Properly end process on error

kernel/src/trap.rs

@@ -18,17 +18,18 @@ pub fn timer() {
     processor().tick();
 }
 
-pub fn error(tf: &TrapFrame) -> ! {
+pub fn error(tf: &mut TrapFrame) -> ! {
+    use crate::arch::syscall::*;
     error!("{:#x?}", tf);
     let tid = processor().tid();
     error!("On CPU{} Thread {}", cpu::id(), tid);
 
-    processor().manager().exit(tid, 0x100);
-    processor().yield_now();
+    crate::syscall::syscall(SYS_EXIT_GROUP, [0x100, 0, 0, 0, 0, 0], tf);
     unreachable!();
 }
 
 pub fn serial(c: char) {
+    trace!("Serial input: {:X}", c as u8);
     if c == '\r' {
         // in linux, we use '\n' instead
         crate::fs::STDIN.push('\n');