Commit 5688e977 authored by Hans de Goede's avatar Hans de Goede Committed by Ard Biesheuvel
Browse files

efi/libstub: gop: Fix EDID support in mixed-mode 



The efi_edid_discovered_protocol and efi_edid_active_protocol have mixed
mode fields. So all their attributes should be accessed through
the efi_table_attr() helper.

Doing so fixes the upper 32 bits of the 64 bit gop_edid pointer getting
set to random values (followed by a crash at boot) when booting a x86_64
kernel on a machine with 32 bit UEFI like the Asus T100TA.

Fixes: 17029cdd ("efi/libstub: gop: Add support for reading EDID")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: default avatarHans de Goede <johannes.goede@oss.qualcomm.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 8f0b4cce

drivers/firmware/efi/libstub/gop.c

+4 −4
Original line number Diff line number Diff line
@@ -513,15 +513,15 @@ efi_status_t efi_setup_graphics(struct screen_info *si, struct edid_info *edid) 
		status = efi_bs_call(handle_protocol, handle, &EFI_EDID_ACTIVE_PROTOCOL_GUID,

				     (void **)&active_edid);

		if (status == EFI_SUCCESS) {

			gop_size_of_edid = active_edid->size_of_edid;

			gop_edid = active_edid->edid;

			gop_size_of_edid = efi_table_attr(active_edid, size_of_edid);

			gop_edid = efi_table_attr(active_edid, edid);

		} else {

			status = efi_bs_call(handle_protocol, handle,

					     &EFI_EDID_DISCOVERED_PROTOCOL_GUID,

					     (void **)&discovered_edid);

			if (status == EFI_SUCCESS) {

				gop_size_of_edid = discovered_edid->size_of_edid;

				gop_edid = discovered_edid->edid;

				gop_size_of_edid = efi_table_attr(discovered_edid, size_of_edid);

				gop_edid = efi_table_attr(discovered_edid, edid);

			}

		}