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>
This commit is contained in:
Lee, Chun-Yi 2014-07-09 18:39:29 +08:00 committed by Matt Fleming
parent 82f990a822
commit 28d54022e6
2 changed files with 16 additions and 0 deletions

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@ -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 @@ int __init efi_config_init(efi_config_table_type_t *arch_tables)
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) \

View File

@ -78,6 +78,7 @@ MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
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);