Re: Running LibC application from shell causes "Command Error Status: Unsupported" on real hardware, works in VM


Nate DeSimone
 

Probably the version of the UEFI shell you are using to launch the lua interpreter is newer and/or older than the version of edk2 you are using to compile the lua interpreter.

The LibC in AppPkg does a lot of runtime dynamic linking with the UEFI shell using EFI protocols. This is because several things that libc expects the OS to provide such as command line arguments (argc, argv) and relative filesystem paths do not exist in the baseline UEFI spec. The UEFI shell fills in most of the missing pieces.

My shot in the dark guess is that EFI_UNSUPPORTED is coming back because one of the EFI protocols that LibC is looking for during startup is missing.

Thanks,
Nate

-----Original Message-----
From: discuss@edk2.groups.io <discuss@edk2.groups.io> On Behalf Of JackMacWindows
Sent: Saturday, January 25, 2020 4:00 PM
To: discuss@edk2.groups.io
Subject: [edk2-discuss] Running LibC application from shell causes "Command Error Status: Unsupported" on real hardware, works in VM

I’m writing an application for UEFI that provides a Lua shell for users to interact with. I have successfully gotten the code to run inside QEMU with OVMF, but any time I try to run it on real hardware I get "Command Error Status: Unsupported" from the shell. The testing machine I’m using is an Ivy Bridge Dell laptop with UEFI 2.31, but it also didn’t work when testing it on a Kaby Lake laptop with UEFI 2.60. The build files (.inf, .dsc) are almost exactly the same as the Lua 5.2 example listed in AppPkg in LibC. I have added print statements around the program, but none of them appear, including one at the absolute beginning of the entry point. (I overrode ShellCEntryLib to do this.) This indicates that the error is likely relating to linking/executable generation. I’m able to compile and run other applications on real hardware, including the shell as well as Main and Lua in AppPkg.

I have absolutely no idea what I can do to debug this further, as everything I have done to try to fix this has failed. Does anybody have any idea what could be going wrong? The source code can be found at https://github.com/MCJack123/craftos-efi.

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