sys/conf/kern.mk

   1 # $FreeBSD$
   2
   3 #
   4 # Warning flags for compiling the kernel and components of the kernel:
   5 #
   6 CWARNFLAGS?=    -Wall -Wstrict-prototypes \
   7                 -Wmissing-prototypes -Wpointer-arith -Wcast-qual \
   8                 -Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
   9                 -Wmissing-include-dirs -fdiagnostics-show-option \
  10                 -Wno-unknown-pragmas \
  11                 ${CWARNEXTRA}
  12 #
  13 # The following flags are next up for working on:
  14 #       -Wextra
  15
  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
  18 # a false positive.
  19 .if ${COMPILER_TYPE} == "clang"
  20 NO_WCONSTANT_CONVERSION=        -Wno-error=constant-conversion
  21 NO_WSHIFT_COUNT_NEGATIVE=       -Wno-shift-count-negative
  22 NO_WSHIFT_COUNT_OVERFLOW=       -Wno-shift-count-overflow
  23 NO_WSELF_ASSIGN=                -Wno-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 NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare
  28 .if ${COMPILER_VERSION} >= 100000
  29 NO_WMISLEADING_INDENTATION=     -Wno-misleading-indentation
  30 .endif
  31 .if ${COMPILER_VERSION} >= 130000
  32 NO_WUNUSED_BUT_SET_VARIABLE=    -Wno-unused-but-set-variable
  33 .endif
  34 .if ${COMPILER_VERSION} >= 140000
  35 NO_WBITWISE_INSTEAD_OF_LOGICAL= -Wno-bitwise-instead-of-logical
  36 .endif
  37 .if ${COMPILER_VERSION} >= 150000
  38 NO_WSTRICT_PROTOTYPES=          -Wno-strict-prototypes
  39 .endif
  40 # Several other warnings which might be useful in some cases, but not severe
  41 # enough to error out the whole kernel build.  Display them anyway, so there is
  42 # some incentive to fix them eventually.
  43 CWARNEXTRA?=    -Wno-error=tautological-compare -Wno-error=empty-body \
  44                 -Wno-error=parentheses-equality -Wno-error=unused-function \
  45                 -Wno-error=pointer-sign
  46 CWARNEXTRA+=    -Wno-error=shift-negative-value
  47 CWARNEXTRA+=    -Wno-address-of-packed-member
  48 .if ${COMPILER_VERSION} >= 130000
  49 CWARNFLAGS+=    -Wno-error=unused-but-set-variable
  50 .endif
  51 .if ${COMPILER_VERSION} >= 150000
  52 # Clang 15 has much more aggressive diagnostics about inconsistently declared
  53 # array parameters, K&R prototypes, mismatched prototypes, and unused-but-set
  54 # variables. Make these non-fatal for the time being.
  55 CWARNEXTRA+=    -Wno-error=array-parameter
  56 CWARNEXTRA+=    -Wno-error=deprecated-non-prototype
  57 CWARNEXTRA+=    -Wno-error=strict-prototypes
  58 CWARNEXTRA+=    -Wno-error=unused-but-set-variable
  59 NO_WDEPRECATED_NON_PROTOTYPE=-Wno-deprecated-non-prototype
  60 .endif
  61 .endif  # clang
  62
  63 .if ${COMPILER_TYPE} == "gcc"
  64 # Catch-all for all the things that are in our tree, but for which we're
  65 # not yet ready for this compiler.
  66 NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable
  67 CWARNEXTRA?=    -Wno-error=address                              \
  68                 -Wno-error=aggressive-loop-optimizations        \
  69                 -Wno-error=array-bounds                         \
  70                 -Wno-error=attributes                           \
  71                 -Wno-error=cast-qual                            \
  72                 -Wno-error=enum-compare                         \
  73                 -Wno-error=maybe-uninitialized                  \
  74                 -Wno-error=misleading-indentation               \
  75                 -Wno-error=nonnull-compare                      \
  76                 -Wno-error=overflow                             \
  77                 -Wno-error=sequence-point                       \
  78                 -Wno-error=shift-overflow                       \
  79                 -Wno-error=tautological-compare                 \
  80                 -Wno-unused-but-set-variable
  81 .if ${COMPILER_VERSION} >= 70100
  82 CWARNEXTRA+=    -Wno-error=stringop-overflow
  83 .endif
  84 .if ${COMPILER_VERSION} >= 70200
  85 CWARNEXTRA+=    -Wno-error=memset-elt-size
  86 .endif
  87 .if ${COMPILER_VERSION} >= 80000
  88 CWARNEXTRA+=    -Wno-error=packed-not-aligned
  89 .endif
  90 .if ${COMPILER_VERSION} >= 90100
  91 CWARNEXTRA+=    -Wno-address-of-packed-member                   \
  92                 -Wno-error=alloca-larger-than=
  93 .if ${COMPILER_VERSION} >= 120100
  94 CWARNEXTRA+=    -Wno-error=nonnull                              \
  95                 -Wno-dangling-pointer                           \
  96                 -Wno-zero-length-bounds
  97 NO_WINFINITE_RECURSION= -Wno-infinite-recursion
  98 NO_WSTRINGOP_OVERREAD=  -Wno-stringop-overread
  99 .endif
 100 .endif
 101
 102 # GCC produces false positives for functions that switch on an
 103 # enum (GCC bug 87950)
 104 CWARNFLAGS+=    -Wno-return-type
 105 .endif  # gcc
 106
 107 # This warning is utter nonsense
 108 CWARNFLAGS+=    -Wno-format-zero-length
 109
 110 # External compilers may not support our format extensions.  Allow them
 111 # to be disabled.  WARNING: format checking is disabled in this case.
 112 .if ${MK_FORMAT_EXTENSIONS} == "no"
 113 FORMAT_EXTENSIONS=      -Wno-format
 114 .elif ${COMPILER_TYPE} == "clang" || \
 115     (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100)
 116 FORMAT_EXTENSIONS=      -D__printf__=__freebsd_kprintf__
 117 .else
 118 FORMAT_EXTENSIONS=      -fformat-extensions
 119 .endif
 120
 121 #
 122 # On i386, do not align the stack to 16-byte boundaries.  Otherwise GCC 2.95
 123 # and above adds code to the entry and exit point of every function to align the
 124 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
 125 # per function call.  While the 16-byte alignment may benefit micro benchmarks,
 126 # it is probably an overall loss as it makes the code bigger (less efficient
 127 # use of code cache tag lines) and uses more stack (less efficient use of data
 128 # cache tag lines).  Explicitly prohibit the use of FPU, SSE and other SIMD
 129 # operations inside the kernel itself.  These operations are exclusively
 130 # reserved for user applications.
 131 #
 132 # gcc:
 133 # Setting -mno-mmx implies -mno-3dnow
 134 # Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
 135 #
 136 # clang:
 137 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 138 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 139 #
 140 .if ${MACHINE_CPUARCH} == "i386"
 141 CFLAGS.gcc+=    -mpreferred-stack-boundary=2
 142 CFLAGS.clang+=  -mno-aes -mno-avx
 143 CFLAGS+=        -mno-mmx -mno-sse -msoft-float
 144 INLINE_LIMIT?=  8000
 145 .endif
 146
 147 .if ${MACHINE_CPUARCH} == "arm"
 148 INLINE_LIMIT?=  8000
 149 .endif
 150
 151 .if ${MACHINE_CPUARCH} == "aarch64"
 152 # We generally don't want fpu instructions in the kernel.
 153 CFLAGS += -mgeneral-regs-only
 154 # Reserve x18 for pcpu data
 155 CFLAGS += -ffixed-x18
 156 INLINE_LIMIT?=  8000
 157 .endif
 158
 159 #
 160 # For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating
 161 # point registers within the kernel. However, for kernels supporting hardware
 162 # float (FPE), we have to include that in the march so we can have limited
 163 # floating point support in context switching needed for that. This is different
 164 # than userland where we use a hard-float ABI (lp64d).
 165 #
 166 # We also specify the "medium" code model, which generates code suitable for a
 167 # 2GiB addressing range located at any offset, allowing modules to be located
 168 # anywhere in the 64-bit address space.  Note that clang and GCC refer to this
 169 # code model as "medium" and "medany" respectively.
 170 #
 171 .if ${MACHINE_CPUARCH} == "riscv"
 172 CFLAGS+=        -march=rv64imafdc
 173 CFLAGS+=        -mabi=lp64
 174 CFLAGS.clang+=  -mcmodel=medium
 175 CFLAGS.gcc+=    -mcmodel=medany
 176 INLINE_LIMIT?=  8000
 177
 178 .if ${LINKER_FEATURES:Mriscv-relaxations} == ""
 179 CFLAGS+=        -mno-relax
 180 .endif
 181 .endif
 182
 183 #
 184 # For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
 185 # operations inside the kernel itself.  These operations are exclusively
 186 # reserved for user applications.
 187 #
 188 # gcc:
 189 # Setting -mno-mmx implies -mno-3dnow
 190 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
 191 #
 192 # clang:
 193 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 194 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 195 # (-mfpmath= is not supported)
 196 #
 197 .if ${MACHINE_CPUARCH} == "amd64"
 198 CFLAGS.clang+=  -mno-aes -mno-avx
 199 CFLAGS+=        -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \
 200                 -fno-asynchronous-unwind-tables
 201 INLINE_LIMIT?=  8000
 202 .endif
 203
 204 #
 205 # For PowerPC we tell gcc to use floating point emulation.  This avoids using
 206 # floating point registers for integer operations which it has a tendency to do.
 207 # Also explicitly disable Altivec instructions inside the kernel.
 208 #
 209 .if ${MACHINE_CPUARCH} == "powerpc"
 210 CFLAGS+=        -mno-altivec -msoft-float
 211 INLINE_LIMIT?=  15000
 212 .endif
 213
 214 .if ${MACHINE_ARCH} == "powerpcspe"
 215 CFLAGS.gcc+=    -mno-spe
 216 .endif
 217
 218 #
 219 # Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make
 220 # DDB happy. ELFv2, if available, has some other efficiency benefits.
 221 #
 222 .if ${MACHINE_ARCH:Mpowerpc64*} != "" && \
 223     ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000
 224 CFLAGS+=        -mabi=elfv2
 225 .endif
 226
 227 #
 228 # For MIPS we also tell gcc to use floating point emulation
 229 #
 230 .if ${MACHINE_CPUARCH} == "mips"
 231 CFLAGS+=        -msoft-float
 232 INLINE_LIMIT?=  8000
 233 .endif
 234
 235 #
 236 # GCC 3.0 and above like to do certain optimizations based on the
 237 # assumption that the program is linked against libc.  Stop this.
 238 #
 239 CFLAGS+=        -ffreestanding
 240
 241 #
 242 # The C standard leaves signed integer overflow behavior undefined.
 243 # gcc and clang opimizers take advantage of this.  The kernel makes
 244 # use of signed integer wraparound mechanics so we need the compiler
 245 # to treat it as a wraparound and not take shortcuts.
 246 #
 247 CFLAGS+=        -fwrapv
 248
 249 #
 250 # GCC SSP support
 251 #
 252 .if ${MK_SSP} != "no"
 253 CFLAGS+=        -fstack-protector
 254 .endif
 255
 256 #
 257 # Retpoline speculative execution vulnerability mitigation (CVE-2017-5715)
 258 #
 259 .if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \
 260     ${MK_KERNEL_RETPOLINE} != "no"
 261 CFLAGS+=        -mretpoline
 262 .endif
 263
 264 #
 265 # Initialize stack variables on function entry
 266 #
 267 .if ${MK_INIT_ALL_ZERO} == "yes"
 268 .if ${COMPILER_FEATURES:Minit-all}
 269 CFLAGS+= -ftrivial-auto-var-init=zero
 270 .if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000
 271 CFLAGS+= -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
 272 .endif
 273 .else
 274 .warning InitAll (zeros) requested but not supported by compiler
 275 .endif
 276 .elif ${MK_INIT_ALL_PATTERN} == "yes"
 277 .if ${COMPILER_FEATURES:Minit-all}
 278 CFLAGS+= -ftrivial-auto-var-init=pattern
 279 .else
 280 .warning InitAll (pattern) requested but not support by compiler
 281 .endif
 282 .endif
 283
 284 CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}}
 285 CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}}
 286 CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}}
 287
 288 # Tell bmake not to mistake standard targets for things to be searched for
 289 # or expect to ever be up-to-date.
 290 PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
 291                 beforelinking build build-tools buildfiles buildincludes \
 292                 checkdpadd clean cleandepend cleandir cleanobj configure \
 293                 depend distclean distribute exe \
 294                 html includes install installfiles installincludes \
 295                 obj objlink objs objwarn \
 296                 realinstall regress \
 297                 tags whereobj
 298
 299 .PHONY: ${PHONY_NOTMAIN}
 300 .NOTMAIN: ${PHONY_NOTMAIN}
 301
 302 CSTD=           c99
 303
 304 .if ${CSTD} == "k&r"
 305 CFLAGS+=        -traditional
 306 .elif ${CSTD} == "c89" || ${CSTD} == "c90"
 307 CFLAGS+=        -std=iso9899:1990
 308 .elif ${CSTD} == "c94" || ${CSTD} == "c95"
 309 CFLAGS+=        -std=iso9899:199409
 310 .elif ${CSTD} == "c99"
 311 CFLAGS+=        -std=iso9899:1999
 312 .else # CSTD
 313 CFLAGS+=        -std=${CSTD}
 314 .endif # CSTD
 315
 316 # Please keep this if in sync with bsd.sys.mk
 317 .if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld")
 318 # Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld".
 319 .if ${COMPILER_TYPE} == "clang"
 320 # Note: Clang does not like relative paths for ld so we map ld.lld -> lld.
 321 .if ${COMPILER_VERSION} >= 120000
 322 CCLDFLAGS+=     --ld-path=${LD:[1]:S/^ld.//1W}
 323 .else
 324 CCLDFLAGS+=     -fuse-ld=${LD:[1]:S/^ld.//1W}
 325 .endif
 326 .else
 327 # GCC does not support an absolute path for -fuse-ld so we just print this
 328 # warning instead and let the user add the required symlinks.
 329 # However, we can avoid this warning if -B is set appropriately (e.g. for
 330 # CROSS_TOOLCHAIN=...-gcc).
 331 .if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/})
 332 .warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported
 333 .endif
 334 .endif
 335 .endif
 336
 337 # Set target-specific linker emulation name.
 338 LD_EMULATION_aarch64=aarch64elf
 339 LD_EMULATION_amd64=elf_x86_64_fbsd
 340 LD_EMULATION_arm=armelf_fbsd
 341 LD_EMULATION_armv6=armelf_fbsd
 342 LD_EMULATION_armv7=armelf_fbsd
 343 LD_EMULATION_i386=elf_i386_fbsd
 344 LD_EMULATION_mips= elf32btsmip_fbsd
 345 LD_EMULATION_mipshf= elf32btsmip_fbsd
 346 LD_EMULATION_mips64= elf64btsmip_fbsd
 347 LD_EMULATION_mips64hf= elf64btsmip_fbsd
 348 LD_EMULATION_mipsel= elf32ltsmip_fbsd
 349 LD_EMULATION_mipselhf= elf32ltsmip_fbsd
 350 LD_EMULATION_mips64el= elf64ltsmip_fbsd
 351 LD_EMULATION_mips64elhf= elf64ltsmip_fbsd
 352 LD_EMULATION_mipsn32= elf32btsmipn32_fbsd
 353 LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd   # I don't think this is a thing that works
 354 LD_EMULATION_powerpc= elf32ppc_fbsd
 355 LD_EMULATION_powerpcspe= elf32ppc_fbsd
 356 LD_EMULATION_powerpc64= elf64ppc_fbsd
 357 LD_EMULATION_powerpc64le= elf64lppc_fbsd
 358 LD_EMULATION_riscv64= elf64lriscv
 359 LD_EMULATION_riscv64sf= elf64lriscv
 360 LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}}