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Commit 2859dff9 authored by Steve McIntyre's avatar Steve McIntyre Committed by Matt Fleming
Browse files

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: default avatarSteve McIntyre <steve@einval.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 17473c32

drivers/firmware/efi/efi.c

+9 −0
Original line number Diff line number Diff line
@@ -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,

};