With that all architectures using the generic syscall entry code follow the
same scheme, apply stack randomization at the correct and earliest possible
place and skip syscall processing depending on the boolean return value of
syscall_enter_from_user_mode[_work]().

There should be no functional changes, at least there are none intended.

The resulting text size for the syscall entry code on x8664 is slightly
smaller than before these changes.

Testing syscall heavy workloads and micro benchmarks shows a small
performance gain for the general rework, but the last patch, which changes
the logic to be more understandable has no measurable impact in either
direction.

The series applies on Linus tree and is also available from git:

        git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git entry-rework-v1

Hi Thomas,

Thanks for the series.

I have an Alpha GENERIC_ENTRY series posted and planned for the next
merge window:

https://lore.kernel.org/linux-alpha/20260706170019.2941459-1-linmag7@gmail.com/T/#t (local)

Only its final patch intersects with this work.

That patch removes Alpha's architecture-specific syscall_trace_enter()
and syscall_trace_leave() implementations, so the Alpha changes in
patches 11 and 12 will disappear once the GENERIC_ENTRY conversion is
applied.

It also currently uses syscall_enter_from_user_mode(), so I will need to
rebase it onto the new entry interface introduced by this series. I
expect the integration to be confined to the final GENERIC_ENTRY patch.

The Alpha-specific changes in patches 11 and 12 look correct to me.

Acked-by: Magnus Lindholm <linmag7@gmail.com>