From 7809ed32f0f5c415b2840e6c3aab9d8f348c9b98 Mon Sep 17 00:00:00 2001
From: longjin <longjin@RinGoTek.cn>
Date: Sun, 13 Aug 2023 08:21:54 +0000
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0per=20cpu=E5=8F=98=E9=87=8F?=
 =?UTF-8?q?=E6=94=AF=E6=8C=81?=
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---
 kernel/src/arch/x86_64/cpu.rs    |  7 +--
 kernel/src/filesystem/vfs/mod.rs |  2 +-
 kernel/src/mm/mod.rs             |  1 +
 kernel/src/mm/percpu.rs          | 90 ++++++++++++++++++++++++++++++++
 kernel/src/mm/syscall.rs         |  2 +-
 5 files changed, 97 insertions(+), 5 deletions(-)
 create mode 100644 kernel/src/mm/percpu.rs

diff --git a/kernel/src/arch/x86_64/cpu.rs b/kernel/src/arch/x86_64/cpu.rs
index 1e15bc06c..ac1be208d 100644
--- a/kernel/src/arch/x86_64/cpu.rs
+++ b/kernel/src/arch/x86_64/cpu.rs
@@ -1,12 +1,13 @@
 use core::arch::asm;
 
-use super::asm::current::current_pcb;
+use x86::cpuid::{cpuid, CpuIdResult};
 
 /// @brief 获取当前cpu的apic id
 #[inline]
 pub fn current_cpu_id() -> u32 {
-    // TODO: apic重构后，使用apic id来设置这里
-    current_pcb().cpu_id as u32
+    let cpuid_res: CpuIdResult = cpuid!(0x1);
+    let cpu_id = (cpuid_res.ebx >> 24) & 0xff;
+    return cpu_id;
 }
 
 /// @brief 通过pause指令，让cpu休息一会儿。降低空转功耗
diff --git a/kernel/src/filesystem/vfs/mod.rs b/kernel/src/filesystem/vfs/mod.rs
index 0e4a1c1e0..d037e068f 100644
--- a/kernel/src/filesystem/vfs/mod.rs
+++ b/kernel/src/filesystem/vfs/mod.rs
@@ -162,7 +162,7 @@ pub trait IndexNode: Any + Sync + Send + Debug {
     }
 
     /// @brief 重新设置文件的大小
-    /// 
+    ///
     /// 如果文件大小增加，则文件内容不变，但是文件的空洞部分会被填充为0
     /// 如果文件大小减小，则文件内容会被截断
     ///
diff --git a/kernel/src/mm/mod.rs b/kernel/src/mm/mod.rs
index 8364e3c9f..6d1facddc 100644
--- a/kernel/src/mm/mod.rs
+++ b/kernel/src/mm/mod.rs
@@ -28,6 +28,7 @@ pub mod kernel_mapper;
 pub mod mmio_buddy;
 pub mod no_init;
 pub mod page;
+pub mod percpu;
 pub mod syscall;
 pub mod ucontext;
 
diff --git a/kernel/src/mm/percpu.rs b/kernel/src/mm/percpu.rs
new file mode 100644
index 000000000..b2c2b2ee0
--- /dev/null
+++ b/kernel/src/mm/percpu.rs
@@ -0,0 +1,90 @@
+use core::sync::atomic::AtomicUsize;
+
+use alloc::vec::Vec;
+
+use crate::{
+    include::bindings::bindings::smp_get_total_cpu, libs::lazy_init::Lazy,
+    smp::core::smp_get_processor_id,
+};
+
+/// 系统中的CPU数量
+///
+/// todo: 待smp模块重构后，从smp模块获取CPU数量。
+/// 目前由于smp模块初始化时机较晚，导致大部分内核模块无法在早期初始化PerCpu变量。
+const CPU_NUM: AtomicUsize = AtomicUsize::new(PerCpu::MAX_CPU_NUM);
+
+#[derive(Debug)]
+pub struct PerCpu;
+
+impl PerCpu {
+    pub const MAX_CPU_NUM: usize = 128;
+    /// # 初始化PerCpu
+    ///
+    /// 该函数应该在内核初始化时调用一次。
+    ///
+    /// 该函数会调用`smp_get_total_cpu()`获取CPU数量，然后将其存储在`CPU_NUM`中。
+    #[allow(dead_code)]
+    pub fn init() {
+        if CPU_NUM.load(core::sync::atomic::Ordering::SeqCst) != 0 {
+            panic!("PerCpu::init() called twice");
+        }
+        let cpus = unsafe { smp_get_total_cpu() } as usize;
+        assert!(cpus > 0, "PerCpu::init(): smp_get_total_cpu() returned 0");
+        CPU_NUM.store(cpus, core::sync::atomic::Ordering::SeqCst);
+    }
+}
+
+/// PerCpu变量
+///
+/// 该结构体的每个实例都是线程安全的，因为每个CPU都有自己的变量。
+///
+/// 一种简单的使用方法是：使用该结构体提供的`define_lazy`方法定义一个全局变量，
+/// 然后在内核初始化时调用`init`、`new`方法去初始化它。
+///
+/// 当然，由于Lazy<T>有运行时开销，所以也可以直接全局声明一个Option，
+/// 然后手动初始化然后赋值到Option中。（这样需要在初始化的时候，手动确保并发安全）
+#[derive(Debug)]
+#[allow(dead_code)]
+pub struct PerCpuVar<T> {
+    inner: Vec<T>,
+}
+
+#[allow(dead_code)]
+impl<T> PerCpuVar<T> {
+    /// # 初始化PerCpu变量
+    ///
+    /// ## 参数
+    ///
+    /// - `data` - 每个CPU的数据的初始值。 传入的Vec的长度必须等于CPU的数量，否则返回None。
+    pub fn new(data: Vec<T>) -> Option<Self> {
+        let cpu_num = CPU_NUM.load(core::sync::atomic::Ordering::SeqCst);
+        if cpu_num == 0 {
+            panic!("PerCpu::init() not called");
+        }
+
+        if data.len() != cpu_num {
+            return None;
+        }
+
+        return Some(Self { inner: data });
+    }
+
+    /// 定义一个Lazy的PerCpu变量，稍后再初始化
+    pub const fn define_lazy() -> Lazy<Self> {
+        Lazy::<Self>::new()
+    }
+
+    pub fn get(&self) -> &T {
+        let cpu_id = smp_get_processor_id();
+        &self.inner[cpu_id as usize]
+    }
+
+    pub fn get_mut(&mut self) -> &mut T {
+        let cpu_id = smp_get_processor_id();
+        &mut self.inner[cpu_id as usize]
+    }
+}
+
+/// PerCpu变量是线程安全的，因为每个CPU都有自己的变量。
+unsafe impl<T> Sync for PerCpuVar<T> {}
+unsafe impl<T> Send for PerCpuVar<T> {}
diff --git a/kernel/src/mm/syscall.rs b/kernel/src/mm/syscall.rs
index 233d858a1..48b2aafd8 100644
--- a/kernel/src/mm/syscall.rs
+++ b/kernel/src/mm/syscall.rs
@@ -78,7 +78,7 @@ impl Syscall {
         if new_addr == address_space.brk {
             return Ok(address_space.brk);
         }
-        
+
         unsafe {
             address_space
                 .set_brk(VirtAddr::new(page_align_up(new_addr.data())))