Re: [patch 00/18] entry: Consolidate and rework syscall entry handling

Magnus Lindholm <[email protected]> Sat, 11 Jul 2026 14:29:12 +0200
Newsgroups gmane.linux.documentation,gmane.linux.kernel,gmane.linux.ports.ppc64.devel,gmane.linux.ports.riscv,gmane.linux.ports.arm.kernel,gmane.linux.ports.alpha,gmane.linux.ports.mips,gmane.linux.ports.parisc,gmane.linux.ports.sh.devel,gmane.linux.uml.devel,gmane.linux.kernel.arc,gmane.linux.ports.hexagon,gmane.linux.ports.sparc,gmane.linux.kernel.cross-arch
Message-ID <CA+=Fv5RpgQ-UeGAT+VcLufte2gAp0H=J5GqZEFR_SuQsmnzy=A@mail.gmail.com>
>
> 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/[email protected]/T/#t

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 <[email protected]>