Macro arch_map_data 

macro_rules! arch_map_data {
    {} => { ... };
    {
        BidiTryFrom<$type_name1:ty, $type_name2:ident> {
            $(
                $field1:ident = $field2:ident;
            )*
            $(..$d:expr)?
        }
        $($token:tt)*
    } => { ... };
}

Implement TryFrom between 2 uapi struct of different ABI with a common type.