Michael Brown
29e6f9835e
[i386] Add data32 prefixes to all lgdt/lidt instructions
With a 16-bit operand, lgdt/lidt will load only a 24-bit base address,
ignoring the high-order bits. This meant that we could fail to fully
restore the GDT across a call into gPXE, if the GDT happened to be
located above the 16MB mark.
Not all of our lgdt/lidt instructions require a data32 prefix (for
example, reloading the real-mode IDT can never require a 32-bit base
address), but by adding them everywhere we will hopefully not forget
the necessary ones in future.