arch/sh/lib/copy_page.S

   1 /*
   2  * copy_page, __copy_user_page, __copy_user implementation of SuperH
   3  *
   4  * Copyright (C) 2001  Niibe Yutaka & Kaz Kojima
   5  * Copyright (C) 2002  Toshinobu Sugioka
   6  * Copyright (C) 2006  Paul Mundt
   7  */
   8 #include <linux/linkage.h>
   9 #include <asm/page.h>
  10
  11 /*
  12  * copy_page
  13  * @to: P1 address
  14  * @from: P1 address
  15  *
  16  * void copy_page(void *to, void *from)
  17  */
  18
  19 /*
  20  * r0, r1, r2, r3, r4, r5, r6, r7 --- scratch
  21  * r8 --- from + PAGE_SIZE
  22  * r9 --- not used
  23  * r10 --- to
  24  * r11 --- from
  25  */
  26 ENTRY(copy_page)
  27         mov.l   r8,@-r15
  28         mov.l   r10,@-r15
  29         mov.l   r11,@-r15
  30         mov     r4,r10
  31         mov     r5,r11
  32         mov     r5,r8
  33         mov     #(PAGE_SIZE >> 10), r0
  34         shll8   r0
  35         shll2   r0
  36         add     r0,r8
  37         !
  38 1:      mov.l   @r11+,r0
  39         mov.l   @r11+,r1
  40         mov.l   @r11+,r2
  41         mov.l   @r11+,r3
  42         mov.l   @r11+,r4
  43         mov.l   @r11+,r5
  44         mov.l   @r11+,r6
  45         mov.l   @r11+,r7
  46 #if defined(CONFIG_CPU_SH4)
  47         movca.l r0,@r10
  48 #else
  49         mov.l   r0,@r10
  50 #endif
  51         add     #32,r10
  52         mov.l   r7,@-r10
  53         mov.l   r6,@-r10
  54         mov.l   r5,@-r10
  55         mov.l   r4,@-r10
  56         mov.l   r3,@-r10
  57         mov.l   r2,@-r10
  58         mov.l   r1,@-r10
  59         cmp/eq  r11,r8
  60         bf/s    1b
  61          add    #28,r10
  62         !
  63         mov.l   @r15+,r11
  64         mov.l   @r15+,r10
  65         mov.l   @r15+,r8
  66         rts
  67          nop
  68
  69 /*
  70  * __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
  71  * Return the number of bytes NOT copied
  72  */
  73 #define EX(...)                 \
  74         9999: __VA_ARGS__ ;             \
  75         .section __ex_table, "a";       \
  76         .long 9999b, 6000f      ;       \
  77         .previous
  78 #define EX_NO_POP(...)                  \
  79         9999: __VA_ARGS__ ;             \
  80         .section __ex_table, "a";       \
  81         .long 9999b, 6005f      ;       \
  82         .previous
  83 ENTRY(__copy_user)
  84         ! Check if small number of bytes
  85         mov     #11,r0
  86         mov     r4,r3
  87         cmp/gt  r0,r6           ! r6 (len) > r0 (11)
  88         bf/s    .L_cleanup_loop_no_pop
  89          add    r6,r3           ! last destination address
  90
  91         ! Calculate bytes needed to align to src
  92         mov.l   r11,@-r15
  93         neg     r5,r0
  94         mov.l   r10,@-r15
  95         add     #4,r0
  96         mov.l   r9,@-r15
  97         and     #3,r0
  98         mov.l   r8,@-r15
  99         tst     r0,r0
 100         bt      2f
 101
 102 1:
 103         ! Copy bytes to long word align src
 104 EX(     mov.b   @r5+,r1         )
 105         dt      r0
 106         add     #-1,r6
 107 EX(     mov.b   r1,@r4          )
 108         bf/s    1b
 109          add    #1,r4
 110
 111         ! Jump to appropriate routine depending on dest
 112 2:      mov     #3,r1
 113         mov     r6, r2
 114         and     r4,r1
 115         shlr2   r2
 116         shll2   r1
 117         mova    .L_jump_tbl,r0
 118         mov.l   @(r0,r1),r1
 119         jmp     @r1
 120          nop
 121
 122         .align 2
 123 .L_jump_tbl:
 124         .long   .L_dest00
 125         .long   .L_dest01
 126         .long   .L_dest10
 127         .long   .L_dest11
 128
 129 /*
 130  * Come here if there are less than 12 bytes to copy
 131  *
 132  * Keep the branch target close, so the bf/s callee doesn't overflow
 133  * and result in a more expensive branch being inserted. This is the
 134  * fast-path for small copies, the jump via the jump table will hit the
 135  * default slow-path cleanup. -PFM.
 136  */
 137 .L_cleanup_loop_no_pop:
 138         tst     r6,r6           ! Check explicitly for zero
 139         bt      1f
 140
 141 2:
 142 EX_NO_POP(      mov.b   @r5+,r0         )
 143         dt      r6
 144 EX_NO_POP(      mov.b   r0,@r4          )
 145         bf/s    2b
 146          add    #1,r4
 147
 148 1:      mov     #0,r0           ! normal return
 149 5000:
 150
 151 # Exception handler:
 152 .section .fixup, "ax"
 153 6005:
 154         mov.l   8000f,r1
 155         mov     r3,r0
 156         jmp     @r1
 157          sub    r4,r0
 158         .align  2
 159 8000:   .long   5000b
 160
 161 .previous
 162         rts
 163          nop
 164
 165 ! Destination = 00
 166
 167 .L_dest00:
 168         ! Skip the large copy for small transfers
 169         mov     #(32+32-4), r0
 170         cmp/gt  r6, r0          ! r0 (60) > r6 (len)
 171         bt      1f
 172
 173         ! Align dest to a 32 byte boundary
 174         neg     r4,r0
 175         add     #0x20, r0
 176         and     #0x1f, r0
 177         tst     r0, r0
 178         bt      2f
 179
 180         sub     r0, r6
 181         shlr2   r0
 182 3:
 183 EX(     mov.l   @r5+,r1         )
 184         dt      r0
 185 EX(     mov.l   r1,@r4          )
 186         bf/s    3b
 187          add    #4,r4
 188
 189 2:
 190 EX(     mov.l   @r5+,r0         )
 191 EX(     mov.l   @r5+,r1         )
 192 EX(     mov.l   @r5+,r2         )
 193 EX(     mov.l   @r5+,r7         )
 194 EX(     mov.l   @r5+,r8         )
 195 EX(     mov.l   @r5+,r9         )
 196 EX(     mov.l   @r5+,r10        )
 197 EX(     mov.l   @r5+,r11        )
 198 #ifdef CONFIG_CPU_SH4
 199 EX(     movca.l r0,@r4          )
 200 #else
 201 EX(     mov.l   r0,@r4          )
 202 #endif
 203         add     #-32, r6
 204 EX(     mov.l   r1,@(4,r4)      )
 205         mov     #32, r0
 206 EX(     mov.l   r2,@(8,r4)      )
 207         cmp/gt  r6, r0          ! r0 (32) > r6 (len)
 208 EX(     mov.l   r7,@(12,r4)     )
 209 EX(     mov.l   r8,@(16,r4)     )
 210 EX(     mov.l   r9,@(20,r4)     )
 211 EX(     mov.l   r10,@(24,r4)    )
 212 EX(     mov.l   r11,@(28,r4)    )
 213         bf/s    2b
 214          add    #32,r4
 215
 216 1:      mov     r6, r0
 217         shlr2   r0
 218         tst     r0, r0
 219         bt      .L_cleanup
 220 1:
 221 EX(     mov.l   @r5+,r1         )
 222         dt      r0
 223 EX(     mov.l   r1,@r4          )
 224         bf/s    1b
 225          add    #4,r4
 226
 227         bra     .L_cleanup
 228          nop
 229
 230 ! Destination = 10
 231
 232 .L_dest10:
 233         mov     r2,r7
 234         shlr2   r7
 235         shlr    r7
 236         tst     r7,r7
 237         mov     #7,r0
 238         bt/s    1f
 239          and    r0,r2
 240 2:
 241         dt      r7
 242 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 243 EX(     mov.l   @r5+,r0         )
 244 EX(     mov.l   @r5+,r1         )
 245 EX(     mov.l   @r5+,r8         )
 246 EX(     mov.l   @r5+,r9         )
 247 EX(     mov.l   @r5+,r10        )
 248 EX(     mov.w   r0,@r4          )
 249         add     #2,r4
 250         xtrct   r1,r0
 251         xtrct   r8,r1
 252         xtrct   r9,r8
 253         xtrct   r10,r9
 254
 255 EX(     mov.l   r0,@r4          )
 256 EX(     mov.l   r1,@(4,r4)      )
 257 EX(     mov.l   r8,@(8,r4)      )
 258 EX(     mov.l   r9,@(12,r4)     )
 259
 260 EX(     mov.l   @r5+,r1         )
 261 EX(     mov.l   @r5+,r8         )
 262 EX(     mov.l   @r5+,r0         )
 263         xtrct   r1,r10
 264         xtrct   r8,r1
 265         xtrct   r0,r8
 266         shlr16  r0
 267 EX(     mov.l   r10,@(16,r4)    )
 268 EX(     mov.l   r1,@(20,r4)     )
 269 EX(     mov.l   r8,@(24,r4)     )
 270 EX(     mov.w   r0,@(28,r4)     )
 271         bf/s    2b
 272          add    #30,r4
 273 #else
 274 EX(     mov.l   @(28,r5),r0     )
 275 EX(     mov.l   @(24,r5),r8     )
 276 EX(     mov.l   @(20,r5),r9     )
 277 EX(     mov.l   @(16,r5),r10    )
 278 EX(     mov.w   r0,@(30,r4)     )
 279         add     #-2,r4
 280         xtrct   r8,r0
 281         xtrct   r9,r8
 282         xtrct   r10,r9
 283 EX(     mov.l   r0,@(28,r4)     )
 284 EX(     mov.l   r8,@(24,r4)     )
 285 EX(     mov.l   r9,@(20,r4)     )
 286
 287 EX(     mov.l   @(12,r5),r0     )
 288 EX(     mov.l   @(8,r5),r8      )
 289         xtrct   r0,r10
 290 EX(     mov.l   @(4,r5),r9      )
 291         mov.l   r10,@(16,r4)
 292 EX(     mov.l   @r5,r10         )
 293         xtrct   r8,r0
 294         xtrct   r9,r8
 295         xtrct   r10,r9
 296 EX(     mov.l   r0,@(12,r4)     )
 297 EX(     mov.l   r8,@(8,r4)      )
 298         swap.w  r10,r0
 299 EX(     mov.l   r9,@(4,r4)      )
 300 EX(     mov.w   r0,@(2,r4)      )
 301
 302         add     #32,r5
 303         bf/s    2b
 304          add    #34,r4
 305 #endif
 306         tst     r2,r2
 307         bt      .L_cleanup
 308
 309 1:      ! Read longword, write two words per iteration
 310 EX(     mov.l   @r5+,r0         )
 311         dt      r2
 312 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 313 EX(     mov.w   r0,@r4          )
 314         shlr16  r0
 315 EX(     mov.w   r0,@(2,r4)      )
 316 #else
 317 EX(     mov.w   r0,@(2,r4)      )
 318         shlr16  r0
 319 EX(     mov.w   r0,@r4          )
 320 #endif
 321         bf/s    1b
 322          add    #4,r4
 323
 324         bra     .L_cleanup
 325          nop
 326
 327 ! Destination = 01 or 11
 328
 329 .L_dest01:
 330 .L_dest11:
 331         ! Read longword, write byte, word, byte per iteration
 332 EX(     mov.l   @r5+,r0         )
 333         dt      r2
 334 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 335 EX(     mov.b   r0,@r4          )
 336         shlr8   r0
 337         add     #1,r4
 338 EX(     mov.w   r0,@r4          )
 339         shlr16  r0
 340 EX(     mov.b   r0,@(2,r4)      )
 341         bf/s    .L_dest01
 342          add    #3,r4
 343 #else
 344 EX(     mov.b   r0,@(3,r4)      )
 345         shlr8   r0
 346         swap.w  r0,r7
 347 EX(     mov.b   r7,@r4          )
 348         add     #1,r4
 349 EX(     mov.w   r0,@r4          )
 350         bf/s    .L_dest01
 351          add    #3,r4
 352 #endif
 353
 354 ! Cleanup last few bytes
 355 .L_cleanup:
 356         mov     r6,r0
 357         and     #3,r0
 358         tst     r0,r0
 359         bt      .L_exit
 360         mov     r0,r6
 361
 362 .L_cleanup_loop:
 363 EX(     mov.b   @r5+,r0         )
 364         dt      r6
 365 EX(     mov.b   r0,@r4          )
 366         bf/s    .L_cleanup_loop
 367          add    #1,r4
 368
 369 .L_exit:
 370         mov     #0,r0           ! normal return
 371
 372 5000:
 373
 374 # Exception handler:
 375 .section .fixup, "ax"
 376 6000:
 377         mov.l   8000f,r1
 378         mov     r3,r0
 379         jmp     @r1
 380          sub    r4,r0
 381         .align  2
 382 8000:   .long   5000b
 383
 384 .previous
 385         mov.l   @r15+,r8
 386         mov.l   @r15+,r9
 387         mov.l   @r15+,r10
 388         rts
 389          mov.l  @r15+,r11