update_cpus_node(9)

🌸 update_cpus_node(9) — like, the kernel API manual bestie 💅

okay so picture this: it's a (9) page, it lives in the Kernel API Manual, and its whole personality is updating the cpus node. we're doing this, let's go 🫶

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✨ NAME ✨

update_cpus_node — bestie, this one updates the cpus node of the flattened device tree, and it does it by using the of_root device node. that's the whole gig. iconic, honestly. 👑

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🦋 SYNOPSIS 🦋

int update_cpus_node (void *fdt );

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🎀 ARGUMENTS 🎀

• fdt — the flattened device tree of the kernel. that's it, that's the whole argument. she takes one (1) thing and she takes it seriously 💜

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🌈 DESCRIPTION 🌈

so what actually happens? it returns 0 on success, and a negative errno on error. no cap, that's literally the contract. success = 0, sad path = negative errno. write it on your hand, iykyk ✨

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💀 NOTE 💀

heads up bestie, this is the fine print and we do NOT skip fine print 🙈

it's expecting no subnodes under /cpus/<node> with device_type == "cpu". like, zero. none. not a single one.

and if that ever changes? if someone out there decides to sneak subnodes in? then you gotta update this function to include them too. don't leave her hanging, fr fr. 🍓

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🔥 SEE ALSO 🔥

• Kernel file ./arch/powerpc/kexec/core_64.c — go read it, it's giving main character energy
• add_node_props(9) — her friend!! say hi!! 💖

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that's the whole page, you ate that 🌟 stay hydrated, read your kernel source, and remember: 0 is success and negative errno is not a vibe check you want to fail. mwah 💅

kisses from the ./arch/powerpc/kexec girlies — this one's dated October 2026, and it's still signed update_cpus_node(9) if anyone asks 🧚