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   1 /* unaligned.h: unaligned access handler
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #ifndef _ASM_UNALIGNED_H
  13 #define _ASM_UNALIGNED_H
  14
  15
  16 /*
  17  * Unaligned accesses on uClinux can't be performed in a fault handler - the
  18  * CPU detects them as imprecise exceptions making this impossible.
  19  *
  20  * With the FR451, however, they are precise, and so we used to fix them up in
  21  * the memory access fault handler.  However, instruction bundling make this
  22  * impractical.  So, now we fall back to using memcpy.
  23  */
  24 #ifdef CONFIG_MMU
  25
  26 /*
  27  * The asm statement in the macros below is a way to get GCC to copy a
  28  * value from one variable to another without having any clue it's
  29  * actually doing so, so that it won't have any idea that the values
  30  * in the two variables are related.
  31  */
  32
  33 #define get_unaligned(ptr) ({                           \
  34         typeof((*(ptr))) __x;                           \
  35         void *__ptrcopy;                                \
  36         asm("" : "=r" (__ptrcopy) : "0" (ptr));         \
  37         memcpy(&__x, __ptrcopy, sizeof(*(ptr)));        \
  38         __x;                                            \
  39 })
  40
  41 #define put_unaligned(val, ptr) ({                      \
  42         typeof((*(ptr))) __x = (val);                   \
  43         void *__ptrcopy;                                \
  44         asm("" : "=r" (__ptrcopy) : "0" (ptr));         \
  45         memcpy(__ptrcopy, &__x, sizeof(*(ptr)));        \
  46 })
  47
  48 extern int handle_misalignment(unsigned long esr0, unsigned long ear0, unsigned long epcr0);
  49
  50 #else
  51
  52 #define get_unaligned(ptr)                                                      \
  53 ({                                                                              \
  54         typeof(*(ptr)) x;                                                       \
  55         const char *__p = (const char *) (ptr);                                 \
  56                                                                                 \
  57         switch (sizeof(x)) {                                                    \
  58         case 1:                                                                 \
  59                 x = *(ptr);                                                     \
  60                 break;                                                          \
  61         case 2:                                                                 \
  62         {                                                                       \
  63                 uint8_t a;                                                      \
  64                 asm("   ldub%I2         %M2,%0          \n"                     \
  65                     "   ldub%I3.p       %M3,%1          \n"                     \
  66                     "   slli            %0,#8,%0        \n"                     \
  67                     "   or              %0,%1,%0        \n"                     \
  68                     : "=&r"(x), "=&r"(a)                                        \
  69                     : "m"(__p[0]),  "m"(__p[1])                                 \
  70                     );                                                          \
  71                 break;                                                          \
  72         }                                                                       \
  73                                                                                 \
  74         case 4:                                                                 \
  75         {                                                                       \
  76                 uint8_t a;                                                      \
  77                 asm("   ldub%I2         %M2,%0          \n"                     \
  78                     "   ldub%I3.p       %M3,%1          \n"                     \
  79                     "   slli            %0,#8,%0        \n"                     \
  80                     "   or              %0,%1,%0        \n"                     \
  81                     "   ldub%I4.p       %M4,%1          \n"                     \
  82                     "   slli            %0,#8,%0        \n"                     \
  83                     "   or              %0,%1,%0        \n"                     \
  84                     "   ldub%I5.p       %M5,%1          \n"                     \
  85                     "   slli            %0,#8,%0        \n"                     \
  86                     "   or              %0,%1,%0        \n"                     \
  87                     : "=&r"(x), "=&r"(a)                                        \
  88                     : "m"(__p[0]),  "m"(__p[1]), "m"(__p[2]), "m"(__p[3])       \
  89                     );                                                          \
  90                 break;                                                          \
  91         }                                                                       \
  92                                                                                 \
  93         case 8:                                                                 \
  94         {                                                                       \
  95                 union { uint64_t x; u32 y[2]; } z;                              \
  96                 uint8_t a;                                                      \
  97                 asm("   ldub%I3         %M3,%0          \n"                     \
  98                     "   ldub%I4.p       %M4,%2          \n"                     \
  99                     "   slli            %0,#8,%0        \n"                     \
 100                     "   or              %0,%2,%0        \n"                     \
 101                     "   ldub%I5.p       %M5,%2          \n"                     \
 102                     "   slli            %0,#8,%0        \n"                     \
 103                     "   or              %0,%2,%0        \n"                     \
 104                     "   ldub%I6.p       %M6,%2          \n"                     \
 105                     "   slli            %0,#8,%0        \n"                     \
 106                     "   or              %0,%2,%0        \n"                     \
 107                     "   ldub%I7         %M7,%1          \n"                     \
 108                     "   ldub%I8.p       %M8,%2          \n"                     \
 109                     "   slli            %1,#8,%1        \n"                     \
 110                     "   or              %1,%2,%1        \n"                     \
 111                     "   ldub%I9.p       %M9,%2          \n"                     \
 112                     "   slli            %1,#8,%1        \n"                     \
 113                     "   or              %1,%2,%1        \n"                     \
 114                     "   ldub%I10.p      %M10,%2         \n"                     \
 115                     "   slli            %1,#8,%1        \n"                     \
 116                     "   or              %1,%2,%1        \n"                     \
 117                     : "=&r"(z.y[0]), "=&r"(z.y[1]), "=&r"(a)                    \
 118                     : "m"(__p[0]), "m"(__p[1]), "m"(__p[2]), "m"(__p[3]),       \
 119                       "m"(__p[4]), "m"(__p[5]), "m"(__p[6]), "m"(__p[7])        \
 120                     );                                                          \
 121                 x = z.x;                                                        \
 122                 break;                                                          \
 123         }                                                                       \
 124                                                                                 \
 125         default:                                                                \
 126                 x = 0;                                                          \
 127                 BUG();                                                          \
 128                 break;                                                          \
 129         }                                                                       \
 130                                                                                 \
 131         x;                                                                      \
 132 })
 133
 134 #define put_unaligned(val, ptr)                                                         \
 135 do {                                                                                    \
 136         char *__p = (char *) (ptr);                                                     \
 137         int x;                                                                          \
 138                                                                                         \
 139         switch (sizeof(*ptr)) {                                                         \
 140         case 2:                                                                         \
 141         {                                                                               \
 142                 asm("   stb%I1.p        %0,%M1          \n"                             \
 143                     "   srli            %0,#8,%0        \n"                             \
 144                     "   stb%I2          %0,%M2          \n"                             \
 145                     : "=r"(x), "=m"(__p[1]),  "=m"(__p[0])                              \
 146                     : "0"(val)                                                          \
 147                     );                                                                  \
 148                 break;                                                                  \
 149         }                                                                               \
 150                                                                                         \
 151         case 4:                                                                         \
 152         {                                                                               \
 153                 asm("   stb%I1.p        %0,%M1          \n"                             \
 154                     "   srli            %0,#8,%0        \n"                             \
 155                     "   stb%I2.p        %0,%M2          \n"                             \
 156                     "   srli            %0,#8,%0        \n"                             \
 157                     "   stb%I3.p        %0,%M3          \n"                             \
 158                     "   srli            %0,#8,%0        \n"                             \
 159                     "   stb%I4          %0,%M4          \n"                             \
 160                     : "=r"(x), "=m"(__p[3]),  "=m"(__p[2]), "=m"(__p[1]), "=m"(__p[0])  \
 161                     : "0"(val)                                                          \
 162                     );                                                                  \
 163                 break;                                                                  \
 164         }                                                                               \
 165                                                                                         \
 166         case 8:                                                                         \
 167         {                                                                               \
 168                 uint32_t __high, __low;                                                 \
 169                 __high = (uint64_t)val >> 32;                                           \
 170                 __low = val & 0xffffffff;                                               \
 171                 asm("   stb%I2.p        %0,%M2          \n"                             \
 172                     "   srli            %0,#8,%0        \n"                             \
 173                     "   stb%I3.p        %0,%M3          \n"                             \
 174                     "   srli            %0,#8,%0        \n"                             \
 175                     "   stb%I4.p        %0,%M4          \n"                             \
 176                     "   srli            %0,#8,%0        \n"                             \
 177                     "   stb%I5.p        %0,%M5          \n"                             \
 178                     "   srli            %0,#8,%0        \n"                             \
 179                     "   stb%I6.p        %1,%M6          \n"                             \
 180                     "   srli            %1,#8,%1        \n"                             \
 181                     "   stb%I7.p        %1,%M7          \n"                             \
 182                     "   srli            %1,#8,%1        \n"                             \
 183                     "   stb%I8.p        %1,%M8          \n"                             \
 184                     "   srli            %1,#8,%1        \n"                             \
 185                     "   stb%I9          %1,%M9          \n"                             \
 186                     : "=&r"(__low), "=&r"(__high), "=m"(__p[7]), "=m"(__p[6]),          \
 187                       "=m"(__p[5]), "=m"(__p[4]), "=m"(__p[3]), "=m"(__p[2]),           \
 188                       "=m"(__p[1]), "=m"(__p[0])                                        \
 189                     : "0"(__low), "1"(__high)                                           \
 190                     );                                                                  \
 191                 break;                                                                  \
 192         }                                                                               \
 193                                                                                         \
 194         default:                                                                        \
 195                 *(ptr) = (val);                                                         \
 196                 break;                                                                  \
 197         }                                                                               \
 198 } while(0)
 199
 200 #endif
 201
 202 #endif