1 # SPDX-License-Identifier: GPL-2.0
2 # ============================================
3 # make W=... settings
4 #
5 # There are four warning groups enabled by W=1
6 # They are independent, and can be combined li
7 # ============================================
8
9 # Default set of warnings, always enabled
10 KBUILD_CFLAGS += -Wall
11 KBUILD_CFLAGS += -Wundef
12 KBUILD_CFLAGS += -Werror=implicit-function-dec
13 KBUILD_CFLAGS += -Werror=implicit-int
14 KBUILD_CFLAGS += -Werror=return-type
15 KBUILD_CFLAGS += -Werror=strict-prototypes
16 KBUILD_CFLAGS += -Wno-format-security
17 KBUILD_CFLAGS += -Wno-trigraphs
18 KBUILD_CFLAGS += $(call cc-disable-warning,fra
19 KBUILD_CFLAGS += $(call cc-disable-warning, ad
20 KBUILD_CFLAGS += -Wmissing-declarations
21 KBUILD_CFLAGS += -Wmissing-prototypes
22
23 ifneq ($(CONFIG_FRAME_WARN),0)
24 KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_
25 endif
26
27 KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror
28 KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y)
29 KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) +=
30
31 ifdef CONFIG_CC_IS_CLANG
32 # The kernel builds with '-std=gnu11' so use o
33 KBUILD_CFLAGS += -Wno-gnu
34 else
35
36 # gcc inanely warns about local variables call
37 KBUILD_CFLAGS += -Wno-main
38 endif
39
40 # These result in bogus false positives
41 KBUILD_CFLAGS += $(call cc-disable-warning, da
42
43 # Variable Length Arrays (VLAs) should not be
44 KBUILD_CFLAGS += -Wvla
45
46 # disable pointer signed / unsigned warnings i
47 KBUILD_CFLAGS += -Wno-pointer-sign
48
49 # In order to make sure new function cast mism
50 # in the kernel (to avoid tripping CFI checkin
51 # globally built with -Wcast-function-type.
52 KBUILD_CFLAGS += $(call cc-option, -Wcast-func
53
54 # The allocators already balk at large sizes,
55 # warnings for bounds checks involving those p
56 # -Wno-alloc-size-larger-than would normally b
57 # of gcc (<9.1) weirdly don't handle the optio
58 # warnings are produced (?!). Using -Walloc-si
59 # doesn't work (as it is documented to), silen
60 # version 9.1 (and producing an error more rec
61 # than PTRDIFF_MAX also don't work prior to ve
62 # ignored, continuing to default to PTRDIFF_MA
63 # choice, we must perform a versioned check to
64 # https://lore.kernel.org/lkml/20210824115859.
65 KBUILD_CFLAGS-$(call gcc-min-version, 90100) +
66 KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_C
67
68 # Prohibit date/time macros, which would make
69 KBUILD_CFLAGS += -Werror=date-time
70
71 # enforce correct pointer usage
72 KBUILD_CFLAGS += $(call cc-option,-Werror=inco
73
74 # Require designated initializers for all mark
75 KBUILD_CFLAGS += $(call cc-option,-Werror=desi
76
77 # Warn if there is an enum types mismatch
78 KBUILD_CFLAGS += $(call cc-option,-Wenum-conve
79
80 KBUILD_CFLAGS += -Wextra
81 KBUILD_CFLAGS += -Wunused
82
83 #
84 # W=1 - warnings which may be relevant and do
85 #
86 ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
87
88 KBUILD_CFLAGS += -Wmissing-format-attribute
89 KBUILD_CFLAGS += -Wmissing-include-dirs
90 KBUILD_CFLAGS += $(call cc-option, -Wunused-co
91
92 KBUILD_CPPFLAGS += -Wundef
93 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
94
95 else
96
97 # Some diagnostics enabled by default are nois
98 # Suppress them by using -Wno... except for W=
99 KBUILD_CFLAGS += $(call cc-disable-warning, un
100 KBUILD_CFLAGS += $(call cc-disable-warning, un
101 KBUILD_CFLAGS += $(call cc-disable-warning, pa
102 KBUILD_CFLAGS += $(call cc-disable-warning, fo
103 ifdef CONFIG_CC_IS_GCC
104 KBUILD_CFLAGS += $(call cc-disable-warning, fo
105 else
106 # Clang checks for overflow/truncation with '%
107 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id
108 KBUILD_CFLAGS += $(call cc-disable-warning, fo
109 KBUILD_CFLAGS += $(call cc-disable-warning, fo
110 endif
111 KBUILD_CFLAGS += $(call cc-disable-warning, st
112
113 KBUILD_CFLAGS += -Wno-override-init # alias fo
114
115 ifdef CONFIG_CC_IS_CLANG
116 # Clang before clang-16 would warn on default
117 ifneq ($(call clang-min-version, 160000),y)
118 # Disable -Wformat
119 KBUILD_CFLAGS += -Wno-format
120 # Then re-enable flags that were part of the -
121 # problematic.
122 KBUILD_CFLAGS += -Wformat-extra-args -Wformat-
123 KBUILD_CFLAGS += -Wformat-zero-length -Wnonnul
124 # Requires clang-12+.
125 ifeq ($(call clang-min-version, 120000),y)
126 KBUILD_CFLAGS += -Wformat-insufficient-args
127 endif
128 endif
129 KBUILD_CFLAGS += $(call cc-disable-warning, po
130 KBUILD_CFLAGS += -Wno-tautological-constant-ou
131 KBUILD_CFLAGS += $(call cc-disable-warning, un
132 KBUILD_CFLAGS += -Wno-enum-compare-conditional
133 KBUILD_CFLAGS += -Wno-enum-enum-conversion
134 endif
135
136 endif
137
138 #
139 # W=2 - warnings which occur quite often but m
140 #
141 ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),)
142
143 KBUILD_CFLAGS += -Wdisabled-optimization
144 KBUILD_CFLAGS += -Wshadow
145 KBUILD_CFLAGS += $(call cc-option, -Wlogical-o
146 KBUILD_CFLAGS += $(call cc-option, -Wunused-ma
147
148 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
149
150 else
151
152 # The following turn off the warnings enabled
153 KBUILD_CFLAGS += -Wno-missing-field-initialize
154 KBUILD_CFLAGS += -Wno-type-limits
155 KBUILD_CFLAGS += -Wno-shift-negative-value
156
157 ifdef CONFIG_CC_IS_GCC
158 KBUILD_CFLAGS += -Wno-maybe-uninitialized
159 endif
160
161 endif
162
163 #
164 # W=3 - more obscure warnings, can most likely
165 #
166 ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
167
168 KBUILD_CFLAGS += -Wbad-function-cast
169 KBUILD_CFLAGS += -Wcast-align
170 KBUILD_CFLAGS += -Wcast-qual
171 KBUILD_CFLAGS += -Wconversion
172 KBUILD_CFLAGS += -Wpacked
173 KBUILD_CFLAGS += -Wpadded
174 KBUILD_CFLAGS += -Wpointer-arith
175 KBUILD_CFLAGS += -Wredundant-decls
176 KBUILD_CFLAGS += -Wsign-compare
177 KBUILD_CFLAGS += -Wswitch-default
178
179 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3
180
181 else
182
183 # The following turn off the warnings enabled
184 KBUILD_CFLAGS += -Wno-sign-compare
185 KBUILD_CFLAGS += -Wno-unused-parameter
186
187 endif
188
189 #
190 # W=e - error out on warnings
191 #
192 ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),)
193
194 KBUILD_CFLAGS += -Werror
195
196 endif
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