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/efi.c b/drivers/firmware/efi/efi.c
index ac88ec0..36ffa17 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -23,6 +23,7 @@
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/io.h>
+#include <linux/platform_device.h>
struct efi __read_mostly efi = {
.mps = EFI_INVALID_TABLE_ADDR,
@@ -324,6 +325,20 @@
return 0;
}
+#ifdef CONFIG_EFI_VARS_MODULE
+static int __init efi_load_efivars(void)
+{
+ struct platform_device *pdev;
+
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return 0;
+
+ pdev = platform_device_register_simple("efivars", 0, NULL, 0);
+ return IS_ERR(pdev) ? PTR_ERR(pdev) : 0;
+}
+device_initcall(efi_load_efivars);
+#endif
+
#ifdef CONFIG_EFI_PARAMS_FROM_FDT
#define UEFI_PARAM(name, prop, field) \