[PATCH v4 0/3] bootconfig: Support embedding a bootconfig in kernel for non initrd boot

[Masami Hiramatsu <mhiramat@kernel.org>]

Hi,

Here are the 4th version of the patchset to enable kernel embedded bootconfig
for non-initrd kernel boot environment. I've fixed Makefile to determine
update by checking the contents of embedding bootconfig file with filechk macro.
Thanks Masahiro! Here is the previous version [1] (sorry, I missed to update the
version tag in that series)

[1] https://lore.kernel.org/all/164724890153.731226.1478494969800777757.stgit@devnote2/T/#u

You can embed a bootconfig file into the kernel as a default bootconfig,
which will be used if there is no initrd or no bootconfig is attached to initrd. 

This needs 2 options: CONFIG_EMBED_BOOT_CONFIG=y and set the file
path to CONFIG_EMBED_BOOT_CONFIG_FILE. Even if you embed the bootconfig file
to the kernel, it will not be enabled unless you pass "bootconfig" kernel
command line option at boot. Moreover, since this is just a "default"
bootconfig, you can override it with a new bootconfig if you attach another
bootconfig to the initrd (if possible).
CONFIG_EMBED_BOOT_CONFIG_FILE can take both absolute and relative path, but
to simplify and make it independent from the build environment, I recommend
you to use an absolute path for that.

This is requested by Padmanabha at the below thread[2];

[2] https://lore.kernel.org/all/20220307184011.GA2570@pswork/T/#u


KNOWN ISSUE:

According to the report from Padmanabha[3], the embedded bootconfig data may not
be updated if you do incremental build the kernel with CONFIG_LTO. This is
under investigation.

[3] https://lore.kernel.org/all/20220321183500.GA4065@pswork/T/#u

Thank you,

---

Masami Hiramatsu (3):
      bootconfig: Check the checksum before removing the bootconfig from initrd
      bootconfig: Support embedding a bootconfig file in kernel
      docs: bootconfig: Add how to embed the bootconfig into kernel


 Documentation/admin-guide/bootconfig.rst |   30 ++++++++++++++++++++++++++---
 include/linux/bootconfig.h               |   10 ++++++++++
 init/Kconfig                             |   21 ++++++++++++++++++++
 init/main.c                              |   31 +++++++++++++++---------------
 lib/.gitignore                           |    1 +
 lib/Makefile                             |   10 ++++++++++
 lib/bootconfig.c                         |   23 ++++++++++++++++++++++
 7 files changed, 108 insertions(+), 18 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>