kernel/git/stable/linux.git/Documentation/admin-guide/bootconfig.rst, branch master

Documentation: bootconfig: document build-time cmdline rendering

2026-07-02T12:15:45+00:00

Add a section describing CONFIG_CMDLINE_FROM_BOOTCONFIG: what it does (renders the embedded "kernel" subtree to a flat cmdline at build time so early_param() handlers see the values), what it requires (BOOT_CONFIG_EMBED, a non-empty BOOT_CONFIG_EMBED_FILE, CONFIG_CMDLINE to be empty, and ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG -- currently x86 only), the bootconfig opt-in semantics, the initrd-vs-embedded precedence, and the soft-error overflow behavior. This addresses feedback from the Sashiko AI review and Masami Hiramatsu to document the CONFIG_CMDLINE requirement, which is enforced at the Kconfig level but was not mentioned in the documentation, potentially confusing users who might satisfy all other requirements but still find the option hidden in menuconfig if CONFIG_CMDLINE is non-empty. Link: https://lore.kernel.org/all/20260626-bootconfig_using_tools-v7-6-24ab72139c29@debian.org/ Signed-off-by: Breno Leitao Signed-off-by: Masami Hiramatsu (Google)

bootconfig: Terminate value search if it hits a newline

2026-02-05T13:21:07+00:00

Terminate the value search for a key if it hits a newline and make the value empty. When we pass a bootconfig with an empty value terminated by the newline, like below:: foo = bar = value Current bootconfig interprets it as a single entry:: foo = "bar = value"; The Documentation/admin-guide/bootconfig.rst defines the value itself is terminated by newline: The value has to be terminated by semi-colon (``;``) or newline (``\n``). but it does not define when the value search is terminated. This changes the behavior to be more line-oriented, so that it is clearer in how it works. - The value search of key-value pair will be terminated by a comment or newline. - The value search of an array will continue beyond comments and newlines. Thus, with this update, the above example is interpreted as:: foo = ""; bar = "value"; And the below example will cause a syntax error because "bar" is expected as a key but it has ','. foo = bar, buz According to this change, one wrong example config is updated. Link: https://lore.kernel.org/all/177025238503.14982.17059549076175612447.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Julius Werner

Documentation: Remove duplicate word size in bootconfig

2025-07-08T14:11:10+00:00

Remove duplicate word size in bootconfig.rst Signed-off-by: Sumeet Pawnikar Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250705151618.4806-1-sumeet4linux@gmail.com

Allow forcing unconditional bootconfig processing

2023-02-21T23:27:48+00:00

The BOOT_CONFIG family of Kconfig options allows a bootconfig file containing kernel boot parameters to be embedded into an initrd or into the kernel itself. This can be extremely useful when deploying kernels in cases where some of the boot parameters depend on the kernel version rather than on the server hardware, firmware, or workload. Unfortunately, the "bootconfig" kernel parameter must be specified in order to cause the kernel to look for the embedded bootconfig file, and it clearly does not help to embed this "bootconfig" kernel parameter into that file. Therefore, provide a new BOOT_CONFIG_FORCE Kconfig option that causes the kernel to act as if the "bootconfig" kernel parameter had been specified. In other words, kernels built with CONFIG_BOOT_CONFIG_FORCE=y will look for the embedded bootconfig file even when the "bootconfig" kernel parameter is omitted. This permits kernel-version-dependent kernel boot parameters to be embedded into the kernel image without the need to (for example) update large numbers of boot loaders. Link: https://lore.kernel.org/all/20230105005838.GA1772817@paulmck-ThinkPad-P17-Gen-1/ Signed-off-by: Paul E. McKenney Cc: Masami Hiramatsu Cc: Jonathan Corbet Cc: Andrew Morton Cc: Nick Desaulniers Cc: Vlastimil Babka Cc: Johannes Weiner Cc: Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)

Documentation: Fixed a typo in bootconfig.rst

2022-12-03T10:48:29+00:00

Fixed a typo in the word 'concatenated'. Signed-off-by: Kushagra Verma Link: https://lore.kernel.org/r/HK0PR01MB2801DA243B726141A97FE92EF8179@HK0PR01MB2801.apcprd01.prod.exchangelabs.com Signed-off-by: Jonathan Corbet

docs: bootconfig: Add how to embed the bootconfig into kernel

2022-04-26T21:58:51+00:00

Add a description how to embed the bootconfig file into kernel. Link: https://lkml.kernel.org/r/164921228987.1090670.16843569536974147213.stgit@devnote2 Cc: Padmanabha Srinivasaiah Cc: Jonathan Corbet Cc: Randy Dunlap Cc: Nick Desaulniers Cc: Sami Tolvanen Cc: Nathan Chancellor Cc: Masahiro Yamada Cc: Linux Kbuild mailing list Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google)

docs: bootconfig: Add how to use bootconfig for kernel parameters

2021-09-08T19:10:41+00:00

Add a section to describe how to use the bootconfig for specifying kernel and init parameters. This is an important section because it is the reason why this document is under the admin-guide. Link: https://lkml.kernel.org/r/163077086399.222577.5881779375643977991.stgit@devnote2 Signed-off-by: Masami Hiramatsu Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Signed-off-by: Steven Rostedt (VMware)

docs: bootconfig: Update for mixing value and subkeys

2021-06-10T17:41:26+00:00

Update document for the mixing value and subkeys on a key. Link: https://lkml.kernel.org/r/162262196510.264090.15044943496205914148.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

docs: admin-guide: bootconfig: Fix feils to fails

2021-01-07T21:44:58+00:00

s/feils/fails/p Signed-off-by: Bhaskar Chowdhury Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20210107125610.1576368-1-unixbhaskar@gmail.com Signed-off-by: Jonathan Corbet

docs: bootconfig: Add the endianness of fields

2020-12-01T04:22:11+00:00

Add a description about the endianness of the size and the checksum fields. Those must be stored as le32 instead of u32. This will allow us to apply bootconfig to the cross build initrd without caring the endianness. Link: https://lkml.kernel.org/r/160583936246.547349.10964204130590955409.stgit@devnote2 Reported-by: Steven Rostedt Suggested-by: Linus Torvalds Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)