FSP, that is build against EDK2 2018 or newer, is able to back up and
restore the bootloader IDT on entry/exit. Even though it sets up its
own IDT, FSP checks the bootloader IDT size and deadloops without
warning if it's too big.
On x86_64 coreboot the IDT is naturally bigger than on x86_32 and thus
x86_32 FSP might die on entry. Work around this issue by:
* Back up and restore the IDT in protected_mode_call_wrapper
* Load zero IDT in protected mode before jumping to function
TEST: Can boot on SPR FSP (x86_32) using x86_64 coreboot with
exceptions in romstage enabled.
Change-Id: I56367d8153aa10a9b1bcaa5ffde8ebe202e8c00c
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85789
Reviewed-by: Shuo Liu <shuo.liu@intel.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com>
de8e4d930d