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
30 namespace art {
31
32 #if defined(__linux__)
arch_prctl(int code,void * val)33 static void arch_prctl(int code, void* val) {
34 syscall(__NR_arch_prctl, code, val);
35 }
36 #endif
37
InitCpu()38 void 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
CleanupCpu()59 void 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