arch/sh/mm/clear_page.S

   1 /*
   2  * __clear_user_page, __clear_user, clear_page implementation of SuperH
   3  *
   4  * Copyright (C) 2001  Kaz Kojima
   5  * Copyright (C) 2001, 2002  Niibe Yutaka
   6  * Copyright (C) 2006  Paul Mundt
   7  */
   8 #include <linux/linkage.h>
   9 #include <asm/page.h>
  10
  11 /*
  12  * clear_page_slow
  13  * @to: P1 address
  14  *
  15  * void clear_page_slow(void *to)
  16  */
  17
  18 /*
  19  * r0 --- scratch
  20  * r4 --- to
  21  * r5 --- to + PAGE_SIZE
  22  */
  23 ENTRY(clear_page_slow)
  24         mov     r4,r5
  25         mov.l   .Llimit,r0
  26         add     r0,r5
  27         mov     #0,r0
  28         !
  29 1:
  30 #if defined(CONFIG_CPU_SH3)
  31         mov.l   r0,@r4
  32 #elif defined(CONFIG_CPU_SH4)
  33         movca.l r0,@r4
  34         mov     r4,r1
  35 #endif
  36         add     #32,r4
  37         mov.l   r0,@-r4
  38         mov.l   r0,@-r4
  39         mov.l   r0,@-r4
  40         mov.l   r0,@-r4
  41         mov.l   r0,@-r4
  42         mov.l   r0,@-r4
  43         mov.l   r0,@-r4
  44 #if defined(CONFIG_CPU_SH4)
  45         ocbwb   @r1
  46 #endif
  47         cmp/eq  r5,r4
  48         bf/s    1b
  49          add    #28,r4
  50         !
  51         rts
  52          nop
  53 .Llimit:        .long   (PAGE_SIZE-28)
  54
  55 ENTRY(__clear_user)
  56         !
  57         mov     #0, r0
  58         mov     #0xe0, r1       ! 0xffffffe0
  59         !
  60         ! r4..(r4+31)&~32          -------- not aligned [ Area 0 ]
  61         ! (r4+31)&~32..(r4+r5)&~32 -------- aligned     [ Area 1 ]
  62         ! (r4+r5)&~32..r4+r5       -------- not aligned [ Area 2 ]
  63         !
  64         ! Clear area 0
  65         mov     r4, r2
  66         !
  67         tst     r1, r5          ! length < 32
  68         bt      .Larea2         ! skip to remainder
  69         !
  70         add     #31, r2
  71         and     r1, r2
  72         cmp/eq  r4, r2
  73         bt      .Larea1
  74         mov     r2, r3
  75         sub     r4, r3
  76         mov     r3, r7
  77         mov     r4, r2
  78         !
  79 .L0:    dt      r3
  80 0:      mov.b   r0, @r2
  81         bf/s    .L0
  82          add    #1, r2
  83         !
  84         sub     r7, r5
  85         mov     r2, r4
  86 .Larea1:
  87         mov     r4, r3
  88         add     r5, r3
  89         and     r1, r3
  90         cmp/hi  r2, r3
  91         bf      .Larea2
  92         !
  93         ! Clear area 1
  94 #if defined(CONFIG_CPU_SH4)
  95 1:      movca.l r0, @r2
  96 #else
  97 1:      mov.l   r0, @r2
  98 #endif
  99         add     #4, r2
 100 2:      mov.l   r0, @r2
 101         add     #4, r2
 102 3:      mov.l   r0, @r2
 103         add     #4, r2
 104 4:      mov.l   r0, @r2
 105         add     #4, r2
 106 5:      mov.l   r0, @r2
 107         add     #4, r2
 108 6:      mov.l   r0, @r2
 109         add     #4, r2
 110 7:      mov.l   r0, @r2
 111         add     #4, r2
 112 8:      mov.l   r0, @r2
 113         add     #4, r2
 114         cmp/hi  r2, r3
 115         bt/s    1b
 116          nop
 117         !
 118         ! Clear area 2
 119 .Larea2:
 120         mov     r4, r3
 121         add     r5, r3
 122         cmp/hs  r3, r2
 123         bt/s    .Ldone
 124          sub    r2, r3
 125 .L2:    dt      r3
 126 9:      mov.b   r0, @r2
 127         bf/s    .L2
 128          add    #1, r2
 129         !
 130 .Ldone: rts
 131          mov    #0, r0  ! return 0 as normal return
 132
 133         ! return the number of bytes remained
 134 .Lbad_clear_user:
 135         mov     r4, r0
 136         add     r5, r0
 137         rts
 138          sub    r2, r0
 139
 140 .section __ex_table,"a"
 141         .align 2
 142         .long   0b, .Lbad_clear_user
 143         .long   1b, .Lbad_clear_user
 144         .long   2b, .Lbad_clear_user
 145         .long   3b, .Lbad_clear_user
 146         .long   4b, .Lbad_clear_user
 147         .long   5b, .Lbad_clear_user
 148         .long   6b, .Lbad_clear_user
 149         .long   7b, .Lbad_clear_user
 150         .long   8b, .Lbad_clear_user
 151         .long   9b, .Lbad_clear_user
 152 .previous
 153
 154 #if defined(CONFIG_CPU_SH4)
 155 /*
 156  * __clear_user_page
 157  * @to: P3 address (with same color)
 158  * @orig_to: P1 address
 159  *
 160  * void __clear_user_page(void *to, void *orig_to)
 161  */
 162
 163 /*
 164  * r0 --- scratch
 165  * r4 --- to
 166  * r5 --- orig_to
 167  * r6 --- to + PAGE_SIZE
 168  */
 169 ENTRY(__clear_user_page)
 170         mov.l   .Lpsz,r0
 171         mov     r4,r6
 172         add     r0,r6
 173         mov     #0,r0
 174         !
 175 1:      ocbi    @r5
 176         add     #32,r5
 177         movca.l r0,@r4
 178         mov     r4,r1
 179         add     #32,r4
 180         mov.l   r0,@-r4
 181         mov.l   r0,@-r4
 182         mov.l   r0,@-r4
 183         mov.l   r0,@-r4
 184         mov.l   r0,@-r4
 185         mov.l   r0,@-r4
 186         mov.l   r0,@-r4
 187         add     #28,r4
 188         cmp/eq  r6,r4
 189         bf/s    1b
 190          ocbwb  @r1
 191         !
 192         rts
 193          nop
 194 .Lpsz:  .long   PAGE_SIZE
 195
 196 #endif
 197