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authorArnd Bergmann <arnd@arndb.de>2020-10-26 23:03:13 +0100
committerMasahiro Yamada <masahiroy@kernel.org>2020-11-25 03:36:10 +0900
commit095fbca0a94930b58f977284ef1b759b98700f8b (patch)
tree5d14193f8af5a9e4a95f8c6b921a00087ae5380c /scripts/Makefile.extrawarn
parent418baf2c28f3473039f2f7377760bd8f6897ae18 (diff)
downloadlwn-095fbca0a94930b58f977284ef1b759b98700f8b.tar.gz
lwn-095fbca0a94930b58f977284ef1b759b98700f8b.zip
Makefile.extrawarn: move -Wcast-align to W=3
This warning behaves differently depending on the architecture and compiler. Using x86 gcc, we get no output at all because gcc knows the architecture can handle unaligned accesses. Using x86 clang, or gcc on an architecture that needs to manually deal with unaligned accesses, the build log is completely flooded with these warnings, as they are commonly invoked by inline functions of networking headers, e.g. include/linux/skbuff.h:1426:26: warning: cast increases required alignment of target type [-Wcast-align] The compiler is correct to point this out, as we are dealing with undefined behavior that does cause problems in practice, but there is also no good way to rewrite the code in commonly included headers to a safer method. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/Makefile.extrawarn')
-rw-r--r--scripts/Makefile.extrawarn2
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 95e4cdb94fe9..6baee1200615 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -60,7 +60,6 @@ endif
#
ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
-KBUILD_CFLAGS += -Wcast-align
KBUILD_CFLAGS += -Wdisabled-optimization
KBUILD_CFLAGS += -Wnested-externs
KBUILD_CFLAGS += -Wshadow
@@ -80,6 +79,7 @@ endif
ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
KBUILD_CFLAGS += -Wbad-function-cast
+KBUILD_CFLAGS += -Wcast-align
KBUILD_CFLAGS += -Wcast-qual
KBUILD_CFLAGS += -Wconversion
KBUILD_CFLAGS += -Wpacked