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