Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 1 | // Copyright 2020 The Pigweed Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| 4 | // use this file except in compliance with the License. You may obtain a copy of |
| 5 | // the License at |
| 6 | // |
| 7 | // https://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| 11 | // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| 12 | // License for the specific language governing permissions and limitations under |
| 13 | // the License. |
| 14 | #include "pw_thread/thread.h" |
| 15 | |
| 16 | #include "FreeRTOS.h" |
| 17 | #include "pw_assert/assert.h" |
| 18 | #include "pw_preprocessor/compiler.h" |
| 19 | #include "pw_thread/id.h" |
| 20 | #include "pw_thread_freertos/config.h" |
| 21 | #include "pw_thread_freertos/context.h" |
| 22 | #include "pw_thread_freertos/options.h" |
| 23 | #include "task.h" |
| 24 | |
| 25 | using pw::thread::freertos::Context; |
| 26 | |
| 27 | namespace pw::thread { |
| 28 | namespace { |
| 29 | #if PW_THREAD_JOINING_ENABLED |
| 30 | constexpr EventBits_t kThreadDoneBit = 1 << 0; |
| 31 | #endif // PW_THREAD_JOINING_ENABLED |
| 32 | } // namespace |
| 33 | |
| 34 | void Context::RunThread(void* void_context_ptr) { |
| 35 | Context& context = *static_cast<Context*>(void_context_ptr); |
| 36 | context.entry_(context.arg_); |
| 37 | |
| 38 | // Use a task only critical section to guard against join() and detach(). |
| 39 | vTaskSuspendAll(); |
| 40 | if (context.detached()) { |
| 41 | // There is no threadsafe way to re-use detached threads, as there's no way |
| 42 | // to signal the vTaskDelete success. Joining MUST be used for this. |
| 43 | // However to enable unit test coverage we go ahead and clear this. |
| 44 | context.set_task_handle(nullptr); |
| 45 | |
| 46 | #if PW_THREAD_JOINING_ENABLED |
| 47 | // Just in case someone abused our API, ensure their use of the event group |
| 48 | // is properly handled by the kernel regardless. |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 49 | vEventGroupDelete(&context.join_event_group()); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 50 | #endif // PW_THREAD_JOINING_ENABLED |
| 51 | |
| 52 | #if PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 53 | // The thread was detached before the task finished, free any allocations |
| 54 | // it ran on. |
| 55 | if (context.dynamically_allocated()) { |
| 56 | delete &context; |
| 57 | } |
| 58 | #endif // PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 59 | |
| 60 | // Re-enable the scheduler before we delete this execution. |
| 61 | xTaskResumeAll(); |
| 62 | vTaskDelete(nullptr); |
| 63 | PW_UNREACHABLE; |
| 64 | } |
| 65 | |
| 66 | // Otherwise the task finished before the thread was detached or joined, defer |
| 67 | // cleanup to Thread's join() or detach(). |
| 68 | context.set_thread_done(); |
| 69 | xTaskResumeAll(); |
| 70 | |
| 71 | #if PW_THREAD_JOINING_ENABLED |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 72 | xEventGroupSetBits(&context.join_event_group(), kThreadDoneBit); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 73 | #endif // PW_THREAD_JOINING_ENABLED |
| 74 | |
| 75 | while (true) { |
| 76 | #if INCLUDE_vTaskSuspend == 1 |
| 77 | // Use indefinite suspension when available. |
| 78 | vTaskSuspend(nullptr); |
| 79 | #else |
| 80 | vTaskDelay(portMAX_DELAY); |
| 81 | #endif // INCLUDE_vTaskSuspend == 1 |
| 82 | } |
| 83 | PW_UNREACHABLE; |
| 84 | } |
| 85 | |
| 86 | void Context::TerminateThread(Context& context) { |
| 87 | // Stop the other task first. |
| 88 | PW_DCHECK_NOTNULL(context.task_handle(), "We shall not delete ourselves!"); |
| 89 | vTaskDelete(context.task_handle()); |
| 90 | |
| 91 | // Mark the context as unused for potential later re-use. |
| 92 | context.set_task_handle(nullptr); |
| 93 | |
| 94 | #if PW_THREAD_JOINING_ENABLED |
| 95 | // Just in case someone abused our API, ensure their use of the event group is |
| 96 | // properly handled by the kernel regardless. |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 97 | vEventGroupDelete(&context.join_event_group()); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 98 | #endif // PW_THREAD_JOINING_ENABLED |
| 99 | |
| 100 | #if PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 101 | // Then free any allocations it ran on. |
| 102 | if (context.dynamically_allocated()) { |
| 103 | delete &context; |
| 104 | } |
| 105 | #endif // PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 106 | } |
| 107 | |
| 108 | Thread::Thread(const thread::Options& facade_options, |
| 109 | ThreadRoutine entry, |
| 110 | void* arg) |
| 111 | : native_type_(nullptr) { |
| 112 | // Cast the generic facade options to the backend specific option of which |
| 113 | // only one type can exist at compile time. |
| 114 | auto options = static_cast<const freertos::Options&>(facade_options); |
| 115 | if (options.static_context() != nullptr) { |
| 116 | // Use the statically allocated context. |
| 117 | native_type_ = options.static_context(); |
| 118 | // Can't use a context more than once. |
| 119 | PW_DCHECK_PTR_EQ(native_type_->task_handle(), nullptr); |
| 120 | // Reset the state of the static context in case it was re-used. |
| 121 | native_type_->set_detached(false); |
| 122 | native_type_->set_thread_done(false); |
| 123 | #if PW_THREAD_JOINING_ENABLED |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 124 | const EventGroupHandle_t event_group_handle = |
| 125 | xEventGroupCreateStatic(&native_type_->join_event_group()); |
| 126 | PW_DCHECK_PTR_EQ(event_group_handle, |
| 127 | &native_type_->join_event_group(), |
| 128 | "Failed to create the joining event group"); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 129 | #endif // PW_THREAD_JOINING_ENABLED |
| 130 | |
| 131 | // In order to support functions which return and joining, a delegate is |
| 132 | // deep copied into the context with a small wrapping function to actually |
| 133 | // invoke the task with its arg. |
| 134 | native_type_->set_thread_routine(entry, arg); |
| 135 | const TaskHandle_t task_handle = |
| 136 | xTaskCreateStatic(Context::RunThread, |
| 137 | options.name(), |
| 138 | options.static_context()->stack().size(), |
| 139 | native_type_, |
| 140 | options.priority(), |
| 141 | options.static_context()->stack().data(), |
| 142 | &options.static_context()->tcb()); |
| 143 | PW_CHECK_NOTNULL(task_handle); // Ensure it succeeded. |
| 144 | native_type_->set_task_handle(task_handle); |
| 145 | } else { |
| 146 | #if !PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 147 | PW_CRASH( |
| 148 | "dynamic thread allocations are not enabled and no static_context " |
| 149 | "was provided"); |
| 150 | #else // PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 151 | // Dynamically allocate the context and the task. |
| 152 | native_type_ = new pw::thread::freertos::Context(); |
| 153 | native_type_->set_dynamically_allocated(); |
| 154 | #if PW_THREAD_JOINING_ENABLED |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 155 | const EventGroupHandle_t event_group_handle = |
| 156 | xEventGroupCreateStatic(&native_type_->join_event_group()); |
| 157 | PW_DCHECK_PTR_EQ(event_group_handle, |
| 158 | &native_type_->join_event_group(), |
| 159 | "Failed to create the joining event group"); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 160 | #endif // PW_THREAD_JOINING_ENABLED |
| 161 | |
| 162 | // In order to support functions which return and joining, a delegate is |
| 163 | // deep copied into the context with a small wrapping function to actually |
| 164 | // invoke the task with its arg. |
| 165 | native_type_->set_thread_routine(entry, arg); |
| 166 | TaskHandle_t task_handle; |
| 167 | const BaseType_t result = xTaskCreate(Context::RunThread, |
| 168 | options.name(), |
| 169 | options.stack_size_words(), |
| 170 | native_type_, |
| 171 | options.priority(), |
| 172 | &task_handle); |
| 173 | |
| 174 | // Ensure it succeeded. |
| 175 | PW_CHECK_UINT_EQ(result, pdPASS); |
| 176 | native_type_->set_task_handle(task_handle); |
| 177 | #endif // !PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | void Thread::detach() { |
Ewout van Bekkum | 47941cc | 2021-04-12 15:39:19 -0700 | [diff] [blame] | 182 | PW_CHECK(joinable()); |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 183 | |
| 184 | #if INCLUDE_vTaskSuspend == 1 |
| 185 | // No need to suspend extra tasks. |
| 186 | vTaskSuspend(native_type_->task_handle()); |
| 187 | #else |
| 188 | vTaskSuspendAll(); |
| 189 | #endif // INCLUDE_vTaskSuspend == 1 |
| 190 | native_type_->set_detached(); |
| 191 | const bool thread_done = native_type_->thread_done(); |
| 192 | #if INCLUDE_vTaskSuspend == 1 |
| 193 | // No need to suspend extra tasks. |
| 194 | vTaskResume(native_type_->task_handle()); |
| 195 | #else |
| 196 | vTaskResumeAll(); |
| 197 | #endif // INCLUDE_vTaskSuspend == 1 |
| 198 | |
| 199 | if (thread_done) { |
| 200 | // The task finished (hit end of Context::RunThread) before we invoked |
| 201 | // detach, clean up the thread. |
| 202 | Context::TerminateThread(*native_type_); |
| 203 | } else { |
| 204 | // We're detaching before the task finished, defer cleanup to the task at |
| 205 | // the end of Context::RunThread. |
| 206 | } |
| 207 | |
| 208 | // Update to no longer represent a thread of execution. |
| 209 | native_type_ = nullptr; |
| 210 | } |
| 211 | |
| 212 | #if PW_THREAD_JOINING_ENABLED |
| 213 | void Thread::join() { |
| 214 | PW_CHECK(joinable()); |
| 215 | PW_CHECK(this_thread::get_id() != get_id()); |
| 216 | |
| 217 | // Wait indefinitely until kThreadDoneBit is set. |
Ewout van Bekkum | a69bcd0 | 2021-03-10 08:47:27 -0800 | [diff] [blame] | 218 | while (xEventGroupWaitBits(&native_type_->join_event_group(), |
Ewout van Bekkum | ae6c03a | 2021-01-19 14:53:19 -0800 | [diff] [blame] | 219 | kThreadDoneBit, |
| 220 | pdTRUE, // Clear the bits. |
| 221 | pdFALSE, // Any bits is fine, N/A. |
| 222 | portMAX_DELAY) != kThreadDoneBit) { |
| 223 | } |
| 224 | |
| 225 | // No need for a critical section here as the thread at this point is |
| 226 | // waiting to be terminated. |
| 227 | Context::TerminateThread(*native_type_); |
| 228 | |
| 229 | // Update to no longer represent a thread of execution. |
| 230 | native_type_ = nullptr; |
| 231 | } |
| 232 | #endif // PW_THREAD_JOINING_ENABLED |
| 233 | |
| 234 | } // namespace pw::thread |