1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 #include "common/vsoc/shm/lock.h" 17 18 #include "sys/types.h" 19 20 #include "common/vsoc/lib/compat.h" 21 #include "common/vsoc/lib/single_sided_signal.h" 22 23 namespace vsoc { 24 namespace layout { 25 26 void HostLock::Lock() { 27 uint32_t tid = gettid(); 28 uint32_t expected_value; 29 uint32_t* uaddr = reinterpret_cast<uint32_t*>(&lock_uint32_); 30 31 while (1) { 32 if (TryLock(tid, &expected_value)) { 33 return; 34 } 35 SingleSidedSignal::AwaitSignal(expected_value, uaddr); 36 } 37 } 38 39 void HostLock::Unlock() { 40 Sides sides_to_signal = UnlockCommon(gettid()); 41 if (sides_to_signal != Sides::NoSides) { 42 SingleSidedSignal::Signal(&lock_uint32_); 43 } 44 } 45 46 bool HostLock::Recover() { 47 return RecoverSingleSided(); 48 } 49 50 } // namespace layout 51 } // namespace vsoc 52
