From 3d8c59d4ac80ea105d9ad2d9e4d994805b57aacd Mon Sep 17 00:00:00 2001
From: zhangxinyu <840317537@qq.com>
Date: Tue, 23 May 2023 14:41:16 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E4=B8=80=E4=B8=AAloader?=
 =?UTF-8?q?=E6=A8=A1=E5=9D=97=E7=94=A8=E6=9D=A5=E5=8A=A0=E8=BD=BD=E6=89=80?=
 =?UTF-8?q?=E6=9C=89=E7=9A=84app,=20=E4=B8=80=E8=B5=B7=E5=88=B0=E5=86=85?=
 =?UTF-8?q?=E5=AD=98=E4=B8=AD=E7=9A=84=E6=8C=87=E5=AE=9A=E4=BD=8D=E7=BD=AE?=
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---
 ch3-coop/os/build.rs      |  1 +
 ch3-coop/os/src/loader.rs | 54 +++++++++++++++++++++++++++++++++++++++
 ch3-coop/os/src/main.rs   | 13 ++++++----
 3 files changed, 63 insertions(+), 5 deletions(-)
 create mode 100644 ch3-coop/os/src/loader.rs

diff --git a/ch3-coop/os/build.rs b/ch3-coop/os/build.rs
index 026b308..0d4cdb2 100644
--- a/ch3-coop/os/build.rs
+++ b/ch3-coop/os/build.rs
@@ -2,6 +2,7 @@ use std::fs::{read_dir, File};
 use std::io::{Result, Write};
 
 fn main() {
+    // 主要功能是把用户的应用程序加载到内核中
     println!("cargo:rerun-if-changed=../user/src/");
     println!("cargo:rerun-if-changed={}", TARGET_PATH);
     insert_app_data().unwrap();
diff --git a/ch3-coop/os/src/loader.rs b/ch3-coop/os/src/loader.rs
new file mode 100644
index 0000000..b5fa6d5
--- /dev/null
+++ b/ch3-coop/os/src/loader.rs
@@ -0,0 +1,54 @@
+use core::arch::asm;
+
+use crate::config::*;
+
+extern "C" {
+    fn _num_app();
+}
+
+// 得到用户app的数量
+fn get_num_app() -> usize{
+    unsafe{
+        _num_app as usize as *const usize.read_volatile()
+    }
+}
+
+// 把把 app一次性都加载到内存, 并分配二进制空间
+pub fn load_app() {
+    // 得到符号位
+    let num_app_ptr = _num_app as usize as *const usize;
+
+    // 得到 符号开始的前8个字节, 这里保存的app的数量
+    let num_app = get_num_app();
+
+    // 得到 app数组的起始位置 num_app_ptr.add(1)跳过上方的 metadata, num_app+1 是确保切免得长度足够, 因为后面还有一个符号在linker.ld中  .quad app_2_end 表示结束的内存地址
+    let app_start = unsafe {
+        core::slice::from_raw_parts(num_app_ptr.add(1), num_app+1)
+    };
+
+    // 清除缓存
+    unsafe { asm!("fence.i" :::: "volatile"); }
+
+    // 加载app
+    for app_id in 0..num_app {
+        // 得到每个app的起始位置
+        let base_ptr = APP_BASE_ADDRESS + app_id * APP_SIZE_LIMIT;
+
+        // 清理这个应用可以占用的内存(好像可以不用做吧? 下面直接dst.copy_from_slice全部覆盖了)
+        (base_ptr..base_ptr + APP_SIZE_LIMIT).for_each(|addr| unsafe {
+            (addr as *mut u8).write_volatile(0)
+        });
+
+        // 加载 app_start 处二进制数据到内存里
+        let src = unsafe {
+            let app_size = app_start[app_id + 1] - app_start[app_id];  // 下一个app的起始位置, 减去当前的起始位置就是app的大小
+            core::slice::from_raw_parts(app_start[app_id] as *const u8, app_size)
+        };
+
+        // 得到app占用的内存, 后面需要把app 二进制数据加载到这里
+        let dst = unsafe {
+            core::slice::from_raw_parts_mut(base_ptr as *mut u8, src.len())
+        };
+        dst.copy_from_slice(src);
+    }
+}
\ No newline at end of file
diff --git a/ch3-coop/os/src/main.rs b/ch3-coop/os/src/main.rs
index 5dbc93a..ffc78a9 100644
--- a/ch3-coop/os/src/main.rs
+++ b/ch3-coop/os/src/main.rs
@@ -8,10 +8,12 @@ use lang_items::console;
 
 pub mod lang_items;
 pub mod sbi;
-pub mod batch;
+// pub mod batch;
 pub mod sync;
-pub mod trap;
+// pub mod trap;
 pub mod syscall;
+pub mod loader;
+pub mod config;
 
 // 汇编脚本引入, 调整内核的内存布局之后, 会跳入到 rust_main中执行
 global_asm!(include_str!("entry.asm"));
@@ -36,9 +38,10 @@ 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();
-    batch::init();
-    batch::run_next_app();
+    loader::load_app();
+    // trap::init();
+    // batch::init();
+    // batch::run_next_app();
 }
 
 /// ## 初始化bss段