Re: [RFC PATCH 2/2] efi: remove deprecated 'efivars' sysfs interface

Ard Biesheuvel
2022-06-16T16:33:14Z

On Thu, 16 Jun 2022 at 18:20, Kees Cook <keescook@chromium.org> wrote:
>
> On Thu, Jun 16, 2022 at 02:47:40PM +0200, Ard Biesheuvel wrote:
> > Commit 5d9db883761a ("efi: Add support for a UEFI variable filesystem")
> > dated Oct 5, 2012, introduced a new efivarfs pseudo-filesystem to
> > replace the efivars sysfs interface that was used up to that point to
> > expose EFI variables to user space.
> >
> > The main problem with the sysfs interface was that it only supported up
> > to 1024 bytes of payload per file, whereas the underlying variables
> > themselves are only bounded by a platform specific per-variable and
> > global limit that is typically much higher than 1024 bytes.
> >
> > The deprecated sysfs interface is only enabled on x86 and Itanium, other
> > EFI enabled architectures only support the efivarfs pseudo-filesystem.
>
> Does anything still use the sysfs interface? (e.g. do paths to it exist
> in anything meaningful in, say, a Debian code search?)
>

All the hits I get there are in code that refers to
/sys/firmware/efi/vars as the 'legacy' path, and also carries a
reference to efivarfs. (i.e., /sys/firmware/efi/efivars)