spum_nsp_ctx_max_payload(9)

✨ spum_nsp_ctx_max_payload ✨

okay so bestie, welcome to the spum_nsp_ctx_max_payload(9) page — it lives in the Kernel API Manual and it's literally here to tell you the biggest payload a SPU message can carry for a given cipher + hash alg context 🎀

---

💖 NAME 💖

spum_nsp_ctx_max_payload — figure out the max length of the payload for a SPU message, for a given cipher and hash alg context. that's it, that's the job 🫶

---

🌸 SYNOPSIS 🌸

u32 spum_nsp_ctx_max_payload (enum spu_cipher_alg cipher_alg , enum
spu_cipher_mode cipher_mode , unsigned int blocksize );

---

🦋 ARGUMENTS 🦋

• cipher_alg — the cipher algorithm, like which cipher we're doing the math for 🔥
• cipher_mode — the cipher mode, the whole how of it 💅
• blocksize — the size of one block of data for this algo, the unit of everything downstream ✨

---

👑 DESCRIPTION 👑

ok so here's the vibe: the max payload must be a multiple of the blocksize. why? because if a request is too big to fit in a single SPU message, the request gets broken up into chunks that are each max_payload sized. and every single one of those chunks has to be a multiple of blocksize too. no cap 🧚

it's giving "my payload has to divide evenly or the whole thing falls apart" and honestly? iconic. ⭐

---

🌈 RETURN 🌈

max payload length, in bytes 💜

---

🍓 SEE ALSO 🍓

kernel file ./drivers/crypto/bcm/spu.c — and the whole friend group:

• spum_ns2_ctx_max_payload(9)
• spum_response_hdr_len(9)
• spum_hash_pad_len(9)
• spum_gcm_ccm_pad_len(9)
• spum_assoc_resp_len(9)
• spum_aead_ivlen(9)
• spum_hash_type(9)
• spum_digest_size(9)
• spum_create_request(9)
• spum_cipher_req_init(9)
• spum_cipher_req_finish(9)
• spum_request_pad(9)
• spum_xts_tweak_in_payload(9)
• spum_tx_status_len(9)
• spum_rx_status_len(9)
• spum_status_process(9)
• spum_ccm_update_iv(9)
• spum_wordalign_padlen(9)

---

aaaand that's the page!! 💖 this little cutie comes to you from ./drivers/crypto/bcm, dated October 2026 — mwah, go read the other spum_* pages, ily, bye 👑✨