libgcc/config/pa/linux-atomic.c

   1 /* Linux-specific atomic operations for PA Linux.
   2    Copyright (C) 2008-2019 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 (int *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   if (__builtin_expect (lws_errno == -EFAULT || lws_errno == -ENOSYS, 0))
  58     __builtin_trap ();
  59
  60   /* If the kernel LWS call succeeded (lws_errno == 0), lws_ret contains
  61      the old value from memory.  If this value is equal to OLDVAL, the
  62      new value was written to memory.  If not, return -EBUSY.  */
  63   if (!lws_errno && lws_ret != oldval)
  64     lws_errno = -EBUSY;
  65
  66   return lws_errno;
  67 }
  68
  69 static inline long
  70 __kernel_cmpxchg2 (void *mem, const void *oldval, const void *newval,
  71                    int val_size)
  72 {
  73   register unsigned long lws_mem asm("r26") = (unsigned long) (mem);
  74   register unsigned long lws_old asm("r25") = (unsigned long) oldval;
  75   register unsigned long lws_new asm("r24") = (unsigned long) newval;
  76   register int lws_size asm("r23") = val_size;
  77   register long lws_ret   asm("r28");
  78   register long lws_errno asm("r21");
  79   asm volatile (        "ble    0xb0(%%sr2, %%r0)       \n\t"
  80                         "ldi    %6, %%r20               \n\t"
  81         : "=r" (lws_ret), "=r" (lws_errno), "+r" (lws_mem),
  82           "+r" (lws_old), "+r" (lws_new), "+r" (lws_size)
  83         : "i" (2)
  84         : "r1", "r20", "r22", "r29", "r31", "fr4", "memory"
  85   );
  86
  87   /* If the kernel LWS call is successful, lws_ret contains 0.  */
  88   if (__builtin_expect (lws_ret == 0, 1))
  89     return 0;
  90
  91   if (__builtin_expect (lws_errno == -EFAULT || lws_errno == -ENOSYS, 0))
  92     __builtin_trap ();
  93
  94   /* If the kernel LWS call fails with no error, return -EBUSY */
  95   if (__builtin_expect (!lws_errno, 0))
  96     return -EBUSY;
  97
  98   return lws_errno;
  99 }
 100 #define HIDDEN __attribute__ ((visibility ("hidden")))
 101
 102 /* Big endian masks  */
 103 #define INVERT_MASK_1 24
 104 #define INVERT_MASK_2 16
 105
 106 #define MASK_1 0xffu
 107 #define MASK_2 0xffffu
 108
 109 #define FETCH_AND_OP_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 110   TYPE HIDDEN                                                           \
 111   __sync_fetch_and_##OP##_##WIDTH (TYPE *ptr, TYPE val)                 \
 112   {                                                                     \
 113     TYPE tmp, newval;                                                   \
 114     long failure;                                                       \
 115                                                                         \
 116     do {                                                                \
 117       tmp = __atomic_load_n (ptr, __ATOMIC_RELAXED);                    \
 118       newval = PFX_OP (tmp INF_OP val);                                 \
 119       failure = __kernel_cmpxchg2 (ptr, &tmp, &newval, INDEX);          \
 120     } while (failure != 0);                                             \
 121                                                                         \
 122     return tmp;                                                         \
 123   }
 124
 125 FETCH_AND_OP_2 (add,   , +, long long, 8, 3)
 126 FETCH_AND_OP_2 (sub,   , -, long long, 8, 3)
 127 FETCH_AND_OP_2 (or,    , |, long long, 8, 3)
 128 FETCH_AND_OP_2 (and,   , &, long long, 8, 3)
 129 FETCH_AND_OP_2 (xor,   , ^, long long, 8, 3)
 130 FETCH_AND_OP_2 (nand, ~, &, long long, 8, 3)
 131
 132 FETCH_AND_OP_2 (add,   , +, short, 2, 1)
 133 FETCH_AND_OP_2 (sub,   , -, short, 2, 1)
 134 FETCH_AND_OP_2 (or,    , |, short, 2, 1)
 135 FETCH_AND_OP_2 (and,   , &, short, 2, 1)
 136 FETCH_AND_OP_2 (xor,   , ^, short, 2, 1)
 137 FETCH_AND_OP_2 (nand, ~, &, short, 2, 1)
 138
 139 FETCH_AND_OP_2 (add,   , +, signed char, 1, 0)
 140 FETCH_AND_OP_2 (sub,   , -, signed char, 1, 0)
 141 FETCH_AND_OP_2 (or,    , |, signed char, 1, 0)
 142 FETCH_AND_OP_2 (and,   , &, signed char, 1, 0)
 143 FETCH_AND_OP_2 (xor,   , ^, signed char, 1, 0)
 144 FETCH_AND_OP_2 (nand, ~, &, signed char, 1, 0)
 145
 146 #define OP_AND_FETCH_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 147   TYPE HIDDEN                                                           \
 148   __sync_##OP##_and_fetch_##WIDTH (TYPE *ptr, TYPE val)                 \
 149   {                                                                     \
 150     TYPE tmp, newval;                                                   \
 151     long failure;                                                       \
 152                                                                         \
 153     do {                                                                \
 154       tmp = __atomic_load_n (ptr, __ATOMIC_RELAXED);                    \
 155       newval = PFX_OP (tmp INF_OP val);                                 \
 156       failure = __kernel_cmpxchg2 (ptr, &tmp, &newval, INDEX);          \
 157     } while (failure != 0);                                             \
 158                                                                         \
 159     return PFX_OP (tmp INF_OP val);                                     \
 160   }
 161
 162 OP_AND_FETCH_2 (add,   , +, long long, 8, 3)
 163 OP_AND_FETCH_2 (sub,   , -, long long, 8, 3)
 164 OP_AND_FETCH_2 (or,    , |, long long, 8, 3)
 165 OP_AND_FETCH_2 (and,   , &, long long, 8, 3)
 166 OP_AND_FETCH_2 (xor,   , ^, long long, 8, 3)
 167 OP_AND_FETCH_2 (nand, ~, &, long long, 8, 3)
 168
 169 OP_AND_FETCH_2 (add,   , +, short, 2, 1)
 170 OP_AND_FETCH_2 (sub,   , -, short, 2, 1)
 171 OP_AND_FETCH_2 (or,    , |, short, 2, 1)
 172 OP_AND_FETCH_2 (and,   , &, short, 2, 1)
 173 OP_AND_FETCH_2 (xor,   , ^, short, 2, 1)
 174 OP_AND_FETCH_2 (nand, ~, &, short, 2, 1)
 175
 176 OP_AND_FETCH_2 (add,   , +, signed char, 1, 0)
 177 OP_AND_FETCH_2 (sub,   , -, signed char, 1, 0)
 178 OP_AND_FETCH_2 (or,    , |, signed char, 1, 0)
 179 OP_AND_FETCH_2 (and,   , &, signed char, 1, 0)
 180 OP_AND_FETCH_2 (xor,   , ^, signed char, 1, 0)
 181 OP_AND_FETCH_2 (nand, ~, &, signed char, 1, 0)
 182
 183 #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP)                           \
 184   int HIDDEN                                                            \
 185   __sync_fetch_and_##OP##_4 (int *ptr, int val)                         \
 186   {                                                                     \
 187     int tmp;                                                            \
 188     long failure;                                                       \
 189                                                                         \
 190     do {                                                                \
 191       tmp = __atomic_load_n (ptr, __ATOMIC_RELAXED);                    \
 192       failure = __kernel_cmpxchg (ptr, tmp, PFX_OP (tmp INF_OP val));   \
 193     } while (failure != 0);                                             \
 194                                                                         \
 195     return tmp;                                                         \
 196   }
 197
 198 FETCH_AND_OP_WORD (add,   , +)
 199 FETCH_AND_OP_WORD (sub,   , -)
 200 FETCH_AND_OP_WORD (or,    , |)
 201 FETCH_AND_OP_WORD (and,   , &)
 202 FETCH_AND_OP_WORD (xor,   , ^)
 203 FETCH_AND_OP_WORD (nand, ~, &)
 204
 205 #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP)                           \
 206   int HIDDEN                                                            \
 207   __sync_##OP##_and_fetch_4 (int *ptr, int val)                         \
 208   {                                                                     \
 209     int tmp;                                                            \
 210     long failure;                                                       \
 211                                                                         \
 212     do {                                                                \
 213       tmp = __atomic_load_n (ptr, __ATOMIC_RELAXED);                    \
 214       failure = __kernel_cmpxchg (ptr, tmp, PFX_OP (tmp INF_OP val));   \
 215     } while (failure != 0);                                             \
 216                                                                         \
 217     return PFX_OP (tmp INF_OP val);                                     \
 218   }
 219
 220 OP_AND_FETCH_WORD (add,   , +)
 221 OP_AND_FETCH_WORD (sub,   , -)
 222 OP_AND_FETCH_WORD (or,    , |)
 223 OP_AND_FETCH_WORD (and,   , &)
 224 OP_AND_FETCH_WORD (xor,   , ^)
 225 OP_AND_FETCH_WORD (nand, ~, &)
 226
 227 typedef unsigned char bool;
 228
 229 #define COMPARE_AND_SWAP_2(TYPE, WIDTH, INDEX)                          \
 230   TYPE HIDDEN                                                           \
 231   __sync_val_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval,          \
 232                                        TYPE newval)                     \
 233   {                                                                     \
 234     TYPE actual_oldval;                                                 \
 235     long fail;                                                          \
 236                                                                         \
 237     while (1)                                                           \
 238       {                                                                 \
 239         actual_oldval = __atomic_load_n (ptr, __ATOMIC_RELAXED);        \
 240                                                                         \
 241         if (__builtin_expect (oldval != actual_oldval, 0))              \
 242           return actual_oldval;                                         \
 243                                                                         \
 244         fail = __kernel_cmpxchg2 (ptr, &actual_oldval, &newval, INDEX); \
 245                                                                         \
 246         if (__builtin_expect (!fail, 1))                                \
 247           return actual_oldval;                                         \
 248       }                                                                 \
 249   }                                                                     \
 250                                                                         \
 251   bool HIDDEN                                                           \
 252   __sync_bool_compare_and_swap_##WIDTH (TYPE *ptr, TYPE oldval,         \
 253                                         TYPE newval)                    \
 254   {                                                                     \
 255     long failure = __kernel_cmpxchg2 (ptr, &oldval, &newval, INDEX);    \
 256     return (failure == 0);                                              \
 257   }
 258
 259 COMPARE_AND_SWAP_2 (long long, 8, 3)
 260 COMPARE_AND_SWAP_2 (short, 2, 1)
 261 COMPARE_AND_SWAP_2 (char, 1, 0)
 262
 263 int HIDDEN
 264 __sync_val_compare_and_swap_4 (int *ptr, int oldval, int newval)
 265 {
 266   long fail;
 267   int actual_oldval;
 268
 269   while (1)
 270     {
 271       actual_oldval = __atomic_load_n (ptr, __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 (int *ptr, int oldval, int newval)
 285 {
 286   long failure = __kernel_cmpxchg (ptr, oldval, newval);
 287   return (failure == 0);
 288 }
 289
 290 #define SYNC_LOCK_TEST_AND_SET_2(TYPE, WIDTH, INDEX)                    \
 291 TYPE HIDDEN                                                             \
 292   __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val)                \
 293   {                                                                     \
 294     TYPE oldval;                                                        \
 295     long failure;                                                       \
 296                                                                         \
 297     do {                                                                \
 298       oldval = __atomic_load_n (ptr, __ATOMIC_RELAXED);                 \
 299       failure = __kernel_cmpxchg2 (ptr, &oldval, &val, INDEX);          \
 300     } while (failure != 0);                                             \
 301                                                                         \
 302     return oldval;                                                      \
 303   }
 304
 305 SYNC_LOCK_TEST_AND_SET_2 (long long, 8, 3)
 306 SYNC_LOCK_TEST_AND_SET_2 (short, 2, 1)
 307 SYNC_LOCK_TEST_AND_SET_2 (signed char, 1, 0)
 308
 309 int HIDDEN
 310 __sync_lock_test_and_set_4 (int *ptr, int val)
 311 {
 312   long failure;
 313   int oldval;
 314
 315   do {
 316     oldval = __atomic_load_n (ptr, __ATOMIC_RELAXED);
 317     failure = __kernel_cmpxchg (ptr, oldval, val);
 318   } while (failure != 0);
 319
 320   return oldval;
 321 }
 322
 323 void HIDDEN
 324 __sync_lock_release_8 (long long *ptr)
 325 {
 326   /* All accesses must be complete before we release the lock.  */
 327   __sync_synchronize ();
 328   *(double *)ptr = 0;
 329 }
 330
 331 #define SYNC_LOCK_RELEASE_1(TYPE, WIDTH)                        \
 332   void HIDDEN                                                   \
 333   __sync_lock_release_##WIDTH (TYPE *ptr)                       \
 334   {                                                             \
 335     /* All accesses must be complete before we release          \
 336        the lock.  */                                            \
 337     __sync_synchronize ();                                      \
 338     *ptr = 0;                                                   \
 339   }
 340
 341 SYNC_LOCK_RELEASE_1 (int, 4)
 342 SYNC_LOCK_RELEASE_1 (short, 2)
 343 SYNC_LOCK_RELEASE_1 (signed char, 1)