efi: Autoload efivars
The original patch is from Ben Hutchings's contribution to debian
kernel. Got Ben's permission to remove the code of efi-pstore.c and
send to linux-efi:
https://github.com/BlankOn/linux-debian/blob/master/debian/patches/features/all/efi-autoload-efivars.patch
efivars is generally useful to have on EFI systems, and in some cases
it may be impossible to load it after a kernel upgrade in order to
complete a boot loader update. At the same time we don't want to waste
memory on non-EFI systems by making them built-in.
Instead, give them module aliases as if they are platform drivers, and
register a corresponding platform device whenever EFI runtime services
are available. This should trigger udev to load them.
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 463c565..f256ecd 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -78,6 +78,7 @@
MODULE_DESCRIPTION("sysfs interface to EFI Variables");
MODULE_LICENSE("GPL");
MODULE_VERSION(EFIVARS_VERSION);
+MODULE_ALIAS("platform:efivars");
LIST_HEAD(efivar_sysfs_list);
EXPORT_SYMBOL_GPL(efivar_sysfs_list);