Re: [PATCH] powerpc: build-time fixup alternate feature relative addresses

Le 29/01/2024 à 07:25, Sathvika Vasireddy a écrit :

Hi Christophe, Nick

On 1/26/24 12:32 AM, Christophe Leroy wrote:

quoted

Hi Nic,

Le 21/05/2017 à 03:01, Nicholas Piggin a écrit :

quoted

Implement build-time fixup of alternate feature relative addresses for
the out-of-line ("else") patch code. This is done post-link with a new
powerpc build tool that parses relocations and fixup structures, and
adjusts branch instructions.

This gives us the ability to link patch code anywhere in the kernel,
without branches to targets outside the patch code having to be
reached directly (without a linker stub). This allows patch code to be
moved out from the head section, and avoids build failures with
unresolvable branche.

Is it worth keeping this hanging in patchwork ? It seems outdated and 
doesn't apply. Could this me done with objtool instead ?

Christophe

Yes, this can be done with objtool. I am working on this and will post 
an RFC this week.

Nice.

I've open an issue to track his at 
https://github.com/linuxppc/issues/issues/479 and have retired Nic's 
patch in patchwork.

Christophe