Re: [PATCH 3/4] sparc32: implement futex atomics, with casa detected at run time

[John Paul Adrian Glaubitz]

On Thu, 2026-10-15 at 11:23 +0200, Arnd Bergmann wrote:
> On Thu, Oct 15, 2026, at 10:55, Ramin Moussavi wrote:
> > sparc32 has no futex_atomic_cmpxchg_inatomic() or
> > arch_futex_atomic_op_inuser() of its own. The generic versions only
> > work on UP, so FUTEX depends on !(SPARC32 && SMP) and an SMP kernel
> > has no futexes at all; NPTL cannot run on it.
> 
> I believe there are existing patches for LEON with CASA that
> should just be merged, I would not worry about supporting broken
> CPUs that never had this.

I think you mean the series by Imre Kaloz [1]? If yes, he actually
implements CASA emulation unless I'm missing something.

Adrian

> [1] https://lore.kernel.org/sparclinux/20260927005821.8369-1-kaloz@xxxxxxxxxx/

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