STRUCT OPTEE_MSG_ARG(9)

✨ struct optee_msg_arg — call argument ✨

okay so bestie, welcome to the struct optee_msg_arg(9) page from the Kernel API Manual — yes we're in kernel land today and honestly? it's giving main character energy 🫶 this one's short and sweet, so let's go 💅

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🌸 NAME 🌸

struct optee_msg_arg — literally the call argument. that's it. that's the vibe 🎀

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🦋 SYNOPSIS 🦋

struct optee_msg_arg {
    u32 cmd;
    u32 func;
    u32 session;
    u32 cancel_id;
    u32 pad;
    u32 ret;
    u32 ret_origin;
    u32 num_params;
    struct optee_msg_param params[];
};

look at her. flawless. no notes. 🔥

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💖 Members 💖

• cmd — the command, bestie. it's one of OPTEE_MSG_CMD_* or OPTEE_MSG_RPC_CMD_* ✨
• func — the Trusted Application function, and it's specific to the Trusted Application, iykyk. only used when cmd == OPTEE_MSG_CMD_INVOKE_COMMAND 👑
• session — lowkey the plot twist of this struct: it's an in parameter for all OPTEE_MSG_CMD_*… except for OPTEE_MSG_CMD_OPEN_SESSION, where it's an output parameter instead 🙈
• cancel_id — the cancellation id, a unique value that identifies this request 🎯
• pad — padding for alignment. she's just here for the vibes, keeping things lined up 💅
• ret — return value 🍓
• ret_origin — the origin of the return value 👀
• num_params — number of parameters supplied to the OS Command ⭐
• params — the actual parameters supplied to the OS Command, a whole array of them 🌈

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💀 Description 💀

okay so real talk: all normal calls to Trusted OS use this struct, fr fr. periodt. 🧚

if cmd needs more info than what these fields can hold, you can pass it as a parameter tagged as meta — that's you setting the OPTEE_MSG_ATTR_META bit in the corresponding attrs field 🔥

⚠️ but heads up bestie: all parameters tagged as meta have to come first. no cap. that's the rule and we respect her 💖

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💜 SEE ALSO 💜

• Kernel file ./drivers/tee/optee/optee_msg.h struct
• optee_msg_param_tmem(9)
• struct optee_msg_param_rmem(9)
• struct optee_msg_param_fmem(9)
• struct optee_msg_param_value(9)
• struct optee_msg_param(9)
• OPTEE_MSG_GET_ARG_SIZE(9)

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and that's the page, gorgeous 💅 huge shoutout to ./drivers/tee/optee for hosting this icon, October 2026 for the date stamp, all under the Kernel API Manual banner 🌸 now go forth and slay your TEE calls, bestie — you got this 🫶✨