[PATCH] ARM: Allow for kernel command line concatenation

oskar.andero at sonyericsson.com oskar.andero at sonyericsson.com
Fri Apr 8 05:36:23 EDT 2011

From: Victor Boivie <victor.boivie at sonyericsson.com>

This patch allows the provided CONFIG_CMDLINE to be concatenated
with the one provided by the boot loader. This is useful to
merge the static values defined in CONFIG_CMDLINE with the
boot loader's (possibly) more dynamic values, such as startup
reasons and more.

Signed-off-by: Victor Boivie <victor.boivie at sonyericsson.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson at sonyericsson.com>
Signed-off-by: Oskar Andero <oskar.andero at sonyericsson.com>
Acked-by: Nicolas Pitre <nicolas.pitre at linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
 arch/arm/Kconfig        |   21 ++++++++++++++++++---
 arch/arm/kernel/setup.c |   13 +++++++++----
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5b9f78b..fe34ed7 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1743,16 +1743,31 @@ config CMDLINE
 	  time by entering them here. As a minimum, you should specify the
 	  memory size and the root device (e.g., mem=64M root=/dev/nfs).
+	prompt "Kernel command line type" if CMDLINE != ""
+	bool "Use bootloader kernel arguments if available"
+	help
+	  Uses the command-line options passed by the boot loader. If
+	  the boot loader doesn't provide any, the default kernel command
+	  string provided in CMDLINE will be used.
+	bool "Extend bootloader kernel arguments"
+	help
+	  The command-line arguments provided by the boot loader will be
+	  appended to the default kernel command string.
 	bool "Always use the default kernel command string"
-	depends on CMDLINE != ""
 	  Always use the default kernel command string, even if the boot
 	  loader passes other arguments to the kernel.
 	  This is useful if you cannot or don't want to change the
 	  command-line options your boot loader passes to the kernel.
-	  If unsure, say N.
 config XIP_KERNEL
 	bool "Kernel Execute-In-Place from ROM"
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 006c1e8..6dce209 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -672,11 +672,16 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
 static int __init parse_tag_cmdline(const struct tag *tag)
-	strlcpy(default_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
+	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
+	strlcat(default_command_line, tag->u.cmdline.cmdline,
+#elif defined(CONFIG_CMDLINE_FORCE)
 	pr_warning("Ignoring tag cmdline (using the default kernel command line)\n");
+	strlcpy(default_command_line, tag->u.cmdline.cmdline,
 	return 0;

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