Try batch but kernel panicked.

os/src/trap/context.rs

@@ -0,0 +1,23 @@
+use riscv::register::sstatus::{Sstatus, self, SPP};
+
+#[repr(C)]
+pub struct TrapContext {
+    x: [usize; 32],
+    sstatus: Sstatus,
+    sepc: usize,
+}
+
+impl TrapContext {
+    pub fn set_sp(&mut self, sp: usize) { self.x[2] = sp; }
+    pub fn app_init_context(entry: usize, sp: usize) -> Self {
+        let mut sstatus = sstatus::read();
+        sstatus.set_spp(SPP::User);
+        let mut cx = Self {
+            x: [0; 32],
+            sstatus,
+            sepc: entry,
+        };
+        cx.set_sp(sp);
+        cx
+    }
+}