diff options
Diffstat (limited to 'scripts/Makefile.warn')
| -rw-r--r-- | scripts/Makefile.warn | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/scripts/Makefile.warn b/scripts/Makefile.warn new file mode 100644 index 000000000000..68e6fafcb80c --- /dev/null +++ b/scripts/Makefile.warn @@ -0,0 +1,235 @@ +# SPDX-License-Identifier: GPL-2.0 +# ========================================================================== +# make W=... settings +# +# There are four warning groups enabled by W=1, W=2, W=3, and W=e +# They are independent, and can be combined like W=12 or W=123e. +# ========================================================================== + +# Default set of warnings, always enabled +KBUILD_CFLAGS += -Wall +KBUILD_CFLAGS += -Wextra +KBUILD_CFLAGS += -Wundef +KBUILD_CFLAGS += -Werror=implicit-function-declaration +KBUILD_CFLAGS += -Werror=implicit-int +KBUILD_CFLAGS += -Werror=return-type +KBUILD_CFLAGS += -Werror=strict-prototypes +KBUILD_CFLAGS += -Wno-format-security +KBUILD_CFLAGS += -Wno-trigraphs +KBUILD_CFLAGS += $(call cc-option, -Wno-frame-address) +KBUILD_CFLAGS += $(call cc-option, -Wno-address-of-packed-member) +KBUILD_CFLAGS += -Wmissing-declarations +KBUILD_CFLAGS += -Wmissing-prototypes + +ifneq ($(CONFIG_FRAME_WARN),0) +KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN) +endif + +KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds + +ifdef CONFIG_CC_IS_CLANG +# The kernel builds with '-std=gnu11' and '-fms-extensions' so use of GNU and +# Microsoft extensions is acceptable. +KBUILD_CFLAGS += -Wno-gnu +KBUILD_CFLAGS += -Wno-microsoft-anon-tag + +# Clang checks for overflow/truncation with '%p', while GCC does not: +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219 +KBUILD_CFLAGS += $(call cc-option, -Wno-format-overflow-non-kprintf) +KBUILD_CFLAGS += $(call cc-option, -Wno-format-truncation-non-kprintf) + +# Clang may emit a warning when a const variable, such as the dummy variables +# in typecheck(), or const member of an aggregate type are not initialized, +# which can result in unexpected behavior. However, in many audited cases of +# the "field" variant of the warning, this is intentional because the field is +# never used within a particular call path, the field is within a union with +# other non-const members, or the containing object is not const so the field +# can be modified via memcpy() / memset(). While the variable warning also gets +# disabled with this same switch, there should not be too much coverage lost +# because -Wuninitialized will still flag when an uninitialized const variable +# is used. +KBUILD_CFLAGS += $(call cc-option, -Wno-default-const-init-unsafe) +else + +# gcc inanely warns about local variables called 'main' +KBUILD_CFLAGS += -Wno-main +endif + +# These result in bogus false positives +KBUILD_CFLAGS += $(call cc-option, -Wno-dangling-pointer) + +# Stack Variable Length Arrays (VLAs) must not be used in the kernel. +# Function array parameters should, however, be usable, but -Wvla will +# warn for those. Clang has no way yet to distinguish between the VLA +# types, so depend on GCC for now to keep stack VLAs out of the tree. +# https://github.com/llvm/llvm-project/issues/57098 +# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98217 +KBUILD_CFLAGS += $(call cc-option,-Wvla-larger-than=1) + +# disable pointer signed / unsigned warnings in gcc 4.0 +KBUILD_CFLAGS += -Wno-pointer-sign + +# In order to make sure new function cast mismatches are not introduced +# in the kernel (to avoid tripping CFI checking), the kernel should be +# globally built with -Wcast-function-type. +KBUILD_CFLAGS += $(call cc-option, -Wcast-function-type) + +# Currently, disable -Wstringop-overflow for GCC 11, globally. +KBUILD_CFLAGS-$(CONFIG_CC_NO_STRINGOP_OVERFLOW) += $(call cc-option, -Wno-stringop-overflow) +KBUILD_CFLAGS-$(CONFIG_CC_STRINGOP_OVERFLOW) += $(call cc-option, -Wstringop-overflow) + +# Currently, disable -Wunterminated-string-initialization as broken +KBUILD_CFLAGS += $(call cc-option, -Wno-unterminated-string-initialization) + +# The allocators already balk at large sizes, so silence the compiler +# warnings for bounds checks involving those possible values. While +# -Wno-alloc-size-larger-than would normally be used here, earlier versions +# of gcc (<9.1) weirdly don't handle the option correctly when _other_ +# warnings are produced (?!). Using -Walloc-size-larger-than=SIZE_MAX +# doesn't work (as it is documented to), silently resolving to "0" prior to +# version 9.1 (and producing an error more recently). Numeric values larger +# than PTRDIFF_MAX also don't work prior to version 9.1, which are silently +# ignored, continuing to default to PTRDIFF_MAX. So, left with no other +# choice, we must perform a versioned check to disable this warning. +# https://lore.kernel.org/lkml/20210824115859.187f272f@canb.auug.org.au +KBUILD_CFLAGS-$(call gcc-min-version, 90100) += -Wno-alloc-size-larger-than +KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH) + +# Prohibit date/time macros, which would make the build non-deterministic +KBUILD_CFLAGS += -Werror=date-time + +# enforce correct pointer usage +KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types) + +# Require designated initializers for all marked structures +KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init) + +# Warn if there is an enum types mismatch +KBUILD_CFLAGS += $(call cc-option,-Wenum-conversion) + +KBUILD_CFLAGS += -Wunused + +# +# W=1 - warnings which may be relevant and do not occur too often +# +ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) + +KBUILD_CFLAGS += -Wmissing-format-attribute +KBUILD_CFLAGS += -Wmissing-include-dirs +KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable) + +KBUILD_CPPFLAGS += -Wundef +KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 + +else + +# Some diagnostics enabled by default are noisy. +# Suppress them by using -Wno... except for W=1. +KBUILD_CFLAGS += $(call cc-option, -Wno-unused-but-set-variable) +KBUILD_CFLAGS += $(call cc-option, -Wno-unused-const-variable) +KBUILD_CFLAGS += $(call cc-option, -Wno-packed-not-aligned) +KBUILD_CFLAGS += $(call cc-option, -Wno-format-overflow) +ifdef CONFIG_CC_IS_GCC +KBUILD_CFLAGS += $(call cc-option, -Wno-format-truncation) +endif +KBUILD_CFLAGS += $(call cc-option, -Wno-stringop-truncation) + +KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang + +ifdef CONFIG_CC_IS_CLANG +# Clang before clang-16 would warn on default argument promotions. +ifneq ($(call clang-min-version, 160000),y) +# Disable -Wformat +KBUILD_CFLAGS += -Wno-format +# Then re-enable flags that were part of the -Wformat group that aren't +# problematic. +KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier +KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull +# Requires clang-12+. +ifeq ($(call clang-min-version, 120000),y) +KBUILD_CFLAGS += -Wformat-insufficient-args +endif +endif +KBUILD_CFLAGS += $(call cc-option, -Wno-pointer-to-enum-cast) +KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare +KBUILD_CFLAGS += $(call cc-option, -Wno-unaligned-access) +KBUILD_CFLAGS += -Wno-enum-compare-conditional +endif + +endif + +# +# W=2 - warnings which occur quite often but may still be relevant +# +ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) + +KBUILD_CFLAGS += -Wdisabled-optimization +KBUILD_CFLAGS += -Wshadow +KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) +KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) + +KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2 + +else + +# The following turn off the warnings enabled by -Wextra +KBUILD_CFLAGS += -Wno-missing-field-initializers +KBUILD_CFLAGS += -Wno-type-limits +KBUILD_CFLAGS += -Wno-shift-negative-value + +ifdef CONFIG_CC_IS_CLANG +KBUILD_CFLAGS += -Wno-enum-enum-conversion +endif + +ifdef CONFIG_CC_IS_GCC +KBUILD_CFLAGS += -Wno-maybe-uninitialized +endif + +endif + +# +# W=3 - more obscure warnings, can most likely be ignored +# +ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),) + +KBUILD_CFLAGS += -Wbad-function-cast +KBUILD_CFLAGS += -Wcast-align +KBUILD_CFLAGS += -Wcast-qual +KBUILD_CFLAGS += -Wconversion +KBUILD_CFLAGS += -Wpacked +KBUILD_CFLAGS += -Wpadded +KBUILD_CFLAGS += -Wpointer-arith +KBUILD_CFLAGS += -Wredundant-decls +KBUILD_CFLAGS += -Wsign-compare +KBUILD_CFLAGS += -Wswitch-default + +KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3 + +else + +# The following turn off the warnings enabled by -Wextra +KBUILD_CFLAGS += -Wno-sign-compare +KBUILD_CFLAGS += -Wno-unused-parameter + +endif + +# +# W=e and CONFIG_WERROR - error out on warnings +# +ifneq ($(findstring e, $(KBUILD_EXTRA_WARN))$(CONFIG_WERROR),) + +KBUILD_CPPFLAGS += -Werror +KBUILD_AFLAGS += -Wa,--fatal-warnings +KBUILD_LDFLAGS += --fatal-warnings +KBUILD_USERCFLAGS += -Werror +KBUILD_USERLDFLAGS += -Wl,--fatal-warnings +KBUILD_RUSTFLAGS += -Dwarnings + +# While hostprog flags are used during build bootstrapping (thus should not +# depend on CONFIG_ symbols), -Werror is disruptive and should be opted into. +# Only apply -Werror to hostprogs built after the initial Kconfig stage. +KBUILD_HOSTCFLAGS += -Werror +KBUILD_HOSTLDFLAGS += -Wl,--fatal-warnings +KBUILD_HOSTRUSTFLAGS += -Dwarnings + +endif |