[PATCH 1/3] gcc-plugins/stackleak: Provide verbose mode

[Kees Cook]

In order to compare instrumentation between builds, make the verbose
mode of the plugin available during the build. This is rarely needed
(behind EXPERT) and very noisy (disabled for COMPILE_TEST).

Cc: Alexander Popov <alex.popov@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 scripts/Makefile.gcc-plugins |  2 ++
 security/Kconfig.hardening   | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 1d16ca1b78c9..f67153b260c0 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -37,6 +37,8 @@ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\
 		+= -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE)
 gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK)		\
 		+= -fplugin-arg-stackleak_plugin-arch=$(SRCARCH)
+gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK_VERBOSE)	\
+		+= -fplugin-arg-stackleak_plugin-verbose
 ifdef CONFIG_GCC_PLUGIN_STACKLEAK
     DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable
 endif
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index d051f8ceefdd..ded4d7c0d132 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -174,6 +174,16 @@ config GCC_PLUGIN_STACKLEAK
 	   * https://grsecurity.net/
 	   * https://pax.grsecurity.net/
 
+config GCC_PLUGIN_STACKLEAK_VERBOSE
+	bool "Report stack depth analysis instrumentation" if EXPERT
+	depends on GCC_PLUGIN_STACKLEAK
+	depends on !COMPILE_TEST	# too noisy
+	help
+	  This option will cause a warning to be printed each time the
+	  stackleak plugin finds a function it thinks needs to be
+	  instrumented. This is useful for comparing coverage between
+	  builds.
+
 config STACKLEAK_TRACK_MIN_SIZE
 	int "Minimum stack frame size of functions tracked by STACKLEAK"
 	default 100
-- 
2.30.2