Makefile: Do not quote value for CONFIG_CC_IMPLICIT_FALLTHROUGH
Andreas reported that a specific build environment for an external
module, being a bit broken, does pass CC_IMPLICIT_FALLTHROUGH quoted as
argument to gcc, causing an error
gcc-11: error: "-Wimplicit-fallthrough=5": linker input file not found: No such file or directory
Until this is more generally fixed as outlined in [1], by fixing
scripts/link-vmlinux.sh, scripts/gen_autoksyms.sh, etc to not directly
include the include/config/auto.conf, and in a second step, change
Kconfig to generate the auto.conf without "", workaround the issue by
explicitly unquoting CC_IMPLICIT_FALLTHROUGH.
Reported-by: Andreas Beckmann <anbe@debian.org>
Link: https://bugs.debian.org/1001083
Link: https://lore.kernel.org/linux-kbuild/CAK7LNAR-VXwHFEJqCcrFDZj+_4+Xd6oynbj_0eS8N504_ydmyw@mail.gmail.com/ [1]
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Makefile b/Makefile
index 8e35d78..ef967a2 100644
--- a/Makefile
+++ b/Makefile
@@ -789,7 +789,7 @@
KBUILD_CFLAGS += $(stackp-flags-y)
KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
-KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
+KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH:"%"=%)
ifdef CONFIG_CC_IS_CLANG
KBUILD_CPPFLAGS += -Qunused-arguments
