continued work on rtic trampoline

Co-authored-by: Salon <salon64@users.noreply.github.com>

ci/expected/lm3s6965/trampoline.run

@@ -0,0 +1,6 @@
+gpioa lock
+gpioa unlock
+SysTick start
+idle
+SysTick start
+idle end

examples/lm3s6965/examples/trampoline.rs

@@ -0,0 +1,65 @@
+//! examples/bouncy_trampoline.rs
+
+#![no_std]
+#![no_main]
+#![deny(warnings)]
+#![deny(unsafe_code)]
+#![deny(missing_docs)]
+
+use panic_semihosting as _;
+
+// `examples/bouncy_trampoline.rs` testing trampoline feature 
+#[rtic::app(device = lm3s6965)]
+mod app {
+    use cortex_m_semihosting::{debug, hprintln};
+    use lm3s6965::Interrupt;
+
+    #[shared]
+    struct Shared {
+        h_priority: u8,
+    }
+
+    #[local]
+    struct Local {}
+
+    #[init]
+    fn init(_: init::Context) -> (Shared, Local) {
+        // Trigger SW0 interrupt to test NMI preemption
+        rtic::pend(Interrupt::GPIOA);
+        (Shared { h_priority: 0 }, Local {})
+    }
+
+    #[idle]
+    fn idle(_: idle::Context) -> ! {
+        hprintln!("idle");
+
+        // pend another interrupt to test trampoline
+        cortex_m::peripheral::SCB::set_pendst();   
+        hprintln!("idle end");
+        
+        debug::exit(debug::EXIT_SUCCESS);
+        loop {
+            cortex_m::asm::wfi();
+        }
+    }
+
+    #[task(binds = SysTick, trampoline = GPIOC, priority = 2, shared = [h_priority])]
+    fn sys_tick(_: sys_tick::Context) {
+        hprintln!("SysTick start");
+    }
+
+    #[task(binds = GPIOA, priority = 1, shared = [h_priority])]
+    fn gpioa(mut ctx: gpioa::Context) {
+        ctx.shared.h_priority.lock(|_| {
+            hprintln!("gpioa lock");
+            cortex_m::peripheral::SCB::set_pendst();   
+            cortex_m::asm::delay(100_000_000);
+            hprintln!("gpioa unlock");
+        });
+    }
+
+    #[task(binds = GPIOB, priority = 3, shared = [h_priority])]
+    fn high_priority_task(_: high_priority_task::Context) {
+        hprintln!("High priority task");
+    }
+}

rtic-macros/src/codegen/bindings/cortex.rs

@@ -102,7 +102,20 @@ mod source_masking {
             } else {
                 None
             }
-        })) {
+        })
+        // Add trampoline tasks if present and not exceptions
+        .chain(app.hardware_tasks.values().filter_map(|task| {
+            if let Some(trampoline) = &task.args.trampoline {
+                if !is_exception(trampoline) {
+                    Some((&task.args.priority, trampoline))
+                } else {
+                    None
+                }
+            } else {
+                None
+            }
+        }))
+    ) {
             let v: &mut Vec<_> = prio_to_masks.entry(priority - 1).or_default();
             v.push(quote!(#device::Interrupt::#name as u32));
             mask_ids.push(quote!(#device::Interrupt::#name as u32));
@@ -245,7 +258,7 @@ pub fn pre_init_enable_interrupts(app: &App, analysis: &CodegenAnalysis) -> Vec<
         if let Some(trampoline) = &task.args.trampoline {
             if is_exception(trampoline) {
                 // We do exceptions in another pass
-                return None;
+                None
             } else {
                 // If there's a trampoline, we need to unmask and set priority for it too
                 Some((&task.args.priority, trampoline))
@@ -362,6 +375,27 @@ pub fn architecture_specific_analysis(app: &App, _: &SyntaxAnalysis) -> parse::R
         }
     }
 
+    // Check that a exception is not used with shared resources
+    // TODO provide warning when a exception is used with source masking since it then ignores locks in priority ceilings
+    #[cfg(feature = "cortex-m-source-masking")]
+    for (name, task) in &app.hardware_tasks {
+        if is_exception(name) && !app.shared_resources.is_empty(){
+            if let Some(trampoline) = task.args.trampoline.as_ref() {
+                if is_exception(trampoline) {
+                    return Err(parse::Error::new(
+                        trampoline.span(),
+                        "cannot use exceptions as trampoline tasks when using source masking",
+                    ));
+                }
+            } else {
+                return Err(parse::Error::new(
+                    name.span(),
+                    "cannot use exceptions with shared resources as hardware tasks when using source masking, consider adding the trampoline attribute",
+                ));
+            }
+        }
+    }
+
     Ok(())
 }
 

rtic-macros/src/codegen/hardware_tasks.rs

@@ -38,10 +38,8 @@ pub fn codegen(app: &App, analysis: &Analysis) -> TokenStream2 {
                 #(#cfgs)*
                 #(#config)*
                 unsafe fn #symbol() {
-                    info!("Pend trampoline");
                     use #rt_err::Interrupt;
                     rtic::pend(Interrupt::#trampoline_symbol);
-                    info!("Exit trampoline handler");
                 }
 
                 #[allow(non_snake_case)]