From: Mauro Carvalho Chehab Date: Mon, 17 Feb 2020 16:12:00 +0000 (+0100) Subject: docs: filesystems: convert efivarfs.txt to ReST X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=06dedb45b79c6550b878244879f33b6e614126bd;p=linux.git docs: filesystems: convert efivarfs.txt to ReST Trivial changes: - Add a SPDX header; - Adjust document title; - Mark a literal block as such; - Add it to filesystems/index.rst. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/215691d747055c4ccb038ec7d78d8d1fe87fe2c0.1581955849.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet --- diff --git a/Documentation/filesystems/efivarfs.rst b/Documentation/filesystems/efivarfs.rst new file mode 100644 index 0000000000000..90ac65683e7e9 --- /dev/null +++ b/Documentation/filesystems/efivarfs.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================= +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 + +Due to the presence of numerous firmware bugs where removing non-standard +UEFI variables causes the system firmware to fail to POST, efivarfs +files that are not well-known standardized variables are created +as immutable files. This doesn't prevent removal - "chattr -i" will work - +but it does prevent this kind of failure from being accomplished +accidentally. diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt deleted file mode 100644 index 686a64bba775e..0000000000000 --- a/Documentation/filesystems/efivarfs.txt +++ /dev/null @@ -1,23 +0,0 @@ - -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 - -Due to the presence of numerous firmware bugs where removing non-standard -UEFI variables causes the system firmware to fail to POST, efivarfs -files that are not well-known standardized variables are created -as immutable files. This doesn't prevent removal - "chattr -i" will work - -but it does prevent this kind of failure from being accomplished -accidentally. diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst index d6d69f1c92877..4230f49d27324 100644 --- a/Documentation/filesystems/index.rst +++ b/Documentation/filesystems/index.rst @@ -60,6 +60,7 @@ Documentation for filesystem implementations. debugfs dlmfs ecryptfs + efivarfs fuse overlayfs virtiofs