[PATCH v2 1/8] bootconfig: Set CONFIG_BOOT_CONFIG=n by default

[Masami Hiramatsu <mhiramat@kernel.org>]

Set CONFIG_BOOT_CONFIG=n by default. This also warns
user if CONFIG_BOOT_CONFIG=n but "bootconfig" is given
in the kernel command line.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 V2: Use pr_warn() for warning message.
     Remove unneeded "default n" line from Kconfig.
---
 init/Kconfig         |    1 -
 init/main.c          |    8 ++++++++
 kernel/trace/Kconfig |    3 ++-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 452bc1835cd4..e76e9241552c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1227,7 +1227,6 @@ endif
 config BOOT_CONFIG
 	bool "Boot config support"
 	depends on BLK_DEV_INITRD
-	default y
 	help
 	  Extra boot config allows system admin to pass a config file as
 	  complemental extension of kernel cmdline when booting.
diff --git a/init/main.c b/init/main.c
index f95b014a5479..ae4e37681247 100644
--- a/init/main.c
+++ b/init/main.c
@@ -418,6 +418,14 @@ static void __init setup_boot_config(const char *cmdline)
 }
 #else
 #define setup_boot_config(cmdline)	do { } while (0)
+
+static int __init warn_bootconfig(char *str)
+{
+	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOTCONFIG is not set.\n");
+	return 0;
+}
+early_param("bootconfig", warn_bootconfig);
+
 #endif
 
 /* Change NUL term back to "=", to make "param" the whole string. */
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 91e885194dbc..795c3e02d3f1 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -143,7 +143,8 @@ if FTRACE
 
 config BOOTTIME_TRACING
 	bool "Boot-time Tracing support"
-	depends on BOOT_CONFIG && TRACING
+	depends on TRACING
+	select BOOT_CONFIG
 	default y
 	help
 	  Enable developer to setup ftrace subsystem via supplemental