arch/sparc/lib/copy_in_user.S

   1 /* copy_in_user.S: Copy from userspace to userspace.
   2  *
   3  * Copyright (C) 1999, 2000, 2004 David S. Miller (davem@redhat.com)
   4  */
   5
   6 #include <linux/linkage.h>
   7 #include <asm/asi.h>
   8
   9 #define XCC xcc
  10
  11 #define EX(x,y)                 \
  12 98:     x,y;                    \
  13         .section __ex_table,"a";\
  14         .align 4;               \
  15         .word 98b, __retl_one;  \
  16         .text;                  \
  17         .align 4;
  18
  19         .register       %g2,#scratch
  20         .register       %g3,#scratch
  21
  22         .text
  23         .align  32
  24
  25         /* Don't try to get too fancy here, just nice and
  26          * simple.  This is predominantly used for well aligned
  27          * small copies in the compat layer.  It is also used
  28          * to copy register windows around during thread cloning.
  29          */
  30
  31 ENTRY(___copy_in_user)  /* %o0=dst, %o1=src, %o2=len */
  32         cmp             %o2, 0
  33         be,pn           %XCC, 85f
  34          or             %o0, %o1, %o3
  35         cmp             %o2, 16
  36         bleu,a,pn       %XCC, 80f
  37          or             %o3, %o2, %o3
  38
  39         /* 16 < len <= 64 */
  40         andcc           %o3, 0x7, %g0
  41         bne,pn          %XCC, 90f
  42          nop
  43
  44         andn            %o2, 0x7, %o4
  45         and             %o2, 0x7, %o2
  46 1:      subcc           %o4, 0x8, %o4
  47         EX(ldxa [%o1] %asi, %o5)
  48         EX(stxa %o5, [%o0] %asi)
  49         add             %o1, 0x8, %o1
  50         bgu,pt          %XCC, 1b
  51          add            %o0, 0x8, %o0
  52         andcc           %o2, 0x4, %g0
  53         be,pt           %XCC, 1f
  54          nop
  55         sub             %o2, 0x4, %o2
  56         EX(lduwa [%o1] %asi, %o5)
  57         EX(stwa %o5, [%o0] %asi)
  58         add             %o1, 0x4, %o1
  59         add             %o0, 0x4, %o0
  60 1:      cmp             %o2, 0
  61         be,pt           %XCC, 85f
  62          nop
  63         ba,pt           %xcc, 90f
  64          nop
  65
  66 80:     /* 0 < len <= 16 */
  67         andcc           %o3, 0x3, %g0
  68         bne,pn          %XCC, 90f
  69          nop
  70
  71 82:
  72         subcc           %o2, 4, %o2
  73         EX(lduwa [%o1] %asi, %g1)
  74         EX(stwa %g1, [%o0] %asi)
  75         add             %o1, 4, %o1
  76         bgu,pt          %XCC, 82b
  77          add            %o0, 4, %o0
  78
  79 85:     retl
  80          clr            %o0
  81
  82         .align  32
  83 90:
  84         subcc           %o2, 1, %o2
  85         EX(lduba [%o1] %asi, %g1)
  86         EX(stba %g1, [%o0] %asi)
  87         add             %o1, 1, %o1
  88         bgu,pt          %XCC, 90b
  89          add            %o0, 1, %o0
  90         retl
  91          clr            %o0
  92 ENDPROC(___copy_in_user)