i386 EFI booting is broken (ExitBootServices called in two places)

[Kyle Evans]

On Mon, Feb 25, 2019 at 8:18 PM Rebecca Cran <rebecca at bluestop.org> wrote:
>
> I've been working on some EFI changes, and in the process found that
> i386 booting is broken. On real hardware - my MinnowBoard Turbot - the
> loader hangs when calling ExitBootServices, while in a VM I get a panic
> saying "exec returned".
>
> The problem appears to be that ExitBootServices is called twice:
> elf32_exec in arch/i386/efimd.c calls bi_load which calls
> bi_load_efi_data in bootinfo.c - which calls ExitBootServices the first
> time. Then elf32_exec keeps going, and after printing "Start @ 0x....."
> calls ldr_enter which tries to call ExitBootServices again - this time
> with a mapkey whose value is zero since it never attempts to fetch the
> memory map. I'm guessing that subsequently causes the exec to fail.
>

efimd.c should be garbage collected and the ldr_enter called removed.
r328169 removed the copy of bootinfo that demonstrated the expected
ordering: bi_load returned ldr_bootinfo(), then elf32_exec finished it
off with ldr_enter. These details are captured in MI bootinfo bits
nowadays and none of this is of use in the current world.