STRUCT RPMB_FRAME(9)

💅 NAME 💅

okay so bestie, gather round — this is struct rpmb_frame, the RPMB frame structure for authenticated access. it's the little 512-byte icon that makes your secure storage talk nice. no cap, she's important. ✨

🎀 SYNOPSIS 🎀

struct rpmb_frame {
    u8 stuff[196];
    u8 key_mac[32];
    u8 data[256];
    u8 nonce[16];
    __be32 write_counter;
    __be16 addr;
    __be16 block_count;
    __be16 result;
    __be16 req_resp;
 };

🌸 Members 🌸

like literally every field, in order, no skipping, i would never 💖

• stuff — okay so these are the stuff bytes, a padding/reserved area of 196 bytes sitting right at the beginning of the RPMB frame. they don't carry meaningful data at all (they're just vibing), but they're required to make the frame exactly 512 bytes. padding queen behavior, we respect it. 👑
• key_mac — the authentication key or the message authentication code (MAC), depending on the request/response type. the MAC gets delivered in the last block of data (or the only block, iykyk). two moods, one field. ✨
• data — the data to be written or read by signed access. that's the whole point, bestie.
• nonce — a random number generated by the host for the requests, and then copied to the response by the RPMB engine. random girlie keeps things fresh. 🎲
• write_counter — counter value for the total amount of the successful authenticated data write requests made by the host. she's counting everything. 😭
• addr — address of the data to be programmed to or read from the RPMB. and heads up: the address is the serial number of the accessed block (half sector 256B). yes, half sector, 256B, write that down. 🫶
• block_count — number of blocks (again: half sectors, 256B) requested to be read/programmed. same unit, keep up bestie 💅
• result — includes information about the status of the write counter (valid, expired) and the result of the access made to the RPMB. so she's holding both the counter tea and the access tea. multi-tasking icon.
• req_resp — defines the type of request and response to/from the memory. the whole conversation direction, honestly.

🦋 Description 🦋

the stuff bytes and the big-endian properties are modeled to fit to the spec. that's it, that's the design choice — and honestly? slay, she matches the spec exactly. 🌈

⭐ SEE ALSO ⭐

• Kernel file ./include/linux/rpmb.h enum rpmb_type(9), struct rpmb_descr(9), struct rpmb_dev(9)

go read those next, bestie, they're literally the rest of the lore 📚💜

and that's the whole page!! 🎀 this lil masterpiece lives under ./include/linux, dated October 2026, and it's section 9 of the Kernel API Manual — so go forth and auth your RPMB frames with main character energy 💅✨🦋