[PATCH v4 10/14] kbuild: Introduce FRAME_WARN_BUMP_FLAG
From: Kees Cook <hidden>
Date: 2018-07-11 20:37:06
Also in:
dm-devel, lkml
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
When building with CONFIG_FRAME_WARN, it is sometimes useful to give certain compilation units small additional headroom. This is normally useful when VLA removal exposes a large stack allocation, especially with FRAME_WARN at 1024 or smaller. This adds 20%. Signed-off-by: Kees Cook <redacted> --- Makefile | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/Makefile b/Makefile
index c9132594860b..06fe93edd052 100644
--- a/Makefile
+++ b/Makefile@@ -684,7 +684,13 @@ endif ifneq ($(CONFIG_FRAME_WARN),0) KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) +# Small code (mostly exposed by VLA removal) needs some additional +# headroom, especially for a FRAME_WARN of 1024. This adds 20% which +# can be used by the CFLAG_FRAME_WARN_BUMP option. +FRAME_WARN_BUMP_SIZE := $(shell expr $(CONFIG_FRAME_WARN) / 5 + $(CONFIG_FRAME_WARN)) +FRAME_WARN_BUMP_FLAG := $(call cc-option,-Wframe-larger-than=$(FRAME_WARN_BUMP_SIZE)) endif +export FRAME_WARN_BUMP_FLAG stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector stackp-flags-$(CONFIG_STACKPROTECTOR) := -fstack-protector
--
2.17.1