lkml.org 
[lkml]   [2022]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 3/3] docs: bootconfig: Add how to embed the bootconfig into kernel
On Sun, 13 Mar 2022 19:03:20 -0700
Randy Dunlap <rdunlap@infradead.org> wrote:

>
>
> On 3/13/22 18:54, Masami Hiramatsu wrote:
> > Add a description how to embed the bootconfig file into kernel.
> >
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > ---
> > Changes in v2:
> > - Corrected the text accoding to Randy's suggestion.
> > - Do not reccomend to use relative path for CONFIG_EMBED_BOOT_CONFIG_FILE.
> > ---
> > Documentation/admin-guide/bootconfig.rst | 30 +++++++++++++++++++++++++++---
> > 1 file changed, 27 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> > index a1860fc0ca88..1af1a172fdd4 100644
> > --- a/Documentation/admin-guide/bootconfig.rst
> > +++ b/Documentation/admin-guide/bootconfig.rst
> > @@ -158,9 +158,15 @@ Each key-value pair is shown in each line with following style::
> > Boot Kernel With a Boot Config
> > ==============================
> >
> > -Since the boot configuration file is loaded with initrd, it will be added
> > -to the end of the initrd (initramfs) image file with padding, size,
> > -checksum and 12-byte magic word as below.
> > +There are two options to boot the kernel with bootconfig: attaching the
> > +bootconfig to the initrd image or embedding it in the kernel itself.
> > +
> > +Attaching a Boot Config to Initrd
> > +---------------------------------
> > +
> > +Since the boot configuration file is loaded with initrd by default,
> > +it will be added to the end of the initrd (initramfs) image file with
> > +padding, size, checksum and 12-byte magic word as below.
> >
> > [initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n]
> >
> > @@ -196,6 +202,24 @@ To remove the config from the image, you can use -d option as below::
> > Then add "bootconfig" on the normal kernel command line to tell the
> > kernel to look for the bootconfig at the end of the initrd file.
> >
> > +Embedding a Boot Config into Kernel
> > +-----------------------------------
> > +
> > +If you can not use initrd, you can also embed the bootconfig file in the
> > +kernel by Kconfig options. In this case, you need to recompile the kernel
> > +with the following configs::
> > +
> > + COFNIG_EMBED_BOOT_CONFIG=y
>
> CONFIG_

Oops, it's a typo...

>
> > + CONFIG_EMBED_BOOT_CONFIG_FILE="/PATH/TO/BOOTCONFIG/FILE"
> > +
> > +``CONFIG_EMBED_BOOT_CONFIG_FILE`` requires a correct absolute path to
> > +the bootconfig file. The kernel will embed it as the default bootconfig.
> > +
> > +Just as when attaching the bootconfig to the initrd, you need ``bootconfig``
> > +option to the kernel command line to enable the embedded bootconfig.
>
> on the

OK.

Thank you!

>
> preferably.
>
> > +
> > +Note that even if you set this option, you can override the embedded
> > +bootconfig by another bootconfig which attached to the initrd.
> >
> > Kernel parameters via Boot Config
> > =================================
> >
>
> thanks.
> --
> ~Randy


--
Masami Hiramatsu <mhiramat@kernel.org>

\
 
 \ /
  Last update: 2022-03-14 09:06    [W:0.037 / U:0.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site