user app can invoke kernel syscall!!!!

abi/src/lib.rs

@@ -3,8 +3,16 @@
 use core::ffi::c_void;
 use shared::keyboard::{KeyCode, KeyEvent, KeyState, Modifiers};
 
+// Instead of extern, declare a static pointer in a dedicated section
 #[unsafe(no_mangle)]
-pub unsafe fn call_abi(_call: *const Syscall) {}
+#[unsafe(link_section = ".user_reloc")]
+pub static mut call_abi_ptr: usize = 0;
+
+// Helper to call it
+pub unsafe fn call_abi(call: *const Syscall) {
+    let f: extern "C" fn(*const Syscall) = unsafe { core::mem::transmute(call_abi_ptr) };
+    f(call);
+}
 
 #[repr(C)]
 pub enum Syscall {