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