ports/sysdeps/arm/bits/atomic.h

   1 /* Atomic operations.  Pure ARM version.
   2    Copyright (C) 2002-2014 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdint.h>
  20
  21 typedef int8_t atomic8_t;
  22 typedef uint8_t uatomic8_t;
  23 typedef int_fast8_t atomic_fast8_t;
  24 typedef uint_fast8_t uatomic_fast8_t;
  25
  26 typedef int32_t atomic32_t;
  27 typedef uint32_t uatomic32_t;
  28 typedef int_fast32_t atomic_fast32_t;
  29 typedef uint_fast32_t uatomic_fast32_t;
  30
  31 typedef intptr_t atomicptr_t;
  32 typedef uintptr_t uatomicptr_t;
  33 typedef intmax_t atomic_max_t;
  34 typedef uintmax_t uatomic_max_t;
  35
  36 void __arm_link_error (void);
  37
  38 #ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
  39 # define atomic_full_barrier() __sync_synchronize ()
  40 #else
  41 # define atomic_full_barrier() __arm_assisted_full_barrier ()
  42 #endif
  43
  44 /* An OS-specific bits/atomic.h file will define this macro if
  45    the OS can provide something.  If not, we'll fail to build
  46    with a compiler that doesn't supply the operation.  */
  47 #ifndef __arm_assisted_full_barrier
  48 # define __arm_assisted_full_barrier()  __arm_link_error()
  49 #endif
  50
  51 /* Use the atomic builtins provided by GCC in case the backend provides
  52    a pattern to do this efficiently.  */
  53 #if __GNUC_PREREQ (4, 7) && defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
  54
  55 # define atomic_exchange_acq(mem, value)                                \
  56   __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE)
  57
  58 # define atomic_exchange_rel(mem, value)                                \
  59   __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE)
  60
  61 /* Atomic exchange (without compare).  */
  62
  63 # define __arch_exchange_8_int(mem, newval, model)      \
  64   (__arm_link_error (), (typeof (*mem)) 0)
  65
  66 # define __arch_exchange_16_int(mem, newval, model)     \
  67   (__arm_link_error (), (typeof (*mem)) 0)
  68
  69 # define __arch_exchange_32_int(mem, newval, model)     \
  70   __atomic_exchange_n (mem, newval, model)
  71
  72 # define __arch_exchange_64_int(mem, newval, model)     \
  73   (__arm_link_error (), (typeof (*mem)) 0)
  74
  75 /* Compare and exchange with "acquire" semantics, ie barrier after.  */
  76
  77 # define atomic_compare_and_exchange_bool_acq(mem, new, old)    \
  78   __atomic_bool_bysize (__arch_compare_and_exchange_bool, int,  \
  79                         mem, new, old, __ATOMIC_ACQUIRE)
  80
  81 # define atomic_compare_and_exchange_val_acq(mem, new, old)     \
  82   __atomic_val_bysize (__arch_compare_and_exchange_val, int,    \
  83                        mem, new, old, __ATOMIC_ACQUIRE)
  84
  85 /* Compare and exchange with "release" semantics, ie barrier before.  */
  86
  87 # define atomic_compare_and_exchange_bool_rel(mem, new, old)    \
  88   __atomic_bool_bysize (__arch_compare_and_exchange_bool, int,  \
  89                         mem, new, old, __ATOMIC_RELEASE)
  90
  91 # define atomic_compare_and_exchange_val_rel(mem, new, old)      \
  92   __atomic_val_bysize (__arch_compare_and_exchange_val, int,    \
  93                        mem, new, old, __ATOMIC_RELEASE)
  94
  95 /* Compare and exchange.
  96    For all "bool" routines, we return FALSE if exchange succesful.  */
  97
  98 # define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \
  99   ({__arm_link_error (); oldval; })
 100
 101 # define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \
 102   ({__arm_link_error (); oldval; })
 103
 104 # define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \
 105   ({                                                                    \
 106     typeof (*mem) __oldval = (oldval);                                  \
 107     !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,   \
 108                                   model, __ATOMIC_RELAXED);             \
 109   })
 110
 111 # define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
 112   ({__arm_link_error (); oldval; })
 113
 114 # define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \
 115   ({__arm_link_error (); oldval; })
 116
 117 # define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \
 118   ({__arm_link_error (); oldval; })
 119
 120 # define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \
 121   ({                                                                    \
 122     typeof (*mem) __oldval = (oldval);                                  \
 123     __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0,    \
 124                                  model, __ATOMIC_RELAXED);              \
 125     __oldval;                                                           \
 126   })
 127
 128 # define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \
 129   ({__arm_link_error (); oldval; })
 130
 131 #elif defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
 132 /* Atomic compare and exchange.  */
 133 # define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
 134   __sync_val_compare_and_swap ((mem), (oldval), (newval))
 135 #else
 136 # define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
 137   __arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval))
 138 #endif
 139
 140 #if !__GNUC_PREREQ (4, 7) || !defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
 141 /* We don't support atomic operations on any non-word types.
 142    So make them link errors.  */
 143 # define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \
 144   ({ __arm_link_error (); oldval; })
 145
 146 # define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
 147   ({ __arm_link_error (); oldval; })
 148
 149 # define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \
 150   ({ __arm_link_error (); oldval; })
 151 #endif
 152
 153 /* An OS-specific bits/atomic.h file will define this macro if
 154    the OS can provide something.  If not, we'll fail to build
 155    with a compiler that doesn't supply the operation.  */
 156 #ifndef __arm_assisted_compare_and_exchange_val_32_acq
 157 # define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \
 158   ({ __arm_link_error (); oldval; })
 159 #endif