Cross compile kernel error

Question

While compiling rt kernel following this http://www.frank-durr.de/?p=203 I got that error

Answer 1

By the looks of it, you're running the make bzimage command on your rasberrypi. The link http://www.frank-durr.de/?p=203 is for instructions as to how to cross-compile the rpi kernel (which is to say, compile the kernel on another platform, such as a PC running linux). In the instructions given, I suspect, commands beginning user@host are intended to be run on said host, whereas the only command beginning pi@raspberry$ is to be run on the raspberrypi. The only instruction to be run on the pi, is sudo modprobe configs, then from your host, scp pi@raspberry:/proc/config.gz ./ to get the config.gz file from your raspberrypi (that config file will tell make what config settings to use when building the kernel, rather than asking you to set them all manually, starting from the defaults).

However, if you do want to compile on the Pi, the error message above, is telling you that gcc failed to compile due to a syntax error. You need to look at the file it was trying to compile and figure out what's causing the error. Normally, if you're compiling from a path often followed (by others) the code won't contain bugs, so you've probably broken something. A good way is through unresolved merges, or other upstream scripts that failed.
The error message is saying there was an unexpected "(" on line 1. Now I'd not expect a C file to begin with a "(" unless it's been minified to be all on 1 line (unlikely for the kernel source), so I suggest you inspect the files it's created and check they look right.

It's probably worth pointing out, the instructions you're following are not intended to explain how to compile the kernel on the pi. You should be able to do that, just like re-compiling a normal linux kernel. However I seem to remember reading that on the Pi 1, a full kernel compile could take days (compared to hours on a PC), so these are probably not the droids you're looking for.