Re: What compiler version to use for the kernel

[Paul M. <le...@li...>]

On Wed, May 30, 2007 at 09:38:54AM +0200, EXTERNAL Brunner Markus (Praktikant;  ST-FIR/Eng) wrote:
> I have problems using newer versions of gcc with my old 2.4.22 kernel. 
> GCC 3.2.3 with binutils 2.15 is the latest compiler I can use. Newer
> ones result in a "Unable to handle kernel paging request" error most of
> the time.
> 
> Does anybody still use 2.4 kernels? What compiler version do you use?
> 
> Unfortunatelly 2.4.22 is the only kernel runnig on that board so far,
> but I will port the latest 2.4 kernel to the board soon. 

There hasn't been any updates for the 2.4 kernels in years. I vaguely
recall pushing some fixes about 3 years ago, but it's been completely
unsupported since then. It's very possible you're going to hit bugs, and
I wouldn't expect the kernel or compilers to produce something usable
from that codebase. If you get something that even partially works,
you're certainly ahead of the curve.

> It's a sh3-dsp (7720) based board, are there any hints for porting? 
> I've seen that there is dsp support in 2.4.34, but no 7720 in the cpu
> type to select. 
> Is that sufficient for my 7720, or will I need to migrate the patches
> from my current kernel?

If you can find a close enough subtype thats in the kernel, you can
probably patch around that. You'll have to pay special attention to the
exception vector tables to make sure there are no mismatches across the
subtypes. Most of the SH-3 subtypes end up being "reasonably" close to
each other, so perhaps you'll get lucky.

The CONFIG_SH_DSP code is known to be buggy in 2.4, there are a number of
issues related to the stack frame layout. You may be able to dig those
out of 2.6 and backport, but there's really not much point.

2.4 stopped being viable almost 4 years ago now, it's at the point now
where it's just sad. You can either switch to 2.6, continue hacking on
your out of tree patches, or switch to another OS. 2.4 has not and will
not be supported.