为内核添加动态内存分配器

ch4/os/Cargo.toml

@@ -13,3 +13,4 @@ debug=true
 riscv = { git = "https://github.com/rcore-os/riscv", features = ["inline-asm"] }
 lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
 sbi-rt = { version = "0.0.2", features = ["legacy"] }
+buddy_system_allocator = "0.6"

ch4/os/src/config.rs

@@ -1,8 +1,9 @@
 pub const APP_BASE_ADDRESS: usize = 0x80400000;  // 载入的app的起始的地址
 pub const APP_SIZE_LIMIT: usize = 0x20000;  // app的最大的二进制文件能够使用的大小
 pub const MAX_APP_NUM: usize = 10;  // 支持最大的用户应用数量
+pub const KERNEL_HEAP_SIZE: usize = 0x30_0000;  // 内核的堆大小 3M
 
-pub const USER_STACK_SIZE: usize = 4096 * 2;  // 栈大小为8kb
+pub const USER_STACK_SIZE: usize = 4096 * 2;  // 每个应用用户态的栈大小为8kb
-pub const KERNEL_STACK_SIZE: usize = 4096 * 2;
+pub const KERNEL_STACK_SIZE: usize = 4096 * 2; // 每个应用的内核栈
 
 pub use crate::board::*;

ch4/os/src/main.rs

@@ -2,6 +2,8 @@
 #![no_std]
 #![no_main]
 
+extern crate alloc;
+
 use core::arch::global_asm;
 use sbi::{console_put_char, shutdown};
 use lang_items::console;
@@ -15,6 +17,7 @@ pub mod loader;
 pub mod config;
 pub mod task;
 pub mod timer;
+pub mod mm;
 
 #[path = "boards/qemu.rs"]
 mod board;
@@ -44,12 +47,14 @@ pub fn rust_main(){
     println!("sbss: {:#x}, ebss: {:#x}", sbss as usize, ebss as usize);
     println!("boot_stack_top_bound: {:#x}, boot_stack_lower_bound: {:#x}", boot_stack_top_bound as usize, boot_stack_lower_bound as usize);
 
-    trap::init();
+    // 初始化动态内存分配器, 使我们能在内核中使用动态大小数据类型
+    mm::heap_allocator::init_heap();
 
+    trap::init();
     loader::load_app();
     trap::enable_timer_interrupt();  // 允许定时器中断
     timer::set_next_trigger();  // 在进入用户态之前, 设置一个时钟中断, 防止第一个用户任务死循环
-    task::run_first_task();
+    // task::run_first_task();
 
     panic!("Disable run here")
 }

ch4/os/src/mm/heap_allocator.rs

@@ -0,0 +1,59 @@
+use alloc::boxed::Box;
+use alloc::vec;
+use buddy_system_allocator::LockedHeap;
+use crate::config::KERNEL_HEAP_SIZE;
+use crate::println;
+
+
+// 动态内存分配器
+#[global_allocator]
+static HEAP_ALLOCATOR: LockedHeap = LockedHeap::empty();
+
+// 堆的空间
+static mut HEAP_SPACE: [u8; KERNEL_HEAP_SIZE] = [0; KERNEL_HEAP_SIZE];
+
+
+// 为内存分配器, 绑定一个空间用来实现动态内存分配
+pub fn init_heap() {
+    unsafe {
+        HEAP_ALLOCATOR
+            .lock()
+            .init(HEAP_SPACE.as_ptr() as usize, KERNEL_HEAP_SIZE);
+    }
+    // heap_test()
+}
+
+pub fn heap_test() {
+    use alloc::boxed::Box;
+    use alloc::vec::Vec;
+    extern "C" {
+        fn sbss();
+        fn ebss();
+    }
+    let bss_range = sbss as usize..ebss as usize;
+    println!("bss_range {:?}", bss_range);
+
+    let a = Box::new(5);
+    println!("a: {:?}  ptr: {:p}", a, a.as_ref());
+    let b = Box::new(6);
+    println!("b: {:?}  ptr: {:p}", b, b.as_ref());
+
+
+    unsafe {
+        println!("HEAP_SPACE: {:?}", HEAP_SPACE.as_ptr())
+    }
+
+    let mut v = vec![];
+    for i in 0..500{
+        v.push(i);
+    }
+
+    for i in 0..500{
+        v.pop();
+    }
+
+    println!("{:?}", v);
+
+    // 通过输出打印, 发现 a 和b 均被分配在了 HEAP_SPACE 中, 且 HEAP_SPACE 被分配在了 bss段中, 这个段由我们 linker.ld 进行手动布局
+    // 目前整个bss段的大小都是3M, 说明当前bss段中只有这一个 数据
+}

ch4/os/src/mm/mod.rs

@@ -0,0 +1 @@
+pub mod heap_allocator;