From: Ard Biesheuvel ardb@kernel.org
[ Upstream commit 46908326c6b801201f1e46f5ed0db6e85bef74ae ]
Branden reports that commit
f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction")
regresses UEFI platforms that implement GetVariable but not SetVariable when booting kernels that have EFIBC (bootloader control) enabled.
The reason is that EFIBC is a user of the efivars abstraction, which was updated to permit users that rely only on the read capability, but not on the write capability. EFIBC is in the latter category, so it has to check explicitly whether efivars supports writes.
Fixes: f88814cc2578c1 ("efi/efivars: Expose RT service availability via efivars abstraction") Tested-by: Branden Sherrell sherrellbc@gmail.com Link: https://lore.kernel.org/linux-efi/AE217103-C96F-4AFC-8417-83EC11962004@gmail... Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/efi/efibc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/efibc.c b/drivers/firmware/efi/efibc.c index 35dccc88ac0af..15a47539dc563 100644 --- a/drivers/firmware/efi/efibc.c +++ b/drivers/firmware/efi/efibc.c @@ -84,7 +84,7 @@ static int __init efibc_init(void) { int ret;
- if (!efi_enabled(EFI_RUNTIME_SERVICES)) + if (!efivars_kobject() || !efivar_supports_writes()) return -ENODEV;
ret = register_reboot_notifier(&efibc_reboot_notifier);