mirror/buildroot
1
0
Fork 0
mirror of https://gitlab.com/buildroot.org/buildroot.git synced 2026-10-22 08:52:29 -09:00
Code Issues Packages Projects Releases Wiki Activity

docs/manual/writing-rules: align use of genimage partition types

Browse Source 
Buildroot boards use a mixture of the GPT Partition Type "L" (generic
Linux filesystem) and "root-x86", "root-arm", etc (UAPI Root
Filesystem) for root filesystem partitions.

To have consistent guidance on building disk images with genimage,
update the docs to recommend using the UAPI Root Filesystem types. The
UAPI Root Filesystem types are part of the UAPI Discoverable Partitions
Specification (DPS) which helps set a wider standard for system boot.

See https://uapi-group.org/specifications/specs/discoverable_partitions_specification/

Signed-off-by: Brandon Maier <brandon.maier@gmail.com>
[Arnout: some additional rewording mainly based on input from Niklas
Cassel]
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
This commit is contained in:
Brandon Maier
2024-11-17 15:00:38 -06:00
committed by Arnout Vandecappelle
parent 0dadf9c38e
commit 529df0b580
1 changed files with 26 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
docs/manual/writing-rules.adoc
View File

@@ -141,9 +141,9 @@ endif
=== The +genimage.cfg+ file
+genimage.cfg+ files contain the output image layout that genimage utility
uses to create final .img file.
An example follows:
uses to create final .img file. See the
https://github.com/pengutronix/genimage/blob/master/README.rst[upstream
documentation] for details. In Buildroot it is formatted as follows.
----
image efi-part.vfat {
@@ -198,22 +198,30 @@ image sdimage.img {
chance, the byte count. In comments instead use +GB+, +MB+, +KB+
(not +kb+) in place of +G+, +M+, +K+.
* For GPT partitions, the +partition-type-uuid+ value must be +U+ for
the EFI System Partition (expanded to
+c12a7328-f81f-11d2-ba4b-00a0c93ec93b+ by _genimage_), +F+ for a FAT
partition (expanded to +ebd0a0a2-b9e5-4433-87c0-68b6b72699c7+ by
_genimage_) or +L+ for the root filesystem or other filesystems
(expanded to +0fc63daf-8483-4772-8e79-3d69d8477de4+ by
_genimage_). Even though +L+ is the default value of _genimage_, we
prefer to have it explicitly specified in our +genimage.cfg+
files. Finally, these shortcuts should be used without double
quotes, e.g +partition-type-uuid = U+. If an explicit GUID is
specified, lower-case letters should be used.
* Every +partition+ of a GPT image (e.g. +partition-table-type = gpt+) must
explicitly set +partition-type-uuid+. It must not be double-quoted. Buildroot
follows the
https://uapi-group.org/specifications/specs/discoverable_partitions_specification/[UAPI
Discoverable Partitions Specification] whenever possible. This means that the
partitions define a specific +partition-type-uuid+ depending on the intended
mountpoint.
+
_genimage_ provides
https://github.com/pengutronix/genimage/?tab=readme-ov-file#the-image-section[shortcuts
for many of the partition types in the Discoverable Partitions Specification],
and these shortcuts must be used whenever possible. If a GUID shortcut is not
supported by _genimage_, the full GUID must be written in lower-case letters.
Some common shortcuts are as follows:
The +genimage.cfg+ files are the input for the genimage tool used in
Buildroot to generate the final image file(i.e. sdcard.img). For further
details about the _genimage_ language, refer to
https://github.com/pengutronix/genimage/blob/master/README.rst[].
** +U+ for the EFI System Partition (expanded to
+c12a7328-f81f-11d2-ba4b-00a0c93ec93b+ by _genimage_).
** +root-\{arch\}+ for the root filesystem partition, where +\{arch\}+ is the
system architecture (for example +root-x86+, +root-x86-64+, +root-arm+, or
+root-arm64+).
** +L+ for other Linux filesystem partitions (expanded to
+0fc63daf-8483-4772-8e79-3d69d8477de4+ by _genimage_).
=== The documentation