add AppManager

os/src/batch.rs

@@ -0,0 +1,86 @@
+use core::arch::asm;
+use core::cell::UnsafeCell;
+use lazy_static::lazy_static;
+use crate::println;
+
+const MAX_APP_NUMBER: usize = 32;
+const APP_BASE_ADDRESS: usize = 0x80400000;
+const APP_SIZE_LIMIT: usize = 0x20000;
+
+struct AppManager {
+    app_count: usize,
+    current: usize,
+    start_addresses: [usize; MAX_APP_NUMBER + 1],
+}
+
+lazy_static! {
+    static ref APP_MANAGER: UnsafeCell<AppManager> = unsafe {
+        UnsafeCell::new({
+            extern "C" {
+                fn _num_app();
+            }
+
+            let num_app_ptr = _num_app() as usize as *const usize;
+            let num_app = num_app_ptr.read_volatile();
+            let mut start_addresses: [usize; MAX_APP_NUMBER + 1] = [0; MAX_APP_NUMBER + 1];
+            let start_addresses_raw: &[usize] = core::slice::from_raw_parts(
+                num_app_ptr.add(1), num_app + 1
+            );
+            start_addresses[..=num_app].copy_from_slice(start_addresses_raw);
+            AppManager {
+                app_count: num_app,
+                current: 0,
+                start_addresses
+            }
+        })
+    };
+}
+
+impl AppManager {
+    pub fn print_app_information(&self) {
+        println!("[kernel] Application count is {}.", self.app_count);
+
+        for i in 0..self.app_count {
+            println!("[kernel] Application_{} ({:#x} -> {:#x})",
+                     i,
+                     self.start_addresses[i],
+                     self.start_addresses[i + 1]);
+        }
+    }
+
+    pub fn get_current_app(&self) -> usize {
+        self.current
+    }
+
+    pub fn move_to_next_app(&mut self) {
+        self.current += 1;
+    }
+
+    unsafe fn load_app(&self, app_id: usize) {
+        if app_id >= self.app_count {
+            panic!("Application id is invalid!");
+        }
+
+        println!("[kernel] Loading application_{}...", app_id);
+
+        core::slice::from_raw_parts_mut(
+            APP_BASE_ADDRESS as *mut u8,
+            APP_SIZE_LIMIT
+        ).fill(0);
+
+        let app_source = core::slice::from_raw_parts(
+            self.start_addresses[app_id] as *const u8,
+            self.start_addresses[app_id + 1] - self.start_addresses[app_id]
+        );
+        let app_destination = core::slice::from_raw_parts_mut(
+            APP_BASE_ADDRESS as *mut u8,
+            APP_SIZE_LIMIT
+        );
+        app_destination.copy_from_slice(app_source);
+
+        // 保证指令缓存的更新
+        // 因为上述代码会修改指令数据段
+        asm!("fence.i");
+    }
+}
+