kernel/spinlock.cpp

   1 /*
   2 lightOS kernel
   3 Copyright (C) 2007-2009 Jörg Pfähler
   4
   5 This program is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU General Public License
   7 as published by the Free Software Foundation; either version 2
   8 of the License, or (at your option) any later version.
   9
  10 This program 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
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  18 */
  19 #include <kernel/spinlock.hpp>
  20 #include <kernel/processor.hpp>
  21 using namespace kernel;
  22
  23 void reentrant_spinlock::lock()
  24 {
  25         if (mAtom == 0 && mProcessorId == processor::id())return;
  26         while (!mAtom.compare_and_exchange(1, 0)){}
  27         mProcessorId = processor::id();
  28 }
  29 void reentrant_spinlock::unlock()
  30 {
  31         mProcessorId = -1;
  32         mAtom = 1;
  33 }