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 79# GCC produces false positives for functions that switch on an 80# enum (GCC bug 87950) 81CWARNFLAGS+= -Wno-return-type 82.endif # gcc 83 84# This warning is utter nonsense 85CWARNFLAGS+= -Wno-format-zero-length 86 87# External compilers may not support our format extensions. Allow them 88# to be disabled. WARNING: format checking is disabled in this case. 89.if ${MK_FORMAT_EXTENSIONS} == "no" 90FORMAT_EXTENSIONS= -Wno-format 91.elif ${COMPILER_TYPE} == "clang" 92FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 93.else 94FORMAT_EXTENSIONS= -fformat-extensions 95.endif 96 97# 98# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 99# and above adds code to the entry and exit point of every function to align the 100# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 101# per function call. While the 16-byte alignment may benefit micro benchmarks, 102# it is probably an overall loss as it makes the code bigger (less efficient 103# use of code cache tag lines) and uses more stack (less efficient use of data 104# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 105# operations inside the kernel itself. These operations are exclusively 106# reserved for user applications. 107# 108# gcc: 109# Setting -mno-mmx implies -mno-3dnow 110# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 111# 112# clang: 113# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 114# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 115# 116.if ${MACHINE_CPUARCH} == "i386" 117CFLAGS.gcc+= -mpreferred-stack-boundary=2 118CFLAGS.clang+= -mno-aes -mno-avx 119CFLAGS+= -mno-mmx -mno-sse -msoft-float 120INLINE_LIMIT?= 8000 121.endif 122 123.if ${MACHINE_CPUARCH} == "arm" 124INLINE_LIMIT?= 8000 125.endif 126 127.if ${MACHINE_CPUARCH} == "aarch64" 128# We generally don't want fpu instructions in the kernel. 129CFLAGS += -mgeneral-regs-only 130# Reserve x18 for pcpu data 131CFLAGS += -ffixed-x18 132INLINE_LIMIT?= 8000 133.endif 134 135# 136# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 137# point registers within the kernel. However, for kernels supporting hardware 138# float (FPE), we have to include that in the march so we can have limited 139# floating point support in context switching needed for that. This is different 140# than userland where we use a hard-float ABI (lp64d). 141# 142# We also specify the "medium" code model, which generates code suitable for a 143# 2GiB addressing range located at any offset, allowing modules to be located 144# anywhere in the 64-bit address space. Note that clang and GCC refer to this 145# code model as "medium" and "medany" respectively. 146# 147.if ${MACHINE_CPUARCH} == "riscv" 148CFLAGS+= -march=rv64imafdc 149CFLAGS+= -mabi=lp64 150CFLAGS.clang+= -mcmodel=medium 151CFLAGS.gcc+= -mcmodel=medany 152INLINE_LIMIT?= 8000 153 154.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 155CFLAGS+= -mno-relax 156.endif 157.endif 158 159# 160# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 161# operations inside the kernel itself. These operations are exclusively 162# reserved for user applications. 163# 164# gcc: 165# Setting -mno-mmx implies -mno-3dnow 166# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 167# 168# clang: 169# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 170# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 171# (-mfpmath= is not supported) 172# 173.if ${MACHINE_CPUARCH} == "amd64" 174CFLAGS.clang+= -mno-aes -mno-avx 175CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 176 -fno-asynchronous-unwind-tables 177INLINE_LIMIT?= 8000 178.endif 179 180# 181# For PowerPC we tell gcc to use floating point emulation. This avoids using 182# floating point registers for integer operations which it has a tendency to do. 183# Also explicitly disable Altivec instructions inside the kernel. 184# 185.if ${MACHINE_CPUARCH} == "powerpc" 186CFLAGS+= -mno-altivec -msoft-float 187INLINE_LIMIT?= 15000 188.endif 189 190.if ${MACHINE_ARCH} == "powerpcspe" 191CFLAGS.gcc+= -mno-spe 192.endif 193 194# 195# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 196# DDB happy. ELFv2, if available, has some other efficiency benefits. 197# 198.if ${MACHINE_ARCH:Mpowerpc64*} != "" 199CFLAGS+= -mabi=elfv2 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 ${CC} but -fuse-ld= is not supported 298.endif 299.endif 300.endif 301 302# Set target-specific linker emulation name. 303LD_EMULATION_aarch64=aarch64elf 304LD_EMULATION_amd64=elf_x86_64_fbsd 305LD_EMULATION_arm=armelf_fbsd 306LD_EMULATION_armv6=armelf_fbsd 307LD_EMULATION_armv7=armelf_fbsd 308LD_EMULATION_i386=elf_i386_fbsd 309LD_EMULATION_powerpc= elf32ppc_fbsd 310LD_EMULATION_powerpcspe= elf32ppc_fbsd 311LD_EMULATION_powerpc64= elf64ppc_fbsd 312LD_EMULATION_powerpc64le= elf64lppc_fbsd 313LD_EMULATION_riscv64= elf64lriscv 314LD_EMULATION_riscv64sf= elf64lriscv 315LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 316