8 files changed, 80 insertions, 9 deletions

diff --git a/embassy-executor/Cargo.toml b/embassy-executor/Cargo.toml
index 25c3f0abd..1a611720c 100644
--- a/embassy-executor/Cargo.toml
+++ b/embassy-executor/Cargo.toml
@@ -30,9 +30,13 @@ nightly = []
 
 integrated-timers = ["dep:embassy-time"]
 
+# Trace interrupt invocations with rtos-trace.
+rtos-trace-interrupt = ["rtos-trace"]
+
 [dependencies]
 defmt = { version = "0.3", optional = true }
 log = { version = "0.4.14", optional = true }
+rtos-trace = { version = "0.1.2", optional = true }
 
 futures-util = { version = "0.3.17", default-features = false }
 embassy-macros  = { version = "0.1.0", path = "../embassy-macros"}
@@ -40,7 +44,8 @@ embassy-time  = { version = "0.1.0", path = "../embassy-time", optional = true}
 atomic-polyfill = "1.0.1"
 critical-section = "1.1"
 cfg-if = "1.0.0"
+static_cell = "1.0"
 
 # WASM dependencies
-wasm-bindgen = { version = "0.2.76", features = ["nightly"], optional = true }
-js-sys = { version = "0.3", optional = true }
\ No newline at end of file
+wasm-bindgen = { version = "0.2.82", optional = true }
+js-sys = { version = "0.3", optional = true }
diff --git a/embassy-executor/src/arch/cortex_m.rs b/embassy-executor/src/arch/cortex_m.rs
index d6e758dfb..4b27a264e 100644
--- a/embassy-executor/src/arch/cortex_m.rs
+++ b/embassy-executor/src/arch/cortex_m.rs
@@ -41,7 +41,7 @@ impl Executor {
     /// Executor instance in a place where it'll live forever and grants you mutable
     /// access. There's a few ways to do this:
     ///
-    /// - a [Forever](crate::util::Forever) (safe)
+    /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
     /// - a `static mut` (unsafe)
     /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
     ///
diff --git a/embassy-executor/src/arch/riscv32.rs b/embassy-executor/src/arch/riscv32.rs
index 7a7d5698c..2a4b006da 100644
--- a/embassy-executor/src/arch/riscv32.rs
+++ b/embassy-executor/src/arch/riscv32.rs
@@ -43,7 +43,7 @@ impl Executor {
     /// Executor instance in a place where it'll live forever and grants you mutable
     /// access. There's a few ways to do this:
     ///
-    /// - a [Forever](crate::util::Forever) (safe)
+    /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
     /// - a `static mut` (unsafe)
     /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
     ///
diff --git a/embassy-executor/src/arch/std.rs b/embassy-executor/src/arch/std.rs
index b93ab8a79..701f0eb18 100644
--- a/embassy-executor/src/arch/std.rs
+++ b/embassy-executor/src/arch/std.rs
@@ -40,7 +40,7 @@ impl Executor {
     /// Executor instance in a place where it'll live forever and grants you mutable
     /// access. There's a few ways to do this:
     ///
-    /// - a [Forever](crate::util::Forever) (safe)
+    /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
     /// - a `static mut` (unsafe)
     /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
     ///
diff --git a/embassy-executor/src/arch/wasm.rs b/embassy-executor/src/arch/wasm.rs
index 9d5aa31ed..98091cfbb 100644
--- a/embassy-executor/src/arch/wasm.rs
+++ b/embassy-executor/src/arch/wasm.rs
@@ -59,7 +59,7 @@ impl Executor {
     /// Executor instance in a place where it'll live forever and grants you mutable
     /// access. There's a few ways to do this:
     ///
-    /// - a [Forever](crate::util::Forever) (safe)
+    /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
     /// - a `static mut` (unsafe)
     /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
     pub fn start(&'static mut self, init: impl FnOnce(Spawner)) {
diff --git a/embassy-executor/src/arch/xtensa.rs b/embassy-executor/src/arch/xtensa.rs
index 20bd7b8a5..f908aaa70 100644
--- a/embassy-executor/src/arch/xtensa.rs
+++ b/embassy-executor/src/arch/xtensa.rs
@@ -43,7 +43,7 @@ impl Executor {
     /// Executor instance in a place where it'll live forever and grants you mutable
     /// access. There's a few ways to do this:
     ///
-    /// - a [Forever](crate::util::Forever) (safe)
+    /// - a [StaticCell](https://docs.rs/static_cell/latest/static_cell/) (safe)
     /// - a `static mut` (unsafe)
     /// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
     ///
diff --git a/embassy-executor/src/lib.rs b/embassy-executor/src/lib.rs
index 9328a7378..e4cbd04b9 100644
--- a/embassy-executor/src/lib.rs
+++ b/embassy-executor/src/lib.rs
@@ -38,7 +38,38 @@ cfg_if::cfg_if! {
     }
 }
 
+#[doc(hidden)]
+/// Implementation details for embassy macros. DO NOT USE.
+pub mod export {
+    #[cfg(feature = "rtos-trace")]
+    pub use rtos_trace::trace;
+
+    /// Expands the given block of code when `embassy-executor` is compiled with
+    /// the `rtos-trace-interrupt` feature.
+    #[doc(hidden)]
+    #[macro_export]
+    #[cfg(feature = "rtos-trace-interrupt")]
+    macro_rules! rtos_trace_interrupt {
+        ($($tt:tt)*) => { $($tt)* };
+    }
+
+    /// Does not expand the given block of code when `embassy-executor` is
+    /// compiled without the `rtos-trace-interrupt` feature.
+    #[doc(hidden)]
+    #[macro_export]
+    #[cfg(not(feature = "rtos-trace-interrupt"))]
+    macro_rules! rtos_trace_interrupt {
+        ($($tt:tt)*) => {};
+    }
+}
+
 pub mod raw;
 
 mod spawner;
 pub use spawner::*;
+
+/// Do not use. Used for macros and HALs only. Not covered by semver guarantees.
+#[doc(hidden)]
+pub mod _export {
+    pub use static_cell::StaticCell;
+}
diff --git a/embassy-executor/src/raw/mod.rs b/embassy-executor/src/raw/mod.rs
index afe67decb..e1258ebb5 100644
--- a/embassy-executor/src/raw/mod.rs
+++ b/embassy-executor/src/raw/mod.rs
@@ -5,7 +5,7 @@
 //! ## WARNING: here be dragons!
 //!
 //! Using this module requires respecting subtle safety contracts. If you can, prefer using the safe
-//! executor wrappers in [`executor`](crate::executor) and the [`embassy_executor::task`](embassy_macros::task) macro, which are fully safe.
+//! [executor wrappers](crate::Executor) and the [`embassy_executor::task`](embassy_macros::task) macro, which are fully safe.
 
 mod run_queue;
 #[cfg(feature = "integrated-timers")]
@@ -26,6 +26,8 @@ use critical_section::CriticalSection;
 use embassy_time::driver::{self, AlarmHandle};
 #[cfg(feature = "integrated-timers")]
 use embassy_time::Instant;
+#[cfg(feature = "rtos-trace")]
+use rtos_trace::trace;
 
 use self::run_queue::{RunQueue, RunQueueItem};
 use self::util::UninitCell;
@@ -247,7 +249,7 @@ impl<F: Future + 'static, const N: usize> TaskPool<F, N> {
 ///
 /// This is the core of the Embassy executor. It is low-level, requiring manual
 /// handling of wakeups and task polling. If you can, prefer using one of the
-/// higher level executors in [`crate::executor`].
+/// [higher level executors](crate::Executor).
 ///
 /// The raw executor leaves it up to you to handle wakeups and scheduling:
 ///
@@ -306,6 +308,9 @@ impl Executor {
     /// - `task` must NOT be already enqueued (in this executor or another one).
     #[inline(always)]
     unsafe fn enqueue(&self, cs: CriticalSection, task: NonNull<TaskHeader>) {
+        #[cfg(feature = "rtos-trace")]
+        trace::task_ready_begin(task.as_ptr() as u32);
+
         if self.run_queue.enqueue(cs, task) {
             (self.signal_fn)(self.signal_ctx)
         }
@@ -323,6 +328,9 @@ impl Executor {
     pub(super) unsafe fn spawn(&'static self, task: NonNull<TaskHeader>) {
         task.as_ref().executor.set(self);
 
+        #[cfg(feature = "rtos-trace")]
+        trace::task_new(task.as_ptr() as u32);
+
         critical_section::with(|cs| {
             self.enqueue(cs, task);
         })
@@ -365,9 +373,15 @@ impl Executor {
                 return;
             }
 
+            #[cfg(feature = "rtos-trace")]
+            trace::task_exec_begin(p.as_ptr() as u32);
+
             // Run the task
             task.poll_fn.read()(p as _);
 
+            #[cfg(feature = "rtos-trace")]
+            trace::task_exec_end();
+
             // Enqueue or update into timer_queue
             #[cfg(feature = "integrated-timers")]
             self.timer_queue.update(p);
@@ -381,6 +395,9 @@ impl Executor {
             let next_expiration = self.timer_queue.next_expiration();
             driver::set_alarm(self.alarm, next_expiration.as_ticks());
         }
+
+        #[cfg(feature = "rtos-trace")]
+        trace::system_idle();
     }
 
     /// Get a spawner that spawns tasks in this executor.
@@ -426,3 +443,21 @@ unsafe fn _embassy_time_schedule_wake(at: Instant, waker: &core::task::Waker) {
     let expires_at = task.expires_at.get();
     task.expires_at.set(expires_at.min(at));
 }
+
+#[cfg(feature = "rtos-trace")]
+impl rtos_trace::RtosTraceOSCallbacks for Executor {
+    fn task_list() {
+        // We don't know what tasks exist, so we can't send them.
+    }
+    #[cfg(feature = "integrated-timers")]
+    fn time() -> u64 {
+        Instant::now().as_micros()
+    }
+    #[cfg(not(feature = "integrated-timers"))]
+    fn time() -> u64 {
+        0
+    }
+}
+
+#[cfg(feature = "rtos-trace")]
+rtos_trace::global_os_callbacks! {Executor}