On Wed, 27 May 2026 09:41:33 -0700
Breno Leitao [off-list ref] wrote:
The userspace pieces (xbc_snprint_cmdline() in lib/, tools/bootconfig -C)
already landed; this series wires the rendered cmdline into the kernel.
Motivation: today the embedded bootconfig is parsed at runtime, after
parse_early_param() has already run, so early_param() handlers can't
see embedded values. Folding the kernel.* subtree into the cmdline at
build time gives a CONFIG_CMDLINE-equivalent for embedded-bootconfig
users without forcing them to maintain two cmdline sources.
Behaviorally, the "kernel" subtree is rendered to a flat string at
build time and stashed in .init.rodata. setup_arch() prepends it to
boot_command_line before parse_early_param() runs. Overflow is a soft
error: the helper logs and leaves boot_command_line untouched rather
than panicking, so an oversized embedded bconf cannot brick a boot.
Thanks Breno, yes, that is what I think about.
Let me check it. And could you also check Sashiko's comments?
https://sashiko.dev/#/patchset/20260527-bootconfig_using_tools-v1-0-b6906a86e7d5%40debian.org
Thanks,
Signed-off-by: Breno Leitao <leitao@debian.org>
---
Breno Leitao (4):
bootconfig: return 0 from xbc_snprint_cmdline() for a leaf root
bootconfig: render embedded bootconfig as a kernel cmdline at build time
bootconfig: add xbc_prepend_embedded_cmdline() helper
x86/setup: prepend embedded bootconfig cmdline before parse_early_param
Makefile | 5 ++++
arch/x86/Kconfig | 1 +
arch/x86/kernel/setup.c | 3 +++
include/linux/bootconfig.h | 7 ++++++
init/Kconfig | 33 ++++++++++++++++++++++++++
init/main.c | 19 ++++++++++++---
lib/Makefile | 16 +++++++++++++
lib/bootconfig.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++
lib/embedded-cmdline.S | 16 +++++++++++++
tools/bootconfig/Makefile | 2 +-
10 files changed, 156 insertions(+), 4 deletions(-)
---
base-commit: e7e28506af98ce4e1059e5ec59334b335c00a246
change-id: 20260508-bootconfig_using_tools-cfa7aa9d6a5a
Best regards,
--
Breno Leitao [off-list ref]
--
Masami Hiramatsu (Google) [off-list ref]