From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: [PATCH 04/20] efivarfs: Add documentation for the EFI variable filesystem Date: Fri, 26 Oct 2012 08:51:47 +0100 Message-ID: <1351237923-10313-5-git-send-email-matt@console-pimps.org> References: <1351237923-10313-1-git-send-email-matt@console-pimps.org> Return-path: In-Reply-To: <1351237923-10313-1-git-send-email-matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Matthew Garrett , Jeremy Kerr , Andy Whitcroft , Jan Beulich , Chun-Yi Lee , Matt Fleming List-Id: linux-efi@vger.kernel.org From: Matt Fleming Signed-off-by: Matt Fleming --- Documentation/filesystems/00-INDEX | 2 ++ Documentation/filesystems/efivarfs.txt | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) create mode 100644 Documentation/filesystems/efivarfs.txt diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index 8c624a1..7b52ba7 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -38,6 +38,8 @@ dnotify_test.c - example program for dnotify ecryptfs.txt - docs on eCryptfs: stacked cryptographic filesystem for Linux. +efivarfs.txt + - info for the efivarfs filesystem. exofs.txt - info, usage, mount options, design about EXOFS. ext2.txt diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt new file mode 100644 index 0000000..c477af0 --- /dev/null +++ b/Documentation/filesystems/efivarfs.txt @@ -0,0 +1,16 @@ + +efivarfs - a (U)EFI variable filesystem + +The efivarfs filesystem was created to address the shortcomings of +using entries in sysfs to maintain EFI variables. The old sysfs EFI +variables code only supported variables of up to 1024 bytes. This +limitation existed in version 0.99 of the EFI specification, but was +removed before any full releases. Since variables can now be larger +than a single page, sysfs isn't the best interface for this. + +Variables can be created, deleted and modified with the efivarfs +filesystem. + +efivarfs is typically mounted like this, + + mount -t efivarfs none /sys/firmware/efi/efivars -- 1.7.11.7