tree bf7990810494e090c3e27a970ae96d07ceabe26f
parent cefcd4fe2e3aaf792c14c9e56dab89e3d7a65d02
author Ard Biesheuvel <ardb@kernel.org> 1711123305 +0100
committer Ard Biesheuvel <ardb@kernel.org> 1711268913 +0100

x86/efistub: Don't clear BSS twice in mixed mode

Clearing BSS should only be done once, at the very beginning.
efi_pe_entry() is the entrypoint from the firmware, which may not clear
BSS and so it is done explicitly. However, efi_pe_entry() is also used
as an entrypoint by the mixed mode startup code, in which case BSS will
already have been cleared, and doing it again at this point will corrupt
global variables holding the firmware's GDT/IDT and segment selectors.

So make the memset() conditional on whether the EFI stub is running in
native mode.

Fixes: b3810c5a2cc4a666 ("x86/efistub: Clear decompressor BSS in native EFI entrypoint")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>