sysdeps/unix/sysv/linux/s390/elision-unlock.c

   1 /* Commit an elided pthread lock.
   2    Copyright (C) 2014-2015 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 <pthreadP.h>
  20 #include <lowlevellock.h>
  21
  22 int
  23 __lll_unlock_elision(int *futex, int private)
  24 {
  25   /* If the lock is free, we elided the lock earlier.  This does not
  26      necessarily mean that we are in a transaction, because the user code may
  27      have closed the transaction, but that is impossible to detect reliably.  */
  28   if (*futex == 0)
  29     {
  30       __asm__ volatile (".machinemode \"zarch_nohighgprs\"\n\t"
  31                         ".machine \"all\""
  32                         : : : "memory");
  33       __builtin_tend();
  34     }
  35   else
  36     lll_unlock ((*futex), private);
  37   return 0;
  38 }