libgcc/config/pa/linux-atomic.c

   1 /* Linux-specific atomic operations for PA Linux.
   2    Copyright (C) 2008-2014 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 /* All PA-RISC implementations supported by linux have strongly
  32    ordered loads and stores.  Only cache flushes and purges can be
  33    delayed.  The data cache implementations are all globally
  34    coherent.  Thus, there is no need to synchonize memory accesses.
  35
  36    GCC automatically issues a asm memory barrier when it encounters
  37    a __sync_synchronize builtin.  Thus, we do not need to define this
  38    builtin.
  39
  40    We implement byte, short and int versions of each atomic operation
  41    using the kernel helper defined below.  There is no support for
  42    64-bit operations yet.  */
  43
  44 /* A privileged instruction to crash a userspace program with SIGILL.  */
  45 #define ABORT_INSTRUCTION asm ("iitlbp %r0,(%sr0, %r0)")
  46
  47 /* Determine kernel LWS function call (0=32-bit, 1=64-bit userspace).  */
  48 #define LWS_CAS (sizeof(long) == 4 ? 0 : 1)
  49
  50 /* Kernel helper for compare-and-exchange a 32-bit value.  */
  51 static inline long
  52 __kernel_cmpxchg (int oldval, int newval, int *mem)
  53 {
  54   register unsigned long lws_mem asm("r26") = (unsigned long) (mem);
  55   register long lws_ret   asm("r28");
  56   register long lws_errno asm("r21");
  57   register int lws_old asm("r25") = oldval;
  58   register int lws_new asm("r24") = newval;
  59   asm volatile (        "ble    0xb0(%%sr2, %%r0)       \n\t"
  60                         "ldi    %5, %%r20               \n\t"
  61         : "=r" (lws_ret), "=r" (lws_errno), "=r" (lws_mem),
  62           "=r" (lws_old), "=r" (lws_new)
  63         : "i" (LWS_CAS), "2" (lws_mem), "3" (lws_old), "4" (lws_new)
  64         : "r1", "r20", "r22", "r23", "r29", "r31", "memory"
  65   );
  66   if (__builtin_expect (lws_errno == -EFAULT || lws_errno == -ENOSYS, 0))
  67     ABORT_INSTRUCTION;
  68
  69   /* If the kernel LWS call succeeded (lws_errno == 0), lws_ret contains
  70      the old value from memory.  If this value is equal to OLDVAL, the
  71      new value was written to memory.  If not, return -EBUSY.  */
  72   if (!lws_errno && lws_ret != oldval)
  73     lws_errno = -EBUSY;
  74
  75   return lws_errno;
  76 }
  77
  78 static inline long
  79 __kernel_cmpxchg2 (void * oldval, void * newval, void *mem, int val_size)
  80 {
  81   register unsigned long lws_mem asm("r26") = (unsigned long) (mem);
  82   register long lws_ret   asm("r28");
  83   register long lws_errno asm("r21");
  84   register unsigned long lws_old asm("r25") = (unsigned long) oldval;
  85   register unsigned long lws_new asm("r24") = (unsigned long) newval;
  86   register int lws_size asm("r23") = val_size;
  87   asm volatile (        "ble    0xb0(%%sr2, %%r0)       \n\t"
  88                         "ldi    %2, %%r20               \n\t"
  89         : "=r" (lws_ret), "=r" (lws_errno)
  90         : "i" (2), "r" (lws_mem), "r" (lws_old), "r" (lws_new), "r" (lws_size)
  91         : "r1", "r20", "r22", "r29", "r31", "fr4", "memory"
  92   );
  93   if (__builtin_expect (lws_errno == -EFAULT || lws_errno == -ENOSYS, 0))
  94     ABORT_INSTRUCTION;
  95
  96   /* If the kernel LWS call fails, retrun EBUSY */
  97   if (!lws_errno && lws_ret)
  98     lws_errno = -EBUSY;
  99
 100   return lws_errno;
 101 }
 102 #define HIDDEN __attribute__ ((visibility ("hidden")))
 103
 104 /* Big endian masks  */
 105 #define INVERT_MASK_1 24
 106 #define INVERT_MASK_2 16
 107
 108 #define MASK_1 0xffu
 109 #define MASK_2 0xffffu
 110
 111 #define FETCH_AND_OP_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 112   TYPE HIDDEN                                                           \
 113   __sync_fetch_and_##OP##_##WIDTH (TYPE *ptr, TYPE val)                 \
 114   {                                                                     \
 115     TYPE tmp, newval;                                                   \
 116     int failure;                                                        \
 117                                                                         \
 118     do {                                                                \
 119       tmp = *ptr;                                                       \
 120       newval = PFX_OP (tmp INF_OP val);                                 \
 121       failure = __kernel_cmpxchg2 (&tmp, &newval, ptr, INDEX);          \
 122     } while (failure != 0);                                             \
 123                                                                         \
 124     return tmp;                                                         \
 125   }
 126
 127 FETCH_AND_OP_2 (add,   , +, long long, 8, 3)
 128 FETCH_AND_OP_2 (sub,   , -, long long, 8, 3)
 129 FETCH_AND_OP_2 (or,    , |, long long, 8, 3)
 130 FETCH_AND_OP_2 (and,   , &, long long, 8, 3)
 131 FETCH_AND_OP_2 (xor,   , ^, long long, 8, 3)
 132 FETCH_AND_OP_2 (nand, ~, &, long long, 8, 3)
 133
 134 FETCH_AND_OP_2 (add,   , +, short, 2, 1)
 135 FETCH_AND_OP_2 (sub,   , -, short, 2, 1)
 136 FETCH_AND_OP_2 (or,    , |, short, 2, 1)
 137 FETCH_AND_OP_2 (and,   , &, short, 2, 1)
 138 FETCH_AND_OP_2 (xor,   , ^, short, 2, 1)
 139 FETCH_AND_OP_2 (nand, ~, &, short, 2, 1)
 140
 141 FETCH_AND_OP_2 (add,   , +, signed char, 1, 0)
 142 FETCH_AND_OP_2 (sub,   , -, signed char, 1, 0)
 143 FETCH_AND_OP_2 (or,    , |, signed char, 1, 0)
 144 FETCH_AND_OP_2 (and,   , &, signed char, 1, 0)
 145 FETCH_AND_OP_2 (xor,   , ^, signed char, 1, 0)
 146 FETCH_AND_OP_2 (nand, ~, &, signed char, 1, 0)
 147
 148 #define OP_AND_FETCH_2(OP, PFX_OP, INF_OP, TYPE, WIDTH, INDEX)          \
 149   TYPE HIDDEN                                                           \
 150   __sync_##OP##_and_fetch_##WIDTH (TYPE *ptr, TYPE val)                 \
 151   {                                                                     \
 152     TYPE tmp, newval;                                                   \
 153     int failure;                                                        \
 154                                                                         \
 155     do {                                                                \
 156       tmp = *ptr;                                                       \
 157       newval = PFX_OP (tmp INF_OP val);                                 \
 158       failure = __kernel_cmpxchg2 (&tmp, &newval, ptr, INDEX);          \
 159     } while (failure != 0);                                             \
 160                                                                         \
 161     return PFX_OP (tmp INF_OP val);                                     \
 162   }
 163
 164 OP_AND_FETCH_2 (add,   , +, long long, 8, 3)
 165 OP_AND_FETCH_2 (sub,   , -, long long, 8, 3)
 166 OP_AND_FETCH_2 (or,    , |, long long, 8, 3)
 167 OP_AND_FETCH_2 (and,   , &, long long, 8, 3)
 168 OP_AND_FETCH_2 (xor,   , ^, long long, 8, 3)
 169 OP_AND_FETCH_2 (nand, ~, &, long long, 8, 3)
 170
 171 OP_AND_FETCH_2 (add,   , +, short, 2, 1)
 172 OP_AND_FETCH_2 (sub,   , -, short, 2, 1)
 173 OP_AND_FETCH_2 (or,    , |, short, 2, 1)
 174 OP_AND_FETCH_2 (and,   , &, short, 2, 1)
 175 OP_AND_FETCH_2 (xor,   , ^, short, 2, 1)
 176 OP_AND_FETCH_2 (nand, ~, &, short, 2, 1)
 177
 178 OP_AND_FETCH_2 (add,   , +, signed char, 1, 0)
 179 OP_AND_FETCH_2 (sub,   , -, signed char, 1, 0)
 180 OP_AND_FETCH_2 (or,    , |, signed char, 1, 0)
 181 OP_AND_FETCH_2 (and,   , &, signed char, 1, 0)
 182 OP_AND_FETCH_2 (xor,   , ^, signed char, 1, 0)
 183 OP_AND_FETCH_2 (nand, ~, &, signed char, 1, 0)
 184
 185 #define FETCH_AND_OP_WORD(OP, PFX_OP, INF_OP)                           \
 186   int HIDDEN                                                            \
 187   __sync_fetch_and_##OP##_4 (int *ptr, int val)                         \
 188   {                                                                     \
 189     int failure, tmp;                                                   \
 190                                                                         \
 191     do {                                                                \
 192       tmp = *ptr;                                                       \
 193       failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr);   \
 194     } while (failure != 0);                                             \
 195                                                                         \
 196     return tmp;                                                         \
 197   }
 198
 199 FETCH_AND_OP_WORD (add,   , +)
 200 FETCH_AND_OP_WORD (sub,   , -)
 201 FETCH_AND_OP_WORD (or,    , |)
 202 FETCH_AND_OP_WORD (and,   , &)
 203 FETCH_AND_OP_WORD (xor,   , ^)
 204 FETCH_AND_OP_WORD (nand, ~, &)
 205
 206 #define OP_AND_FETCH_WORD(OP, PFX_OP, INF_OP)                           \
 207   int HIDDEN                                                            \
 208   __sync_##OP##_and_fetch_4 (int *ptr, int val)                         \
 209   {                                                                     \
 210     int tmp, failure;                                                   \
 211                                                                         \
 212     do {                                                                \
 213       tmp = *ptr;                                                       \
 214       failure = __kernel_cmpxchg (tmp, PFX_OP (tmp INF_OP val), ptr);   \
 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     int fail;                                                           \
 236                                                                         \
 237     while (1)                                                           \
 238       {                                                                 \
 239         actual_oldval = *ptr;                                           \
 240                                                                         \
 241         if (__builtin_expect (oldval != actual_oldval, 0))              \
 242           return actual_oldval;                                         \
 243                                                                         \
 244         fail = __kernel_cmpxchg2 (&actual_oldval, &newval, ptr, 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     int failure = __kernel_cmpxchg2 (&oldval, &newval, ptr, 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   int actual_oldval, fail;
 267
 268   while (1)
 269     {
 270       actual_oldval = *ptr;
 271
 272       if (__builtin_expect (oldval != actual_oldval, 0))
 273         return actual_oldval;
 274
 275       fail = __kernel_cmpxchg (actual_oldval, newval, ptr);
 276
 277       if (__builtin_expect (!fail, 1))
 278         return actual_oldval;
 279     }
 280 }
 281
 282 bool HIDDEN
 283 __sync_bool_compare_and_swap_4 (int *ptr, int oldval, int newval)
 284 {
 285   int failure = __kernel_cmpxchg (oldval, newval, ptr);
 286   return (failure == 0);
 287 }
 288
 289 #define SYNC_LOCK_TEST_AND_SET_2(TYPE, WIDTH, INDEX)                    \
 290 TYPE HIDDEN                                                             \
 291   __sync_lock_test_and_set_##WIDTH (TYPE *ptr, TYPE val)                \
 292   {                                                                     \
 293     TYPE oldval;                                                        \
 294     int failure;                                                        \
 295                                                                         \
 296     do {                                                                \
 297       oldval = *ptr;                                                    \
 298       failure = __kernel_cmpxchg2 (&oldval, &val, ptr, INDEX);          \
 299     } while (failure != 0);                                             \
 300                                                                         \
 301     return oldval;                                                      \
 302   }
 303
 304 SYNC_LOCK_TEST_AND_SET_2 (long long, 8, 3)
 305 SYNC_LOCK_TEST_AND_SET_2 (short, 2, 1)
 306 SYNC_LOCK_TEST_AND_SET_2 (signed char, 1, 0)
 307
 308 int HIDDEN
 309 __sync_lock_test_and_set_4 (int *ptr, int val)
 310 {
 311   int failure, oldval;
 312
 313   do {
 314     oldval = *ptr;
 315     failure = __kernel_cmpxchg (oldval, val, ptr);
 316   } while (failure != 0);
 317
 318   return oldval;
 319 }
 320
 321 #define SYNC_LOCK_RELEASE_2(TYPE, WIDTH, INDEX)                 \
 322   void HIDDEN                                                   \
 323   __sync_lock_release_##WIDTH (TYPE *ptr)                       \
 324   {                                                             \
 325     TYPE failure, oldval, zero = 0;                             \
 326                                                                 \
 327     do {                                                        \
 328       oldval = *ptr;                                            \
 329       failure = __kernel_cmpxchg2 (&oldval, &zero, ptr, INDEX); \
 330     } while (failure != 0);                                     \
 331   }
 332
 333 SYNC_LOCK_RELEASE_2 (long long, 8, 3)
 334 SYNC_LOCK_RELEASE_2 (short, 2, 1)
 335 SYNC_LOCK_RELEASE_2 (signed char, 1, 0)
 336
 337 void HIDDEN
 338 __sync_lock_release_4 (int *ptr)
 339 {
 340   int failure, oldval;
 341
 342   do {
 343     oldval = *ptr;
 344     failure = __kernel_cmpxchg (oldval, 0, ptr);
 345   } while (failure != 0);
 346 }