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.endif # clang 50 51.if ${COMPILER_TYPE} == "gcc" 52# Catch-all for all the things that are in our tree, but for which we're 53# not yet ready for this compiler. 54NO_WUNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable 55CWARNEXTRA?= -Wno-error=address \ 56 -Wno-error=aggressive-loop-optimizations \ 57 -Wno-error=array-bounds \ 58 -Wno-error=attributes \ 59 -Wno-error=cast-qual \ 60 -Wno-error=enum-compare \ 61 -Wno-error=maybe-uninitialized \ 62 -Wno-error=misleading-indentation \ 63 -Wno-error=nonnull-compare \ 64 -Wno-error=overflow \ 65 -Wno-error=sequence-point \ 66 -Wno-error=shift-overflow \ 67 -Wno-error=tautological-compare \ 68 -Wno-error=unused-function 69.if ${COMPILER_VERSION} >= 70100 70CWARNEXTRA+= -Wno-error=stringop-overflow 71.endif 72.if ${COMPILER_VERSION} >= 70200 73CWARNEXTRA+= -Wno-error=memset-elt-size 74.endif 75.if ${COMPILER_VERSION} >= 80000 76CWARNEXTRA+= -Wno-error=packed-not-aligned 77.endif 78.if ${COMPILER_VERSION} >= 90100 79CWARNEXTRA+= -Wno-address-of-packed-member \ 80 -Wno-error=alloca-larger-than= 81.if ${COMPILER_VERSION} >= 120100 82CWARNEXTRA+= -Wno-error=nonnull \ 83 -Wno-dangling-pointer \ 84 -Wno-zero-length-bounds 85NO_WINFINITE_RECURSION= -Wno-infinite-recursion 86NO_WSTRINGOP_OVERREAD= -Wno-stringop-overread 87.endif 88.endif 89 90# GCC produces false positives for functions that switch on an 91# enum (GCC bug 87950) 92CWARNFLAGS+= -Wno-return-type 93.endif # gcc 94 95# This warning is utter nonsense 96CWARNFLAGS+= -Wno-format-zero-length 97 98# External compilers may not support our format extensions. Allow them 99# to be disabled. WARNING: format checking is disabled in this case. 100.if ${MK_FORMAT_EXTENSIONS} == "no" 101FORMAT_EXTENSIONS= -Wno-format 102.elif ${COMPILER_TYPE} == "clang" || \ 103 (${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100) 104FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 105.else 106FORMAT_EXTENSIONS= -fformat-extensions 107.endif 108 109# 110# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 111# and above adds code to the entry and exit point of every function to align the 112# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 113# per function call. While the 16-byte alignment may benefit micro benchmarks, 114# it is probably an overall loss as it makes the code bigger (less efficient 115# use of code cache tag lines) and uses more stack (less efficient use of data 116# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 117# operations inside the kernel itself. These operations are exclusively 118# reserved for user applications. 119# 120# gcc: 121# Setting -mno-mmx implies -mno-3dnow 122# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 123# 124# clang: 125# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 126# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 127# 128.if ${MACHINE_CPUARCH} == "i386" 129CFLAGS.gcc+= -mpreferred-stack-boundary=2 130CFLAGS.clang+= -mno-aes -mno-avx 131CFLAGS+= -mno-mmx -mno-sse -msoft-float 132INLINE_LIMIT?= 8000 133.endif 134 135.if ${MACHINE_CPUARCH} == "arm" 136INLINE_LIMIT?= 8000 137.endif 138 139.if ${MACHINE_CPUARCH} == "aarch64" 140# We generally don't want fpu instructions in the kernel. 141CFLAGS += -mgeneral-regs-only 142# Reserve x18 for pcpu data 143CFLAGS += -ffixed-x18 144INLINE_LIMIT?= 8000 145.endif 146 147# 148# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 149# point registers within the kernel. However, we include the F and D extensions 150# in -march so we can have limited floating point support in context switching 151# code. This is different than userland where we use a hard-float ABI (lp64d). 152# 153# We also specify the "medium" code model, which generates code suitable for a 154# 2GiB addressing range located at any offset, allowing modules to be located 155# anywhere in the 64-bit address space. Note that clang and GCC refer to this 156# code model as "medium" and "medany" respectively. 157# 158.if ${MACHINE_CPUARCH} == "riscv" 159CFLAGS+= -march=rv64imafdc 160CFLAGS+= -mabi=lp64 161CFLAGS.clang+= -mcmodel=medium 162CFLAGS.gcc+= -mcmodel=medany 163INLINE_LIMIT?= 8000 164 165.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 166CFLAGS+= -mno-relax 167.endif 168.endif 169 170# 171# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 172# operations inside the kernel itself. These operations are exclusively 173# reserved for user applications. 174# 175# gcc: 176# Setting -mno-mmx implies -mno-3dnow 177# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 178# 179# clang: 180# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 181# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 182# (-mfpmath= is not supported) 183# 184.if ${MACHINE_CPUARCH} == "amd64" 185CFLAGS.clang+= -mno-aes -mno-avx 186CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 187 -fno-asynchronous-unwind-tables 188INLINE_LIMIT?= 8000 189.endif 190 191# 192# For PowerPC we tell gcc to use floating point emulation. This avoids using 193# floating point registers for integer operations which it has a tendency to do. 194# Also explicitly disable Altivec instructions inside the kernel. 195# 196.if ${MACHINE_CPUARCH} == "powerpc" 197CFLAGS+= -mno-altivec -msoft-float 198INLINE_LIMIT?= 15000 199.endif 200 201.if ${MACHINE_ARCH} == "powerpcspe" 202CFLAGS.gcc+= -mno-spe 203.endif 204 205# 206# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 207# DDB happy. ELFv2, if available, has some other efficiency benefits. 208# 209.if ${MACHINE_ARCH:Mpowerpc64*} != "" && \ 210 ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000 211CFLAGS+= -mabi=elfv2 212.endif 213 214# 215# GCC 3.0 and above like to do certain optimizations based on the 216# assumption that the program is linked against libc. Stop this. 217# 218CFLAGS+= -ffreestanding 219 220# 221# The C standard leaves signed integer overflow behavior undefined. 222# gcc and clang opimizers take advantage of this. The kernel makes 223# use of signed integer wraparound mechanics so we need the compiler 224# to treat it as a wraparound and not take shortcuts. 225# 226CFLAGS+= -fwrapv 227 228# 229# GCC SSP support 230# 231.if ${MK_SSP} != "no" 232CFLAGS+= -fstack-protector 233.endif 234 235# 236# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 237# 238.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 239 ${MK_KERNEL_RETPOLINE} != "no" 240CFLAGS+= -mretpoline 241.endif 242 243# 244# Initialize stack variables on function entry 245# 246.if ${MK_INIT_ALL_ZERO} == "yes" 247.if ${COMPILER_FEATURES:Minit-all} 248CFLAGS+= -ftrivial-auto-var-init=zero 249.if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000 250CFLAGS+= -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang 251.endif 252.else 253.warning InitAll (zeros) requested but not supported by compiler 254.endif 255.elif ${MK_INIT_ALL_PATTERN} == "yes" 256.if ${COMPILER_FEATURES:Minit-all} 257CFLAGS+= -ftrivial-auto-var-init=pattern 258.else 259.warning InitAll (pattern) requested but not support by compiler 260.endif 261.endif 262 263CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 264CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 265CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 266 267# Tell bmake not to mistake standard targets for things to be searched for 268# or expect to ever be up-to-date. 269PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 270 beforelinking build build-tools buildfiles buildincludes \ 271 checkdpadd clean cleandepend cleandir cleanobj configure \ 272 depend distclean distribute exe \ 273 html includes install installfiles installincludes \ 274 obj objlink objs objwarn \ 275 realinstall regress \ 276 tags whereobj 277 278.PHONY: ${PHONY_NOTMAIN} 279.NOTMAIN: ${PHONY_NOTMAIN} 280 281CSTD= gnu99 282 283.if ${CSTD} == "k&r" 284CFLAGS+= -traditional 285.elif ${CSTD} == "c89" || ${CSTD} == "c90" 286CFLAGS+= -std=iso9899:1990 287.elif ${CSTD} == "c94" || ${CSTD} == "c95" 288CFLAGS+= -std=iso9899:199409 289.elif ${CSTD} == "c99" 290CFLAGS+= -std=iso9899:1999 291.else # CSTD 292CFLAGS+= -std=${CSTD} 293.endif # CSTD 294 295# Please keep this if in sync with bsd.sys.mk 296.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld") 297# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld". 298.if ${COMPILER_TYPE} == "clang" 299# Note: Clang does not like relative paths for ld so we map ld.lld -> lld. 300.if ${COMPILER_VERSION} >= 120000 301CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W} 302.else 303CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W} 304.endif 305.else 306# GCC does not support an absolute path for -fuse-ld so we just print this 307# warning instead and let the user add the required symlinks. 308# However, we can avoid this warning if -B is set appropriately (e.g. for 309# CROSS_TOOLCHAIN=...-gcc). 310.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/}) 311.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported 312.endif 313.endif 314.endif 315 316# Set target-specific linker emulation name. 317LD_EMULATION_aarch64=aarch64elf 318LD_EMULATION_amd64=elf_x86_64_fbsd 319LD_EMULATION_arm=armelf_fbsd 320LD_EMULATION_armv6=armelf_fbsd 321LD_EMULATION_armv7=armelf_fbsd 322LD_EMULATION_i386=elf_i386_fbsd 323LD_EMULATION_powerpc= elf32ppc_fbsd 324LD_EMULATION_powerpcspe= elf32ppc_fbsd 325LD_EMULATION_powerpc64= elf64ppc_fbsd 326LD_EMULATION_powerpc64le= elf64lppc_fbsd 327LD_EMULATION_riscv64= elf64lriscv 328LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 329