tpm2_pcr_read(9)

💅 tpm2_pcr_read — read a PCR value

okay so bestie, welcome to the Kernel API Manual ✨ this one's from the 9 section (that's the kernel-dev girlies) and it's all about tpm2_pcr_read — literally just reading a PCR value, no cap 🫶

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🌸 SYNOPSIS 🌸

int tpm2_pcr_read (struct tpm_chip *chip , u32 pcr_idx , struct
     tpm_digest *digest , u16 *digest_size_ptr );

that's the whole signature, copy it exactly, don't be cute with it 💖

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🎀 ARGUMENTS 🎀

• chip — the TPM chip you're working with. your main character 🫶
• pcr_idx — the index of the PCR you wanna read. which one? that one. 👑
• digest — the PCR bank and the buffer where the current PCR value gets written. it's giving "two jobs, one struct" 💅
• digest_size_ptr — a pointer to the variable that stores the digest size. yeah, pointer-to-the-size, iconic ✨

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⭐ RETURN ⭐

same as with tpm_transmit_cmd. that's it, that's the whole vibe. go check that one for the details, iykyk 💀

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🌈 SEE ALSO 🌈

kernel file: ./drivers/char/tpm/tpm2-cmd.c

the whole friend group 💜:

• tpm2_calc_ordinal_duration(9)
• tpm2_pcr_extend(9)
• tpm2_get_random(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 bestie, this page is short and sweet — read it, use it, and go read tpm_transmit_cmd if you want the return-value tea 🔥

k bye, this page lives in ./drivers/char/tpm, dated October 2026, and it slayed 💅✨🍓