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