Merge tag 'bootconfig-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull bootconfig updates from Masami Hiramatsu:

 - Support build-time command line building for embedded bootconfig

 - Fix xbc_snprint_cmdline() to render descendant keys when the root has
   both a value and subkeys, and treats empty subtrees correctly.

 - Add build-time pipeline using tools/bootconfig -C to render the
   embedded bootconfig "kernel" subtree into .init.rodata as a cmdline
   string.

 - Clean build-time tools/bootconfig from make clean

 - Add helper to prepend embedded bootconfig cmdline into
   boot_command_line early before parse_early_param()

 - Wire early prepend helper in x86 setup_arch() so early_param handlers
   see values from the embedded bootconfig (currently x86 only)

 - Avoid duplicating "kernel" keys in setup_boot_config()

 - Refactor setup_boot_config() to share bootconfig_cmdline_requested()

 - Document CONFIG_CMDLINE_FROM_BOOTCONFIG usage, requirements, and
   precedence

* tag 'bootconfig-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  init/main.c: use bootconfig_cmdline_requested() for the runtime opt-in
  bootconfig: skip runtime kernel.* render once prepended early
  x86/setup: prepend embedded bootconfig cmdline before parse_early_param
  Documentation: bootconfig: document build-time cmdline rendering
  bootconfig: add xbc_prepend_embedded_cmdline() helper
  bootconfig: clean build-time tools/bootconfig from make clean
  bootconfig: render embedded bootconfig as a kernel cmdline at build time
  bootconfig: render descendant keys when xbc_snprint_cmdline() root has a value

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a8c873356f17..cda6adb9f69c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -6,6 +6,7 @@
  * parts of early kernel initialization.
  */
 #include <linux/acpi.h>
+#include <linux/bootconfig.h>
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/crash_dump.h>
@@ -880,7 +881,6 @@ static void __init x86_report_nx(void)
  *
  * Note: On x86_64, fixmaps are ready for use even before this is called.
  */
-
 void __init setup_arch(char **cmdline_p)
 {
 #ifdef CONFIG_X86_32
@@ -924,6 +924,18 @@ void __init setup_arch(char **cmdline_p)
 	builtin_cmdline_added = true;
 #endif
 
+#ifdef CONFIG_CMDLINE_FROM_BOOTCONFIG
+	/*
+	 * Prepend the build-time-rendered embedded "kernel" keys here so
+	 * parse_early_param() below sees them, using the same opt-in as the
+	 * runtime parser, plus the build-time CONFIG_BOOT_CONFIG_FORCE.
+	 */
+	if (bootconfig_cmdline_requested(boot_command_line, NULL) ||
+	    IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE))
+		xbc_prepend_embedded_cmdline(boot_command_line,
+					     COMMAND_LINE_SIZE);
+#endif
+
 	strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
 	*cmdline_p = command_line;