libgcc/config/pa/linux-atomic.c

   1 /* Linux-specific atomic operations for PA Linux.
   2    Copyright (C) 2008-2021 Free Software Foundation, Inc.
   3    Based on code contributed by CodeSourcery for ARM EABI Linux.
   4    Modifications for PA Linux by Helge Deller <deller@gmx.de>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  */
  26
  27 #define EFAULT  14
  28 #define EBUSY   16
  29 #define ENOSYS 251
  30
  31 /* PA-RISC 2.0 supports out-of-order execution for loads and stores.
  32    Thus, we need to synchonize memory accesses.  For more info, see:
  33    "Advanced Performance Features of the 64-bit PA-8000" by Doug Hunt.
  34
  35    We implement byte, short and int versions of each atomic operation
  36    using the kernel helper defined below.  There is no support for
  37    64-bit operations yet.  */
  38
  39 /* Determine kernel LWS function call (0=32-bit, 1=64-bit userspace).  */
  40 #define LWS_CAS (sizeof(long) == 4 ? 0 : 1)
  41
  42 /* Kernel helper for compare-and-exchange a 32-bit value.  */
  43 static inline long
  44 __kernel_cmpxchg (volatile void *mem, int oldval, int newval)
  45 {
  46   register unsigned long lws_mem asm("r26") = (unsigned long) (mem);
  47   register int lws_old asm("r25") = oldval;
  48   register int lws_new asm("r24") = newval;
  49   register long lws_ret   asm("r28");
  50   register long lws_errno asm("r21");
  51   asm volatile (        "ble    0xb0(%%sr2, %%r0)       \n\t"
  52                         "ldi    %2, %%r20               \n\t"
  53         : "=r" (lws_ret), "=r" (lws_errno)
  54         : "i" (LWS_CAS), "r" (lws_mem), "r" (lws_old), "r" (lws_new)
  55         : "r1", "r20", "r22", "r23", "r29", "r31", "memory"
  56   );
  57
  58   /* If the kernel LWS call succeeded (lws_errno == 0), lws_ret contains
  59      the old value from memory.  If this value is equal to OLDVAL, the
  60      new value was written to memory.  If not, return -EBUSY.  */
  61   if (!lws_errno && lws_ret != oldval)
  62     return -EBUSY;
  63
  64   return lws_errno;
  65 }
  66
  67 static inline long
  68 __kernel_cmpxchg2 (volatile void *mem, const void *oldval, const void *newval,
  69                    int val_size)
  70 {
  71   register unsigned long lws_mem asm("r26") = (unsigned long) (mem);
  72   register unsigned long lws_old asm("r25") = (unsigned long) oldval;
  73   register unsigned long lws_new asm("r24") = (unsigned long) newval;
  74   register int lws_size asm("r23") = val_size;
  75   register long lws_ret   asm("r28");
  76   register long lws_errno asm("r21");
  77   asm volatile (        "ble    0xb0(%%sr2, %%r0)       \n\t"
  78                         "ldi    %6, %%r20               \n\t"
  79         : "=r" (lws_ret), "=r" (lws_errno), "+r" (lws_mem),
  80           "+r" (lws_old), "+r" (lws_new), "+r" (lws_size)
  81         : "i" (2)
  82         : "r1", "r20", "r22", "r29", "r31", "fr4", "memory"
  83   );
  84
  85   /* If the kernel LWS call is successful, lws_ret contains 0.  */
  86   if (__builtin_expect (lws_ret == 0, 1))
  87     return 0;
  88
  89   /* If the kernel LWS call fails with no error, return -EBUSY */
  90   if (__builtin_expect (!lws_errno, 0))
  91     return -EBUSY;
  92
  93   return lws_errno;
  94 }
  95 #define HIDDEN __attribute__ ((visibility ("hidden")))
  96
  97 /* Big endian masks  */
  98 #define INVERT_MASK_1 24
  99 #define INVERT_MASK_2 16
 100
 101 #define MASK_1 0xffu
 102 #define MASK_2 0xffffu
 103
 104 #define FETCH_AND_OP_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 105   TYPE HIDDEN                                                           \
 106   __sync_fetch_and_##OP##_##WIDTH (volatile void *ptr, TYPE val)        \
 107   {                                                                     \
 108     TYPE tmp, newval;                                                   \
 109     long failure;                                                       \
 110                                                                         \
 111     do {                                                                \
 112       tmp = __atomic_load_n ((volatile TYPE *)ptr, __ATOMIC_RELAXED);   \
 113       newval = PFX_OP (tmp INF_OP val);                                 \
 114       failure = __kernel_cmpxchg2 (ptr, &tmp, &newval, INDEX);          \
 115     } while (failure != 0);                                             \
 116                                                                         \
 117     return tmp;                                                         \
 118   }
 119
 120 FETCH_AND_OP_2 (add,   , +, long long unsigned int, 8, 3)
 121 FETCH_AND_OP_2 (sub,   , -, long long unsigned int, 8, 3)
 122 FETCH_AND_OP_2 (or,    , |, long long unsigned int, 8, 3)
 123 FETCH_AND_OP_2 (and,   , &, long long unsigned int, 8, 3)
 124 FETCH_AND_OP_2 (xor,   , ^, long long unsigned int, 8, 3)
 125 FETCH_AND_OP_2 (nand, ~, &, long long unsigned int, 8, 3)
 126
 127 FETCH_AND_OP_2 (add,   , +, short unsigned int, 2, 1)
 128 FETCH_AND_OP_2 (sub,   , -, short unsigned int, 2, 1)
 129 FETCH_AND_OP_2 (or,    , |, short unsigned int, 2, 1)
 130 FETCH_AND_OP_2 (and,   , &, short unsigned int, 2, 1)
 131 FETCH_AND_OP_2 (xor,   , ^, short unsigned int, 2, 1)
 132 FETCH_AND_OP_2 (nand, ~, &, short unsigned int, 2, 1)
 133
 134 FETCH_AND_OP_2 (add,   , +, unsigned char, 1, 0)
 135 FETCH_AND_OP_2 (sub,   , -, unsigned char, 1, 0)
 136 FETCH_AND_OP_2 (or,    , |, unsigned char, 1, 0)
 137 FETCH_AND_OP_2 (and,   , &, unsigned char, 1, 0)
 138 FETCH_AND_OP_2 (xor,   , ^, unsigned char, 1, 0)
 139 FETCH_AND_OP_2 (nand, ~, &, unsigned char, 1, 0)
 140
 141 #define OP_AND_FETCH_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 142   TYPE HIDDEN                                                           \
 143   __sync_##OP##_and_fetch_##WIDTH (volatile void *ptr, TYPE val)        \
 144   {                                                                     \
 145     TYPE tmp, newval;                                                   \
 146     long failure;                                                       \
 147                                                                         \
 148     do {                                                                \
 149       tmp = __atomic_load_n ((volatile TYPE *)ptr, __ATOMIC_RELAXED);   \
 150       newval = PFX_OP (tmp INF_OP val);                                 \
 151       failure = __kernel_cmpxchg2 (ptr, &tmp, &newval, INDEX);          \
 152     } while (failure != 0);                                             \
 153                                                                         \
 154     return PFX_OP (tmp INF_OP val);                                     \
 155   }
 156
 157 OP_AND_FETCH_2 (add,   , +, long long unsigned int, 8, 3)
 158 OP_AND_FETCH_2 (sub,   , -, long long unsigned int, 8, 3)
 159 OP_AND_FETCH_2 (or,    , |, long long unsigned int, 8, 3)
 160 OP_AND_FETCH_2 (and,   , &, long long unsigned int, 8, 3)
 161 OP_AND_FETCH_2 (xor,   , ^, long long unsigned int, 8, 3)
 162 OP_AND_FETCH_2 (nand, ~, &, long long unsigned int, 8, 3)
 163
 164 OP_AND_FETCH_2 (add,   , +, short unsigned int, 2, 1)
 165 OP_AND_FETCH_2 (sub,   , -, short unsigned int, 2, 1)
 166 OP_AND_FETCH_2 (or,    , |, short unsigned int, 2, 1)
 167 OP_AND_FETCH_2 (and,   , &, short unsigned int, 2, 1)
 168 OP_AND_FETCH_2 (xor,   , ^, short unsigned int, 2, 1)
 169 OP_AND_FETCH_2 (nand, ~, &, short unsigned int, 2, 1)
 170
 171 OP_AND_FETCH_2 (add,   , +, unsigned char, 1, 0)
 172 OP_AND_FETCH_2 (sub,   , -, unsigned char, 1, 0)
 173 OP_AND_FETCH_2 (or,    , |, unsigned char, 1, 0)
 174 OP_AND_FETCH_2 (and,   , &, unsigned char, 1, 0)
 175 OP_AND_FETCH_2 (xor,   , ^, unsigned char, 1, 0)
 176 OP_AND_FETCH_2 (nand, ~, &, unsigned char, 1, 0)
 177
 178 #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP)                           \
 179   unsigned int HIDDEN                                                   \
 180   __sync_fetch_and_##OP##_4 (volatile void *ptr, unsigned int val)      \
 181   {                                                                     \
 182     unsigned int tmp;                                                   \
 183     long failure;                                                       \
 184                                                                         \
 185     do {                                                                \
 186       tmp = __atomic_load_n ((volatile unsigned int *)ptr,              \
 187                              __ATOMIC_RELAXED);                         \
 188       failure = __kernel_cmpxchg (ptr, tmp, PFX_OP (tmp INF_OP val));   \
 189     } while (failure != 0);                                             \
 190                                                                         \
 191     return tmp;                                                         \
 192   }
 193
 194 FETCH_AND_OP_WORD (add,   , +)
 195 FETCH_AND_OP_WORD (sub,   , -)
 196 FETCH_AND_OP_WORD (or,    , |)
 197 FETCH_AND_OP_WORD (and,   , &)
 198 FETCH_AND_OP_WORD (xor,   , ^)
 199 FETCH_AND_OP_WORD (nand, ~, &)
 200
 201 #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP)                           \
 202   unsigned int HIDDEN                                                   \
 203   __sync_##OP##_and_fetch_4 (volatile void *ptr, unsigned int val)      \
 204   {                                                                     \
 205     unsigned int tmp;                                                   \
 206     long failure;                                                       \
 207                                                                         \
 208     do {                                                                \
 209       tmp = __atomic_load_n ((volatile unsigned int *)ptr,              \
 210                              __ATOMIC_RELAXED);                         \
 211       failure = __kernel_cmpxchg (ptr, tmp, PFX_OP (tmp INF_OP val));   \
 212     } while (failure != 0);                                             \
 213                                                                         \
 214     return PFX_OP (tmp INF_OP val);                                     \
 215   }
 216
 217 OP_AND_FETCH_WORD (add,   , +)
 218 OP_AND_FETCH_WORD (sub,   , -)
 219 OP_AND_FETCH_WORD (or,    , |)
 220 OP_AND_FETCH_WORD (and,   , &)
 221 OP_AND_FETCH_WORD (xor,   , ^)
 222 OP_AND_FETCH_WORD (nand, ~, &)
 223
 224 typedef unsigned char bool;
 225
 226 #define COMPARE_AND_SWAP_2(TYPE, WIDTH, INDEX)                          \
 227   TYPE HIDDEN                                                           \
 228   __sync_val_compare_and_swap_##WIDTH (volatile void *ptr, TYPE oldval, \
 229                                        TYPE newval)                     \
 230   {                                                                     \
 231     TYPE actual_oldval;                                                 \
 232     long fail;                                                          \
 233                                                                         \
 234     while (1)                                                           \
 235       {                                                                 \
 236         actual_oldval = __atomic_load_n ((volatile TYPE *)ptr,          \
 237                                          __ATOMIC_RELAXED);             \
 238                                                                         \
 239         if (__builtin_expect (oldval != actual_oldval, 0))              \
 240           return actual_oldval;                                         \
 241                                                                         \
 242         fail = __kernel_cmpxchg2 (ptr, &actual_oldval, &newval, INDEX); \
 243                                                                         \
 244         if (__builtin_expect (!fail, 1))                                \
 245           return actual_oldval;                                         \
 246       }                                                                 \
 247   }                                                                     \
 248                                                                         \
 249   _Bool HIDDEN                                                          \
 250   __sync_bool_compare_and_swap_##WIDTH (volatile void *ptr,             \
 251                                         TYPE oldval, TYPE newval)       \
 252   {                                                                     \
 253     long failure = __kernel_cmpxchg2 (ptr, &oldval, &newval, INDEX);    \
 254     return (failure == 0);                                              \
 255   }
 256
 257 COMPARE_AND_SWAP_2 (long long unsigned int, 8, 3)
 258 COMPARE_AND_SWAP_2 (short unsigned int, 2, 1)
 259 COMPARE_AND_SWAP_2 (unsigned char, 1, 0)
 260
 261 unsigned int HIDDEN
 262 __sync_val_compare_and_swap_4 (volatile void *ptr, unsigned int oldval,
 263                                unsigned int newval)
 264 {
 265   long fail;
 266   unsigned int actual_oldval;
 267
 268   while (1)
 269     {
 270       actual_oldval = __atomic_load_n ((volatile unsigned int *)ptr,
 271                                        __ATOMIC_RELAXED);
 272
 273       if (__builtin_expect (oldval != actual_oldval, 0))
 274         return actual_oldval;
 275
 276       fail = __kernel_cmpxchg (ptr, actual_oldval, newval);
 277
 278       if (__builtin_expect (!fail, 1))
 279         return actual_oldval;
 280     }
 281 }
 282
 283 _Bool HIDDEN
 284 __sync_bool_compare_and_swap_4 (volatile void *ptr, unsigned int oldval,
 285                                 unsigned int newval)
 286 {
 287   long failure = __kernel_cmpxchg (ptr, oldval, newval);
 288   return (failure == 0);
 289 }
 290
 291 #define SYNC_LOCK_TEST_AND_SET_2(TYPE, WIDTH, INDEX)                    \
 292 TYPE HIDDEN                                                             \
 293   __sync_lock_test_and_set_##WIDTH (volatile void *ptr, TYPE val)       \
 294   {                                                                     \
 295     TYPE oldval;                                                        \
 296     long failure;                                                       \
 297                                                                         \
 298     do {                                                                \
 299       oldval = __atomic_load_n ((volatile TYPE *)ptr,                   \
 300                                 __ATOMIC_RELAXED);                      \
 301       failure = __kernel_cmpxchg2 (ptr, &oldval, &val, INDEX);          \
 302     } while (failure != 0);                                             \
 303                                                                         \
 304     return oldval;                                                      \
 305   }
 306
 307 SYNC_LOCK_TEST_AND_SET_2 (long long unsigned int, 8, 3)
 308 SYNC_LOCK_TEST_AND_SET_2 (short unsigned int, 2, 1)
 309 SYNC_LOCK_TEST_AND_SET_2 (unsigned char, 1, 0)
 310
 311 unsigned int HIDDEN
 312 __sync_lock_test_and_set_4 (volatile void *ptr, unsigned int val)
 313 {
 314   long failure;
 315   unsigned int oldval;
 316
 317   do {
 318     oldval = __atomic_load_n ((volatile unsigned int *)ptr, __ATOMIC_RELAXED);
 319     failure = __kernel_cmpxchg (ptr, oldval, val);
 320   } while (failure != 0);
 321
 322   return oldval;
 323 }
 324
 325 #define SYNC_LOCK_RELEASE_1(TYPE, WIDTH, INDEX)                 \
 326   void HIDDEN                                                   \
 327   __sync_lock_release_##WIDTH (volatile void *ptr)              \
 328   {                                                             \
 329     TYPE oldval, val = 0;                                       \
 330     long failure;                                               \
 331                                                                 \
 332     do {                                                        \
 333       oldval = __atomic_load_n ((volatile TYPE *)ptr,           \
 334                                 __ATOMIC_RELAXED);              \
 335       failure = __kernel_cmpxchg2 (ptr, &oldval, &val, INDEX);  \
 336     } while (failure != 0);                                     \
 337   }
 338
 339 SYNC_LOCK_RELEASE_1 (long long unsigned int, 8, 3)
 340 SYNC_LOCK_RELEASE_1 (short unsigned int, 2, 1)
 341 SYNC_LOCK_RELEASE_1 (unsigned char, 1, 0)
 342
 343 void HIDDEN
 344 __sync_lock_release_4 (volatile void *ptr)
 345 {
 346   long failure;
 347   unsigned int oldval;
 348
 349   do {
 350     oldval = __atomic_load_n ((volatile unsigned int *)ptr, __ATOMIC_RELAXED);
 351     failure = __kernel_cmpxchg (ptr, oldval, 0);
 352   } while (failure != 0);
 353 }