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 inconsistently declared 51# array parameters, K&R prototypes, mismatched prototypes, and unused-but-set 52# variables. Make these non-fatal for the time being. 53CWARNEXTRA+= -Wno-error=array-parameter 54CWARNEXTRA+= -Wno-error=deprecated-non-prototype 55CWARNEXTRA+= -Wno-error=strict-prototypes 56CWARNEXTRA+= -Wno-error=unused-but-set-variable 57.endif 58.endif # clang 59 60.if ${COMPILER_TYPE} == "gcc" 61# Catch-all for all the things that are in our tree, but for which we're 62# not yet ready for this compiler. 63NO_WUNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable 64CWARNEXTRA?= -Wno-error=address \ 65 -Wno-error=aggressive-loop-optimizations \ 66 -Wno-error=array-bounds \ 67 -Wno-error=attributes \ 68 -Wno-error=cast-qual \ 69 -Wno-error=enum-compare \ 70 -Wno-error=maybe-uninitialized \ 71 -Wno-error=misleading-indentation \ 72 -Wno-error=nonnull-compare \ 73 -Wno-error=overflow \ 74 -Wno-error=sequence-point \ 75 -Wno-error=shift-overflow \ 76 -Wno-error=tautological-compare \ 77 -Wno-error=unused-function \ 78 -Wno-unused-but-set-variable 79.if ${COMPILER_VERSION} >= 70100 80CWARNEXTRA+= -Wno-error=stringop-overflow 81.endif 82.if ${COMPILER_VERSION} >= 70200 83CWARNEXTRA+= -Wno-error=memset-elt-size 84.endif 85.if ${COMPILER_VERSION} >= 80000 86CWARNEXTRA+= -Wno-error=packed-not-aligned 87.endif 88.if ${COMPILER_VERSION} >= 90100 89CWARNEXTRA+= -Wno-address-of-packed-member \ 90 -Wno-error=alloca-larger-than= 91.if ${COMPILER_VERSION} >= 120100 92CWARNEXTRA+= -Wno-error=nonnull \ 93 -Wno-dangling-pointer \ 94 -Wno-zero-length-bounds 95NO_WINFINITE_RECURSION= -Wno-infinite-recursion 96NO_WSTRINGOP_OVERREAD= -Wno-stringop-overread 97.endif 98.endif 99 100# GCC produces false positives for functions that switch on an 101# enum (GCC bug 87950) 102CWARNFLAGS+= -Wno-return-type 103.endif # gcc 104 105# This warning is utter nonsense 106CWARNFLAGS+= -Wno-format-zero-length 107 108# External compilers may not support our format extensions. Allow them 109# to be disabled. WARNING: format checking is disabled in this case. 110.if ${MK_FORMAT_EXTENSIONS} == "no" 111FORMAT_EXTENSIONS= -Wno-format 112.elif ${COMPILER_TYPE} == "clang" || \ 113 (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100) 114FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 115.else 116FORMAT_EXTENSIONS= -fformat-extensions 117.endif 118 119# 120# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 121# and above adds code to the entry and exit point of every function to align the 122# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 123# per function call. While the 16-byte alignment may benefit micro benchmarks, 124# it is probably an overall loss as it makes the code bigger (less efficient 125# use of code cache tag lines) and uses more stack (less efficient use of data 126# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 127# operations inside the kernel itself. These operations are exclusively 128# reserved for user applications. 129# 130# gcc: 131# Setting -mno-mmx implies -mno-3dnow 132# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 133# 134# clang: 135# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 136# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 137# 138.if ${MACHINE_CPUARCH} == "i386" 139CFLAGS.gcc+= -mpreferred-stack-boundary=2 140CFLAGS.clang+= -mno-aes -mno-avx 141CFLAGS+= -mno-mmx -mno-sse -msoft-float 142INLINE_LIMIT?= 8000 143.endif 144 145.if ${MACHINE_CPUARCH} == "arm" 146INLINE_LIMIT?= 8000 147.endif 148 149.if ${MACHINE_CPUARCH} == "aarch64" 150# We generally don't want fpu instructions in the kernel. 151CFLAGS += -mgeneral-regs-only 152# Reserve x18 for pcpu data 153CFLAGS += -ffixed-x18 154INLINE_LIMIT?= 8000 155.endif 156 157# 158# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 159# point registers within the kernel. However, for kernels supporting hardware 160# float (FPE), we have to include that in the march so we can have limited 161# floating point support in context switching needed for that. This is different 162# than userland where we use a hard-float ABI (lp64d). 163# 164# We also specify the "medium" code model, which generates code suitable for a 165# 2GiB addressing range located at any offset, allowing modules to be located 166# anywhere in the 64-bit address space. Note that clang and GCC refer to this 167# code model as "medium" and "medany" respectively. 168# 169.if ${MACHINE_CPUARCH} == "riscv" 170CFLAGS+= -march=rv64imafdc 171CFLAGS+= -mabi=lp64 172CFLAGS.clang+= -mcmodel=medium 173CFLAGS.gcc+= -mcmodel=medany 174INLINE_LIMIT?= 8000 175 176.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 177CFLAGS+= -mno-relax 178.endif 179.endif 180 181# 182# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 183# operations inside the kernel itself. These operations are exclusively 184# reserved for user applications. 185# 186# gcc: 187# Setting -mno-mmx implies -mno-3dnow 188# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 189# 190# clang: 191# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 192# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 193# (-mfpmath= is not supported) 194# 195.if ${MACHINE_CPUARCH} == "amd64" 196CFLAGS.clang+= -mno-aes -mno-avx 197CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 198 -fno-asynchronous-unwind-tables 199INLINE_LIMIT?= 8000 200.endif 201 202# 203# For PowerPC we tell gcc to use floating point emulation. This avoids using 204# floating point registers for integer operations which it has a tendency to do. 205# Also explicitly disable Altivec instructions inside the kernel. 206# 207.if ${MACHINE_CPUARCH} == "powerpc" 208CFLAGS+= -mno-altivec -msoft-float 209INLINE_LIMIT?= 15000 210.endif 211 212.if ${MACHINE_ARCH} == "powerpcspe" 213CFLAGS.gcc+= -mno-spe 214.endif 215 216# 217# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 218# DDB happy. ELFv2, if available, has some other efficiency benefits. 219# 220.if ${MACHINE_ARCH:Mpowerpc64*} != "" 221CFLAGS+= -mabi=elfv2 222.endif 223 224# 225# GCC 3.0 and above like to do certain optimizations based on the 226# assumption that the program is linked against libc. Stop this. 227# 228CFLAGS+= -ffreestanding 229 230# 231# The C standard leaves signed integer overflow behavior undefined. 232# gcc and clang opimizers take advantage of this. The kernel makes 233# use of signed integer wraparound mechanics so we need the compiler 234# to treat it as a wraparound and not take shortcuts. 235# 236CFLAGS+= -fwrapv 237 238# 239# GCC SSP support 240# 241.if ${MK_SSP} != "no" 242CFLAGS+= -fstack-protector 243.endif 244 245# 246# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 247# 248.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 249 ${MK_KERNEL_RETPOLINE} != "no" 250CFLAGS+= -mretpoline 251.endif 252 253# 254# Initialize stack variables on function entry 255# 256.if ${MK_INIT_ALL_ZERO} == "yes" 257.if ${COMPILER_FEATURES:Minit-all} 258CFLAGS+= -ftrivial-auto-var-init=zero \ 259 -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang 260.else 261.warning InitAll (zeros) requested but not support by compiler 262.endif 263.elif ${MK_INIT_ALL_PATTERN} == "yes" 264.if ${COMPILER_FEATURES:Minit-all} 265CFLAGS+= -ftrivial-auto-var-init=pattern 266.else 267.warning InitAll (pattern) requested but not support by compiler 268.endif 269.endif 270 271CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 272CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 273CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 274 275# Tell bmake not to mistake standard targets for things to be searched for 276# or expect to ever be up-to-date. 277PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 278 beforelinking build build-tools buildfiles buildincludes \ 279 checkdpadd clean cleandepend cleandir cleanobj configure \ 280 depend distclean distribute exe \ 281 html includes install installfiles installincludes \ 282 obj objlink objs objwarn \ 283 realinstall regress \ 284 tags whereobj 285 286.PHONY: ${PHONY_NOTMAIN} 287.NOTMAIN: ${PHONY_NOTMAIN} 288 289CSTD= c99 290 291.if ${CSTD} == "k&r" 292CFLAGS+= -traditional 293.elif ${CSTD} == "c89" || ${CSTD} == "c90" 294CFLAGS+= -std=iso9899:1990 295.elif ${CSTD} == "c94" || ${CSTD} == "c95" 296CFLAGS+= -std=iso9899:199409 297.elif ${CSTD} == "c99" 298CFLAGS+= -std=iso9899:1999 299.else # CSTD 300CFLAGS+= -std=${CSTD} 301.endif # CSTD 302 303# Please keep this if in sync with bsd.sys.mk 304.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld") 305# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld". 306.if ${COMPILER_TYPE} == "clang" 307# Note: Clang does not like relative paths for ld so we map ld.lld -> lld. 308.if ${COMPILER_VERSION} >= 120000 309CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W} 310.else 311CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W} 312.endif 313.else 314# GCC does not support an absolute path for -fuse-ld so we just print this 315# warning instead and let the user add the required symlinks. 316# However, we can avoid this warning if -B is set appropriately (e.g. for 317# CROSS_TOOLCHAIN=...-gcc). 318.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/}) 319.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported 320.endif 321.endif 322.endif 323 324# Set target-specific linker emulation name. 325LD_EMULATION_aarch64=aarch64elf 326LD_EMULATION_amd64=elf_x86_64_fbsd 327LD_EMULATION_arm=armelf_fbsd 328LD_EMULATION_armv6=armelf_fbsd 329LD_EMULATION_armv7=armelf_fbsd 330LD_EMULATION_i386=elf_i386_fbsd 331LD_EMULATION_powerpc= elf32ppc_fbsd 332LD_EMULATION_powerpcspe= elf32ppc_fbsd 333LD_EMULATION_powerpc64= elf64ppc_fbsd 334LD_EMULATION_powerpc64le= elf64lppc_fbsd 335LD_EMULATION_riscv64= elf64lriscv 336LD_EMULATION_riscv64sf= elf64lriscv 337LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 338