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| -rw-r--r-- | Makefile | 16 |
1 files changed, 16 insertions, 0 deletions
@@ -636,6 +636,22 @@ KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) endif # Handle stack protector mode. +# +# Since kbuild can potentially perform two passes (first with the old +# .config values and then with updated .config values), we cannot error out +# if a desired compiler option is unsupported. If we were to error, kbuild +# could never get to the second pass and actually notice that we changed +# the option to something that was supported. +# +# Additionally, we don't want to fallback and/or silently change which compiler +# flags will be used, since that leads to producing kernels with different +# security feature characteristics depending on the compiler used. ("But I +# selected CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!") +# +# The middle ground is to warn here so that the failed option is obvious, but +# to let the build fail with bad compiler flags so that we can't produce a +# kernel when there is a CONFIG and compiler mismatch. +# ifdef CONFIG_CC_STACKPROTECTOR_REGULAR stackp-flag := -fstack-protector ifeq ($(call cc-option, $(stackp-flag)),) |