Remove the shim kernel crate

kernel/src/syscall/exit.rs

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use crate::{
+    prelude::*,
+    process::{posix_thread::do_exit, TermStatus},
+    syscall::SyscallReturn,
+};
+
+pub fn sys_exit(exit_code: i32, _ctx: &Context) -> Result<SyscallReturn> {
+    debug!("exid code = {}", exit_code);
+
+    let current_thread = current_thread!();
+    let term_status = TermStatus::Exited(exit_code as _);
+    do_exit(current_thread, term_status)?;
+
+    Ok(SyscallReturn::Return(0))
+}