From be54a39592ff60fae6e729abaa3d4a26dd7f5624 Mon Sep 17 00:00:00 2001
From: Zhang Junyang <junyang@stu.pku.edu.cn>
Date: Mon, 12 Aug 2024 13:04:53 +0000
Subject: [PATCH] Remove the preempt guard from the IRQ guard

---
 ostd/src/task/processor.rs | 10 ++++++++++
 ostd/src/trap/irq.rs       | 13 ++-----------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/ostd/src/task/processor.rs b/ostd/src/task/processor.rs
index 4588b6732..48471908b 100644
--- a/ostd/src/task/processor.rs
+++ b/ostd/src/task/processor.rs
@@ -71,6 +71,11 @@ pub fn preempt(task: &Arc<Task>) {
 ///
 /// If the current task's status not [`TaskStatus::Runnable`], it will not be
 /// added to the scheduler.
+///
+/// # Panics
+///
+/// This function will panic if called while holding preemption locks or with
+/// local IRQ disabled.
 fn switch_to_task(next_task: Arc<Task>) {
     let preemt_lock_count = PREEMPT_LOCK_COUNT.load();
     if preemt_lock_count != 0 {
@@ -80,6 +85,11 @@ fn switch_to_task(next_task: Arc<Task>) {
         );
     }
 
+    assert!(
+        crate::arch::irq::is_local_enabled(),
+        "Switching task with local IRQ disabled"
+    );
+
     let irq_guard = crate::trap::disable_local();
 
     let current_task_ptr = CURRENT_TASK_PTR.load();
diff --git a/ostd/src/trap/irq.rs b/ostd/src/trap/irq.rs
index e6dbe7d1f..2d3935bf0 100644
--- a/ostd/src/trap/irq.rs
+++ b/ostd/src/trap/irq.rs
@@ -9,7 +9,6 @@ use trapframe::TrapFrame;
 use crate::{
     arch::irq::{self, IrqCallbackHandle, IRQ_ALLOCATOR},
     prelude::*,
-    task::{disable_preempt, DisablePreemptGuard},
     Error,
 };
 
@@ -135,7 +134,6 @@ pub fn disable_local() -> DisabledLocalIrqGuard {
 #[must_use]
 pub struct DisabledLocalIrqGuard {
     was_enabled: bool,
-    preempt_guard: DisablePreemptGuard,
 }
 
 impl !Send for DisabledLocalIrqGuard {}
@@ -146,11 +144,7 @@ impl DisabledLocalIrqGuard {
         if was_enabled {
             irq::disable_local();
         }
-        let preempt_guard = disable_preempt();
-        Self {
-            was_enabled,
-            preempt_guard,
-        }
+        Self { was_enabled }
     }
 
     /// Transfers the saved IRQ status of this guard to a new guard.
@@ -158,10 +152,7 @@ impl DisabledLocalIrqGuard {
     pub fn transfer_to(&mut self) -> Self {
         let was_enabled = self.was_enabled;
         self.was_enabled = false;
-        Self {
-            was_enabled,
-            preempt_guard: disable_preempt(),
-        }
+        Self { was_enabled }
     }
 }