[PATCH v2 4/7] cmdline: Add capability to prepend the command line

From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	danielwa@cisco.com, robh@kernel.org,
	daniel@gimpelevich.san-francisco.ca.us
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-arch@vger.kernel.org, devicetree@vger.kernel.org
Subject: [PATCH v2 4/7] cmdline: Add capability to prepend the command line
Date: Tue,  2 Mar 2021 17:25:20 +0000 (UTC)	[thread overview]
Message-ID: <e1a498d02d47ec2420b404bd5f3e4a00fc628532.1614705851.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1614705851.git.christophe.leroy@csgroup.eu>

This patchs adds an option of prepend a text to the command
line instead of appending it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 include/linux/cmdline.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h
index ae3610bb0ee2..144346051e01 100644
--- a/include/linux/cmdline.h
+++ b/include/linux/cmdline.h
@@ -31,7 +31,7 @@ static __always_inline size_t cmdline_strlcat(char *dest, const char *src, size_
 }
 
 /*
- * This function will append a builtin command line to the command
+ * This function will append or prepend a builtin command line to the command
  * line provided by the bootloader. Kconfig options can be used to alter
  * the behavior of this builtin command line.
  * @dest: The destination of the final appended/prepended string.
@@ -50,6 +50,9 @@ static __always_inline void cmdline_build(char *dest, const char *src, size_t le
 		cmdline_strlcat(dest, CONFIG_CMDLINE, length);
 		return;
 	}
+
+	if (IS_ENABLED(CONFIG_CMDLINE_PREPEND) && sizeof(CONFIG_CMDLINE) > 1)
+		cmdline_strlcat(dest, CONFIG_CMDLINE " ", length);
 #endif
 	if (dest != src)
 		cmdline_strlcat(dest, src, length);
-- 
2.25.0

