1 # SPDX-License-Identifier: GPL-2.0
2 # ==========================================================================
5 # There are four warning groups enabled by W=1, W=2, W=3, and W=e
6 # They are independent, and can be combined like W=12 or W=123e.
7 # ==========================================================================
9 KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
11 # backward compatibility
12 KBUILD_EXTRA_WARN ?= $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)
14 ifeq ("$(origin W)", "command line")
15 KBUILD_EXTRA_WARN := $(W)
18 export KBUILD_EXTRA_WARN
21 # W=1 - warnings which may be relevant and do not occur too often
23 ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
25 KBUILD_CFLAGS += -Wextra -Wunused -Wno-unused-parameter
26 KBUILD_CFLAGS += -Wmissing-declarations
27 KBUILD_CFLAGS += -Wmissing-format-attribute
28 KBUILD_CFLAGS += -Wmissing-prototypes
29 KBUILD_CFLAGS += -Wold-style-definition
30 KBUILD_CFLAGS += -Wmissing-include-dirs
31 KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable)
32 KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable)
33 KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned)
34 KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation)
35 # The following turn off the warnings enabled by -Wextra
36 KBUILD_CFLAGS += -Wno-missing-field-initializers
37 KBUILD_CFLAGS += -Wno-sign-compare
38 KBUILD_CFLAGS += -Wno-type-limits
39 KBUILD_CFLAGS += -Wno-shift-negative-value
41 KBUILD_CPPFLAGS += -Wundef
42 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
46 # Some diagnostics enabled by default are noisy.
47 # Suppress them by using -Wno... except for W=1.
49 ifdef CONFIG_CC_IS_CLANG
50 KBUILD_CFLAGS += -Wno-initializer-overrides
51 # Clang before clang-16 would warn on default argument promotions.
52 ifneq ($(call clang-min-version, 160000),y)
54 KBUILD_CFLAGS += -Wno-format
55 # Then re-enable flags that were part of the -Wformat group that aren't
57 KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier
58 KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull
60 ifeq ($(call clang-min-version, 120000),y)
61 KBUILD_CFLAGS += -Wformat-insufficient-args
64 KBUILD_CFLAGS += -Wno-sign-compare
65 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
66 KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare
67 KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access)
68 KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict)
74 # W=2 - warnings which occur quite often but may still be relevant
76 ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
78 KBUILD_CFLAGS += -Wdisabled-optimization
79 KBUILD_CFLAGS += -Wshadow
80 KBUILD_CFLAGS += $(call cc-option, -Wlogical-op)
81 KBUILD_CFLAGS += -Wmissing-field-initializers
82 KBUILD_CFLAGS += -Wtype-limits
83 KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized)
84 KBUILD_CFLAGS += $(call cc-option, -Wunused-macros)
86 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
91 # W=3 - more obscure warnings, can most likely be ignored
93 ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
95 KBUILD_CFLAGS += -Wbad-function-cast
96 KBUILD_CFLAGS += -Wcast-align
97 KBUILD_CFLAGS += -Wcast-qual
98 KBUILD_CFLAGS += -Wconversion
99 KBUILD_CFLAGS += -Wpacked
100 KBUILD_CFLAGS += -Wpadded
101 KBUILD_CFLAGS += -Wpointer-arith
102 KBUILD_CFLAGS += -Wredundant-decls
103 KBUILD_CFLAGS += -Wsign-compare
104 KBUILD_CFLAGS += -Wswitch-default
105 KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat)
107 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3
112 # W=e - error out on warnings
114 ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),)
116 KBUILD_CFLAGS += -Werror