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    SubjectRe: [PATCH RFC bootconfig] Allow forcing unconditional bootconfig processing
    On Sun, Jan 08, 2023 at 12:22:15AM +0900, Masami Hiramatsu wrote:
    > On Wed, 4 Jan 2023 16:58:38 -0800
    > "Paul E. McKenney" <> wrote:
    > > 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.
    > I like this because this is a simple solution. We have another option
    > to specify "bootconfig" in CONFIG_CMDLINE, but it can be overwritten by
    > bootloader. Thus, it is better to have this option so that user can
    > always enable bootconfig.

    Glad you like it!

    In addition, if the help text is accurate, another shortcoming of
    CONFIG_CMDLINE is that its semantics vary from one architecture to
    another. Some have CONFIG_CMDLINE override the boot-loader supplied
    parameters, and others differ in the order in which the parameters
    are processed.

    > Acked-by: Masami Hiramatsu (Google) <>

    Thank you!

    > BTW, maybe CONFIG_BOOT_CONFIG_EMBED is better to select this.
    > (or at least recommend to enable this)

    Like this?

    Thanx, Paul


    commit d09a1505c51a70da38b34ac38062977299aef742
    Author: Paul E. McKenney <>
    Date: Sat Jan 7 08:09:22 2023 -0800

    bootconfig: Default BOOT_CONFIG_FORCE to y if BOOT_CONFIG_EMBED

    When a kernel is built with CONFIG_BOOT_CONFIG_EMBED=y, the intention
    will normally be to unconditionally provide the specified kernel-boot
    arguments to the kernel, as opposed to requiring a separately provided
    bootconfig parameter. Therefore, make the BOOT_CONFIG_FORCE Kconfig
    option default to y in kernels built with CONFIG_BOOT_CONFIG_EMBED=y.

    The old semantics may be obtained by manually overriding this default.

    Suggested-by: Masami Hiramatsu <>
    Signed-off-by: Paul E. McKenney <>

    diff --git a/init/Kconfig b/init/Kconfig
    index 0fb19fa0edba9..97a0f14d9020d 100644
    --- a/init/Kconfig
    +++ b/init/Kconfig
    @@ -1379,6 +1379,7 @@ config BOOT_CONFIG
    bool "Force unconditional bootconfig processing"
    depends on BOOT_CONFIG
    + default y if BOOT_CONFIG_EMBED
    With this Kconfig option set, BOOT_CONFIG processing is carried
    out even when the "bootconfig" kernel-boot parameter is omitted.
     \ /
      Last update: 2023-03-26 23:31    [W:9.584 / U:0.008 seconds]
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