arch/parisc/lib/lusercopy.S

   1 /*
   2  *    User Space Access Routines
   3  *
   4  *    Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
   5  *    Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
   6  *    Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
   7  *    Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
   8  *
   9  *
  10  *    This program is free software; you can redistribute it and/or modify
  11  *    it under the terms of the GNU General Public License as published by
  12  *    the Free Software Foundation; either version 2, or (at your option)
  13  *    any later version.
  14  *
  15  *    This program is distributed in the hope that it will be useful,
  16  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *    GNU General Public License for more details.
  19  *
  20  *    You should have received a copy of the GNU General Public License
  21  *    along with this program; if not, write to the Free Software
  22  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 /*
  26  * These routines still have plenty of room for optimization
  27  * (word & doubleword load/store, dual issue, store hints, etc.).
  28  */
  29
  30 /*
  31  * The following routines assume that space register 3 (sr3) contains
  32  * the space id associated with the current users address space.
  33  */
  34
  35
  36         .text
  37
  38 #include <asm/assembly.h>
  39 #include <asm/errno.h>
  40
  41         /*
  42          * get_sr gets the appropriate space value into
  43          * sr1 for kernel/user space access, depending
  44          * on the flag stored in the task structure.
  45          */
  46
  47         .macro  get_sr
  48         mfctl       %cr30,%r1
  49         ldw         TI_SEGMENT(%r1),%r22
  50         mfsp        %sr3,%r1
  51         or,<>       %r22,%r0,%r0
  52         copy        %r0,%r1
  53         mtsp        %r1,%sr1
  54         .endm
  55
  56         .macro fixup_branch lbl
  57         ldil        L%\lbl, %r1
  58         ldo         R%\lbl(%r1), %r1
  59         bv          %r0(%r1)
  60         .endm
  61
  62         /*
  63          * long lstrncpy_from_user(char *dst, const char *src, long n)
  64          *
  65          * Returns -EFAULT if exception before terminator,
  66          *         N if the entire buffer filled,
  67          *         otherwise strlen (i.e. excludes zero byte)
  68          */
  69
  70         .export lstrncpy_from_user,code
  71 lstrncpy_from_user:
  72         .proc
  73         .callinfo NO_CALLS
  74         .entry
  75         comib,=     0,%r24,$lsfu_done
  76         copy        %r24,%r23
  77         get_sr
  78 1:      ldbs,ma     1(%sr1,%r25),%r1
  79 $lsfu_loop:
  80         stbs,ma     %r1,1(%r26)
  81         comib,=,n   0,%r1,$lsfu_done
  82         addib,<>,n  -1,%r24,$lsfu_loop
  83 2:      ldbs,ma     1(%sr1,%r25),%r1
  84 $lsfu_done:
  85         sub         %r23,%r24,%r28
  86 $lsfu_exit:
  87         bv          %r0(%r2)
  88         nop
  89         .exit
  90
  91         .section .fixup,"ax"
  92 3:      fixup_branch $lsfu_exit
  93         ldi         -EFAULT,%r28
  94         .previous
  95
  96         .section __ex_table,"aw"
  97 #ifdef __LP64__
  98         .dword      1b,3b
  99         .dword      2b,3b
 100 #else
 101         .word       1b,3b
 102         .word       2b,3b
 103 #endif
 104         .previous
 105
 106         .procend
 107
 108         /*
 109          * unsigned long lclear_user(void *to, unsigned long n)
 110          *
 111          * Returns 0 for success.
 112          * otherwise, returns number of bytes not transferred.
 113          */
 114
 115         .export lclear_user,code
 116 lclear_user:
 117         .proc
 118         .callinfo NO_CALLS
 119         .entry
 120         comib,=,n   0,%r25,$lclu_done
 121         get_sr
 122 $lclu_loop:
 123         addib,<>    -1,%r25,$lclu_loop
 124 1:      stbs,ma     %r0,1(%sr1,%r26)
 125
 126 $lclu_done:
 127         bv          %r0(%r2)
 128         copy        %r25,%r28
 129         .exit
 130
 131         .section .fixup,"ax"
 132 2:      fixup_branch $lclu_done
 133         ldo        1(%r25),%r25
 134         .previous
 135
 136         .section __ex_table,"aw"
 137 #ifdef __LP64__
 138         .dword      1b,2b
 139 #else
 140         .word       1b,2b
 141 #endif
 142         .previous
 143
 144         .procend
 145
 146         /*
 147          * long lstrnlen_user(char *s, long n)
 148          *
 149          * Returns 0 if exception before zero byte or reaching N,
 150          *         N+1 if N would be exceeded,
 151          *         else strlen + 1 (i.e. includes zero byte).
 152          */
 153
 154         .export lstrnlen_user,code
 155 lstrnlen_user:
 156         .proc
 157         .callinfo NO_CALLS
 158         .entry
 159         comib,=     0,%r25,$lslen_nzero
 160         copy        %r26,%r24
 161         get_sr
 162 1:      ldbs,ma     1(%sr1,%r26),%r1
 163 $lslen_loop:
 164         comib,=,n   0,%r1,$lslen_done
 165         addib,<>    -1,%r25,$lslen_loop
 166 2:      ldbs,ma     1(%sr1,%r26),%r1
 167 $lslen_done:
 168         bv          %r0(%r2)
 169         sub         %r26,%r24,%r28
 170         .exit
 171
 172 $lslen_nzero:
 173         b           $lslen_done
 174         ldo         1(%r26),%r26 /* special case for N == 0 */
 175
 176         .section .fixup,"ax"
 177 3:      fixup_branch $lslen_done
 178         copy        %r24,%r26    /* reset r26 so 0 is returned on fault */
 179         .previous
 180
 181         .section __ex_table,"aw"
 182 #ifdef __LP64__
 183         .dword      1b,3b
 184         .dword      2b,3b
 185 #else
 186         .word       1b,3b
 187         .word       2b,3b
 188 #endif
 189         .previous
 190
 191         .procend
 192
 193         .end