root/arch/arm/include/asm/sync_bitops.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_SYNC_BITOPS_H__
   3 #define __ASM_SYNC_BITOPS_H__
   4 
   5 #include <asm/bitops.h>
   6 
   7 /* sync_bitops functions are equivalent to the SMP implementation of the
   8  * original functions, independently from CONFIG_SMP being defined.
   9  *
  10  * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But
  11  * under Xen you might be communicating with a completely external entity
  12  * who might be on another CPU (e.g. two uniprocessor guests communicating
  13  * via event channels and grant tables). So we need a variant of the bit
  14  * ops which are SMP safe even on a UP kernel.
  15  */
  16 
  17 #define sync_set_bit(nr, p)             _set_bit(nr, p)
  18 #define sync_clear_bit(nr, p)           _clear_bit(nr, p)
  19 #define sync_change_bit(nr, p)          _change_bit(nr, p)
  20 #define sync_test_and_set_bit(nr, p)    _test_and_set_bit(nr, p)
  21 #define sync_test_and_clear_bit(nr, p)  _test_and_clear_bit(nr, p)
  22 #define sync_test_and_change_bit(nr, p) _test_and_change_bit(nr, p)
  23 #define sync_test_bit(nr, addr)         test_bit(nr, addr)
  24 #define sync_cmpxchg                    cmpxchg
  25 
  26 
  27 #endif