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 34.if ${COMPILER_VERSION} >= 30700 35CWARNEXTRA+= -Wno-error-shift-negative-value 36.endif 37.if ${COMPILER_VERSION} >= 40000 38CWARNEXTRA+= -Wno-address-of-packed-member 39.endif 40.if ${COMPILER_VERSION} >= 100000 41NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation 42.endif 43.endif 44 45.if ${COMPILER_TYPE} == "gcc" 46.if ${COMPILER_VERSION} >= 40800 47# Catch-all for all the things that are in our tree, but for which we're 48# not yet ready for this compiler. 49NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 50CWARNEXTRA?= -Wno-error=address \ 51 -Wno-error=aggressive-loop-optimizations \ 52 -Wno-error=array-bounds \ 53 -Wno-error=attributes \ 54 -Wno-error=cast-qual \ 55 -Wno-error=enum-compare \ 56 -Wno-error=inline \ 57 -Wno-error=maybe-uninitialized \ 58 -Wno-error=overflow \ 59 -Wno-error=sequence-point \ 60 -Wno-unused-but-set-variable 61.if ${COMPILER_VERSION} >= 60100 62CWARNEXTRA+= -Wno-error=misleading-indentation \ 63 -Wno-error=nonnull-compare \ 64 -Wno-error=shift-overflow \ 65 -Wno-error=tautological-compare 66.endif 67.if ${COMPILER_VERSION} >= 70100 68CWARNEXTRA+= -Wno-error=stringop-overflow 69.endif 70.if ${COMPILER_VERSION} >= 70200 71CWARNEXTRA+= -Wno-error=memset-elt-size 72.endif 73.if ${COMPILER_VERSION} >= 80000 74CWARNEXTRA+= -Wno-error=packed-not-aligned 75.endif 76.if ${COMPILER_VERSION} >= 90100 77CWARNEXTRA+= -Wno-address-of-packed-member 78.endif 79.else 80# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 81CWARNEXTRA?= -Wno-uninitialized 82# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 83# the few files that are already known to generate cast-qual warnings. 84NO_WCAST_QUAL= -Wno-cast-qual 85NO_WNONNULL= -Wno-nonnull 86.endif 87.endif 88 89# This warning is utter nonsense 90CWARNFLAGS+= -Wno-format-zero-length 91 92# External compilers may not support our format extensions. Allow them 93# to be disabled. WARNING: format checking is disabled in this case. 94.if ${MK_FORMAT_EXTENSIONS} == "no" 95FORMAT_EXTENSIONS= -Wno-format 96.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 97FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 98.else 99FORMAT_EXTENSIONS= -fformat-extensions 100.endif 101 102# 103# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 104# and above adds code to the entry and exit point of every function to align the 105# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 106# per function call. While the 16-byte alignment may benefit micro benchmarks, 107# it is probably an overall loss as it makes the code bigger (less efficient 108# use of code cache tag lines) and uses more stack (less efficient use of data 109# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 110# operations inside the kernel itself. These operations are exclusively 111# reserved for user applications. 112# 113# gcc: 114# Setting -mno-mmx implies -mno-3dnow 115# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 116# 117# clang: 118# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 119# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 120# 121.if ${MACHINE_CPUARCH} == "i386" 122CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 123CFLAGS.clang+= -mno-aes -mno-avx 124CFLAGS+= -mno-mmx -mno-sse -msoft-float 125INLINE_LIMIT?= 8000 126.endif 127 128.if ${MACHINE_CPUARCH} == "arm" 129INLINE_LIMIT?= 8000 130.endif 131 132.if ${MACHINE_CPUARCH} == "aarch64" 133# We generally don't want fpu instructions in the kernel. 134CFLAGS += -mgeneral-regs-only 135# Reserve x18 for pcpu data 136CFLAGS += -ffixed-x18 137INLINE_LIMIT?= 8000 138.endif 139 140# 141# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 142# point registers within the kernel. We also specify the "medium" code model, 143# which generates code suitable for a 2GiB addressing range located at any 144# offset, allowing modules to be located anywhere in the 64-bit address space. 145# Note that clang and GCC refer to this code model as "medium" and "medany" 146# respectively. 147# 148.if ${MACHINE_CPUARCH} == "riscv" 149CFLAGS+= -march=rv64imafdc -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} == "powerpc64" 199.if ${COMPILER_VERSION} >= 40900 200CFLAGS.gcc+= -mabi=elfv2 201.else 202CFLAGS.gcc+= -mcall-aixdesc 203.endif 204CFLAGS.clang+= -mabi=elfv2 205.endif 206 207# 208# For MIPS we also tell gcc to use floating point emulation 209# 210.if ${MACHINE_CPUARCH} == "mips" 211CFLAGS+= -msoft-float 212INLINE_LIMIT?= 8000 213.endif 214 215# 216# GCC 3.0 and above like to do certain optimizations based on the 217# assumption that the program is linked against libc. Stop this. 218# 219CFLAGS+= -ffreestanding 220 221# 222# The C standard leaves signed integer overflow behavior undefined. 223# gcc and clang opimizers take advantage of this. The kernel makes 224# use of signed integer wraparound mechanics so we need the compiler 225# to treat it as a wraparound and not take shortcuts. 226# 227CFLAGS+= -fwrapv 228 229# 230# GCC SSP support 231# 232.if ${MK_SSP} != "no" && \ 233 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 234CFLAGS+= -fstack-protector 235.endif 236 237# 238# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 239# 240.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 241 ${MK_KERNEL_RETPOLINE} != "no" 242CFLAGS+= -mretpoline 243.endif 244 245# 246# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 247# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 248# cope well with DWARF 4, so force it to genereate DWARF2, which they 249# understand. Do this unconditionally as it is harmless when not needed, 250# but critical for these newer versions. 251# 252.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 253CFLAGS+= -gdwarf-2 254.endif 255 256CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 257CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 258CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 259 260# Tell bmake not to mistake standard targets for things to be searched for 261# or expect to ever be up-to-date. 262PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 263 beforelinking build build-tools buildfiles buildincludes \ 264 checkdpadd clean cleandepend cleandir cleanobj configure \ 265 depend distclean distribute exe \ 266 html includes install installfiles installincludes \ 267 obj objlink objs objwarn \ 268 realinstall regress \ 269 tags whereobj 270 271.PHONY: ${PHONY_NOTMAIN} 272.NOTMAIN: ${PHONY_NOTMAIN} 273 274CSTD= c99 275 276.if ${CSTD} == "k&r" 277CFLAGS+= -traditional 278.elif ${CSTD} == "c89" || ${CSTD} == "c90" 279CFLAGS+= -std=iso9899:1990 280.elif ${CSTD} == "c94" || ${CSTD} == "c95" 281CFLAGS+= -std=iso9899:199409 282.elif ${CSTD} == "c99" 283CFLAGS+= -std=iso9899:1999 284.else # CSTD 285CFLAGS+= -std=${CSTD} 286.endif # CSTD 287 288# Set target-specific linker emulation name. 289LD_EMULATION_aarch64=aarch64elf 290LD_EMULATION_amd64=elf_x86_64_fbsd 291LD_EMULATION_arm=armelf_fbsd 292LD_EMULATION_armv6=armelf_fbsd 293LD_EMULATION_armv7=armelf_fbsd 294LD_EMULATION_i386=elf_i386_fbsd 295LD_EMULATION_mips= elf32btsmip_fbsd 296LD_EMULATION_mipshf= elf32btsmip_fbsd 297LD_EMULATION_mips64= elf64btsmip_fbsd 298LD_EMULATION_mips64hf= elf64btsmip_fbsd 299LD_EMULATION_mipsel= elf32ltsmip_fbsd 300LD_EMULATION_mipselhf= elf32ltsmip_fbsd 301LD_EMULATION_mips64el= elf64ltsmip_fbsd 302LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 303LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 304LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 305LD_EMULATION_powerpc= elf32ppc_fbsd 306LD_EMULATION_powerpcspe= elf32ppc_fbsd 307LD_EMULATION_powerpc64= elf64ppc_fbsd 308LD_EMULATION_riscv64= elf64lriscv 309LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 310