libgcc/config/nds32/linux-atomic.c

   1 /* Linux-specific atomic operations for NDS32 Linux.
   2    Copyright (C) 2012-2024 Free Software Foundation, Inc.
   3
   4 This file is free software; you can redistribute it and/or modify it
   5 under the terms of the GNU General Public License as published by the
   6 Free Software Foundation; either version 3, or (at your option) any
   7 later version.
   8
   9 This file is distributed in the hope that it will be useful, but
  10 WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 General Public License for more details.
  13
  14 Under Section 7 of GPL version 3, you are granted additional
  15 permissions described in the GCC Runtime Library Exception, version
  16 3.1, as published by the Free Software Foundation.
  17
  18 You should have received a copy of the GNU General Public License and
  19 a copy of the GCC Runtime Library Exception along with this program;
  20 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 /* We implement byte, short and int versions of each atomic operation
  24    using the kernel helper defined below.  There is no support for
  25    64-bit operations yet.  */
  26
  27 /* This function copy form NDS32 Linux-kernal. */
  28 static inline int
  29 __kernel_cmpxchg (int oldval, int newval, int *mem)
  30 {
  31   int temp1, temp2, temp3, offset;
  32
  33   asm volatile ("msync\tall\n"
  34                 "movi\t%0, #0\n"
  35                 "1:\n"
  36                 "\tllw\t%1, [%4+%0]\n"
  37                 "\tsub\t%3, %1, %6\n"
  38                 "\tcmovz\t%2, %5, %3\n"
  39                 "\tcmovn\t%2, %1, %3\n"
  40                 "\tscw\t%2, [%4+%0]\n"
  41                 "\tbeqz\t%2, 1b\n"
  42                 : "=&r" (offset), "=&r" (temp3), "=&r" (temp2), "=&r" (temp1)
  43                 : "r" (mem), "r" (newval), "r" (oldval) : "memory");
  44
  45   return temp1;
  46 }
  47
  48 #define HIDDEN __attribute__ ((visibility ("hidden")))
  49
  50 #ifdef __NDS32_EL__
  51 #define INVERT_MASK_1 0
  52 #define INVERT_MASK_2 0
  53 #else
  54 #define INVERT_MASK_1 24
  55 #define INVERT_MASK_2 16
  56 #endif
  57
  58 #define MASK_1 0xffu
  59 #define MASK_2 0xffffu
  60
  61 #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP)                           \
  62   int HIDDEN                                                            \
  63   __sync_fetch_and_##OP##_4 (int *ptr, int val)                         \
  64   {                                                                     \
  65     int failure, tmp;                                                   \
  66                                                                         \
  67     do {                                                                \
  68       tmp = __atomic_load_n (ptr, __ATOMIC_SEQ_CST);                    \
  69       failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr);   \
  70     } while (failure != 0);                                             \
  71                                                                         \
  72     return tmp;                                                         \
  73   }
  74
  75 FETCH_AND_OP_WORD (add,   , +)
  76 FETCH_AND_OP_WORD (sub,   , -)
  77 FETCH_AND_OP_WORD (or,    , |)
  78 FETCH_AND_OP_WORD (and,   , &)
  79 FETCH_AND_OP_WORD (xor,   , ^)
  80 FETCH_AND_OP_WORD (nand, ~, &)
  81
  82 #define NAME_oldval(OP, WIDTH) __sync_fetch_and_##OP##_##WIDTH
  83 #define NAME_newval(OP, WIDTH) __sync_##OP##_and_fetch_##WIDTH
  84
  85 /* Implement both __sync_<op>_and_fetch and __sync_fetch_and_<op> for
  86    subword-sized quantities.  */
  87
  88 #define SUBWORD_SYNC_OP(OP, PFX_OP, INF_OP, TYPE, WIDTH, RETURN)        \
  89   TYPE HIDDEN                                                           \
  90   NAME##_##RETURN (OP, WIDTH) (TYPE *ptr, TYPE val)                     \
  91   {                                                                     \
  92     int *wordptr = (int *) ((unsigned long) ptr & ~3);                  \
  93     unsigned int mask, shift, oldval, newval;                           \
  94     int failure;                                                        \
  95                                                                         \
  96     shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH;     \
  97     mask = MASK_##WIDTH << shift;                                       \
  98                                                                         \
  99     do {                                                                \
 100       oldval = __atomic_load_n (wordptr, __ATOMIC_SEQ_CST);             \
 101       newval = ((PFX_OP (((oldval & mask) >> shift)                     \
 102                          INF_OP (unsigned int) val)) << shift) & mask;  \
 103       newval |= oldval & ~mask;                                         \
 104       failure = __kernel_cmpxchg (oldval, newval, wordptr);             \
 105     } while (failure != 0);                                             \
 106                                                                         \
 107     return (RETURN & mask) >> shift;                                    \
 108   }
 109
 110
 111 SUBWORD_SYNC_OP (add,   , +, unsigned short, 2, oldval)
 112 SUBWORD_SYNC_OP (sub,   , -, unsigned short, 2, oldval)
 113 SUBWORD_SYNC_OP (or,    , |, unsigned short, 2, oldval)
 114 SUBWORD_SYNC_OP (and,   , &, unsigned short, 2, oldval)
 115 SUBWORD_SYNC_OP (xor,   , ^, unsigned short, 2, oldval)
 116 SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, oldval)
 117
 118 SUBWORD_SYNC_OP (add,   , +, unsigned char, 1, oldval)
 119 SUBWORD_SYNC_OP (sub,   , -, unsigned char, 1, oldval)
 120 SUBWORD_SYNC_OP (or,    , |, unsigned char, 1, oldval)
 121 SUBWORD_SYNC_OP (and,   , &, unsigned char, 1, oldval)
 122 SUBWORD_SYNC_OP (xor,   , ^, unsigned char, 1, oldval)
 123 SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, oldval)
 124
 125 #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP)                           \
 126   int HIDDEN                                                            \
 127   __sync_##OP##_and_fetch_4 (int *ptr, int val)                         \
 128   {                                                                     \
 129     int tmp, failure;                                                   \
 130                                                                         \
 131     do {                                                                \
 132       tmp = __atomic_load_n (ptr, __ATOMIC_SEQ_CST);                    \
 133       failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr);   \
 134     } while (failure != 0);                                             \
 135                                                                         \
 136     return PFX_OP (tmp INF_OP val);                                     \
 137   }
 138
 139 OP_AND_FETCH_WORD (add,   , +)
 140 OP_AND_FETCH_WORD (sub,   , -)
 141 OP_AND_FETCH_WORD (or,    , |)
 142 OP_AND_FETCH_WORD (and,   , &)
 143 OP_AND_FETCH_WORD (xor,   , ^)
 144 OP_AND_FETCH_WORD (nand, ~, &)
 145
 146 SUBWORD_SYNC_OP (add,   , +, unsigned short, 2, newval)
 147 SUBWORD_SYNC_OP (sub,   , -, unsigned short, 2, newval)
 148 SUBWORD_SYNC_OP (or,    , |, unsigned short, 2, newval)
 149 SUBWORD_SYNC_OP (and,   , &, unsigned short, 2, newval)
 150 SUBWORD_SYNC_OP (xor,   , ^, unsigned short, 2, newval)
 151 SUBWORD_SYNC_OP (nand, ~, &, unsigned short, 2, newval)
 152
 153 SUBWORD_SYNC_OP (add,   , +, unsigned char, 1, newval)
 154 SUBWORD_SYNC_OP (sub,   , -, unsigned char, 1, newval)
 155 SUBWORD_SYNC_OP (or,    , |, unsigned char, 1, newval)
 156 SUBWORD_SYNC_OP (and,   , &, unsigned char, 1, newval)
 157 SUBWORD_SYNC_OP (xor,   , ^, unsigned char, 1, newval)
 158 SUBWORD_SYNC_OP (nand, ~, &, unsigned char, 1, newval)
 159
 160 int HIDDEN
 161 __sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval)
 162 {
 163   int actual_oldval, fail;
 164
 165   while (1)
 166     {
 167       actual_oldval = __atomic_load_n (ptr, __ATOMIC_SEQ_CST);
 168
 169       if (oldval != actual_oldval)
 170         return actual_oldval;
 171
 172       fail = __kernel_cmpxchg (actual_oldval, newval, ptr);
 173
 174       if (!fail)
 175         return oldval;
 176     }
 177 }
 178
 179 #define SUBWORD_VAL_CAS(TYPE, WIDTH)                                    \
 180   TYPE HIDDEN                                                           \
 181   __sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval,          \
 182                                        TYPE newval)                     \
 183   {                                                                     \
 184     int *wordptr = (int *)((unsigned long) ptr & ~3), fail;             \
 185     unsigned int mask, shift, actual_oldval, actual_newval;             \
 186                                                                         \
 187     shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH;     \
 188     mask = MASK_##WIDTH << shift;                                       \
 189                                                                         \
 190     while (1)                                                           \
 191       {                                                                 \
 192         actual_oldval = __atomic_load_n (wordptr, __ATOMIC_SEQ_CST);    \
 193                                                                         \
 194         if (((actual_oldval & mask) >> shift) != (unsigned int) oldval) \
 195           return (actual_oldval & mask) >> shift;                       \
 196                                                                         \
 197         actual_newval = (actual_oldval & ~mask)                         \
 198                         | (((unsigned int) newval << shift) & mask);    \
 199                                                                         \
 200         fail = __kernel_cmpxchg (actual_oldval, actual_newval,          \
 201                                  wordptr);                              \
 202                                                                         \
 203         if (!fail)                                                      \
 204           return oldval;                                                \
 205       }                                                                 \
 206   }
 207
 208 SUBWORD_VAL_CAS (unsigned short, 2)
 209 SUBWORD_VAL_CAS (unsigned char,  1)
 210
 211 bool HIDDEN
 212 __sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval)
 213 {
 214   int failure = __kernel_cmpxchg (oldval, newval, ptr);
 215   return (failure == 0);
 216 }
 217
 218 #define SUBWORD_BOOL_CAS(TYPE, WIDTH)                                   \
 219   bool HIDDEN                                                           \
 220   __sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval,         \
 221                                         TYPE newval)                    \
 222   {                                                                     \
 223     TYPE actual_oldval                                                  \
 224       = __sync_val_compare_and_swap_##WIDTH (ptr, oldval, newval);      \
 225     return (oldval == actual_oldval);                                   \
 226   }
 227
 228 SUBWORD_BOOL_CAS (unsigned short, 2)
 229 SUBWORD_BOOL_CAS (unsigned char,  1)
 230
 231 int HIDDEN
 232 __sync_lock_test_and_set_4 (int *ptr, int val)
 233 {
 234   int failure, oldval;
 235
 236   do {
 237     oldval = __atomic_load_n (ptr, __ATOMIC_SEQ_CST);
 238     failure = __kernel_cmpxchg (oldval, val, ptr);
 239   } while (failure != 0);
 240
 241   return oldval;
 242 }
 243
 244 #define SUBWORD_TEST_AND_SET(TYPE, WIDTH)                               \
 245   TYPE HIDDEN                                                           \
 246   __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val)                \
 247   {                                                                     \
 248     int failure;                                                        \
 249     unsigned int oldval, newval, shift, mask;                           \
 250     int *wordptr = (int *) ((unsigned long) ptr & ~3);                  \
 251                                                                         \
 252     shift = (((unsigned long) ptr & 3) << 3) ^ INVERT_MASK_##WIDTH;     \
 253     mask = MASK_##WIDTH << shift;                                       \
 254                                                                         \
 255     do {                                                                \
 256       oldval = __atomic_load_n (wordptr, __ATOMIC_SEQ_CST);             \
 257       newval = (oldval & ~mask)                                         \
 258                | (((unsigned int) val << shift) & mask);                \
 259       failure = __kernel_cmpxchg (oldval, newval, wordptr);             \
 260     } while (failure != 0);                                             \
 261                                                                         \
 262     return (oldval & mask) >> shift;                                    \
 263   }
 264
 265 SUBWORD_TEST_AND_SET (unsigned short, 2)
 266 SUBWORD_TEST_AND_SET (unsigned char,  1)
 267
 268 #define SYNC_LOCK_RELEASE(TYPE, WIDTH)                                  \
 269   void HIDDEN                                                           \
 270   __sync_lock_release_##WIDTH (TYPE *ptr)                               \
 271   {                                                                     \
 272     /* All writes before this point must be seen before we release      \
 273        the lock itself.  */                                             \
 274     __builtin_nds32_msync_all ();                                       \
 275     *ptr = 0;                                                           \
 276   }
 277
 278 SYNC_LOCK_RELEASE (int,   4)
 279 SYNC_LOCK_RELEASE (short, 2)
 280 SYNC_LOCK_RELEASE (char,  1)