1# $FreeBSD$ 2 3# 4# Warning flags for compiling the kernel and components of the kernel: 5# 6CWARNFLAGS?= -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" 20NO_WCONSTANT_CONVERSION= -Wno-error=constant-conversion 21NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative 22NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow 23NO_WSELF_ASSIGN= -Wno-self-assign 24NO_WUNNEEDED_INTERNAL_DECL= -Wno-error=unneeded-internal-declaration 25NO_WSOMETIMES_UNINITIALIZED= -Wno-error=sometimes-uninitialized 26NO_WCAST_QUAL= -Wno-error=cast-qual 27NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare 28.if ${COMPILER_VERSION} >= 100000 29NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation 30.endif 31.if ${COMPILER_VERSION} >= 130000 32NO_WUNUSED_BUT_SET_VARIABLE= -Wno-unused-but-set-variable 33.endif 34.if ${COMPILER_VERSION} >= 140000 35NO_WBITWISE_INSTEAD_OF_LOGICAL= -Wno-bitwise-instead-of-logical 36.endif 37.if ${COMPILER_VERSION} >= 150000 38NO_WSTRICT_PROTOTYPES= -Wno-strict-prototypes 39NO_WDEPRECATED_NON_PROTOTYPE= -Wno-deprecated-non-prototype 40.endif 41# Several other warnings which might be useful in some cases, but not severe 42# enough to error out the whole kernel build. Display them anyway, so there is 43# some incentive to fix them eventually. 44CWARNEXTRA?= -Wno-error=tautological-compare -Wno-error=empty-body \ 45 -Wno-error=parentheses-equality -Wno-error=unused-function \ 46 -Wno-error=pointer-sign 47CWARNEXTRA+= -Wno-error=shift-negative-value 48CWARNEXTRA+= -Wno-address-of-packed-member 49.if ${COMPILER_VERSION} >= 150000 50# Clang 15 has much more aggressive diagnostics about K&R prototypes, 51# mismatched prototypes, and unused-but-set variables. Make these 52# non-fatal for the time being. 53CWARNEXTRA+= -Wno-error=deprecated-non-prototype 54CWARNEXTRA+= -Wno-error=strict-prototypes 55CWARNEXTRA+= -Wno-error=unused-but-set-variable 56.endif 57.endif # clang 58 59.if ${COMPILER_TYPE} == "gcc" 60# Catch-all for all the things that are in our tree, but for which we're 61# not yet ready for this compiler. 62NO_WUNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable 63CWARNEXTRA?= -Wno-error=address \ 64 -Wno-error=aggressive-loop-optimizations \ 65 -Wno-error=array-bounds \ 66 -Wno-error=attributes \ 67 -Wno-error=cast-qual \ 68 -Wno-error=enum-compare \ 69 -Wno-error=maybe-uninitialized \ 70 -Wno-error=misleading-indentation \ 71 -Wno-error=nonnull-compare \ 72 -Wno-error=overflow \ 73 -Wno-error=sequence-point \ 74 -Wno-error=shift-overflow \ 75 -Wno-error=tautological-compare \ 76 -Wno-error=unused-function 77.if ${COMPILER_VERSION} >= 70100 78CWARNEXTRA+= -Wno-error=stringop-overflow 79.endif 80.if ${COMPILER_VERSION} >= 70200 81CWARNEXTRA+= -Wno-error=memset-elt-size 82.endif 83.if ${COMPILER_VERSION} >= 80000 84CWARNEXTRA+= -Wno-error=packed-not-aligned 85.endif 86.if ${COMPILER_VERSION} >= 90100 87CWARNEXTRA+= -Wno-address-of-packed-member \ 88 -Wno-error=alloca-larger-than= 89.if ${COMPILER_VERSION} >= 120100 90CWARNEXTRA+= -Wno-error=nonnull \ 91 -Wno-dangling-pointer \ 92 -Wno-zero-length-bounds 93NO_WINFINITE_RECURSION= -Wno-infinite-recursion 94NO_WSTRINGOP_OVERREAD= -Wno-stringop-overread 95.endif 96.endif 97 98# GCC produces false positives for functions that switch on an 99# enum (GCC bug 87950) 100CWARNFLAGS+= -Wno-return-type 101.endif # gcc 102 103# This warning is utter nonsense 104CWARNFLAGS+= -Wno-format-zero-length 105 106# External compilers may not support our format extensions. Allow them 107# to be disabled. WARNING: format checking is disabled in this case. 108.if ${MK_FORMAT_EXTENSIONS} == "no" 109FORMAT_EXTENSIONS= -Wno-format 110.elif ${COMPILER_TYPE} == "clang" || \ 111 (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100) 112FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 113.else 114FORMAT_EXTENSIONS= -fformat-extensions 115.endif 116 117# 118# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 119# and above adds code to the entry and exit point of every function to align the 120# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 121# per function call. While the 16-byte alignment may benefit micro benchmarks, 122# it is probably an overall loss as it makes the code bigger (less efficient 123# use of code cache tag lines) and uses more stack (less efficient use of data 124# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 125# operations inside the kernel itself. These operations are exclusively 126# reserved for user applications. 127# 128# gcc: 129# Setting -mno-mmx implies -mno-3dnow 130# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 131# 132# clang: 133# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 134# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 135# 136.if ${MACHINE_CPUARCH} == "i386" 137CFLAGS.gcc+= -mpreferred-stack-boundary=2 138CFLAGS.clang+= -mno-aes -mno-avx 139CFLAGS+= -mno-mmx -mno-sse -msoft-float 140INLINE_LIMIT?= 8000 141.endif 142 143.if ${MACHINE_CPUARCH} == "arm" 144INLINE_LIMIT?= 8000 145.endif 146 147.if ${MACHINE_CPUARCH} == "aarch64" 148# We generally don't want fpu instructions in the kernel. 149CFLAGS += -mgeneral-regs-only 150# Reserve x18 for pcpu data 151CFLAGS += -ffixed-x18 152INLINE_LIMIT?= 8000 153.endif 154 155# 156# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 157# point registers within the kernel. However, for kernels supporting hardware 158# float (FPE), we have to include that in the march so we can have limited 159# floating point support in context switching needed for that. This is different 160# than userland where we use a hard-float ABI (lp64d). 161# 162# We also specify the "medium" code model, which generates code suitable for a 163# 2GiB addressing range located at any offset, allowing modules to be located 164# anywhere in the 64-bit address space. Note that clang and GCC refer to this 165# code model as "medium" and "medany" respectively. 166# 167.if ${MACHINE_CPUARCH} == "riscv" 168CFLAGS+= -march=rv64imafdc 169CFLAGS+= -mabi=lp64 170CFLAGS.clang+= -mcmodel=medium 171CFLAGS.gcc+= -mcmodel=medany 172INLINE_LIMIT?= 8000 173 174.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 175CFLAGS+= -mno-relax 176.endif 177.endif 178 179# 180# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 181# operations inside the kernel itself. These operations are exclusively 182# reserved for user applications. 183# 184# gcc: 185# Setting -mno-mmx implies -mno-3dnow 186# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 187# 188# clang: 189# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 190# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 191# (-mfpmath= is not supported) 192# 193.if ${MACHINE_CPUARCH} == "amd64" 194CFLAGS.clang+= -mno-aes -mno-avx 195CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 196 -fno-asynchronous-unwind-tables 197INLINE_LIMIT?= 8000 198.endif 199 200# 201# For PowerPC we tell gcc to use floating point emulation. This avoids using 202# floating point registers for integer operations which it has a tendency to do. 203# Also explicitly disable Altivec instructions inside the kernel. 204# 205.if ${MACHINE_CPUARCH} == "powerpc" 206CFLAGS+= -mno-altivec -msoft-float 207INLINE_LIMIT?= 15000 208.endif 209 210.if ${MACHINE_ARCH} == "powerpcspe" 211CFLAGS.gcc+= -mno-spe 212.endif 213 214# 215# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 216# DDB happy. ELFv2, if available, has some other efficiency benefits. 217# 218.if ${MACHINE_ARCH:Mpowerpc64*} != "" && \ 219 ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000 220CFLAGS+= -mabi=elfv2 221.endif 222 223# 224# GCC 3.0 and above like to do certain optimizations based on the 225# assumption that the program is linked against libc. Stop this. 226# 227CFLAGS+= -ffreestanding 228 229# 230# The C standard leaves signed integer overflow behavior undefined. 231# gcc and clang opimizers take advantage of this. The kernel makes 232# use of signed integer wraparound mechanics so we need the compiler 233# to treat it as a wraparound and not take shortcuts. 234# 235CFLAGS+= -fwrapv 236 237# 238# GCC SSP support 239# 240.if ${MK_SSP} != "no" 241CFLAGS+= -fstack-protector 242.endif 243 244# 245# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 246# 247.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 248 ${MK_KERNEL_RETPOLINE} != "no" 249CFLAGS+= -mretpoline 250.endif 251 252# 253# Initialize stack variables on function entry 254# 255.if ${MK_INIT_ALL_ZERO} == "yes" 256.if ${COMPILER_FEATURES:Minit-all} 257CFLAGS+= -ftrivial-auto-var-init=zero \ 258 -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang 259.else 260.warning InitAll (zeros) requested but not support by compiler 261.endif 262.elif ${MK_INIT_ALL_PATTERN} == "yes" 263.if ${COMPILER_FEATURES:Minit-all} 264CFLAGS+= -ftrivial-auto-var-init=pattern 265.else 266.warning InitAll (pattern) requested but not support by compiler 267.endif 268.endif 269 270CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 271CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 272CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 273 274# Tell bmake not to mistake standard targets for things to be searched for 275# or expect to ever be up-to-date. 276PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 277 beforelinking build build-tools buildfiles buildincludes \ 278 checkdpadd clean cleandepend cleandir cleanobj configure \ 279 depend distclean distribute exe \ 280 html includes install installfiles installincludes \ 281 obj objlink objs objwarn \ 282 realinstall regress \ 283 tags whereobj 284 285.PHONY: ${PHONY_NOTMAIN} 286.NOTMAIN: ${PHONY_NOTMAIN} 287 288CSTD= c99 289 290.if ${CSTD} == "k&r" 291CFLAGS+= -traditional 292.elif ${CSTD} == "c89" || ${CSTD} == "c90" 293CFLAGS+= -std=iso9899:1990 294.elif ${CSTD} == "c94" || ${CSTD} == "c95" 295CFLAGS+= -std=iso9899:199409 296.elif ${CSTD} == "c99" 297CFLAGS+= -std=iso9899:1999 298.else # CSTD 299CFLAGS+= -std=${CSTD} 300.endif # CSTD 301 302# Please keep this if in sync with bsd.sys.mk 303.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld") 304# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld". 305.if ${COMPILER_TYPE} == "clang" 306# Note: Clang does not like relative paths for ld so we map ld.lld -> lld. 307.if ${COMPILER_VERSION} >= 120000 308CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W} 309.else 310CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W} 311.endif 312.else 313# GCC does not support an absolute path for -fuse-ld so we just print this 314# warning instead and let the user add the required symlinks. 315# However, we can avoid this warning if -B is set appropriately (e.g. for 316# CROSS_TOOLCHAIN=...-gcc). 317.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/}) 318.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported 319.endif 320.endif 321.endif 322 323# Set target-specific linker emulation name. 324LD_EMULATION_aarch64=aarch64elf 325LD_EMULATION_amd64=elf_x86_64_fbsd 326LD_EMULATION_arm=armelf_fbsd 327LD_EMULATION_armv6=armelf_fbsd 328LD_EMULATION_armv7=armelf_fbsd 329LD_EMULATION_i386=elf_i386_fbsd 330LD_EMULATION_powerpc= elf32ppc_fbsd 331LD_EMULATION_powerpcspe= elf32ppc_fbsd 332LD_EMULATION_powerpc64= elf64ppc_fbsd 333LD_EMULATION_powerpc64le= elf64lppc_fbsd 334LD_EMULATION_riscv64= elf64lriscv 335LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 336