src/os_cpu/bsd_zero/vm/atomic_bsd_zero.inline.hpp

@  rev 7104 : 8067331: Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier
|

*** 236,246 ****
  #else
    // __sync_lock_test_and_set is a bizarrely named atomic exchange
    // operation.  Note that some platforms only support this with the
    // limitation that the only valid value to store is the immediate
    // constant 1.  There is a test for this in JNI_CreateJavaVM().
!   return __sync_lock_test_and_set (dest, exchange_value);
  #endif // M68K
  #endif // ARM
  }
  
  inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value,
--- 236,252 ----
  #else
    // __sync_lock_test_and_set is a bizarrely named atomic exchange
    // operation.  Note that some platforms only support this with the
    // limitation that the only valid value to store is the immediate
    // constant 1.  There is a test for this in JNI_CreateJavaVM().
!   jint result = __sync_lock_test_and_set (dest, exchange_value);
!   // All atomic operations are expected to be full memory barriers
!   // (see atomic.hpp). However, __sync_lock_test_and_set is not
!   // a full memory barrier, but an acquire barrier. Hence, this added
!   // barrier.
!   __sync_synchronize();
!   return result;
  #endif // M68K
  #endif // ARM
  }
  
  inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value,
*** 249,259 ****
    return arm_lock_test_and_set(dest, exchange_value);
  #else
  #ifdef M68K
    return m68k_lock_test_and_set(dest, exchange_value);
  #else
!   return __sync_lock_test_and_set (dest, exchange_value);
  #endif // M68K
  #endif // ARM
  }
  
  inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) {
--- 255,267 ----
    return arm_lock_test_and_set(dest, exchange_value);
  #else
  #ifdef M68K
    return m68k_lock_test_and_set(dest, exchange_value);
  #else
!   intptr_t result = __sync_lock_test_and_set (dest, exchange_value);
!   __sync_synchronize();
!   return result;
  #endif // M68K
  #endif // ARM
  }
  
  inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) {