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 then patch 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. Cc: Ben Hutchings <[email protected]> Cc: Matt Fleming <[email protected]> Signed-off-by: Lee, Chun-Yi <[email protected]> --- arch/x86/platform/efi/efi.c | 15 +++++++++++++++ drivers/firmware/efi/efivars.c | 1 + 2 files changed, 16 insertions(+) diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 87fc96b..c295c08 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -44,6 +44,7 @@ #include <linux/io.h> #include <linux/reboot.h> #include <linux/bcd.h> +#include <linux/platform_device.h> #include <asm/setup.h> #include <asm/efi.h> @@ -780,6 +781,20 @@ void __init efi_late_init(void) efi_bgrt_init(); } +#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 + void __init efi_set_executable(efi_memory_desc_t *md, bool executable) { u64 addr, npages; 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_AUTHOR("Matt Domsch <[email protected]>"); 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); -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
