From 75b5ab134bb5f657ef7979a59106dce0657e8d87 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 5 Mar 2024 15:12:47 -0700 Subject: kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 Clang enables -Wenum-enum-conversion and -Wenum-compare-conditional under -Wenum-conversion. A recent change in Clang strengthened these warnings and they appear frequently in common builds, primarily due to several instances in common headers but there are quite a few drivers that have individual instances as well. include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion] 508 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS + | ~~~~~~~~~~~~~~~~~~~~~ ^ 509 | item]; | ~~~~ drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:955:24: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional] 955 | flags |= is_new_rate ? IWL_MAC_BEACON_CCK | ^ ~~~~~~~~~~~~~~~~~~ 956 | : IWL_MAC_BEACON_CCK_V1; | ~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:1120:21: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional] 1120 | 0) > 10 ? | ^ 1121 | IWL_MAC_BEACON_FILS : | ~~~~~~~~~~~~~~~~~~~ 1122 | IWL_MAC_BEACON_FILS_V1; | ~~~~~~~~~~~~~~~~~~~~~~ Doing arithmetic between or returning two different types of enums could be a bug, so each of the instance of the warning needs to be evaluated. Unfortunately, as mentioned above, there are many instances of this warning in many different configurations, which can break the build when CONFIG_WERROR is enabled. To avoid introducing new instances of the warnings while cleaning up the disruption for the majority of users, disable these warnings for the default build while leaving them on for W=1 builds. Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2002 Link: https://github.com/llvm/llvm-project/commit/8c2ae42b3e1c6aa7c18f873edcebff7c0b45a37e Acked-by: Yonghong Song Signed-off-by: Nathan Chancellor Acked-by: Arnd Bergmann Signed-off-by: Masahiro Yamada --- scripts/Makefile.extrawarn | 2 ++ 1 file changed, 2 insertions(+) (limited to 'scripts/Makefile.extrawarn') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index a9e552a1e910..2f25a1de129d 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -132,6 +132,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) +KBUILD_CFLAGS += -Wno-enum-compare-conditional +KBUILD_CFLAGS += -Wno-enum-enum-conversion endif endif -- cgit v1.2.3 From 44929bfaceaaa6a854ddc6df6de9433fab1eef92 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 6 Mar 2024 21:47:09 +0900 Subject: kbuild: remove GCC's default -Wpacked-bitfield-compat flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 4a5838ad9d2d ("kbuild: Add extra gcc checks") added the -Wpacked-bitfield-compat flag, but there is no need to add it explicitly. GCC manual says: "This warning is enabled by default. Use -Wno-packed-bitfield-compat to disable this warning." The test code in the manual: struct foo { char a:4; char b:8; } __attribute__ ((packed)); ... emits "note: offset of packed bit-field ‘b’ has changed in GCC 4.4" without W=3. Let's remove it, as it is a default with GCC. Clang does not support this flag, so its removal will not affect Clang builds. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor --- scripts/Makefile.extrawarn | 1 - 1 file changed, 1 deletion(-) (limited to 'scripts/Makefile.extrawarn') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 2f25a1de129d..3ce5d503a6da 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -187,7 +187,6 @@ KBUILD_CFLAGS += -Wpointer-arith KBUILD_CFLAGS += -Wredundant-decls KBUILD_CFLAGS += -Wsign-compare KBUILD_CFLAGS += -Wswitch-default -KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat) KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3 -- cgit v1.2.3 From c40845e3195d074b34f8f8e400e28c9403a06588 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 26 Mar 2024 15:47:16 +0100 Subject: kbuild: make -Woverride-init warnings more consistent The -Woverride-init warn about code that may be intentional or not, but the inintentional ones tend to be real bugs, so there is a bit of disagreement on whether this warning option should be enabled by default and we have multiple settings in scripts/Makefile.extrawarn as well as individual subsystems. Older versions of clang only supported -Wno-initializer-overrides with the same meaning as gcc's -Woverride-init, though all supported versions now work with both. Because of this difference, an earlier cleanup of mine accidentally turned the clang warning off for W=1 builds and only left it on for W=2, while it's still enabled for gcc with W=1. There is also one driver that only turns the warning off for newer versions of gcc but not other compilers, and some but not all the Makefiles still use a cc-disable-warning conditional that is no longer needed with supported compilers here. Address all of the above by removing the special cases for clang and always turning the warning off unconditionally where it got in the way, using the syntax that is supported by both compilers. Fixes: 2cd3271b7a31 ("kbuild: avoid duplicate warning options") Signed-off-by: Arnd Bergmann Acked-by: Hamza Mahfooz Acked-by: Jani Nikula Acked-by: Andrew Jeffery Signed-off-by: Jani Nikula Reviewed-by: Linus Walleij Signed-off-by: Masahiro Yamada --- scripts/Makefile.extrawarn | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'scripts/Makefile.extrawarn') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 3ce5d503a6da..c5af566e911a 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -114,6 +114,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation) +KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang + ifdef CONFIG_CC_IS_CLANG # Clang before clang-16 would warn on default argument promotions. ifneq ($(call clang-min-version, 160000),y) @@ -151,10 +153,6 @@ KBUILD_CFLAGS += -Wtype-limits KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized) KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) -ifdef CONFIG_CC_IS_CLANG -KBUILD_CFLAGS += -Winitializer-overrides -endif - KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2 else @@ -164,9 +162,7 @@ KBUILD_CFLAGS += -Wno-missing-field-initializers KBUILD_CFLAGS += -Wno-type-limits KBUILD_CFLAGS += -Wno-shift-negative-value -ifdef CONFIG_CC_IS_CLANG -KBUILD_CFLAGS += -Wno-initializer-overrides -else +ifdef CONFIG_CC_IS_GCC KBUILD_CFLAGS += -Wno-maybe-uninitialized endif -- cgit v1.2.3