feat(kernel): add Port::set_interrupt_line_priority

Author: yvt

src/constance/src/kernel.rs

@@ -296,6 +296,18 @@ pub unsafe trait Port: KernelCfg1 {
     /// [an interrupt context]: crate#contexts
     fn is_interrupt_context() -> bool;
 
+    /// Set the priority of the specified interrupt line.
+    ///
+    /// Precondition: CPU Lock active
+    ///
+    /// Postcondition: CPU Lock active
+    unsafe fn set_interrupt_line_priority(
+        _line: InterruptNum,
+        _priority: InterruptPriority,
+    ) -> Result<(), SetInterruptLinePriorityError> {
+        Err(SetInterruptLinePriorityError::NotSupported)
+    }
+
     /// Enable the specified interrupt line.
     unsafe fn enable_interrupt_line(_line: InterruptNum) -> Result<(), EnableInterruptLineError> {
         Err(EnableInterruptLineError::NotSupported)

src/constance/src/kernel/error.rs

@@ -329,6 +329,8 @@ define_error! {
     /// [`InterruptLine::set_priority`]: super::InterruptLine::set_priority
     /// [`InterruptLine::set_priority_unchecked`]: super::InterruptLine::set_priority_unchecked
     pub enum SetInterruptLinePriorityError: BadContextError, BadParamError {
+        /// The operation is not supported by the port.
+        NotSupported,
         /// CPU Lock is active, or the current context is not [a task context].
         ///
         /// [a task context]: crate#contexts

src/constance/src/kernel/interrupt.rs

@@ -97,11 +97,13 @@ impl<System: Kernel> InterruptLine<System> {
     /// [unmanaged-safe]: crate::kernel::cfg::CfgInterruptHandlerBuilder::unmanaged
     pub unsafe fn set_priority_unchecked(
         self,
-        _value: InterruptPriority,
+        value: InterruptPriority,
     ) -> Result<(), SetInterruptLinePriorityError> {
         let _lock = utils::lock_cpu::<System>()?;
-        // TODO: deny non-task context
-        todo!()
+
+        // Safety: (1) We are the kernel, so it's okay to call `Port`'s methods.
+        //         (2) CPU Lock active
+        unsafe { System::set_interrupt_line_priority(self.0, value) }
     }
 
     /// Enable the interrupt line.