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-current-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 #elif defined(__Fuchsia__)
29 #include <zircon/process.h>
30 #include <zircon/syscalls.h>
31 #include <zircon/syscalls/object.h>
32 #endif
33
34 namespace art {
35
36 #if defined(__linux__)
arch_prctl(int code,void * val)37 static void arch_prctl(int code, void* val) {
38 syscall(__NR_arch_prctl, code, val);
39 }
40 #endif
41
InitCpu()42 void Thread::InitCpu() {
43 MutexLock mu(nullptr, *Locks::modify_ldt_lock_);
44
45 #if defined(__linux__)
46 arch_prctl(ARCH_SET_GS, this);
47 #elif defined(__Fuchsia__)
48 Thread* thread_ptr = this;
49 zx_status_t status = zx_object_set_property(zx_thread_self(),
50 ZX_PROP_REGISTER_GS,
51 &thread_ptr,
52 sizeof(thread_ptr));
53 CHECK_EQ(status, ZX_OK) << "failed to set GS register";
54 #else
55 UNIMPLEMENTED(FATAL) << "Need to set GS";
56 #endif
57
58 // Allow easy indirection back to Thread*.
59 tlsPtr_.self = this;
60
61 // Check that the reads from %gs point to this Thread*.
62 Thread* self_check;
63 __asm__ __volatile__("movq %%gs:(%1), %0"
64 : "=r"(self_check) // output
65 : "r"(THREAD_SELF_OFFSET) // input
66 :); // clobber
67 CHECK_EQ(self_check, this);
68 }
69
CleanupCpu()70 void Thread::CleanupCpu() {
71 // Check that the reads from %gs point to this Thread*.
72 Thread* self_check;
73 __asm__ __volatile__("movq %%gs:(%1), %0"
74 : "=r"(self_check) // output
75 : "r"(THREAD_SELF_OFFSET) // input
76 :); // clobber
77 CHECK_EQ(self_check, this);
78
79 // Do nothing.
80 }
81
82 } // namespace art
83