pw_thread_freertos/thread: Require INCLUDE_xTaskGetSchedulerState == 1

Updates the FreeRTOS pw_thread backend to require INCLUDE_xTaskGetSchedulerState == 1, as vTaskSuspendAll and vTaskResumeAll are not safe to run before the scheduler has been started. Also corrects a typo in an #error for pw_sync_freertos. Change-Id: Ic7f788c2341ca4ab537fab9b2b324ed4eb2aecd4 Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126214 Pigweed-Auto-Submit: Ewout van Bekkum <[email protected]> Commit-Queue: Auto-Submit <[email protected]> Reviewed-by: Wyatt Hepler <[email protected]>
google · Jan 6, 2023 · 034d827 · 034d827
1 parent eebe54a
commit 034d827
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Showing 3 changed files with 17 additions and 12 deletions.
diff --git a/pw_sync_freertos/interrupt_spin_lock.cc b/pw_sync_freertos/interrupt_spin_lock.cc
@@ -21,7 +21,7 @@
 namespace pw::sync {
 
 #if (INCLUDE_xTaskGetSchedulerState != 1) && (configUSE_TIMERS != 1)
-#error "xTaskGetScheduler is required for pw_sync_freertos:interrupt_spin_lock"
+#error "xTaskGetSchedulerState is required for pw::sync::InterruptSpinLock"
 #endif
 
 void InterruptSpinLock::lock() {

diff --git a/pw_thread_freertos/docs.rst b/pw_thread_freertos/docs.rst
@@ -16,6 +16,10 @@ Optional dynamic allocation for threads is supported using ``xTaskCreate()``.
 Optional joining support is enabled via an ``StaticEventGroup_t`` in each
 thread's context.
 
+.. Note::
+  Scheduler State API support is required in your FreeRTOS Configuration, i.e.
+  ``INCLUDE_xTaskGetSchedulerState == 1``.
+
 This backend always permits users to start threads where static contexts are
 passed in as an option. As a quick example, a detached thread can be created as
 follows:

diff --git a/pw_thread_freertos/thread.cc b/pw_thread_freertos/thread.cc
@@ -26,6 +26,11 @@ using pw::thread::freertos::Context;
 
 namespace pw::thread {
 namespace {
+
+#if (INCLUDE_xTaskGetSchedulerState != 1) && (configUSE_TIMERS != 1)
+#error "xTaskGetSchedulerState is required for pw::thread::Thread"
+#endif
+
 #if PW_THREAD_JOINING_ENABLED
 constexpr EventBits_t kThreadDoneBit = 1 << 0;
 #endif  // PW_THREAD_JOINING_ENABLED
@@ -188,27 +193,23 @@ Thread::Thread(const thread::Options& facade_options,
 void Thread::detach() {
   PW_CHECK(joinable());
 
-#if (INCLUDE_vTaskSuspend == 1) && (INCLUDE_xTaskGetSchedulerState == 1)
-  // No need to suspend extra tasks.
   if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
+#if (INCLUDE_vTaskSuspend == 1)
+    // No need to suspend extra tasks.
     vTaskSuspend(native_type_->task_handle());
-  }
 #else
-  // Safe to suspend all tasks while scheduler is not running.
-  vTaskSuspendAll();
+    vTaskSuspendAll();
 #endif  // INCLUDE_vTaskSuspend == 1
+  }
   native_type_->set_detached();
   const bool thread_done = native_type_->thread_done();
-#if (INCLUDE_vTaskSuspend == 1) && (INCLUDE_xTaskGetSchedulerState == 1)
-  // No need to suspend extra tasks, but only safe to call once scheduler is
-  // running.
   if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
+#if (INCLUDE_vTaskSuspend == 1)
     vTaskResume(native_type_->task_handle());
-  }
 #else
-  // Safe to resume all tasks while scheduler is not running.
-  xTaskResumeAll();
+    xTaskResumeAll();
 #endif  // INCLUDE_vTaskSuspend == 1
+  }
 
   if (thread_done) {
     // The task finished (hit end of Context::ThreadEntryPoint) before we