[PATCH v8 2/5] x86: Add cmdline_prepare() helper

[Evgeniy Baskov]

Command line needs to be combined in both compressed and uncompressed
kernel from built-in and boot command line strings, which requires
non-trivial logic depending on CONFIG_CMDLINE_BOOL and
CONFIG_CMDLINE_OVERRIDE.

Add a helper function to avoid code duplication.

Signed-off-by: Evgeniy Baskov <baskov@xxxxxxxxx>
---
 arch/x86/include/asm/shared/cmdline.h | 35 +++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 arch/x86/include/asm/shared/cmdline.h

diff --git a/arch/x86/include/asm/shared/cmdline.h b/arch/x86/include/asm/shared/cmdline.h
new file mode 100644
index 000000000000..01736d66028d
--- /dev/null
+++ b/arch/x86/include/asm/shared/cmdline.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_X86_SETUP_CMDLINE_H
+#define _ASM_X86_SETUP_CMDLINE_H
+
+#define _SETUP
+#include <asm/setup.h> /* For COMMAND_LINE_SIZE */
+#undef _SETUP
+
+#include <linux/string.h>
+
+#ifdef CONFIG_CMDLINE_BOOL
+#define BUILTIN_COMMAND_LINE CONFIG_CMDLINE
+#else
+#define BUILTIN_COMMAND_LINE ""
+#endif
+
+static inline void cmdline_prepare(char *dst, const char *boot_command_line)
+{
+	if (!IS_ENABLED(CONFIG_CMDLINE_BOOL)) {
+		strscpy(dst, boot_command_line, COMMAND_LINE_SIZE);
+	} else {
+		strscpy(dst, BUILTIN_COMMAND_LINE, COMMAND_LINE_SIZE);
+		/*
+		 * Append boot loader cmdline to builtin, if it exists
+		 * and should not be overriden.
+		 */
+		if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE) && boot_command_line[0]) {
+			strlcat(dst, " ", COMMAND_LINE_SIZE);
+			strlcat(dst, boot_command_line, COMMAND_LINE_SIZE);
+		}
+	}
+}
+
+#endif /* _ASM_X86_SETUP_CMDLINE_H */
-- 
2.37.4