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      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 "timer.h"
     23 #include "qurt.h"
     24 
     25 }  // extern "C"
     26 
     27 #include "ash/debug.h"
     28 
     29 #include "chre/core/event_loop.h"
     30 #include "chre/core/event_loop_manager.h"
     31 #include "chre/core/init.h"
     32 #include "chre/core/static_nanoapps.h"
     33 #include "chre/platform/fatal_error.h"
     34 #include "chre/platform/log.h"
     35 #include "chre/platform/memory.h"
     36 #include "chre/platform/mutex.h"
     37 #include "chre/platform/slpi/fastrpc.h"
     38 #include "chre/platform/slpi/preloaded_nanoapps.h"
     39 #include "chre/platform/slpi/uimg_util.h"
     40 #include "chre/util/lock_guard.h"
     41 
     42 #ifdef CHRE_SLPI_SEE
     43 #include "chre/platform/slpi/see/island_vote_client.h"
     44 #endif
     45 
     46 using chre::EventLoop;
     47 using chre::EventLoopManagerSingleton;
     48 using chre::LockGuard;
     49 using chre::Mutex;
     50 using chre::UniquePtr;
     51 
     52 extern "C" int chre_slpi_stop_thread(void);
     53 
     54 // Qualcomm-defined function needed to indicate that the CHRE thread may call
     55 // dlopen() (without it, the thread will deadlock when calling dlopen()). Not in
     56 // any header file in the SLPI tree or Hexagon SDK (3.0), so declaring here.
     57 // Returns 0 to indicate success.
     58 extern "C" int HAP_thread_migrate(qurt_thread_t thread);
     59 
     60 namespace {
     61 
     62 //! Size of the stack for the CHRE thread, in bytes.
     63 constexpr size_t kStackSize = (8 * 1024);
     64 
     65 //! Memory partition where the thread control block (TCB) should be stored,
     66 //! which controls micro-image support.
     67 //! @see qurt_thread_attr_set_tcb_partition
     68 constexpr unsigned char kTcbPartition = chre::isSlpiUimgSupported() ?
     69     QURT_THREAD_ATTR_TCB_PARTITION_TCM : QURT_THREAD_ATTR_TCB_PARTITION_RAM;
     70 
     71 //! The priority to set for the CHRE thread (value between 1-255, with 1 being
     72 //! the highest).
     73 //! @see qurt_thread_attr_set_priority
     74 constexpr unsigned short kThreadPriority = 192;
     75 
     76 //! How long we wait (in microseconds) between checks on whether the CHRE thread
     77 //! has exited after we invoked stop().
     78 constexpr time_timetick_type kThreadStatusPollingIntervalUsec = 5000;  // 5ms
     79 
     80 //! Buffer to use for the CHRE thread's stack.
     81 typename std::aligned_storage<kStackSize>::type gStack;
     82 
     83 //! QuRT OS handle for the CHRE thread.
     84 qurt_thread_t gThreadHandle;
     85 
     86 //! Protects access to thread metadata, like gThreadRunning, during critical
     87 //! sections (starting/stopping the CHRE thread).
     88 Mutex gThreadMutex;
     89 
     90 //! Set to true when the CHRE thread starts, and false when it exits normally.
     91 bool gThreadRunning;
     92 
     93 //! A thread-local storage key, which is currently only used to add a thread
     94 //! destructor callback for the host FastRPC thread.
     95 int gTlsKey;
     96 bool gTlsKeyValid;
     97 
     98 void performDebugDumpCallback(uint16_t /*eventType*/, void *data) {
     99   auto *handle = static_cast<const uint32_t *>(data);
    100   UniquePtr<char> dump = chre::EventLoopManagerSingleton::get()->debugDump();
    101   ashCommitDebugDump(*handle, dump.get(), true /*done*/);
    102 }
    103 
    104 void onDebugDumpRequested(void * /*cookie*/, uint32_t handle) {
    105   static uint32_t debugDumpHandle;
    106 
    107   debugDumpHandle = handle;
    108   chre::EventLoopManagerSingleton::get()->deferCallback(
    109       chre::SystemCallbackType::PerformDebugDump, &debugDumpHandle,
    110       performDebugDumpCallback);
    111 }
    112 
    113 /**
    114  * Entry point for the QuRT thread that runs CHRE.
    115  *
    116  * @param data Argument passed to qurt_thread_create()
    117  */
    118 void chreThreadEntry(void * /*data*/) {
    119   EventLoopManagerSingleton::get()->lateInit();
    120   chre::loadStaticNanoapps();
    121   chre::loadPreloadedNanoapps();
    122   ashRegisterDebugDumpCallback("CHRE", onDebugDumpRequested, nullptr);
    123   EventLoopManagerSingleton::get()->getEventLoop().run();
    124 
    125   ashUnregisterDebugDumpCallback(onDebugDumpRequested);
    126   chre::deinit();
    127 #ifdef CHRE_SLPI_SEE
    128   chre::IslandVoteClientSingleton::deinit();
    129 #endif
    130   gThreadRunning = false;
    131   LOGD("CHRE thread exiting");
    132 }
    133 
    134 void onHostProcessTerminated(void * /*data*/) {
    135   LOGW("Host process died, exiting CHRE (running %d)", gThreadRunning);
    136   chre_slpi_stop_thread();
    137 }
    138 
    139 }  // anonymous namespace
    140 
    141 namespace chre {
    142 
    143 bool inEventLoopThread() {
    144   return (qurt_thread_get_id() == gThreadHandle);
    145 }
    146 
    147 }  // namespace chre
    148 
    149 /**
    150  * Invoked over FastRPC to initialize and start the CHRE thread.
    151  *
    152  * @return 0 on success, nonzero on failure (per FastRPC requirements)
    153  */
    154 extern "C" int chre_slpi_start_thread(void) {
    155   // This lock ensures that we only start the thread once
    156   LockGuard<Mutex> lock(gThreadMutex);
    157   int fastRpcResult = CHRE_FASTRPC_ERROR;
    158 
    159   if (gThreadRunning) {
    160     LOGE("CHRE thread already running");
    161   } else {
    162 #ifdef CHRE_SLPI_SEE
    163     chre::IslandVoteClientSingleton::init("CHRE" /* clientName */);
    164 #endif
    165 
    166     // This must complete before we can receive messages that might result in
    167     // posting an event
    168     chre::init();
    169 
    170     // Human-readable name for the CHRE thread (not const in QuRT API, but they
    171     // make a copy)
    172     char threadName[] = "CHRE";
    173     qurt_thread_attr_t attributes;
    174 
    175     qurt_thread_attr_init(&attributes);
    176     qurt_thread_attr_set_name(&attributes, threadName);
    177     qurt_thread_attr_set_priority(&attributes, kThreadPriority);
    178     qurt_thread_attr_set_stack_addr(&attributes, &gStack);
    179     qurt_thread_attr_set_stack_size(&attributes, kStackSize);
    180     qurt_thread_attr_set_tcb_partition(&attributes, kTcbPartition);
    181 
    182     gThreadRunning = true;
    183     LOGI("Starting CHRE thread");
    184     int result = qurt_thread_create(&gThreadHandle, &attributes,
    185                                     chreThreadEntry, nullptr);
    186     if (result != QURT_EOK) {
    187       LOGE("Couldn't create CHRE thread: %d", result);
    188       gThreadRunning = false;
    189     } else if (HAP_thread_migrate(gThreadHandle) != 0) {
    190       FATAL_ERROR("Couldn't migrate thread");
    191     } else {
    192       LOGD("Started CHRE thread");
    193       fastRpcResult = CHRE_FASTRPC_SUCCESS;
    194     }
    195   }
    196 
    197   return fastRpcResult;
    198 }
    199 
    200 /**
    201  * Blocks until the CHRE thread exits. Called over FastRPC to monitor for
    202  * abnormal termination of the CHRE thread and/or SLPI as a whole.
    203  *
    204  * @return Always returns 0, indicating success (per FastRPC requirements)
    205  */
    206 extern "C" int chre_slpi_wait_on_thread_exit(void) {
    207   if (!gThreadRunning) {
    208     LOGE("Tried monitoring for CHRE thread exit, but thread not running!");
    209   } else {
    210     int status;
    211     int result = qurt_thread_join(gThreadHandle, &status);
    212     if (result != QURT_EOK) {
    213       LOGE("qurt_thread_join failed with result %d", result);
    214     }
    215     LOGI("Detected CHRE thread exit");
    216   }
    217 
    218   return CHRE_FASTRPC_SUCCESS;
    219 }
    220 
    221 /**
    222  * If the CHRE thread is running, requests it to perform graceful shutdown,
    223  * waits for it to exit, then completes teardown.
    224  *
    225  * @return Always returns 0, indicating success (per FastRPC requirements)
    226  */
    227 extern "C" int chre_slpi_stop_thread(void) {
    228   // This lock ensures that we will complete shutdown before the thread can be
    229   // started again
    230   LockGuard<Mutex> lock(gThreadMutex);
    231 
    232   if (!gThreadRunning) {
    233     LOGD("Tried to stop CHRE thread, but not running");
    234   } else {
    235     EventLoopManagerSingleton::get()->getEventLoop().stop();
    236     if (gTlsKeyValid) {
    237       int ret = qurt_tls_delete_key(gTlsKey);
    238       if (ret != QURT_EOK) {
    239         // Note: LOGE is not necessarily safe to use after stopping CHRE
    240         FARF(ERROR, "Deleting TLS key failed: %d", ret);
    241       }
    242       gTlsKeyValid = false;
    243     }
    244 
    245     // Poll until the thread has stopped; note that we can't use
    246     // qurt_thread_join() here because chreMonitorThread() will already be
    247     // blocking in it, and attempting to join the same target from two threads
    248     // is invalid. Technically, we could use a condition variable, but this is
    249     // simpler and we don't care too much about being notified right away.
    250     while (gThreadRunning) {
    251       timer_sleep(kThreadStatusPollingIntervalUsec, T_USEC,
    252                   true /* non_deferrable */);
    253     }
    254     gThreadHandle = 0;
    255 
    256     // Perform this as late as possible - if we are shutting down because we
    257     // detected exit of the host process, FastRPC will unload us once all our
    258     // FastRPC calls have returned. Doing this late helps ensure that the call
    259     // to chre_slpi_get_message_to_host() stays open until we're done with
    260     // cleanup.
    261     chre::HostLinkBase::shutdown();
    262   }
    263 
    264   return CHRE_FASTRPC_SUCCESS;
    265 }
    266 
    267 /**
    268  * Creates a thread-local storage (TLS) key in QuRT, which we use to inject a
    269  * destructor that is called when the current FastRPC thread terminates. This is
    270  * used to get a notification when the original FastRPC thread dies for any
    271  * reason, so we can stop the CHRE thread.
    272  *
    273  * Note that this needs to be invoked from a separate thread on the host process
    274  * side. It doesn't work if called from a thread that will be blocking inside a
    275  * FastRPC call, such as the monitor thread.
    276  *
    277  * @return 0 on success, nonzero on failure (per FastRPC requirements)
    278  */
    279 extern "C" int chre_slpi_initialize_reverse_monitor(void) {
    280   LockGuard<Mutex> lock(gThreadMutex);
    281 
    282   if (!gTlsKeyValid) {
    283     int result = qurt_tls_create_key(&gTlsKey, onHostProcessTerminated);
    284     if (result != QURT_EOK) {
    285       LOGE("Couldn't create TLS key: %d", result);
    286     } else {
    287       // We need to set the value to something for the destructor to be invoked
    288       result = qurt_tls_set_specific(gTlsKey, &gTlsKey);
    289       if (result != QURT_EOK) {
    290         LOGE("Couldn't set TLS data: %d", result);
    291         qurt_tls_delete_key(gTlsKey);
    292       } else {
    293         gTlsKeyValid = true;
    294       }
    295     }
    296   }
    297 
    298   return (gTlsKeyValid) ? CHRE_FASTRPC_SUCCESS : CHRE_FASTRPC_ERROR;
    299 }
    300