[PATCH RFC v2 0/2] arm64: vdso: Implement __vdso_futex_robust_try_unlock()

Sebastian Andrzej Siewior bigeasy at linutronix.de
Tue Apr 28 04:00:54 PDT 2026


On 2026-04-24 15:55:59 [-0300], André Almeida wrote:
> Hi folks,
Hi,

> This is my take on implementing the new vDSO for unlocking a robust futex in
> arm64. If you don't know what's that, Thomas wrote a good summary,
> including the motivation for this work and the x86 implementation:
> 
>    https://lore.kernel.org/lkml/878qb89g7b.ffs@tglx/
> 
> There are some loose ends in my patchset so I'm sending as a RFC to ask
> some questions:
> 
>  - If the process is interrupted between the labels, we need to check the
>  conditional flags and clear the op_pending address from the register. Using
>  objdump I see that op_pending addr is being stored at x2, but I suspect that
>  this isn't stable, so I need to figure out how to make sure that the address
>  will always be stored in the same register.
>  - So far I have implemented only the LL/SC version to make review easier, but I
>  can do the LSE version as well.

I am a bit behind here. In the meantime, were you able to check it with
	https://lore.kernel.org/all/20260404093939.7XgeW_54@linutronix.de/
?

Sebastian



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