1 # SPDX-License-Identifier: GPL-2.0 <<
2 # ============================================ 1 # ==========================================================================
3 # make W=... settings <<
4 # 2 #
5 # There are four warning groups enabled by W=1 !! 3 # make W=... settings
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 += $(call cc-option,-Wenum-conve <<
79 <<
80 KBUILD_CFLAGS += -Wextra <<
81 KBUILD_CFLAGS += -Wunused <<
82 <<
83 # 4 #
84 # W=1 - warnings which may be relevant and do !! 5 # W=1 - warnings that may be relevant and does not occur too often
>> 6 # W=2 - warnings that occur quite often but may still be relevant
>> 7 # W=3 - the more obscure warnings, can most likely be ignored
85 # 8 #
86 ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) !! 9 # $(call cc-option, -W...) handles gcc -W.. options which
87 !! 10 # are not supported by all versions of the compiler
88 KBUILD_CFLAGS += -Wmissing-format-attribute !! 11 # ==========================================================================
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 += $(call cc-disable-warning, st <<
112 <<
113 KBUILD_CFLAGS += -Wno-override-init # alias fo <<
114 12
115 ifdef CONFIG_CC_IS_CLANG !! 13 ifeq ("$(origin W)", "command line")
116 # Clang before clang-16 would warn on default !! 14 export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
117 ifneq ($(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 15 endif
135 16
136 endif !! 17 ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
>> 18 warning- := $(empty)
137 19
138 # !! 20 warning-1 := -Wextra -Wunused -Wno-unused-parameter
139 # W=2 - warnings which occur quite often but m !! 21 warning-1 += -Wmissing-declarations
140 # !! 22 warning-1 += -Wmissing-format-attribute
141 ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) !! 23 warning-1 += $(call cc-option, -Wmissing-prototypes)
>> 24 warning-1 += -Wold-style-definition
>> 25 warning-1 += $(call cc-option, -Wmissing-include-dirs)
>> 26 warning-1 += $(call cc-option, -Wunused-but-set-variable)
>> 27 warning-1 += $(call cc-option, -Wunused-const-variable)
>> 28 warning-1 += $(call cc-disable-warning, missing-field-initializers)
>> 29 warning-1 += $(call cc-disable-warning, sign-compare)
>> 30
>> 31 warning-2 := -Waggregate-return
>> 32 warning-2 += -Wcast-align
>> 33 warning-2 += -Wdisabled-optimization
>> 34 warning-2 += -Wnested-externs
>> 35 warning-2 += -Wshadow
>> 36 warning-2 += $(call cc-option, -Wlogical-op)
>> 37 warning-2 += $(call cc-option, -Wmissing-field-initializers)
>> 38 warning-2 += $(call cc-option, -Wsign-compare)
>> 39 warning-2 += $(call cc-option, -Wmaybe-uninitialized)
>> 40
>> 41 warning-3 := -Wbad-function-cast
>> 42 warning-3 += -Wcast-qual
>> 43 warning-3 += -Wconversion
>> 44 warning-3 += -Wpacked
>> 45 warning-3 += -Wpadded
>> 46 warning-3 += -Wpointer-arith
>> 47 warning-3 += -Wredundant-decls
>> 48 warning-3 += -Wswitch-default
>> 49 warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
>> 50 warning-3 += $(call cc-option, -Wvla)
>> 51
>> 52 warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
>> 53 warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
>> 54 warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
142 55
143 KBUILD_CFLAGS += -Wdisabled-optimization !! 56 ifeq ("$(strip $(warning))","")
144 KBUILD_CFLAGS += -Wshadow !! 57 $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
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 58 endif
160 59
161 endif !! 60 KBUILD_CFLAGS += $(warning)
162 <<
163 # <<
164 # W=3 - more obscure warnings, can most likely <<
165 # <<
166 ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),) <<
167 <<
168 KBUILD_CFLAGS += -Wbad-function-cast <<
169 KBUILD_CFLAGS += -Wcast-align <<
170 KBUILD_CFLAGS += -Wcast-qual <<
171 KBUILD_CFLAGS += -Wconversion <<
172 KBUILD_CFLAGS += -Wpacked <<
173 KBUILD_CFLAGS += -Wpadded <<
174 KBUILD_CFLAGS += -Wpointer-arith <<
175 KBUILD_CFLAGS += -Wredundant-decls <<
176 KBUILD_CFLAGS += -Wsign-compare <<
177 KBUILD_CFLAGS += -Wswitch-default <<
178 <<
179 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3 <<
180 <<
181 else 61 else
182 62
183 # The following turn off the warnings enabled !! 63 ifeq ($(cc-name),clang)
184 KBUILD_CFLAGS += -Wno-sign-compare !! 64 KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
185 KBUILD_CFLAGS += -Wno-unused-parameter !! 65 KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
186 !! 66 KBUILD_CFLAGS += $(call cc-disable-warning, format)
>> 67 KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
>> 68 KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
>> 69 KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
187 endif 70 endif
188 <<
189 # <<
190 # W=e - error out on warnings <<
191 # <<
192 ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),) <<
193 <<
194 KBUILD_CFLAGS += -Werror <<
195 <<
196 endif 71 endif
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