feat: kernel/plat/irq: wire up dispatch

kernel/Cargo.toml

@@ -39,4 +39,4 @@ uart_16550 = "0.3"
 
 [target.'cfg(target_arch = "riscv64")'.dependencies]
 riscv = { version = "0.11", features = ["s-mode"] }
-sbi-rt = { version = "0.0" }
+sbi-rt = { version = "0.0.3" }

kernel/src/arch/riscv/backtrace.rs

@@ -2,19 +2,28 @@ use super::layout::{BSS_END, BSS_START, TEXT_END, TEXT_START};
 use crate::plat::backtrace::FrameWalker;
 use utils::addr::{AddressOps, VirtAddr};
 
-impl FrameWalker {
-    fn read_fp() -> usize {
+#[inline]
+pub fn read_fp() -> usize {
     let fp;
     unsafe { core::arch::asm!("mv {}, fp", out(reg) fp) }
     fp
 }
 
-    fn read_ra() -> usize {
+#[inline]
+pub fn read_sp() -> usize {
+    let sp;
+    unsafe { core::arch::asm!("mv {}, sp", out(reg) sp) }
+    sp
+}
+
+#[inline]
+pub fn read_ra() -> usize {
     let ra;
     unsafe { core::arch::asm!("mv {}, ra", out(reg) ra) }
     ra
 }
 
+impl FrameWalker {
     fn is_valid(&self) -> bool {
         let fp_valid = unsafe { BSS_START.as_virt_addr() <= self.current_fp && self.current_fp < BSS_END.as_virt_addr() };
         let pc_valid = unsafe { TEXT_START.as_virt_addr() <= self.current_pc && self.current_pc < TEXT_END.as_virt_addr() };
@@ -28,8 +37,8 @@ impl FrameWalker {
     pub fn new() -> Self {
         // current_{fp, pc} is deliberately missed for printing
         Self {
-            current_fp: VirtAddr::from(FrameWalker::read_fp()),
-            current_pc: VirtAddr::from(FrameWalker::read_ra()),
+            current_fp: VirtAddr::from(read_fp()),
+            current_pc: VirtAddr::from(read_ra()),
         }
     }
 }

kernel/src/arch/riscv/trap.rs

@@ -1,6 +1,8 @@
+use crate::arch::riscv::backtrace::read_sp;
 use crate::entry::HART_ID;
 use crate::objects::*;
 use crate::plat::console::CONSOLE;
+use crate::plat::irq::IRQ_MANAGER;
 use crate::plat::timer::{Timer, TimerOps};
 use crate::plat::trap::{Trap, TrapContextOps, TrapOps};
 use core::ops::{Index, IndexMut};
@@ -18,8 +20,7 @@ extern "C" {
 
 #[no_mangle]
 extern "C" fn kernel_trap_handler(tf: &mut TrapContext) {
-    // No trap in kernel, except from IDLE thread
-    // TODO: Replace CONSOLE Mutex to ReentrantLock
+    // No trap in kernel
     unsafe { CONSOLE.force_unlock() }
     tf.handle_trap(true);
 }
@@ -56,12 +57,19 @@ impl TrapContextOps for TrapContext {
 
     fn configure_idle_thread(&mut self) {
         self.sepc = idle_thread as usize;
-        self.sstatus = (1 << 5) | (1 << 8); // SPIE + SPP
+        self.sstatus = (1 << 5) // SPIE: enable interrupt in idle thread
+                     | (1 << 8) // SPP:  run in kernel mode in idle thread
+                     ;
     }
 
     fn handle_trap(&mut self, from_kernel: bool) {
         let scause = riscv::register::scause::read();
-        trace!("[Trap] cpu@{} scause: {:?}", HART_ID.get(), scause.cause());
+        trace!(
+            "[Trap] cpu@{} scause: {:?} sp: {:#x}",
+            HART_ID.get(),
+            scause.cause(),
+            read_sp()
+        );
 
         macro_rules! panic_fatal {
             ($msg:expr) => {
@@ -76,6 +84,10 @@ impl TrapContextOps for TrapContext {
             };
         }
 
+        if from_kernel {
+            panic_fatal!("Buggy kernel: trap in kernel mode");
+        }
+
         let tcb = self.as_object_mut();
 
         match scause.cause() {
@@ -85,14 +97,17 @@ impl TrapContextOps for TrapContext {
                     tcb.do_tick();
                 }
             },
+            T::Interrupt(I::SupervisorExternal) => {
+                IRQ_MANAGER.lock().dispatch();
+            },
+            T::Interrupt(I::SupervisorSoft) => {
+                // This should never happen
+                panic_fatal!("Buggy kernel: supervisor software interrupt triggered");
+            },
             T::Exception(E::UserEnvCall) => {
                 tcb.handle_syscall();
                 self.sepc += 4;
             },
-            T::Interrupt(I::SupervisorExternal) => {
-                // TODO: handle external interrupt, e.g. plic
-                panic_fatal!("Unhandled External Interrupt");
-            },
             T::Exception(E::InstructionPageFault) | T::Exception(E::LoadPageFault) | T::Exception(E::StorePageFault) => {
                 if from_kernel {
                     panic_fatal!("Page Fault in Kernel");

kernel/src/plat/irq.rs

@@ -52,7 +52,7 @@ pub struct IrqManager {
     state:   [IrqState; IRQ_NUM],
 }
 
-pub static IRQ_MANAGER: Mutex<Lazy<IrqManager>> = Mutex::new(Lazy::new(IrqManager::new));
+pub static IRQ_MANAGER: Lazy<Mutex<IrqManager>> = Lazy::new(|| Mutex::new(IrqManager::new()));
 
 impl IrqManager {
     pub fn new() -> Self {
@@ -61,4 +61,8 @@ impl IrqManager {
             state:   [IrqState::Inactive; IRQ_NUM],
         }
     }
+
+    pub fn dispatch(&mut self) {
+        todo!("forward to endpoint cap");
+    }
 }