[PATCH v2] arm64: futex: Consolidate 'old == new' check in __lsui_cmpxchg32()

[Will Deacon]

On Thu, 23 Jul 2026 14:03:04 +0100, Will Deacon wrote:
> The LSUI futex implementation relies on a cmpxchg() loop to implement
> FUTEX_OP_XOR, as the architecture doesn't provide unprivileged *EOR
> atomics. Since the unprivileged 'CAST' instructions used to implement
> the cmpxchg() can only operate on 64-bit memory locations, the
> __lsui_cmpxchg32() helper function performs a song and dance to marshall
> the 32-bit futex value into the correct part of a 64-bit register and
> fill the remaining bytes with the neighbouring data.
> 
> [...]

Applied to arm64 (for-next/misc), thanks!

[1/1] arm64: futex: Consolidate 'old == new' check in __lsui_cmpxchg32()
      https://git.kernel.org/arm64/c/25ef34b541eb

Cheers,
-- 
Will

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