cnstr_shdsc_ahash(9)

🌸 cnstr_shdsc_ahash — ahash shared descriptor 🌸

okay so this is a page from the Kernel API Manual (section 9, kernel girlies rise), and it's all about cnstr_shdsc_ahash — the function that builds you an ahash shared descriptor. yes bestie, we're doing crypto descriptor construction today and we're gonna slay it 💅

✨ SYNOPSIS ✨

void cnstr_shdsc_ahash(u32 * const desc, struct alginfo *adata, u32 state,
                       int digestsize, int ctx_len, bool import_ctx, int era);

it returns void — nothing comes back, no cap, the descriptor buffer just gets filled in. 🫶

🦋 ARGUMENTS 🦋

• desc — pointer to the buffer used for descriptor construction. this is the canvas, your main character, the place where the descriptor gets written 💖
• adata — pointer to the authentication transform definitions. lowkey important detail here: a split key is required for SEC Era < 6, and in that case the size of the split key is specified in this one. valid algorithm values are — one of OP_ALG_ALGSEL_{MD5, SHA1, SHA224, SHA256, SHA384, SHA512}. pick your fighter ⭐
• state — the algorithm state, one of OP_ALG_AS_{INIT, FINALIZE, INITFINALIZE, UPDATE}. it's giving phases of a glow-up, honestly 🌈
• digestsize — the algorithm's digest size. how big the digest is. that's the whole vibe 🔥
• ctx_len — size of the Context Register. yes, that's the Context Register specifically, not some other register 🎀
• import_ctx — true if the previous Context Register needs to be restored. and here's the tea: it must be true for ahash update and final, and it must be false for ahash first and digest. so like, no mixing that up, okay? 🙈
• era — the SEC Era. which era we're in. iconic either way 👑

ngl bestie, that import_ctx one is the trap on this page — true for update and final, false for first and digest. memorize it, iykyk 😭

💜 SEE ALSO 💜

• Kernel file ./drivers/crypto/caam/caamhash_desc.c
• cnstr_shdsc_sk_hash(9)

and that's the whole page, no notes 🦋 mwah 💋

sign-off szn — this one lives in ./drivers/crypto/caam, dated October 2026, and it's your girl cnstr_shdsc_ahash(9) signing off. periodt. 💅✨