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