From 2859dff97e54db4795b8b7d9606cb8efcec722ff Mon Sep 17 00:00:00 2001 From: Steve McIntyre Date: Fri, 9 Jan 2015 15:29:53 +0000 Subject: efi: Expose underlying UEFI firmware platform size to userland In some cases (e.g. Intel Bay Trail machines), the kernel will happily run in 64-bit even if the underlying UEFI firmware platform is 32-bit. That's great, but it's difficult for userland utilities like grub-install to do the right thing in such a situation. The kernel already knows about the size of the firmware via efi_enabled(EFI_64BIT). Add an extra sysfs interface /sys/firmware/efi/fw_platform_size to expose that information to userland for low-level utilities to use. Signed-off-by: Steve McIntyre Cc: Matthew Garrett Signed-off-by: Matt Fleming --- drivers/firmware/efi/efi.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/firmware/efi') diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index ff0bbe383b31..9bdbc0533627 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -112,15 +112,24 @@ EFI_ATTR_SHOW(fw_vendor); EFI_ATTR_SHOW(runtime); EFI_ATTR_SHOW(config_table); +static ssize_t fw_platform_size_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32); +} + static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor); static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime); static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table); +static struct kobj_attribute efi_attr_fw_platform_size = + __ATTR_RO(fw_platform_size); static struct attribute *efi_subsys_attrs[] = { &efi_attr_systab.attr, &efi_attr_fw_vendor.attr, &efi_attr_runtime.attr, &efi_attr_config_table.attr, + &efi_attr_fw_platform_size.attr, NULL, }; -- cgit v1.2.3-59-g8ed1b