cpu_function_call(9)

💅 cpu_function_call(9) 💅

okay so real talk, bestie — welcome to the Kernel API Manual, and today's main character is cpu_function_call, from the (9) section (that's the kernel-functions girlies, iykyk). This one's a little cross-CPU errand runner and honestly? iconic.

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✨ NAME ✨

cpu_function_call — call a function on the cpu 🫶

Like, you've got a function, you've got a cpu, and you want that function to happen over there. That's the whole vibe.

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🌸 SYNOPSIS 🌸

int cpu_function_call (int cpu , remote_function_f func , void *info );

Yep, that's the whole signature. Three little args and an int coming back at you. Slay.

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🎀 ARGUMENTS 🎀

• cpu — the target cpu you're queueing this function onto. Like, which cpu is getting the message. 👑
• func — the actual function that's gonna get called. The star of the show, fr fr. ⭐
• info — the argument that gets handed to that function call. The little care package it carries along. 🎁

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🦋 DESCRIPTION 🦋

So here's the tea: it calls the function func on the remote cpu. That's it. That's the whole thing. No cap, no hidden lore — you point at a cpu, you point at a function, and the function gets called over there on that remote cpu. ✨

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🔥 RETURN 🔥

You get back the func return value — or -ENXIO when the cpu is offline. 😭 So if your target cpu is having a little nap (offline, bestie, it's gone), you're getting -ENXIO and that's your answer.

ngl, -ENXIO is the "no such device or address" heartbreak. cpu offline = no function call for you. 💀

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🌈 SEE ALSO 🌈

• Kernel file ./kernel/events/core.c — like, go read the source, it's giving main character energy 💖
• task_function_call(9)
• sys_perf_event_open(9)
• perf_event_create_kernel_counter(9)

All of those are absolutely worth a peek if you're going down the ./kernel/events rabbit hole 🐇✨

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okay that's the page!! mwah 💋 sign-off time: this little masterpiece lives in ./kernel/events, dated October 2026, and it'll always be cpu_function_call(9) to us 🎀💜 bye bestie, go call some functions!! 🦋🌸