> We're really early in the boot -- startup_64 in decompression code -- and > I don't know a way print a message there. Is there a way? > > no_longmode handled by just hanging the machine. Is it enough for no_la57 > case too?
The way to handle it is to check it early in the real mode boot code when you can still print messages. That is how missing long mode is handled. -Andi
