1 # SPDX-License-Identifier: GPL-2.0
2 # ==========================================================================
5 # There are three warning groups enabled by W=1, W=2, W=3.
6 # They are independent, and can be combined like W=12 or W=123.
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
39 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
43 # Some diagnostics enabled by default are noisy.
44 # Suppress them by using -Wno... except for W=1.
46 ifdef CONFIG_CC_IS_CLANG
47 KBUILD_CFLAGS += -Wno-initializer-overrides
48 KBUILD_CFLAGS += -Wno-format
49 KBUILD_CFLAGS += -Wno-sign-compare
50 KBUILD_CFLAGS += -Wno-format-zero-length
51 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
57 # W=2 - warnings which occur quite often but may still be relevant
59 ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
61 KBUILD_CFLAGS += -Wcast-align
62 KBUILD_CFLAGS += -Wdisabled-optimization
63 KBUILD_CFLAGS += -Wnested-externs
64 KBUILD_CFLAGS += -Wshadow
65 KBUILD_CFLAGS += $(call cc-option, -Wlogical-op)
66 KBUILD_CFLAGS += -Wmissing-field-initializers
67 KBUILD_CFLAGS += -Wsign-compare
68 KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized)
69 KBUILD_CFLAGS += $(call cc-option, -Wunused-macros)
71 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
76 # W=3 - more obscure warnings, can most likely be ignored
78 ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
80 KBUILD_CFLAGS += -Wbad-function-cast
81 KBUILD_CFLAGS += -Wcast-qual
82 KBUILD_CFLAGS += -Wconversion
83 KBUILD_CFLAGS += -Wpacked
84 KBUILD_CFLAGS += -Wpadded
85 KBUILD_CFLAGS += -Wpointer-arith
86 KBUILD_CFLAGS += -Wredundant-decls
87 KBUILD_CFLAGS += -Wswitch-default
88 KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat)
90 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3