3 */
 288         add     r6,r3,r5
 289         add     r4,r4,r5
 290         beq     2f
 291         andi.   r0,r6,3
 292         mtctr   r7
 293         bne     5f
 294 1:      lwz     r7,-4(r4)
 295         lwzu    r8,-8(r4)
 296         stw     r7,-4(r6)
 297         stwu    r8,-8(r6)
 298         bdnz    1b
 299         andi.   r5,r5,7
 300 2:      cmplwi  0,r5,4
 301         blt     3f
 302         lwzu    r0,-4(r4)
 303         subi    r5,r5,4
 304         stwu    r0,-4(r6)
 305 3:      cmpwi   0,r5,0
 306         beqlr
 307         mtctr   r5
 308 4:      lbzu    r0,-1(r4)
 309         stbu    r0,-1(r6)
 310         bdnz    4b
 311         blr
 312 5:      mtctr   r0
 313 6:      lbzu    r7,-1(r4)
 314         stbu    r7,-1(r6)
 315         bdnz    6b
 316         subf    r5,r0,r5
 317         rlwinm. r7,r5,32-3,3,31
 318         beq     2b
 319         mtctr   r7
 320         b       1b
 321
 322 _GLOBAL(__copy_tofrom_user)
 323         addi    r4,r4,-4
 324         addi    r6,r3,-4
 325         neg     r0,r3
 326         andi.   r0,r0,CACHELINE_MASK    /* # bytes to start of cache line */
 327         beq     58f
 328
 329         cmplw   0,r5,r0                 /* is this more than total to do? */
 330         blt     63f                     /* if not much to do */
 331         andi.   r8,r0,3                 /* get it word-aligned first */
 332         mtctr   r8
 333         beq+    61f
 334 70:     lbz     r9,4(r4)                /* do some bytes */
 335 71:     stb     r9,4(r6)
 336         addi    r4,r4,1
 337         addi    r6,r6,1
 338         bdnz    70b
 339 61:     subf    r5,r0,r5
 340         srwi.   r0,r0,2
 341         mtctr   r0
 342         beq     58f
 343 72:     lwzu    r9,4(r4)                /* do some words */
 344 73:     stwu    r9,4(r6)
 345         bdnz    72b
 346
 347         EX_TABLE(70b,100f)
 348         EX_TABLE(71b,101f)
 349         EX_TABLE(72b,102f)
 350         EX_TABLE(73b,103f)
 351
 352 58:     srwi.   r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
 353         clrlwi  r5,r5,32-LG_CACHELINE_BYTES
 354         li      r11,4
 355         beq     63f
 356
 357         /* Here we decide how far ahead to prefetch the source */
 358         li      r3,4
 359         cmpwi   r0,1
 360         li      r7,0
 361         ble     114f
 362         li      r7,1
 363 #if MAX_COPY_PREFETCH > 1
 364         /* Heuristically, for large transfers we prefetch
 365            MAX_COPY_PREFETCH cachelines ahead.  For small transfers
 366            we prefetch 1 cacheline ahead. */
 367         cmpwi   r0,MAX_COPY_PREFETCH
 368         ble     112f
 369         li      r7,MAX_COPY_PREFETCH
 370 112:    mtctr   r7
 371 111:    dcbt    r3,r4
 372         addi    r3,r3,CACHELINE_BYTES
 373         bdnz    111b
 374 #else
 375         dcbt    r3,r4
 376         addi    r3,r3,CACHELINE_BYTES
 377 #endif /* MAX_COPY_PREFETCH > 1 */
 378
 379 114:    subf    r8,r7,r0
 380         mr      r0,r7
 381         mtctr   r8
 382
 383 53:     dcbt    r3,r4
 384 54:     dcbz    r11,r6
 385         EX_TABLE(54b,105f)
 386 /* the main body of the cacheline loop */
 387         COPY_16_BYTES_WITHEX(0)
 388 #if L1_CACHE_BYTES >= 32
 389         COPY_16_BYTES_WITHEX(1)
 390 #if L1_CACHE_BYTES >= 64
 391         COPY_16_BYTES_WITHEX(2)
 392         COPY_16_BYTES_WITHEX(3)
 393 #if L1_CACHE_BYTES >= 128
 394         COPY_16_BYTES_WITHEX(4)
 395         COPY_16_BYTES_WITHEX(5)
 396         COPY_16_BYTES_WITHEX(6)
 397         COPY_16_BYTES_WITHEX(7)
 398 #endif
 399 #endif
 400 #endif
 401         bdnz    53b
 402         cmpwi   r0,0
 403         li      r3,4
 404         li      r7,0
 405         bne     114b
 406
 407 63:     srwi.   r0,r5,2
 408         mtctr   r0
 409         beq     64f
 410 30:     lwzu    r0,4(r4)
 411 31:     stwu    r0,4(r6)
 412         bdnz    30b
 413
 414 64:     andi.   r0,r5,3
 415         mtctr   r0
 416         beq+    65f
 417 40:     lbz     r0,4(r4)
 418 41:     stb     r0,4(r6)
 419         addi    r4,r4,1
 420         addi    r6,r6,1
 421         bdnz    40b
 422 65:     li      r3,0
 423         blr
 424
 425 /* read fault, initial single-byte copy */
 426 100:    li      r9,0
 427         b       90f
 428 /* write fault, initial single-byte copy */
 429 101:    li      r9,1
 430 90:     subf    r5,r8,r5
 431         li      r3,0
 432         b       99f
 433 /* read fault, initial word copy */
 434 102:    li      r9,0
 435         b       91f
 436 /* write fault, initial word copy */
 437 103:    li      r9,1
 438 91:     li      r3,2
 439         b       99f
 440
 441 /*
 442  * this stuff handles faults in the cacheline loop and branches to either
 443  * 104f (if in read part) or 105f (if in write part), after updating r5
 444  */
 445         COPY_16_BYTES_EXCODE(0)
 446 #if L1_CACHE_BYTES >= 32
 447         COPY_16_BYTES_EXCODE(1)
 448 #if L1_CACHE_BYTES >= 64
 449         COPY_16_BYTES_EXCODE(2)
 450         COPY_16_BYTES_EXCODE(3)
 451 #if L1_CACHE_BYTES >= 128
 452         COPY_16_BYTES_EXCODE(4)
 453         COPY_16_BYTES_EXCODE(5)
 454         COPY_16_BYTES_EXCODE(6)
 455         COPY_16_BYTES_EXCODE(7)
 456 #endif
 457 #endif
 458 #endif
 459
 460 /* read fault in cacheline loop */
 461 104:    li      r9,0
 462         b       92f
 463 /* fault on dcbz (effectively a write fault) */
 464 /* or write fault in cacheline loop */
 465 105:    li      r9,1
 466 92:     li      r3,LG_CACHELINE_BYTES
 467         mfctr   r8
 468         add     r0,r0,r8
 469         b       106f
 470 /* read fault in final word loop */
 471 108:    li      r9,0
 472         b       93f
 473 /* write fault in final word loop */
 474 109:    li      r9,1
 475 93:     andi.   r5,r5,3
 476         li      r3,2
 477         b       99f
 478 /* read fault in final byte loop */
 479 110:    li      r9,0
 480         b       94f
 481 /* write fault in final byte loop */
 482 111:    li      r9,1
 483 94:     li      r5,0
 484         li      r3,0
 485 /*
 486  * At this stage the number of bytes not copied is
 487  * r5 + (ctr << r3), and r9 is 0 for read or 1 for write.
 488  */
 489 99:     mfctr   r0
 490 106:    slw     r3,r0,r3
 491         add.    r3,r3,r5
 492         beq     120f                    /* shouldn't happen */
 493         cmpwi   0,r9,0
 494         bne     120f
 495 /* for a read fault, first try to continue the copy one byte at a time */
 496         mtctr   r3
 497 130:    lbz     r0,4(r4)
 498 131:    stb     r0,4(r6)
 499         addi    r4,r4,1
 500         addi    r6,r6,1
 501         bdnz    130b
 502 /* then clear out the destination: r3 bytes starting at 4(r6) */
 503 132:    mfctr   r3
 504 120:    blr
 505
 506         EX_TABLE(30b,108b)
 507         EX_TABLE(31b,109b)
 508         EX_TABLE(40b,110b)
 509         EX_TABLE(41b,111b)
 510         EX_TABLE(130b,132b)
 511         EX_TABLE(131b,120b)
 512
 513 EXPORT_SYMBOL(__copy_tofrom_user)