Re: [RFC PATCH v3 1/1] arch: arm64: Implement unaligned atomic emulation

From: André Almeida

Date: Wed Oct 14 2026 - 17:44:20 EST


Em 29/09/2026 23:01, André Almeida escreveu:
Implement support for emulating unaligned atomic operations on arm64.
User applications that wish to enable support for this should use the
pctrl() flag `PR_ARM64_UNALIGN_ATOMIC_EMULATE`.

As discussed at LPC 2026[1], the split lock emulation is probably the first thing that we want to figure from the atomics issues, given that is the trickiest one to emulate correctly given the need serialize two atomic instructions. As suggested by Mark, first we are going to work on an userspace solution that delivers correctness and from there we can better understand what the kernel could provide to help with performance improvements.

Thanks!
André

[1] https://lpc.events/event/20/contributions/2594/