Re: [PATCH v1 1/2] vdso: Add VDSO_UNALIGNED_PACKED config option for ARMv5

[Marc Kleine-Budde]

On 20.10.2026 00:12:57, Arnd Bergmann wrote:
> On Mon, Oct 19, 2026, at 22:12, Ian Rogers wrote:
> > +
> > +config VDSO_UNALIGNED_PACKED
> > +	bool
> > +	default CPU_32v5
> > +	help
> > +	  Use packed structs rather than memcpy() in include/vdso/unaligned.h
> > +	  for unaligned memory accesses. Enabled on ARMv5 where GCC may emit
> > +	  out-of-line memcpy() calls instead of inlining byte accesses.
>
> As explained, I think this misrepresents the problem as Arm specific and
> isn't the correct method for -munaligned-access targets on Arm, which
> include CPU_32v3, CPU_32v4 and CPU_32v4T along with CPU_32v5.
>
> I still hope we can use a version that just produces the intended code
> on both -munaligned-access and -mno-unaligned-access targets like the
> old version did.

FYI: there is the kconfig Symbol HAVE_EFFICIENT_UNALIGNED_ACCESS. Can we
make use of it?

regards,
Marc

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