[PATCH] loongarch: Make CONFIG_CMDLINE work with CONFIG_CMDLINE_EXTEND and CONFIG_CMDLINE_BOOTLOADER

[Dong Zhihong]

This patch tends to fix broken CONFIG_CMDLINE, which is not working with
CONFIG_CMDLINE_EXTEND or CONFIG_CMDLINE_BOOTLOADER. Some code is absent in
arch/loongarch/kernel/setup.c, which should handle built-in command lines
in CONFIG_CMDLINE. The absence of such code causes CONFIG_CMDLINE not
working if CONFIG_CMDLINE_EXTEND or CONFIG_CMDLINE_BOOTLOADER is set to Y.
CONFIG_CMDLINE_FORCE is not affected.

Signed-off-by: Dong Zhihong <donmor3000@xxxxxxxxxxx>
---
 arch/loongarch/kernel/setup.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 78a00359bde3..504218b94879 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -335,6 +335,22 @@ static void __init bootcmdline_init(char **cmdline_p)
 	}
 #endif
 
+#ifdef CONFIG_CMDLINE
+	/*
+	 * If CONFIG_CMDLINE_BOOTLOADER is enabled then we use thei built-in
+	 * command line if no command line given, or we append given command
+	 * line to the built-in one if CONFIG_CMDLINE_EXTEND is enabled.
+	 */
+	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND)) {
+		strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+		strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE);
+	}
+
+	if (IS_ENABLED(CONFIG_CMDLINE_BOOTLOADER) && !boot_command_line[0])
+		strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#endif
+
 out:
 	*cmdline_p = boot_command_line;
 }
-- 
2.25.1