LinuxKPI: Implement efi_enabled(EFI_BOOT)

[wulf]

Summary

efi_enabled(EFI_BOOT) returns true if machine was booted from EFI
Used by drm-kmod and some unported drm drivers like hyperv

MFC after: 1 week

[• hselasky]

sys/compat/linuxkpi/common/include/linux/efi.h

59

Is it possible to catch this compile time with a static assert, CTASSERT() or _Static_assert() ?

[wulf]

Add _Static_assert wrapper for compile-time argument checking

[imp]

sys/compat/linuxkpi/common/include/linux/efi.h

56

I thought we had a more direct EFI enabled variable these days....

bool efi_boot;

in machdep.c. Is there some reason that wasn't used? We use the above to search it out early in boot, why not use the cached result?

[bz]

sys/compat/linuxkpi/common/include/linux/efi.h

30

_BSD_LKPI_ is a new one to me; can that be _LINUXKPI_ ?

[wulf]

sys/compat/linuxkpi/common/include/linux/efi.h

30

It must be _LINUX_EFI_H_. I will fix it.

56

efi_boot is defined on amd64 only while MODINFOMD_EFI_MAP exists on every platform which is able to boot from EFI

[wulf]

Use cached efi_boot value on amd64