4 # Warning flags for compiling the kernel and components of the kernel:
6 CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
7 -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
8 -Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
9 -Wmissing-include-dirs -fdiagnostics-show-option \
10 -Wno-unknown-pragmas \
13 # The following flags are next up for working on:
16 # Disable a few warnings for clang, since there are several places in the
17 # kernel where fixing them is more trouble than it is worth, or where there is
19 .if ${COMPILER_TYPE} == "clang"
20 NO_WCONSTANT_CONVERSION= -Wno-error-constant-conversion
21 NO_WSHIFT_COUNT_NEGATIVE= -Wno-error-shift-count-negative
22 NO_WSHIFT_COUNT_OVERFLOW= -Wno-error-shift-count-overflow
23 NO_WSELF_ASSIGN= -Wno-error-self-assign
24 NO_WUNNEEDED_INTERNAL_DECL= -Wno-error-unneeded-internal-declaration
25 NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized
26 NO_WCAST_QUAL= -Wno-error-cast-qual
27 # Several other warnings which might be useful in some cases, but not severe
28 # enough to error out the whole kernel build. Display them anyway, so there is
29 # some incentive to fix them eventually.
30 CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \
31 -Wno-error-parentheses-equality -Wno-error-unused-function \
32 -Wno-error-pointer-sign
33 .if ${COMPILER_VERSION} >= 30700
34 CWARNEXTRA+= -Wno-error-shift-negative-value
36 .if ${COMPILER_VERSION} >= 40000
37 CWARNEXTRA+= -Wno-error-address-of-packed-member
40 CLANG_NO_IAS= -no-integrated-as
41 .if ${COMPILER_VERSION} < 30500
42 # XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives
43 CLANG_NO_IAS34= -no-integrated-as
47 .if ${COMPILER_TYPE} == "gcc"
48 .if ${COMPILER_VERSION} >= 40800
49 # Catch-all for all the things that are in our tree, but for which we're
50 # not yet ready for this compiler.
51 CWARNEXTRA?= -Wno-error=address \
52 -Wno-error=aggressive-loop-optimizations \
53 -Wno-error=array-bounds \
54 -Wno-error=attributes \
55 -Wno-error=cast-qual \
56 -Wno-error=enum-compare \
58 -Wno-error=maybe-uninitialized \
60 -Wno-error=sequence-point \
61 -Wno-error=unused-but-set-variable
62 .if ${COMPILER_VERSION} >= 60100
63 CWARNEXTRA+= -Wno-error=misleading-indentation \
64 -Wno-error=nonnull-compare \
65 -Wno-error=shift-overflow \
66 -Wno-error=tautological-compare
69 # For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars.
70 CWARNEXTRA?= -Wno-uninitialized
71 # GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for
72 # the few files that are already known to generate cast-qual warnings.
73 NO_WCAST_QUAL= -Wno-cast-qual
77 # External compilers may not support our format extensions. Allow them
78 # to be disabled. WARNING: format checking is disabled in this case.
79 .if ${MK_FORMAT_EXTENSIONS} == "no"
80 FORMAT_EXTENSIONS= -Wno-format
81 .elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
82 FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__
84 FORMAT_EXTENSIONS= -fformat-extensions
88 # On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95
89 # and above adds code to the entry and exit point of every function to align the
90 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
91 # per function call. While the 16-byte alignment may benefit micro benchmarks,
92 # it is probably an overall loss as it makes the code bigger (less efficient
93 # use of code cache tag lines) and uses more stack (less efficient use of data
94 # cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD
95 # operations inside the kernel itself. These operations are exclusively
96 # reserved for user applications.
99 # Setting -mno-mmx implies -mno-3dnow
100 # Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
103 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
104 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
106 .if ${MACHINE_CPUARCH} == "i386"
107 CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2
108 CFLAGS.clang+= -mno-aes -mno-avx
109 CFLAGS+= -mno-mmx -mno-sse -msoft-float
113 .if ${MACHINE_CPUARCH} == "arm"
117 .if ${MACHINE_CPUARCH} == "aarch64"
118 # We generally don't want fpu instructions in the kernel.
119 CFLAGS += -mgeneral-regs-only
120 # Reserve x18 for pcpu data
121 CFLAGS += -ffixed-x18
125 .if ${MACHINE_CPUARCH} == "riscv"
126 CFLAGS.gcc+= -mcmodel=medany -march=rv64imafdc -mabi=lp64
131 # For sparc64 we want the medany code model so modules may be located
132 # anywhere in the 64-bit address space. We also tell GCC to use floating
133 # point emulation. This avoids using floating point registers for integer
134 # operations which it has a tendency to do.
136 .if ${MACHINE_CPUARCH} == "sparc64"
137 CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm
138 CFLAGS.gcc+= -mcmodel=medany -msoft-float
143 # For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
144 # operations inside the kernel itself. These operations are exclusively
145 # reserved for user applications.
148 # Setting -mno-mmx implies -mno-3dnow
149 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
152 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
153 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
154 # (-mfpmath= is not supported)
156 .if ${MACHINE_CPUARCH} == "amd64"
157 CFLAGS.clang+= -mno-aes -mno-avx
158 CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \
159 -fno-asynchronous-unwind-tables
164 # For PowerPC we tell gcc to use floating point emulation. This avoids using
165 # floating point registers for integer operations which it has a tendency to do.
166 # Also explicitly disable Altivec instructions inside the kernel.
168 .if ${MACHINE_CPUARCH} == "powerpc"
169 CFLAGS+= -mno-altivec -msoft-float
173 .if ${MACHINE_ARCH} == "powerpcspe"
174 CFLAGS.gcc+= -mno-spe
178 # Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make
179 # DDB happy. ELFv2, if available, has some other efficiency benefits.
181 .if ${MACHINE_ARCH} == "powerpc64"
182 .if ${COMPILER_VERSION} >= 40900
183 CFLAGS.gcc+= -mabi=elfv2
185 CFLAGS.gcc+= -mcall-aixdesc
187 CFLAGS.clang+= -mabi=elfv2
191 # For MIPS we also tell gcc to use floating point emulation
193 .if ${MACHINE_CPUARCH} == "mips"
194 CFLAGS+= -msoft-float
199 # GCC 3.0 and above like to do certain optimizations based on the
200 # assumption that the program is linked against libc. Stop this.
202 CFLAGS+= -ffreestanding
205 # The C standard leaves signed integer overflow behavior undefined.
206 # gcc and clang opimizers take advantage of this. The kernel makes
207 # use of signed integer wraparound mechanics so we need the compiler
208 # to treat it as a wraparound and not take shortcuts.
215 .if ${MK_SSP} != "no" && \
216 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
217 CFLAGS+= -fstack-protector
221 # Retpoline speculative execution vulnerability mitigation (CVE-2017-5715)
223 .if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \
224 ${MK_KERNEL_RETPOLINE} != "no"
229 # Add -gdwarf-2 when compiling -g. The default starting in clang v3.4
230 # and gcc 4.8 is to generate DWARF version 4. However, our tools don't
231 # cope well with DWARF 4, so force it to genereate DWARF2, which they
232 # understand. Do this unconditionally as it is harmless when not needed,
233 # but critical for these newer versions.
235 .if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == ""
239 CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}}
240 CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}}
242 # Tell bmake not to mistake standard targets for things to be searched for
243 # or expect to ever be up-to-date.
244 PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
245 beforelinking build build-tools buildfiles buildincludes \
246 checkdpadd clean cleandepend cleandir cleanobj configure \
247 depend distclean distribute exe \
248 html includes install installfiles installincludes \
249 obj objlink objs objwarn \
250 realinstall regress \
253 .PHONY: ${PHONY_NOTMAIN}
254 .NOTMAIN: ${PHONY_NOTMAIN}
259 CFLAGS+= -traditional
260 .elif ${CSTD} == "c89" || ${CSTD} == "c90"
261 CFLAGS+= -std=iso9899:1990
262 .elif ${CSTD} == "c94" || ${CSTD} == "c95"
263 CFLAGS+= -std=iso9899:199409
264 .elif ${CSTD} == "c99"
265 CFLAGS+= -std=iso9899:1999
267 CFLAGS+= -std=${CSTD}
270 # Set target-specific linker emulation name.
271 LD_EMULATION_aarch64=aarch64elf
272 LD_EMULATION_amd64=elf_x86_64_fbsd
273 LD_EMULATION_arm=armelf_fbsd
274 LD_EMULATION_armeb=armelfb_fbsd
275 LD_EMULATION_armv6=armelf_fbsd
276 LD_EMULATION_armv7=armelf_fbsd
277 LD_EMULATION_i386=elf_i386_fbsd
278 LD_EMULATION_mips= elf32btsmip_fbsd
279 LD_EMULATION_mipshf= elf32btsmip_fbsd
280 LD_EMULATION_mips64= elf64btsmip_fbsd
281 LD_EMULATION_mips64hf= elf64btsmip_fbsd
282 LD_EMULATION_mipsel= elf32ltsmip_fbsd
283 LD_EMULATION_mipselhf= elf32ltsmip_fbsd
284 LD_EMULATION_mips64el= elf64ltsmip_fbsd
285 LD_EMULATION_mips64elhf= elf64ltsmip_fbsd
286 LD_EMULATION_mipsn32= elf32btsmipn32_fbsd
287 LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works
288 LD_EMULATION_powerpc= elf32ppc_fbsd
289 LD_EMULATION_powerpcspe= elf32ppc_fbsd
290 LD_EMULATION_powerpc64= elf64ppc_fbsd
291 LD_EMULATION_riscv64= elf64lriscv
292 LD_EMULATION_sparc64= elf64_sparc_fbsd
293 LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}}