linux-stable/scripts/Makefile.extrawarn
Nathan Chancellor 81a3a0c1a6 kbuild: Move -Wenum-enum-conversion to W=2
commit 8f6629c004 upstream.

-Wenum-enum-conversion was strengthened in clang-19 to warn for C, which
caused the kernel to move it to W=1 in commit 75b5ab134b ("kbuild:
Move -Wenum-{compare-conditional,enum-conversion} into W=1") because
there were numerous instances that would break builds with -Werror.
Unfortunately, this is not a full solution, as more and more developers,
subsystems, and distributors are building with W=1 as well, so they
continue to see the numerous instances of this warning.

Since the move to W=1, there have not been many new instances that have
appeared through various build reports and the ones that have appeared
seem to be following similar existing patterns, suggesting that most
instances of this warning will not be real issues. The only alternatives
for silencing this warning are adding casts (which is generally seen as
an ugly practice) or refactoring the enums to macro defines or a unified
enum (which may be undesirable because of type safety in other parts of
the code).

Move the warning to W=2, where warnings that occur frequently but may be
relevant should reside.

Cc: stable@vger.kernel.org
Fixes: 75b5ab134b ("kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1")
Link: https://lore.kernel.org/ZwRA9SOcOjjLJcpi@google.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13 12:50:29 +01:00

102 lines
3.0 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# ==========================================================================
# make W=... settings
#
# There are three warning groups enabled by W=1, W=2, W=3.
# They are independent, and can be combined like W=12 or W=123.
# ==========================================================================
KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
# backward compatibility
KBUILD_EXTRA_WARN ?= $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)
ifeq ("$(origin W)", "command line")
KBUILD_EXTRA_WARN := $(W)
endif
export KBUILD_EXTRA_WARN
#
# W=1 - warnings which may be relevant and do not occur too often
#
ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
KBUILD_CFLAGS += -Wextra -Wunused -Wno-unused-parameter
KBUILD_CFLAGS += -Wmissing-declarations
KBUILD_CFLAGS += -Wmissing-format-attribute
KBUILD_CFLAGS += -Wmissing-prototypes
KBUILD_CFLAGS += -Wold-style-definition
KBUILD_CFLAGS += -Wmissing-include-dirs
KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable)
KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable)
KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned)
KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation)
# The following turn off the warnings enabled by -Wextra
KBUILD_CFLAGS += -Wno-missing-field-initializers
KBUILD_CFLAGS += -Wno-sign-compare
KBUILD_CFLAGS += -Wno-type-limits
ifdef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += -Wno-enum-enum-conversion
endif
KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
else
# Some diagnostics enabled by default are noisy.
# Suppress them by using -Wno... except for W=1.
ifdef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += -Wno-initializer-overrides
KBUILD_CFLAGS += -Wno-format
KBUILD_CFLAGS += -Wno-sign-compare
KBUILD_CFLAGS += -Wno-format-zero-length
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 += $(call cc-disable-warning, cast-function-type-strict)
KBUILD_CFLAGS += -Wno-enum-compare-conditional
endif
endif
#
# W=2 - warnings which occur quite often but may still be relevant
#
ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
KBUILD_CFLAGS += -Wdisabled-optimization
KBUILD_CFLAGS += -Wshadow
KBUILD_CFLAGS += $(call cc-option, -Wlogical-op)
KBUILD_CFLAGS += -Wmissing-field-initializers
KBUILD_CFLAGS += -Wtype-limits
KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized)
KBUILD_CFLAGS += $(call cc-option, -Wunused-macros)
KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
endif
#
# W=3 - more obscure warnings, can most likely be ignored
#
ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
KBUILD_CFLAGS += -Wbad-function-cast
KBUILD_CFLAGS += -Wcast-align
KBUILD_CFLAGS += -Wcast-qual
KBUILD_CFLAGS += -Wconversion
KBUILD_CFLAGS += -Wpacked
KBUILD_CFLAGS += -Wpadded
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
endif