Fix OP-TEE ELF loading without trampoline bug

[sangho2]

The return values of parse_trampoline have changed (i.e., it returns UnpatchedBinary for an ELF binary without trampoline), but litebox_shim_optee has not been updated accordingly.

Issue #839

[wdcui]

Why would OPTEE shim see unpatched binary?

[sangho2]

Why would OPTEE shim see unpatched binary?

This is for LVBS. It doesn't use trampoline and doesn't patch binaries.

[wdcui]

Why would OPTEE shim see unpatched binary?

This is for LVBS. It doesn't use trampoline and doesn't patch binaries.

Then would get_syscall_entry_point() return 0?

[sangho2]

Why would OPTEE shim see unpatched binary?

This is for LVBS. It doesn't use trampoline and doesn't patch binaries.

Then would get_syscall_entry_point() return 0?

Currently, it returns the callback's address. Better to make it return zero.

[wdcui]

Why would OPTEE shim see unpatched binary?

This is for LVBS. It doesn't use trampoline and doesn't patch binaries.

Then would get_syscall_entry_point() return 0?

Currently, it returns the callback's address. Better to make it return zero.

Yeah, that's the contract: we expect zero for kernel platforms.

[github-actions]

🤖 SemverChecks 🤖 No breaking API changes detected

Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered.