[PATCH v4 00/12] ARM: vfp: Switch to C API to en/disable softirqs

[Ard Biesheuvel]

On Thu, 23 Mar 2023 at 03:44, Guenter Roeck <linux at roeck-us.net> wrote:
>
> On Mon, Mar 20, 2023 at 02:18:33PM +0100, Ard Biesheuvel wrote:
> > As it turns out, enabling or disabling softirqs from asm code is more
> > tricky than it looks. Simply bumping the associated bit in preempt_count
> > does the trick for uninstrumented kernels, but with lockdep or preempt
> > debug enabled, we really need to call the C versions, as replicating
> > their behavior in asm fully is intractible.
> >
> > So let's rework the existing code a little bit so we can interpose a
> > little C helper 'vfp_entry()' that disables softirqs before calling the
> > existing vfpstate handling code in asm. Re-enabling softirqs from asm
> > code is more straight-forward, as we can simply perform a tail call via
> > a C routine that is guaranteed to be callable as a function.
> >
> > However, since calling these APIs from asm code is still not ideal,
> > let's reimplement the whole thing in C (patch #4)
> >
>
> FWIW, all my qemu tests passed for this series.
>

Thanks for testing!