From e913ca7d16d70b75367ff56a3b201980501d542c Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Thu, 4 Oct 2012 09:57:31 +0100 Subject: [PATCH] efivarfs: Add documentation for the EFI variable filesystem 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 8c624a18f67d..7b52ba7bf32a 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 000000000000..c477af086e65 --- /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 -- 2.30.2