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 #include <linux/linkage.h>
  41
  42         /*
  43          * get_sr gets the appropriate space value into
  44          * sr1 for kernel/user space access, depending
  45          * on the flag stored in the task structure.
  46          */
  47
  48         .macro  get_sr
  49         mfctl       %cr30,%r1
  50         ldw         TI_SEGMENT(%r1),%r22
  51         mfsp        %sr3,%r1
  52         or,<>       %r22,%r0,%r0
  53         copy        %r0,%r1
  54         mtsp        %r1,%sr1
  55         .endm
  56
  57         .macro fixup_branch lbl
  58         ldil        L%\lbl, %r1
  59         ldo         R%\lbl(%r1), %r1
  60         bv          %r0(%r1)
  61         .endm
  62
  63         /*
  64          * long lstrncpy_from_user(char *dst, const char *src, long n)
  65          *
  66          * Returns -EFAULT if exception before terminator,
  67          *         N if the entire buffer filled,
  68          *         otherwise strlen (i.e. excludes zero byte)
  69          */
  70
  71 ENTRY(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 ENDPROC(lstrncpy_from_user)
  91
  92         .section .fixup,"ax"
  93 3:      fixup_branch $lsfu_exit
  94         ldi         -EFAULT,%r28
  95         .previous
  96
  97         .section __ex_table,"aw"
  98         ASM_ULONG_INSN 1b,3b
  99         ASM_ULONG_INSN 2b,3b
 100         .previous
 101
 102         .procend
 103
 104         /*
 105          * unsigned long lclear_user(void *to, unsigned long n)
 106          *
 107          * Returns 0 for success.
 108          * otherwise, returns number of bytes not transferred.
 109          */
 110
 111 ENTRY(lclear_user)
 112         .proc
 113         .callinfo NO_CALLS
 114         .entry
 115         comib,=,n   0,%r25,$lclu_done
 116         get_sr
 117 $lclu_loop:
 118         addib,<>    -1,%r25,$lclu_loop
 119 1:      stbs,ma     %r0,1(%sr1,%r26)
 120
 121 $lclu_done:
 122         bv          %r0(%r2)
 123         copy        %r25,%r28
 124         .exit
 125 ENDPROC(lclear_user)
 126
 127         .section .fixup,"ax"
 128 2:      fixup_branch $lclu_done
 129         ldo        1(%r25),%r25
 130         .previous
 131
 132         .section __ex_table,"aw"
 133         ASM_ULONG_INSN 1b,2b
 134         .previous
 135
 136         .procend
 137
 138         /*
 139          * long lstrnlen_user(char *s, long n)
 140          *
 141          * Returns 0 if exception before zero byte or reaching N,
 142          *         N+1 if N would be exceeded,
 143          *         else strlen + 1 (i.e. includes zero byte).
 144          */
 145
 146 ENTRY(lstrnlen_user)
 147         .proc
 148         .callinfo NO_CALLS
 149         .entry
 150         comib,=     0,%r25,$lslen_nzero
 151         copy        %r26,%r24
 152         get_sr
 153 1:      ldbs,ma     1(%sr1,%r26),%r1
 154 $lslen_loop:
 155         comib,=,n   0,%r1,$lslen_done
 156         addib,<>    -1,%r25,$lslen_loop
 157 2:      ldbs,ma     1(%sr1,%r26),%r1
 158 $lslen_done:
 159         bv          %r0(%r2)
 160         sub         %r26,%r24,%r28
 161         .exit
 162
 163 $lslen_nzero:
 164         b           $lslen_done
 165         ldo         1(%r26),%r26 /* special case for N == 0 */
 166 ENDPROC(lstrnlen_user)
 167
 168         .section .fixup,"ax"
 169 3:      fixup_branch $lslen_done
 170         copy        %r24,%r26    /* reset r26 so 0 is returned on fault */
 171         .previous
 172
 173         .section __ex_table,"aw"
 174         ASM_ULONG_INSN 1b,3b
 175         ASM_ULONG_INSN 2b,3b
 176         .previous
 177
 178         .procend
 179
 180         .end