Move SoftIRQ implementations to softirq component

Cargo.lock

@@ -161,6 +161,7 @@ dependencies = [
  "aster-network",
  "aster-rights",
  "aster-rights-proc",
+ "aster-softirq",
  "aster-time",
  "aster-util",
  "aster-virtio",
@@ -218,6 +219,16 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "aster-softirq"
+version = "0.1.0"
+dependencies = [
+ "component",
+ "intrusive-collections",
+ "ostd",
+ "spin 0.9.8",
+]
+
 [[package]]
 name = "aster-time"
 version = "0.1.0"

Cargo.toml

@@ -16,6 +16,7 @@ members = [
     "kernel/comps/framebuffer",
     "kernel/comps/input",
     "kernel/comps/network",
+    "kernel/comps/softirq",
     "kernel/comps/time",
     "kernel/comps/virtio",
     "kernel/libs/cpio-decoder",

Components.toml

@@ -5,6 +5,7 @@ virtio = { name = "aster-virtio" }
 input = { name = "aster-input" }
 block = { name = "aster-block" }
 console = { name = "aster-console" }
+softirq = { name = "aster-softirq" }
 time = { name = "aster-time" }
 framebuffer = { name = "aster-framebuffer" }
 network = { name = "aster-network" }

Makefile

@@ -135,6 +135,7 @@ OSDK_CRATES := \
 	kernel/comps/framebuffer \
 	kernel/comps/input \
 	kernel/comps/network \
+	kernel/comps/softirq \
 	kernel/comps/time \
 	kernel/comps/virtio \
 	kernel/libs/aster-util \

kernel/Cargo.toml

@@ -12,6 +12,7 @@ aster-block = { path = "comps/block" }
 aster-network = { path = "comps/network" }
 aster-console = { path = "comps/console" }
 aster-framebuffer = { path = "comps/framebuffer" }
+aster-softirq = { path = "comps/softirq" }
 aster-time = { path = "comps/time" }
 aster-virtio = { path = "comps/virtio" }
 aster-rights = { path = "libs/aster-rights" }

kernel/comps/softirq/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "aster-softirq"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ostd = { path = "../../../ostd" }
+component = { path = "../../libs/comp-sys/component" }
+intrusive-collections = "0.9.5"
+spin = "0.9.4"
+
+[features]

kernel/comps/softirq/src/lib.rs

@@ -1,13 +1,22 @@
 // SPDX-License-Identifier: MPL-2.0
 
 //! Software interrupt.
+#![no_std]
+#![deny(unsafe_code)]
+
+extern crate alloc;
 
 use alloc::boxed::Box;
 use core::sync::atomic::{AtomicU8, Ordering};
 
+use component::{init_component, ComponentInitError};
+use ostd::{cpu_local_cell, trap::register_bottom_half_handler};
 use spin::Once;
 
-use crate::{cpu_local_cell, task::disable_preempt};
+pub mod softirq_id;
+mod taskless;
+
+pub use taskless::Taskless;
 
 /// A representation of a software interrupt (softirq) line.
 ///
@@ -95,15 +104,15 @@ impl SoftIrqLine {
 /// A slice that stores the [`SoftIrqLine`]s, whose ID is equal to its offset in the slice.
 static LINES: Once<[SoftIrqLine; SoftIrqLine::NR_LINES as usize]> = Once::new();
 
-/// Initializes the softirq lines.
-///
-/// # Safety
-///
-/// This function must be called only once.
-pub unsafe fn init() {
+#[init_component]
+fn init() -> Result<(), ComponentInitError> {
     let lines: [SoftIrqLine; SoftIrqLine::NR_LINES as usize] =
         core::array::from_fn(|i| SoftIrqLine::new(i as u8));
     LINES.call_once(|| lines);
+    register_bottom_half_handler(process_pending);
+
+    taskless::init();
+    Ok(())
 }
 
 static ENABLED_MASK: AtomicU8 = AtomicU8::new(0);
@@ -139,7 +148,6 @@ pub(crate) fn process_pending() {
         return;
     }
 
-    let _preempt_guard = disable_preempt();
     disable_softirq_local();
 
     for _i in 0..SOFTIRQ_RUN_TIMES {

kernel/comps/softirq/src/taskless.rs

@@ -8,13 +8,12 @@ use core::{
 };
 
 use intrusive_collections::{intrusive_adapter, LinkedList, LinkedListAtomicLink};
-use ostd::{
-    cpu::local::CpuLocal,
-    cpu_local,
-    trap::{self, SoftIrqLine},
-};
+use ostd::{cpu::local::CpuLocal, cpu_local, trap};
 
-use crate::softirq_id::{TASKLESS_SOFTIRQ_ID, TASKLESS_URGENT_SOFTIRQ_ID};
+use super::{
+    softirq_id::{TASKLESS_SOFTIRQ_ID, TASKLESS_URGENT_SOFTIRQ_ID},
+    SoftIrqLine,
+};
 
 /// `Taskless` represents a _taskless_ job whose execution is deferred to a later time.
 ///
@@ -211,7 +210,7 @@ mod test {
     fn init() {
         static DONE: AtomicBool = AtomicBool::new(false);
         if !DONE.load(Ordering::SeqCst) {
-            super::init();
+            let _ = super::super::init();
             DONE.store(true, Ordering::SeqCst);
         }
     }

kernel/src/lib.rs

@@ -70,9 +70,7 @@ pub mod net;
 pub mod prelude;
 mod process;
 mod sched;
-pub mod softirq_id;
 pub mod syscall;
-mod taskless;
 pub mod thread;
 pub mod time;
 mod util;
@@ -109,7 +107,6 @@ pub fn init() {
     fs::rootfs::init(boot::initramfs()).unwrap();
     device::init().unwrap();
     vdso::init();
-    taskless::init();
     process::init();
 }
 

kernel/src/time/softirq.rs

@@ -2,9 +2,8 @@
 
 use alloc::{boxed::Box, vec::Vec};
 
-use ostd::{sync::RwLock, timer, trap::SoftIrqLine};
-
-use crate::softirq_id::TIMER_SOFTIRQ_ID;
+use aster_softirq::{softirq_id::TIMER_SOFTIRQ_ID, SoftIrqLine};
+use ostd::{sync::RwLock, timer};
 
 static TIMER_SOFTIRQ_CALLBACKS: RwLock<Vec<Box<dyn Fn() + Sync + Send>>> = RwLock::new(Vec::new());
 

ostd/src/cpu/local/cell.rs

@@ -39,6 +39,7 @@ use crate::arch;
 ///     println!("2nd FOO VAL: {:?}", FOO.load());
 /// }
 /// ```
+#[macro_export]
 macro_rules! cpu_local_cell {
     ($( $(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = $init:expr; )*) => {
         $(
@@ -55,8 +56,6 @@ macro_rules! cpu_local_cell {
     };
 }
 
-pub(crate) use cpu_local_cell;
-
 /// Inner mutable CPU-local objects.
 ///
 /// CPU-local cell objects are only accessible from the current CPU. When
@@ -71,6 +70,10 @@ pub(crate) use cpu_local_cell;
 /// You should only create the CPU-local cell object using the macro
 /// [`cpu_local_cell!`].
 ///
+/// Please exercise extreme caution when using `CpuLocalCell`. In most cases,
+/// it is necessary to disable interrupts or preemption when using it to prevent
+/// the operated object from being changed, which can lead to race conditions.
+///
 /// For the difference between [`super::CpuLocal`] and [`CpuLocalCell`], see
 /// [`super`].
 pub struct CpuLocalCell<T: 'static>(UnsafeCell<T>);

ostd/src/cpu/local/mod.rs

@@ -28,10 +28,6 @@
 // the CPU-local objects can be shared across CPUs. While through a CPU-local
 // cell object you can only access the value on the current CPU, therefore
 // enabling inner mutability without locks.
-//
-// The cell-variant is currently not a public API because that it is rather
-// hard to be used without introducing races. But it is useful for OSTD's
-// internal implementation.
 
 mod cell;
 mod cpu_local;
@@ -41,7 +37,7 @@ pub(crate) mod single_instr;
 use alloc::vec::Vec;
 
 use align_ext::AlignExt;
-pub(crate) use cell::{cpu_local_cell, CpuLocalCell};
+pub use cell::CpuLocalCell;
 pub use cpu_local::{CpuLocal, CpuLocalDerefGuard};
 use spin::Once;
 

ostd/src/cpu/mod.rs

@@ -13,11 +13,11 @@ cfg_if::cfg_if! {
 }
 
 use bitvec::prelude::BitVec;
-use local::cpu_local_cell;
 use spin::Once;
 
 use crate::{
-    arch::boot::smp::get_num_processors, task::DisabledPreemptGuard, trap::DisabledLocalIrqGuard,
+    arch::boot::smp::get_num_processors, cpu_local_cell, task::DisabledPreemptGuard,
+    trap::DisabledLocalIrqGuard,
 };
 
 /// The number of CPUs.

ostd/src/lib.rs

@@ -51,8 +51,6 @@ pub use ostd_macros::main;
 pub use ostd_pod::Pod;
 
 pub use self::{error::Error, prelude::Result};
-// [`CpuLocalCell`] is easy to be misused, so we don't expose it to the users.
-pub(crate) use crate::cpu::local::cpu_local_cell;
 
 /// Initializes OSTD.
 ///
@@ -87,8 +85,6 @@ pub unsafe fn init() {
     mm::kspace::init_kernel_page_table(mm::init_page_meta());
     mm::dma::init();
 
-    // SAFETY: This function is called only once in the entire system.
-    unsafe { trap::softirq::init() };
     arch::init_on_bsp();
 
     smp::init();

ostd/src/trap/handler.rs

@@ -1,6 +1,47 @@
 // SPDX-License-Identifier: MPL-2.0
 
-use crate::{arch::irq::IRQ_LIST, cpu_local_cell, trap::TrapFrame};
+use alloc::boxed::Box;
+
+use spin::Once;
+
+use crate::{arch::irq::IRQ_LIST, cpu_local_cell, task::disable_preempt, trap::TrapFrame};
+
+static BOTTOM_HALF_HANDLER: Once<Box<dyn Fn() + Sync + Send>> = Once::new();
+
+/// Register a function to the interrupt bottom half execution.
+///
+/// The handling of an interrupt can be divided into two parts: top half and bottom half.
+/// Top half typically performs critical tasks and runs at a high priority.
+/// Relatively, bottom half defers less critical tasks to reduce the time spent in
+/// hardware interrupt context, thus allowing the interrupts to be handled more quickly.
+///
+/// The bottom half handler will be called after the top half with interrupts enabled.
+///
+/// This function can only be registered once. Subsequent calls will do nothing.
+pub fn register_bottom_half_handler<F>(func: F)
+where
+    F: Fn() + Sync + Send + 'static,
+{
+    BOTTOM_HALF_HANDLER.call_once(|| Box::new(func));
+}
+
+fn process_top_half(trap_frame: &TrapFrame, irq_number: usize) {
+    let irq_line = IRQ_LIST.get().unwrap().get(irq_number).unwrap();
+    let callback_functions = irq_line.callback_list();
+    for callback_function in callback_functions.iter() {
+        callback_function.call(trap_frame);
+    }
+}
+
+fn process_bottom_half() {
+    // We need to disable preemption when processing bottom half since
+    // the interrupt is enabled in this context.
+    let _preempt_guard = disable_preempt();
+
+    if let Some(handler) = BOTTOM_HALF_HANDLER.get() {
+        handler()
+    }
+}
 
 pub(crate) fn call_irq_callback_functions(trap_frame: &TrapFrame, irq_number: usize) {
     // For x86 CPUs, interrupts are not re-entrant. Local interrupts will be disabled when
@@ -9,17 +50,10 @@ pub(crate) fn call_irq_callback_functions(trap_frame: &TrapFrame, irq_number: us
     // FIXME: For arch that supports re-entrant interrupts, we may need to record nested level here.
     IN_INTERRUPT_CONTEXT.store(true);
 
-    let irq_line = IRQ_LIST.get().unwrap().get(irq_number).unwrap();
-    let callback_functions = irq_line.callback_list();
-    for callback_function in callback_functions.iter() {
-        callback_function.call(trap_frame);
-    }
-    drop(callback_functions);
-
+    process_top_half(trap_frame, irq_number);
     crate::arch::interrupts_ack(irq_number);
-
     crate::arch::irq::enable_local();
-    crate::trap::softirq::process_pending();
+    process_bottom_half();
 
     IN_INTERRUPT_CONTEXT.store(false);
 }

ostd/src/trap/mod.rs

@@ -4,10 +4,8 @@
 
 mod handler;
 mod irq;
-pub mod softirq;
 
-pub use handler::in_interrupt_context;
-pub use softirq::SoftIrqLine;
+pub use handler::{in_interrupt_context, register_bottom_half_handler};
 
 pub(crate) use self::handler::call_irq_callback_functions;
 pub use self::irq::{disable_local, DisabledLocalIrqGuard, IrqCallbackFunction, IrqLine};