clean_cache_range(9)

💖 clean_cache_range(9) 💖

okay so bestie, this one's a lil kernel API page from the Kernel API Manual, section 9 — the deep magic zone 🧚✨. it's called clean_cache_range and it is literally the "bestie, please flush your cache" of the x86 world. ngl, it's a short one, so we're gonna get through it together, mwah 💅

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🌸 NAME 🌸

clean_cache_range — write back a cache range with CLWB. that's it. that's the whole vibe. 🫶

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✨ SYNOPSIS ✨

void clean_cache_range (void *addr , size_t size );

copy it exactly like that, spacing and all — no cap, do not "fix" the spaces, the manpage said what it said 🎀

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🦋 ARGUMENTS 🦋

• addr — the virtual start address. like, where the party begins 📍
• size — number of bytes to write back. how much of the party we're cleaning up after 🧹

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💜 DESCRIPTION 💜

so what does it actually do? it writes back a cache range using the CLWB (cache line write back) instruction. iconic. that's the whole job, and it does it well 👑

and here's the lil detail you cannot skip, bestie — size is internally rounded up to be cache line size aligned. so if you hand it a number that isn't cache-line-sized, it's not gonna be messy about it, it just rounds up for you. lowkey thoughtful of it ngl 🌈

heads up: because of that rounding, the function may be working with a slightly bigger range than the size you actually passed in. that's the documented behaviour, so don't come for me, i'm just the messenger 😭

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🎀 SEE ALSO 🎀

• Kernel file ./arch/x86/lib/usercopy_64.c — go read the source, iykyk 📖✨

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and that's the whole page! 🍓 short, sweet, slays. this one comes to you from ./arch/x86/lib and it's dated October 2026 — so remember that era, bestie, and go write back some cache lines 💖🔥👑