sgx_enclave_user_handler_t(9)

✨ NAME ✨

okay so bestie, this is sgx_enclave_user_handler_t(9) from the Kernel API Manual 💖 — it's the exit handler function that __vdso_sgx_enter_enclave() accepts. literally the callback for enclave exits, and it's giving main character energy ✨

🎀 SYNOPSIS 🎀

int sgx_enclave_user_handler_t (long rdi , long rsi , long rdx , long rsp , long r8 , long r9 , struct sgx_enclave_run *run );

💅 ARGUMENTS 💅

here's the lineup, bestie:

• rdi — RDI at the time of EEXIT; undefined on AEX, so don't trust it 🙈
• rsi — RSI at the time of EEXIT; undefined on AEX, same vibe 💀
• rdx — RDX at the time of EEXIT; undefined on AEX, fr fr
• rsp — RSP (untrusted) at the time of EEXIT or AEX — that "untrusted" is important, bestie 👀
• r8 — R8 at the time of EEXIT; undefined on AEX, ngl
• r9 — R9 at the time of EEXIT; undefined on AEX, lowkey
• run — the run instance given by the caller 🫶

🔥 DESCRIPTION 🔥

the register parameters contain the snapshot of their values at enclave exit. that's the whole point, and it's iconic ✨

if the ENCLU function number is invalid, -EINVAL will be returned to the caller. periodt.

🌈 RETURN 🌈

vibe check on the return value:

• <= 0 — the given value is returned back to the caller 💅
• > 0 — this is the ENCLU function to invoke, either EENTER or ERESUME 🔥

🦋 SEE ALSO 🦋

the kernel file is ./arch/x86/include/uapi/asm/sgx.h, and these are the related pages you should also peek at:

• enum sgx_page_flags(9)
• struct sgx_enclave_create(9)
• struct sgx_enclave_add_pages(9)
• struct sgx_enclave_init(9)
• struct sgx_enclave_provision(9)
• struct sgx_enclave_restrict_permissions(9)
• struct sgx_enclave_modify_types(9)
• struct sgx_enclave_remove_pages(9)
• struct sgx_enclave_run(9)
• vdso_sgx_enter_enclave_t(9)

mwah 💋 that's the page! source/version: ./arch/x86/include/uapi/asm, date: October 2026, and yes, it's still the sgx_enclave_user_handler_t(9) manual page, bestie. 🌸