Re: arm64: unhandled level 0 translation fault

[Geert Uytterhoeven]

On Fri, Dec 15, 2017 at 3:27 PM, Will Deacon <will.deacon@xxxxxxx> wrote:
> On Fri, Dec 15, 2017 at 02:30:00PM +0100, Geert Uytterhoeven wrote:
>> On Fri, Dec 15, 2017 at 12:23 PM, Dave Martin <Dave.Martin@xxxxxxx> wrote:
>> > The two important differences here seem to be
>> >
>> > 1) Staging the state via current->thread.fpsimd_state instead of loading
>> > directly:
>> >
>> > -       fpsimd_load_state(state);
>> > +       current->thread.fpsimd_state = *state;
>> > +       fpsimd_load_state(&current->thread.fpsimd_state);
>>
>> The change above introduces the breakage.
>
> I finally managed to reproduce this, but only by using the exact same
> compiler as Geert:
>
> https://www.kernel.org/pub/tools/crosstool/files/bin/x86_64/4.9.0/x86_64-gcc-4.9.0-nolibc_aarch64-linux.tar.xz
>
> I then reliably see the problem if I run:
>
>   # /usr/bin/update-ca-certificates
>
> from Debian Jessie.
>
> Note that my normal toolchain (Linaro 7.1.1 build) works fine and also
> if I use the toolchain above but disable CONFIG_ARM64_CRYPTO then things
> work too.
>
> So there's some toolchain-specific interaction between this change and the
> crypto code...
>
> Will



-- 
Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds