arch/sparc64/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 <asm/asi.h>
   7
   8 #define XCC xcc
   9
  10 #define EX(x,y)                 \
  11 98:     x,y;                    \
  12         .section .fixup;        \
  13         .align 4;               \
  14 99:     retl;                   \
  15          mov 1, %o0;            \
  16         .section __ex_table;    \
  17         .align 4;               \
  18         .word 98b, 99b;         \
  19         .text;                  \
  20         .align 4;
  21
  22         .register       %g2,#scratch
  23         .register       %g3,#scratch
  24
  25         .text
  26         .align  32
  27
  28         /* Don't try to get too fancy here, just nice and
  29          * simple.  This is predominantly used for well aligned
  30          * small copies in the compat layer.  It is also used
  31          * to copy register windows around during thread cloning.
  32          */
  33
  34         .globl          ___copy_in_user
  35         .type           ___copy_in_user,#function
  36 ___copy_in_user:        /* %o0=dst, %o1=src, %o2=len */
  37         /* Writing to %asi is _expensive_ so we hardcode it.
  38          * Reading %asi to check for KERNEL_DS is comparatively
  39          * cheap.
  40          */
  41         rd              %asi, %g1
  42         cmp             %g1, ASI_AIUS
  43         bne,pn          %icc, memcpy_user_stub
  44          nop
  45
  46         cmp             %o2, 0
  47         be,pn           %XCC, 85f
  48          or             %o0, %o1, %o3
  49         cmp             %o2, 16
  50         bleu,a,pn       %XCC, 80f
  51          or             %o3, %o2, %o3
  52
  53         /* 16 < len <= 64 */
  54         andcc           %o3, 0x7, %g0
  55         bne,pn          %XCC, 90f
  56          sub            %o0, %o1, %o3
  57
  58         andn            %o2, 0x7, %o4
  59         and             %o2, 0x7, %o2
  60 1:      subcc           %o4, 0x8, %o4
  61         EX(ldxa [%o1] %asi, %o5)
  62         EX(stxa %o5, [%o1 + %o3] ASI_AIUS)
  63         bgu,pt          %XCC, 1b
  64          add            %o1, 0x8, %o1
  65         andcc           %o2, 0x4, %g0
  66         be,pt           %XCC, 1f
  67          nop
  68         sub             %o2, 0x4, %o2
  69         EX(lduwa [%o1] %asi, %o5)
  70         EX(stwa %o5, [%o1 + %o3] ASI_AIUS)
  71         add             %o1, 0x4, %o1
  72 1:      cmp             %o2, 0
  73         be,pt           %XCC, 85f
  74          nop
  75         ba,pt           %xcc, 90f
  76          nop
  77
  78 80:     /* 0 < len <= 16 */
  79         andcc           %o3, 0x3, %g0
  80         bne,pn          %XCC, 90f
  81          sub            %o0, %o1, %o3
  82
  83 82:
  84         subcc           %o2, 4, %o2
  85         EX(lduwa [%o1] %asi, %g1)
  86         EX(stwa %g1, [%o1 + %o3] ASI_AIUS)
  87         bgu,pt          %XCC, 82b
  88          add            %o1, 4, %o1
  89
  90 85:     retl
  91          clr            %o0
  92
  93         .align  32
  94 90:
  95         subcc           %o2, 1, %o2
  96         EX(lduba [%o1] %asi, %g1)
  97         EX(stba %g1, [%o1 + %o3] ASI_AIUS)
  98         bgu,pt          %XCC, 90b
  99          add            %o1, 1, %o1
 100         retl
 101          clr            %o0
 102
 103         .size           ___copy_in_user, .-___copy_in_user
 104
 105         /* Act like copy_{to,in}_user(), ie. return zero instead
 106          * of original destination pointer.  This is invoked when
 107          * copy_{to,in}_user() finds that %asi is kernel space.
 108          */
 109         .globl          memcpy_user_stub
 110         .type           memcpy_user_stub,#function
 111 memcpy_user_stub:
 112         save            %sp, -192, %sp
 113         mov             %i0, %o0
 114         mov             %i1, %o1
 115         call            memcpy
 116          mov            %i2, %o2
 117         ret
 118          restore        %g0, %g0, %o0
 119         .size           memcpy_user_stub, .-memcpy_user_stub