Kernel crosscompilers

[Arnd Bergmann]

On Sat, May 8, 2021 at 12:15 PM Christophe Leroy
<christophe.leroy at csgroup.eu> wrote:
> Le 08/05/2021 à 11:43, Arnd Bergmann a écrit :
> > On Sat, May 8, 2021 at 8:46 AM Christophe Leroy
> > <christophe.leroy at csgroup.eu> wrote:
> >>
> >> Something is going wrong with asm goto output. I implemented get_user() helpers with asm goto this
> >> cycle (commit 5cd29b1fd3e8). I tested it with CLANG before submitting, it was working.
> >
> > BTW, can you point me to those patches? I think it would be nice if we
> > could eventually
> > converge parts of get_user()/put_user() implementation on something
> > that works for all
> > architectures, we do seem to rewrite these way too often. Ideally we'd
> > have something
> > in asm-generic that provides all the wrappers, and just requires an
> > architecture to
> > implement the inline asm helpers for each of the sizes.
> >
>
> The series that is merged for 5.13 is here:
> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=233250&state=*
>
> And of course the result is just
> https://github.com/linuxppc/linux/blob/master/arch/powerpc/include/asm/uaccess.h
> and all its history at
> https://github.com/linuxppc/linux/commits/master/arch/powerpc/include/asm/uaccess.h

Ah, I should have looked there first ;-)

> The fix from today here:
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/cf0a050d124d4f426cdc7a74009d17b01d8d8969.1620465917.git.christophe.leroy@csgroup.eu/
>
> I made a try to use asm-generic/uaccess.h a few weeks ago, but it was not conclusive. I can't
> remember the details, but I can have a new look at it next week if you are interested with the details.

I hope you didn't waste too much time on that. The current asm-generic/uaccess.h
code is not helpful anywhere and needs to be rewritten before we can have
normal architectures using it.

        Arnd