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