Starting with Linux v6.2, there's a loader type assigned to barebox:
commit a27e292b8a54e24f85181d949fac8c51fdec8ff3
Author: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
AuthorDate: Sun Oct 2 14:57:53 2022 +0200
Commit: Borislav Petkov <bp@xxxxxxx>
CommitDate: Mon Oct 17 11:22:33 2022 +0200
Documentation/x86/boot: Reserve type_of_loader=13 for barebox
barebox[1], a bootloader for mostly ARM and MIPS embedded systems, can
also be built as EFI payload for x86[2] to provide redundant power-fail
safe, watchdog-supervised boot up.
Since its v2015.09.0 release, it has been booting Linux on x86 with
type_of_loader=0xff[3]. Reserve 13, the next free id, so that can be
used instead in the future.
[1]: https://www.barebox.org/
[2]: https://www.barebox.org/doc/latest/boards/efi.html
[3]: https://elixir.bootlin.com/barebox/v2022.09.0/source/common/efi/payload/image.c#L217
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20221002125752.3400831-1-a.fatoum@xxxxxxxxxxxxxx
Thus, let's start making use of that.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
efi/payload/image.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/efi/payload/image.c b/efi/payload/image.c
index b7f4b7560b4b..a8748da1df88 100644
--- a/efi/payload/image.c
+++ b/efi/payload/image.c
@@ -261,7 +261,10 @@ static int do_bootm_efi(struct image_data *data)
memset(boot_header, 0, 0x4000);
memcpy(boot_header, image_header, sizeof(*image_header));
- boot_header->type_of_loader = 0xff;
+ /* Refer to Linux kernel commit a27e292b8a54
+ * ("Documentation/x86/boot: Reserve type_of_loader=13 for barebox")
+ */
+ boot_header->type_of_loader = 0x13;
if (data->initrd_file) {
tmp = read_file(data->initrd_file, &size);
--
2.39.2
