objtool: Add CONFIG_STACK_VALIDATION option

Add a CONFIG_STACK_VALIDATION option which will run "objtool check" for
each .o file to ensure the validity of its stack metadata.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92baab69a6bf9bc7043af0bfca9fb964a1d45546.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8bfd1aca7a3d..855265621863 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -342,6 +342,18 @@ config FRAME_POINTER
           larger and slower, but it gives very useful debugging information
           in case of kernel bugs. (precise oopses/stacktraces/warnings)
 
+config STACK_VALIDATION
+        bool "Compile-time stack metadata validation"
+        depends on HAVE_STACK_VALIDATION
+        default n
+        help
+          Add compile-time checks to validate stack metadata, including frame
+          pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
+          that runtime stack traces are more reliable.
+
+          For more information, see
+          tools/objtool/Documentation/stack-validation.txt.
+
 config DEBUG_FORCE_WEAK_PER_CPU
         bool "Force weak per-cpu definitions"
         depends on DEBUG_KERNEL