spu2_request_pad(9)

💅 spu2_request_pad — the Kernel API Manual page, but make it make sense

okay bestie, so this one lives in the Kernel API Manual and it's literally the function that handles the ✨leftovers✨ — the pad bytes at the end of your data. Yes, padding. It's not glamorous but it IS load-bearing, so let's get into it 🎀

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✨ NAME ✨

spu2_request_pad — create pad bytes at the end of the data. that's it, that's the whole vibe 🫶

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🌸 SYNOPSIS 🌸

void spu2_request_pad (u8 *pad_start , u32 gcm_padding , u32
hash_pad_len , enum hash_alg auth_alg , enum hash_mode auth_mode ,
unsigned int total_sent , u32 status_padding );

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🦋 ARGUMENTS 🦋

• pad_start — start of the buffer where the pad bytes are gonna be written. this is the spot, the location, the moment 💫
• gcm_padding — the length of the GCM padding, in bytes. numbers, we love her
• hash_pad_len — how many bytes of padding it takes to extend the data to a full block. the glow-up-to-full-block count ✨
• auth_alg — the authentication algorithm. which one? that's the enum hash_alg of it all
• auth_mode — the authentication mode. again, enum hash_mode, we don't make the rules
• total_sent — the length that gets inserted at the end of the hash pad 👑
• status_padding — how many bytes of padding it takes to align the STATUS word 🔥

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💖 DESCRIPTION 💖

so there may be three forms of pad, and honestly? each one is serving a different purpose. it's giving "three sisters, three destinies" 😭

1. GCM pad — for GCM mode ciphers, pad to 16-byte alignment. sixteenth-byte alignment is the standard, no cap 💅
2. hash pad — pad to a block length, with 0x80 data terminator and size at the end. note the 0x80 terminator, bestie, it's not optional, it's the whole personality 🌈
3. STAT pad — to ensure the STAT field is 4-byte aligned ⭐

fr fr, these three are the only forms of pad described here — don't go inventing a fourth, i'm begging 🙈

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👑 SEE ALSO 👑

kernel file ./drivers/crypto/bcm/spu2.c, plus the whole friend group:

• spu2_cipher_xlate(9)
• spu2_hash_xlate(9)
• spu2_fmd_init(9)
• spu2_fmd_ctrl0_write(9)
• spu2_fmd_ctrl1_write(9)
• spu2_fmd_ctrl2_write(9)
• spu2_fmd_ctrl3_write(9)
• spu2_ctx_max_payload(9)
• spu2_payload_length(9)
• spu2_response_hdr_len(9)
• spu2_hash_pad_len(9)
• spu2_gcm_ccm_pad_len(9)
• spu2_assoc_resp_len(9)
• spu2_aead_ivlen(9)
• spu2_hash_type(9)
• spu2_digest_size(9)
• spu2_create_request(9)
• spu2_cipher_req_init(9)
• spu2_cipher_req_finish(9)
• spu2_xts_tweak_in_payload(9)
• spu2_tx_status_len(9)
• spu2_rx_status_len(9)
• spu2_status_process(9)
• spu2_ccm_update_iv(9)
• spu2_wordalign_padlen(9)

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okay that's the page!! 🎀 sourced from ./drivers/crypto/bcm, dated October 2026 — go forth and pad responsibly, ily, mwah 💜🧚