[PATCH v4 05/10] signal: Introduce TRAP_PERF si_code and si_perf to siginfo

[Marco Elver]

On Thu, 22 Apr 2021 at 08:12, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
[...]
> > So I think we just have to settle on 'unsigned long' here. On many
> > architectures, like 32-bit Arm, the alignment of a structure is that of
> > its largest member. This means that there is no portable way to add
> > 64-bit integers to siginfo_t on 32-bit architectures.
> >
> > In the case of the si_perf field, word size is sufficient since the data
> > it contains is user-defined. On 32-bit architectures, any excess bits of
> > perf_event_attr::sig_data will therefore be truncated when copying into
> > si_perf.
> >
> > Feel free to test the below if you have time, but the below lets me boot
> > 32-bit arm which previously timed out. It also passes all the
> > static_asserts() I added (will send those as separate patches).
> >
> > Once I'm convinced this passes all others tests too, I'll send a patch.
>
> This fixes the issue I've observed on my test systems. Feel free to add:
>
> Reported-by: Marek Szyprowski <m.szyprowski at samsung.com>
>
> Tested-by: Marek Szyprowski <m.szyprowski at samsung.com>

Thank you for testing! It's been sent:
https://lkml.kernel.org/r/20210422064437.3577327-1-elver@google.com

Thanks,
-- Marco