tpm2_get_random(9)

💖 tpm2_get_random — get random bytes from the TPM RNG 💖

okay bestie, so this is tpm2_get_random, and it lives in the Kernel API Manual (section 9, iykyk). it's a kernel-side function, not a command you type — think of it as the little connector between the kernel and the TPM's random number generator. so much power. 🎀

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✨ SYNOPSIS ✨

int tpm2_get_random (struct tpm_chip *chip , u8 *dest , size_t max );

literally the whole vibe right there — you hand it a chip, a destination buffer, and a maximum, and it goes and fetches you some randomness. 🦋

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🌸 ARGUMENTS 🌸

• chip — a tpm_chip instance. this is your TPM bestie, the actual device you're talking to. 🫶
• dest — destination buffer. this is where the random bytes land, so make sure it's somewhere real and it can hold what you're asking for. 💅
• max — the max number of random bytes to pull. key word: max — that's the ceiling you're giving it, not a promise it'll come back with exactly that many. ⭐

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🔥 RETURN 🔥

on success you get back the size of the buffer — glow up, it worked ✨. otherwise you get -errno. and here's the lil detail you cannot skip, no cap: positive TPM return codes are masked to -EIO. so if the TPM hands back something positive-looking, don't get excited, it's getting squashed into -EIO. that's just how it is, periodt. 💀

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👑 SEE ALSO 👑

kernel file ./drivers/char/tpm/tpm2-cmd.c — that's where the magic's written, go read it if you're feeling main character energy 🧚

and the whole TPM2 friend group:

• tpm2_calc_ordinal_duration(9)
• tpm2_pcr_read(9)
• tpm2_pcr_extend(9)
• tpm2_flush_context(9)
• tpm2_get_tpm_pt(9)
• tpm2_shutdown(9)
• tpm2_do_selftest(9)
• tpm2_probe(9)
• tpm2_startup(9)
• tpm2_auto_startup(9)

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ngl this one's short and sweet — a little random-byte delivery service and nothing more. obsessed. 🌈

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and that's a wrap, bestie 💜 this page came from ./drivers/char/tpm, dated October 2026 — go get yourself some entropy, you deserve it 🍓 slay!