One user has expressed the need to both append and prepend some
built-in parameters to the command line provided by the bootloader.
Allthough it is a corner case, it is easy to implement so let's do it.
When the user chooses to prepend the bootloader provided command line
with the built-in command line, he is offered the possibility to enter
an additionnal built-in command line to be appended after the
bootloader provided command line.
It is a complementary feature which has no impact on the already
existing ones and/or the existing defconfig.
Suggested-by: Daniel Walker <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
---
Sending this out as an RFC, applies on top of the series
("Implement GENERIC_CMDLINE"). I will add it to the series next spin
unless someone is against it.
---
include/linux/cmdline.h | 3 +++
init/Kconfig | 12 +++++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
index 020028e2bdf0..fb274a4d5519 100644
--- a/include/linux/cmdline.h
+++ b/include/linux/cmdline.h
@@ -36,6 +36,9 @@ static __always_inline bool __cmdline_build(char *dst, const char *src)
len = cmdline_strlcat(dst, src, COMMAND_LINE_SIZE);
+ if (IS_ENABLED(CONFIG_CMDLINE_PREPEND))
+ len = cmdline_strlcat(dst, " " CONFIG_CMDLINE_MORE, COMMAND_LINE_SIZE);
+
if (IS_ENABLED(CONFIG_CMDLINE_APPEND))
len = cmdline_strlcat(dst, " " CONFIG_CMDLINE, COMMAND_LINE_SIZE);
diff --git a/init/Kconfig b/init/Kconfig
index fa002e3765ab..cd3087ff4f28 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -128,6 +128,14 @@ config CMDLINE
If this string is not empty, additional choices are proposed
below to determine how it will be used by the kernel.
+config CMDLINE_MORE
+ string "Additional default kernel command string" if GENERIC_CMDLINE && CMDLINE_PREPEND
+ default ""
+ help
+ Defines an additional default kernel command string.
+ If this string is not empty, it is appended to the
+ command-line arguments provided by the bootloader
+
choice
prompt "Kernel command line type" if CMDLINE != ""
default CMDLINE_PREPEND if ARCH_WANT_CMDLINE_PREPEND_BY_DEFAULT
@@ -154,7 +162,9 @@ config CMDLINE_PREPEND
bool "Prepend to the bootloader kernel arguments"
help
The default kernel command string will be prepended to the
- command-line arguments provided by the bootloader.
+ command-line arguments provided by the bootloader. When this
+ option is selected, another string can be added which will
+ be appended.
config CMDLINE_FORCE
bool "Always use the default kernel command string"
--
2.25.0
On Sun, Apr 4, 2021 at 12:20 PM Christophe Leroy
<[email protected]> wrote:
>
> One user has expressed the need to both append and prepend some
> built-in parameters to the command line provided by the bootloader.
>
> Allthough it is a corner case, it is easy to implement so let's do it.
>
> When the user chooses to prepend the bootloader provided command line
> with the built-in command line, he is offered the possibility to enter
> an additionnal built-in command line to be appended after the
> bootloader provided command line.
>
> It is a complementary feature which has no impact on the already
> existing ones and/or the existing defconfig.
>
> Suggested-by: Daniel Walker <[email protected]>
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> Sending this out as an RFC, applies on top of the series
> ("Implement GENERIC_CMDLINE"). I will add it to the series next spin
> unless someone is against it.
Well, it works, but you are working around the existing kconfig and
the result is not great. You'd never design it this way.
Rob