stackleak: Allow runtime disabling of kernel stack erasing

Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides
'stack_erasing' sysctl. It can be used in runtime to control kernel
stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index b0a015ef5268..0d5c799688f0 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -182,4 +182,12 @@ config STACKLEAK_METRICS
           can be useful for estimating the STACKLEAK performance impact for
           your workloads.
 
+config STACKLEAK_RUNTIME_DISABLE
+        bool "Allow runtime disabling of kernel stack erasing"
+        depends on GCC_PLUGIN_STACKLEAK
+        help
+          This option provides 'stack_erasing' sysctl, which can be used in
+          runtime to control kernel stack erasing for kernels built with
+          CONFIG_GCC_PLUGIN_STACKLEAK.
+
 endif