arch/x86: Correct multiboot interpretation when building for EFI

When loaded via EFI, we obviously don't have a multiboot info pointer
available (we might have an EFI system table, but zefi doesn't pass
that through yet).  Don't try to parse the "whatever garbage was in
%rbp" as a multiboot table.

The configuration is a little clumsy, as strictly our EFI kconfig just
says we're "building for" EFI but not that we'll boot that way.  And
tests like arch/x86/info are trying to set CONFIG_MULTIBOOT=n
unconditionally, when it really should be something they detect from
devicetree or wherever.

Fixes #33545

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
4 files changed