Unlock context switch lock without potentially screwing up switch_to function

arch/x86_64/src/context.rs

@@ -52,6 +52,7 @@ impl Context {
     }
 
     /// Switch to the next context by restoring its stack and registers
+    #[cold]
     #[inline(never)]
     #[naked]
     pub unsafe fn switch_to(&mut self, next: &mut Context) {
@@ -94,7 +95,12 @@ impl Context {
         asm!("mov $0, rbp" : "=r"(self.rbp) : : "memory" : "intel", "volatile");
         asm!("mov rbp, $0" : : "r"(next.rbp) : "memory" : "intel", "volatile");
 
-        // Unset global lock, set inside of kernel
-        CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
+        asm!("call context_switch_unlock" : : : "memory" : "intel", "volatile");
     }
 }
+
+/// Unset global lock, set inside of kernel
+#[no_mangle]
+extern fn context_switch_unlock(){
+    CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
+}