Re: [RFC PATCH] add sparc support to CT-NG

["Yann E. MORIN" <yann dot morin dot 1998 at anciens dot enib dot fr>]

Sam, Konrad, All,

On Thursday 30 December 2010 20:00:15 Sam Ravnborg wrote:
> Testing so far shows:
> gcc 4.4.1 - kernel boots
> gcc 4.4.4 - kernel halts in the boot process
> gcc 4.5.1 - cannot build a kernel (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35664)
> 
> I will test 4.4.5 and 4.5.2 (saw that Bryan just added 4.5.2).

Yep, it seems 4.4.5, 4.5.2 and upcoming 4.6 all have the fix.

> I have no good way to test userland atm - so no status there.
> Need to setup my system so rootfs is via NFS first.

Well, kernel building and booting is a good indication things are in a
pretty good shape (on the C side at least)! :-)

> I assume patch can be accepted without userland status.

Yes, sure, especially since that patch has been applied upstream.
Simply add the patch in appropriate patches/gcc/version directories, and
send the patch in the same commit as sparc architecture.

> Do crosstool-ng support some way to mark certain gcc versons as broken?

Once upon a time, it did, but I removed it. In this case, I'd mark the sparc
as being experimental (see: docs/8 - Internals.txt), so that users know things
might break.

But there is no way to mark a specific version of a specific compoent to be
broken when a specific option is set.

To guide users, we have samples that are known to work (at least to some
extent) that users can start with, and eventually update things from that.
To save a sample, you need a configured crosstool-Ng tree, and then call:
  ct-ng saveconfig

This creates a new directory below samples/ and associated config files,
for example:
  samples/sparc-unknown-linux-gnu/crosstool.config
  samples/sparc-unknown-linux-gnu/reported.by

Then, just add those files with "hg add". That's pretty easy! ;-)

> For leon (a sparc v8 variant) we will need this too as leon is only supported
> by a limited set of gcc versions.
> I do not expect a 1:1 between working versions and versions which support leon.

That's not a big issue., I think. Currently, lots of combinations will break.
For example, it's not possible to build a glibc-2.12.2 for ARM, as the ports
addon is not available for 2.12.2.

[--SNIP--]
> I have dropped sparc.in.2 as suggested for now - and added ARCH_SUPPORT_TUNE.
> Thanks for the insight in how crosstool works. Good stuff to konw.

You're welcome! If you find the info was not easily found, or was missing,
please do tell, or even update the doc in docs/.

I'm doing poorly when it comes to docs, which I easily forget to update. :-(
I'll try to add a few bits to the arch stuff tonight...

Regards,
Yann E. MORIN.

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