1/*
2 * Copyright (C) 2011 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
17#include "thread.h"
18
19#include "asm_support_x86_64.h"
20#include "base/macros.h"
21#include "thread-inl.h"
22#include "thread_list.h"
23
24#if defined(__linux__)
25#include <asm/prctl.h>
26#include <sys/prctl.h>
27#include <sys/syscall.h>
28#endif
29
30namespace art {
31
32#if defined(__linux__)
33static void arch_prctl(int code, void* val) {
34  syscall(__NR_arch_prctl, code, val);
35}
36#endif
37
38void Thread::InitCpu() {
39  MutexLock mu(nullptr, *Locks::modify_ldt_lock_);
40
41#if defined(__linux__)
42  arch_prctl(ARCH_SET_GS, this);
43#else
44  UNIMPLEMENTED(FATAL) << "Need to set GS";
45#endif
46
47  // Allow easy indirection back to Thread*.
48  tlsPtr_.self = this;
49
50  // Sanity check that reads from %gs point to this Thread*.
51  Thread* self_check;
52  __asm__ __volatile__("movq %%gs:(%1), %0"
53      : "=r"(self_check)  // output
54      : "r"(THREAD_SELF_OFFSET)  // input
55      :);  // clobber
56  CHECK_EQ(self_check, this);
57}
58
59void Thread::CleanupCpu() {
60  // Sanity check that reads from %gs point to this Thread*.
61  Thread* self_check;
62  __asm__ __volatile__("movq %%gs:(%1), %0"
63      : "=r"(self_check)  // output
64      : "r"(THREAD_SELF_OFFSET)  // input
65      :);  // clobber
66  CHECK_EQ(self_check, this);
67
68  // Do nothing.
69}
70
71}  // namespace art
72