On Mon, 8 Jun 2026 07:41:05 -0700
Breno Leitao [off-list ref] wrote:

On Mon, Jun 08, 2026 at 07:19:28PM +0900, Masami Hiramatsu wrote:

quoted

On Fri, 05 Jun 2026 05:03:37 -0700
Breno Leitao [off-list ref] wrote:

quoted

Call xbc_prepend_embedded_cmdline() in setup_arch() right after the
CONFIG_CMDLINE merge and before strscpy(command_line, ...) so the
build-time-rendered embedded bootconfig "kernel" subtree is part of
boot_command_line by the time parse_early_param() runs. early_param()
handlers (mem=, earlycon=, loglevel=, ...) now see values supplied via
CONFIG_BOOT_CONFIG_EMBED_FILE without parsing bootconfig at runtime.

Gate the prepend on the bootconfig opt-in: only fold in the embedded
kernel.* keys when "bootconfig" is present on the command line, or
CONFIG_BOOT_CONFIG_FORCE is set. Applying the embedded cmdline
unconditionally would (a) diverge from how embedded init.* keys are
treated and (b) break fail-safe recovery: a malformed embedded
console=/mem= could panic the boot with no way for the admin to disable
it by dropping "bootconfig" from the bootloader cmdline.
cmdline_find_option_bool() runs before parse_early_param(), so the gate
is cheap and correctly ordered.

Select ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG so the user-visible
CONFIG_BOOT_CONFIG_EMBED_CMDLINE option becomes selectable on x86.

This seems like a dummy config. what code does depend on this flag?

No C code reads ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG directly — it's
a silent gating symbol, the same ARCH_SUPPORTS_* idiom as
ARCH_SUPPORTS_CFI, ARCH_SUPPORTS_LTO_CLANG, etc.

Its only role is the depends on line of BOOT_CONFIG_EMBED_CMDLINE: an
arch selects it once its setup_arch() calls
xbc_prepend_embedded_cmdline(), and that makes the user-visible
BOOT_CONFIG_EMBED_CMDLINE selectable.

Right now, only x86 supports embedded bootconfig, thus, only x86 does
the following (last patch):

	config X86
	+       select ARCH_SUPPORTS_CMDLINE_FROM_BOOTCONFIG

So, no other platform can see CONFIG_BOOT_CONFIG_EMBED_CMDLINE.

Ah, OK. I missed the 3/6, which defined the dependency.

Thanks!

-- 
Masami Hiramatsu (Google) [off-list ref]