Re: [PATCH v2] bootconfig: Apply early options from embedded config

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Wed, 25 Mar 2026 23:22:04 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> > +	/*
> > +	 * Keys that do not match any early_param() handler are silently
> > +	 * ignored — do_early_param() always returns 0.
> > +	 */
> > +	xbc_node_for_each_key_value(root, knode, val) {
> 
> [sashiko comment]
> | Does this loop handle array values correctly?
> | xbc_node_for_each_key_value() only assigns the first value of an array to
> | the val pointer before advancing to the next key. It does not iterate over
> | the child nodes of the array.
> | If the bootconfig contains a multi-value key like
> | kernel.console = "ttyS0", "tty0", will the subsequent values in the array
> | be silently dropped instead of passed to the early_param handlers?
> 
> Also, good catch :) we need to use xbc_node_for_each_array_value()
> for inner loop.

FYI, xbc_snprint_cmdline() translates the arraied parameter as
multiple parameters. For example,

foo = bar, buz;

will be converted to

foo=bar foo=buz

Thus, I think we should do the same thing below;

> 
> > +		if (xbc_node_compose_key_after(root, knode, xbc_namebuf, XBC_KEYLEN_MAX) < 0)
> > +			continue;
> > +
> > +		/*
> > +		 * We need to copy const char *val to a char pointer,
> > +		 * which is what do_early_param() need, given it might
> > +		 * call strsep(), strtok() later.
> > +		 */
> > +		ret = strscpy(val_buf, val, sizeof(val_buf));
> > +		if (ret < 0) {
> > +			pr_warn("ignoring bootconfig value '%s', too long\n",
> > +				xbc_namebuf);
> > +			continue;
> > +		}
> > +		do_early_param(xbc_namebuf, val_buf, NULL, NULL);

So instead of this;

xbc_array_for_each_value(vnode, val) {
	do_early_param(xbc_namebuf, val, NULL, NULL);
}

Maybe it is a good timing to recondier unifying kernel cmdline and bootconfig
from API viewpoint.

Thanks,

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