[PATCH v8 5/5] arm64: futex: support futex with FEAT_LSUI
Yeoreum Yun
yeoreum.yun at arm.com
Wed Sep 17 06:42:03 PDT 2025
[...]
> static __always_inline int
> __lsui_cmpxchg32(u32 __user *uaddr, u32 oldval, u32 newval, u32 *oval)
> {
> uaddr64 = (u64 __user *)PTR_ALIGN_DOWN(uaddr, sizeof(u64));
> u64 oval64, nval64, orig64;
>
> if (get_user(oval64, uaddr64)
> return -EFAULT;
>
> if (IS_ALIGNED(addr, sizeof(u64)) == IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN)) {
> FIELD_MODIFY(GENMASK_U64(31, 0), &oval64, oldval);
> FIELD_MODIFY(GENMASK_U64(31, 0), &nval64, newval);
> } else {
> FIELD_MODIFY(GENMASK_U64(63, 32), &oval64, oldval);
> FIELD_MODIFY(GENMASK_U64(63, 32), &nval64, newval);
> }
> orig64 = oval64;
>
> if (__lsui_cmpxchg64(uaddr_al, &oval64, nval64))
> return -EFAULT;
>
> if (oval64 != orig64)
> return -EAGAIN;
>
> *oval = oldval;
> return 0;
> }
Oh, I misread the condition. Thanks for your suggetion.
Please ignore my previous email.
--
Sincerely,
Yeoreum Yun
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