atomic64_fetch_xor_acquire(9)

📦 version 7.3.1, in nixpkgs unstable

💖 atomic64_fetch_xor_acquire(9) — Kernel API Manual 💖

okay so bestie, welcome to the Kernel API Manual, section 9, and today's main character is atomic64_fetch_xor_acquire. she's a 64-bit atomic XOR queen and honestly she ate. let's get into it 🫶

✨ NAME ✨

atomic64_fetch_xor_acquire — atomic bitwise XOR with acquire ordering 💅

like yes, that's the whole vibe. atomic. bitwise. XOR. acquire ordering. iconic.

🌸 SYNOPSIS 🌸

s64 atomic64_fetch_xor_acquire (s64 i , atomic64_t *v );

that's literally it. two args, no drama, she returns an s64. slay.

🎀 ARGUMENTS 🎀

  • i — an s64 value. yeah just a value, that's her whole job 💜
  • v — a pointer to atomic64_t. this is the thing getting xor'd, bestie 🦋

🔥 DESCRIPTION 🔥

so what she does is: atomically update v to (v ^ i) with acquire ordering. atomically means nobody can slide in halfway through, no cap. the acquire ordering is the memory-barrier fairy dust ✨

⚠️ okay important, do NOT skip this: she is unsafe to use in noinstr code. if you're in noinstr land you use raw_atomic64_fetch_xor_acquire instead. periodt. that's the rule, i don't make them 😭

⭐ RETURN ⭐

she gives you back the original value of v — like the value before the XOR happened. a little time capsule. a souvenir. the pre-glow-up version 💫

🦋 SEE ALSO 🦋

first up, the home base — kernel file ./include/linux/atomic/atomic-instrumented.h. she lives there. say hi 💖

🌈 the atomic_* girlies

🧚 the atomic64_* besties (our girl's homegirls)

🐋 the atomic_long_* crew

okay that's everybody. mwah. go read them, they're all slaying in their own lanes 💜

little sign-off bestie 🎀 — this page lives in ./include/linux/atomic, the version tag on it is October 2026, and the manual is atomic64_fetch_xor_acquire(9). that's it, that's the page. bye, ily, go write some atomics 💖✨

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