1 /*
2 * Copyright (C) 2016 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 <type_traits>
18
19 extern "C" {
20
21 #include "HAP_farf.h"
22 #include "qurt.h"
23 #include "timer.h"
24
25 } // extern "C"
26
27 #include "chre/core/event_loop.h"
28 #include "chre/core/event_loop_manager.h"
29 #include "chre/core/init.h"
30 #include "chre/core/static_nanoapps.h"
31 #include "chre/platform/fatal_error.h"
32 #include "chre/platform/log.h"
33 #include "chre/platform/memory.h"
34 #include "chre/platform/mutex.h"
35 #include "chre/platform/slpi/fastrpc.h"
36 #include "chre/platform/slpi/uimg_util.h"
37 #include "chre/util/lock_guard.h"
38
39 #ifdef CHRE_SLPI_SEE
40 #include "chre/platform/slpi/see/island_vote_client.h"
41 #endif
42
43 using chre::EventLoop;
44 using chre::EventLoopManagerSingleton;
45 using chre::LockGuard;
46 using chre::Mutex;
47 using chre::UniquePtr;
48
49 extern "C" int chre_slpi_stop_thread(void);
50
51 // Qualcomm-defined function needed to indicate that the CHRE thread may call
52 // dlopen() (without it, the thread will deadlock when calling dlopen()). Not in
53 // any header file in the SLPI tree or Hexagon SDK (3.0), so declaring here.
54 // Returns 0 to indicate success.
55 extern "C" int HAP_thread_migrate(qurt_thread_t thread);
56
57 namespace {
58
59 //! Size of the stack for the CHRE thread, in bytes.
60 constexpr size_t kStackSize = (8 * 1024);
61
62 //! Memory partition where the thread control block (TCB) should be stored,
63 //! which controls micro-image support.
64 //! @see qurt_thread_attr_set_tcb_partition
65 constexpr unsigned char kTcbPartition =
66 chre::isSlpiUimgSupported() ? QURT_THREAD_ATTR_TCB_PARTITION_TCM
67 : QURT_THREAD_ATTR_TCB_PARTITION_RAM;
68
69 //! The priority to set for the CHRE thread (value between 1-255, with 1 being
70 //! the highest).
71 //! @see qurt_thread_attr_set_priority
72 constexpr unsigned short kThreadPriority = 192;
73
74 //! How long we wait (in microseconds) between checks on whether the CHRE thread
75 //! has exited after we invoked stop().
76 constexpr time_timetick_type kThreadStatusPollingIntervalUsec = 5000; // 5ms
77
78 //! Buffer to use for the CHRE thread's stack.
79 typename std::aligned_storage<kStackSize>::type gStack;
80
81 //! QuRT OS handle for the CHRE thread.
82 qurt_thread_t gThreadHandle;
83
84 //! Protects access to thread metadata, like gThreadRunning, during critical
85 //! sections (starting/stopping the CHRE thread).
86 Mutex gThreadMutex;
87
88 //! Set to true when the CHRE thread starts, and false when it exits normally.
89 bool gThreadRunning;
90
91 //! A thread-local storage key, which is currently only used to add a thread
92 //! destructor callback for the host FastRPC thread.
93 int gTlsKey;
94 bool gTlsKeyValid;
95
96 /**
97 * Entry point for the QuRT thread that runs CHRE.
98 *
99 * @param data Argument passed to qurt_thread_create()
100 */
chreThreadEntry(void *)101 void chreThreadEntry(void * /*data*/) {
102 EventLoopManagerSingleton::get()->lateInit();
103 chre::loadStaticNanoapps();
104 EventLoopManagerSingleton::get()->getEventLoop().run();
105
106 chre::deinit();
107 #if defined(CHRE_SLPI_SEE) && !defined(IMPORT_CHRE_UTILS)
108 chre::IslandVoteClientSingleton::deinit();
109 #endif
110 // Perform this as late as possible - if we are shutting down because we
111 // detected exit of the host process, FastRPC will unload us once all our
112 // FastRPC calls have returned. Doing this late helps ensure that the call
113 // to chre_slpi_get_message_to_host() stays open until we're done with
114 // cleanup.
115 chre::HostLinkBase::shutdown();
116 gThreadRunning = false;
117 }
118
onHostProcessTerminated(void *)119 void onHostProcessTerminated(void * /*data*/) {
120 LOGW("Host process died, exiting CHRE (running %d)", gThreadRunning);
121 if (gThreadRunning) {
122 EventLoopManagerSingleton::get()->getEventLoop().stop();
123 }
124 }
125
126 } // anonymous namespace
127
128 namespace chre {
129
inEventLoopThread()130 bool inEventLoopThread() {
131 return (qurt_thread_get_id() == gThreadHandle);
132 }
133
134 } // namespace chre
135
136 /**
137 * Invoked over FastRPC to initialize and start the CHRE thread.
138 *
139 * @return 0 on success, nonzero on failure (per FastRPC requirements)
140 */
chre_slpi_start_thread(void)141 extern "C" int chre_slpi_start_thread(void) {
142 // This lock ensures that we only start the thread once
143 LockGuard<Mutex> lock(gThreadMutex);
144 int fastRpcResult = CHRE_FASTRPC_ERROR;
145
146 if (gThreadRunning) {
147 LOGE("CHRE thread already running");
148 } else {
149 #if defined(CHRE_SLPI_SEE) && !defined(IMPORT_CHRE_UTILS)
150 chre::IslandVoteClientSingleton::init("CHRE" /* clientName */);
151 #endif
152
153 // This must complete before we can receive messages that might result in
154 // posting an event
155 chre::init();
156
157 // Human-readable name for the CHRE thread (not const in QuRT API, but they
158 // make a copy)
159 char threadName[] = "CHRE";
160 qurt_thread_attr_t attributes;
161
162 qurt_thread_attr_init(&attributes);
163 qurt_thread_attr_set_name(&attributes, threadName);
164 qurt_thread_attr_set_priority(&attributes, kThreadPriority);
165 qurt_thread_attr_set_stack_addr(&attributes, &gStack);
166 qurt_thread_attr_set_stack_size(&attributes, kStackSize);
167 qurt_thread_attr_set_tcb_partition(&attributes, kTcbPartition);
168
169 gThreadRunning = true;
170 LOGI("Starting CHRE thread");
171 int result = qurt_thread_create(&gThreadHandle, &attributes,
172 chreThreadEntry, nullptr);
173 if (result != QURT_EOK) {
174 LOGE("Couldn't create CHRE thread: %d", result);
175 gThreadRunning = false;
176 } else if (HAP_thread_migrate(gThreadHandle) != 0) {
177 FATAL_ERROR("Couldn't migrate thread");
178 } else {
179 LOGD("Started CHRE thread");
180 fastRpcResult = CHRE_FASTRPC_SUCCESS;
181 }
182 }
183
184 return fastRpcResult;
185 }
186
187 /**
188 * Blocks until the CHRE thread exits. Called over FastRPC to monitor for
189 * abnormal termination of the CHRE thread and/or SLPI as a whole.
190 *
191 * @return Always returns 0, indicating success (per FastRPC requirements)
192 */
chre_slpi_wait_on_thread_exit(void)193 extern "C" int chre_slpi_wait_on_thread_exit(void) {
194 if (!gThreadRunning) {
195 LOGE("Tried monitoring for CHRE thread exit, but thread not running!");
196 } else {
197 int status;
198 int result = qurt_thread_join(gThreadHandle, &status);
199 if (result != QURT_EOK) {
200 LOGE("qurt_thread_join failed with result %d", result);
201 }
202 LOGI("Detected CHRE thread exit");
203 }
204
205 return CHRE_FASTRPC_SUCCESS;
206 }
207
208 /**
209 * If the CHRE thread is running, requests it to perform graceful shutdown,
210 * waits for it to exit, then completes teardown.
211 *
212 * @return Always returns 0, indicating success (per FastRPC requirements)
213 */
chre_slpi_stop_thread(void)214 extern "C" int chre_slpi_stop_thread(void) {
215 // This lock ensures that we will complete shutdown before the thread can be
216 // started again
217 LockGuard<Mutex> lock(gThreadMutex);
218
219 if (!gThreadRunning) {
220 LOGD("Tried to stop CHRE thread, but not running");
221 } else {
222 EventLoopManagerSingleton::get()->getEventLoop().stop();
223 if (gTlsKeyValid) {
224 int ret = qurt_tls_delete_key(gTlsKey);
225 if (ret != QURT_EOK) {
226 // Note: LOGE is not necessarily safe to use after stopping CHRE
227 FARF(ERROR, "Deleting TLS key failed: %d", ret);
228 }
229 gTlsKeyValid = false;
230 }
231
232 // Poll until the thread has stopped; note that we can't use
233 // qurt_thread_join() here because chreMonitorThread() will already be
234 // blocking in it, and attempting to join the same target from two threads
235 // is invalid. Technically, we could use a condition variable, but this is
236 // simpler and we don't care too much about being notified right away.
237 while (gThreadRunning) {
238 timer_sleep(kThreadStatusPollingIntervalUsec, T_USEC,
239 true /* non_deferrable */);
240 }
241 gThreadHandle = 0;
242 }
243
244 return CHRE_FASTRPC_SUCCESS;
245 }
246
247 /**
248 * Creates a thread-local storage (TLS) key in QuRT, which we use to inject a
249 * destructor that is called when the current FastRPC thread terminates. This is
250 * used to get a notification when the original FastRPC thread dies for any
251 * reason, so we can stop the CHRE thread.
252 *
253 * Note that this needs to be invoked from a separate thread on the host process
254 * side. It doesn't work if called from a thread that will be blocking inside a
255 * FastRPC call, such as the monitor thread.
256 *
257 * @return 0 on success, nonzero on failure (per FastRPC requirements)
258 */
chre_slpi_initialize_reverse_monitor(void)259 extern "C" int chre_slpi_initialize_reverse_monitor(void) {
260 LockGuard<Mutex> lock(gThreadMutex);
261
262 if (!gTlsKeyValid) {
263 int result = qurt_tls_create_key(&gTlsKey, onHostProcessTerminated);
264 if (result != QURT_EOK) {
265 LOGE("Couldn't create TLS key: %d", result);
266 } else {
267 // We need to set the value to something for the destructor to be invoked
268 result = qurt_tls_set_specific(gTlsKey, &gTlsKey);
269 if (result != QURT_EOK) {
270 LOGE("Couldn't set TLS data: %d", result);
271 qurt_tls_delete_key(gTlsKey);
272 } else {
273 gTlsKeyValid = true;
274 }
275 }
276 }
277
278 return (gTlsKeyValid) ? CHRE_FASTRPC_SUCCESS : CHRE_FASTRPC_ERROR;
279 }
280