arch/tile/lib/memcpy_user_64.c

   1 /*
   2  * Copyright 2011 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * Do memcpy(), but trap and return "n" when a load or store faults.
  15  *
  16  * Note: this idiom only works when memcpy() compiles to a leaf function.
  17  * If "sp" is updated during memcpy, the "jrp lr" will be incorrect.
  18  *
  19  * Also note that we are capturing "n" from the containing scope here.
  20  */
  21
  22 #define _ST(p, inst, v)                                         \
  23         ({                                                      \
  24                 asm("1: " #inst " %0, %1;"                      \
  25                     ".pushsection .coldtext.memcpy,\"ax\";"     \
  26                     "2: { move r0, %2; jrp lr };"               \
  27                     ".section __ex_table,\"a\";"                \
  28                     ".quad 1b, 2b;"                             \
  29                     ".popsection"                               \
  30                     : "=m" (*(p)) : "r" (v), "r" (n));          \
  31         })
  32
  33 #define _LD(p, inst)                                            \
  34         ({                                                      \
  35                 unsigned long __v;                              \
  36                 asm("1: " #inst " %0, %1;"                      \
  37                     ".pushsection .coldtext.memcpy,\"ax\";"     \
  38                     "2: { move r0, %2; jrp lr };"               \
  39                     ".section __ex_table,\"a\";"                \
  40                     ".quad 1b, 2b;"                             \
  41                     ".popsection"                               \
  42                     : "=r" (__v) : "m" (*(p)), "r" (n));        \
  43                 __v;                                            \
  44         })
  45
  46 #define USERCOPY_FUNC __copy_to_user_inatomic
  47 #define ST1(p, v) _ST((p), st1, (v))
  48 #define ST2(p, v) _ST((p), st2, (v))
  49 #define ST4(p, v) _ST((p), st4, (v))
  50 #define ST8(p, v) _ST((p), st, (v))
  51 #define LD1 LD
  52 #define LD2 LD
  53 #define LD4 LD
  54 #define LD8 LD
  55 #include "memcpy_64.c"
  56
  57 #define USERCOPY_FUNC __copy_from_user_inatomic
  58 #define ST1 ST
  59 #define ST2 ST
  60 #define ST4 ST
  61 #define ST8 ST
  62 #define LD1(p) _LD((p), ld1u)
  63 #define LD2(p) _LD((p), ld2u)
  64 #define LD4(p) _LD((p), ld4u)
  65 #define LD8(p) _LD((p), ld)
  66 #include "memcpy_64.c"
  67
  68 #define USERCOPY_FUNC __copy_in_user_inatomic
  69 #define ST1(p, v) _ST((p), st1, (v))
  70 #define ST2(p, v) _ST((p), st2, (v))
  71 #define ST4(p, v) _ST((p), st4, (v))
  72 #define ST8(p, v) _ST((p), st, (v))
  73 #define LD1(p) _LD((p), ld1u)
  74 #define LD2(p) _LD((p), ld2u)
  75 #define LD4(p) _LD((p), ld4u)
  76 #define LD8(p) _LD((p), ld)
  77 #include "memcpy_64.c"
  78
  79 unsigned long __copy_from_user_zeroing(void *to, const void __user *from,
  80                                        unsigned long n)
  81 {
  82         unsigned long rc = __copy_from_user_inatomic(to, from, n);
  83         if (unlikely(rc))
  84                 memset(to + n - rc, 0, rc);
  85         return rc;
  86 }