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.endif 41 42.if ${COMPILER_TYPE} == "gcc" 43.if ${COMPILER_VERSION} >= 40800 44# Catch-all for all the things that are in our tree, but for which we're 45# not yet ready for this compiler. 46NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 47CWARNEXTRA?= -Wno-error=address \ 48 -Wno-error=aggressive-loop-optimizations \ 49 -Wno-error=array-bounds \ 50 -Wno-error=attributes \ 51 -Wno-error=cast-qual \ 52 -Wno-error=enum-compare \ 53 -Wno-error=inline \ 54 -Wno-error=maybe-uninitialized \ 55 -Wno-error=overflow \ 56 -Wno-error=sequence-point \ 57 -Wno-unused-but-set-variable 58.if ${COMPILER_VERSION} >= 60100 59CWARNEXTRA+= -Wno-error=misleading-indentation \ 60 -Wno-error=nonnull-compare \ 61 -Wno-error=shift-overflow \ 62 -Wno-error=tautological-compare 63.endif 64.if ${COMPILER_VERSION} >= 70200 65CWARNEXTRA+= -Wno-error=memset-elt-size 66.endif 67.if ${COMPILER_VERSION} >= 80000 68CWARNEXTRA+= -Wno-error=packed-not-aligned 69.endif 70.else 71# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 72CWARNEXTRA?= -Wno-uninitialized 73# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 74# the few files that are already known to generate cast-qual warnings. 75NO_WCAST_QUAL= -Wno-cast-qual 76NO_WNONNULL= -Wno-nonnull 77.endif 78.endif 79 80# This warning is utter nonsense 81CWARNFLAGS+= -Wno-format-zero-length 82 83# External compilers may not support our format extensions. Allow them 84# to be disabled. WARNING: format checking is disabled in this case. 85.if ${MK_FORMAT_EXTENSIONS} == "no" 86FORMAT_EXTENSIONS= -Wno-format 87.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 88FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 89.else 90FORMAT_EXTENSIONS= -fformat-extensions 91.endif 92 93# 94# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 95# and above adds code to the entry and exit point of every function to align the 96# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 97# per function call. While the 16-byte alignment may benefit micro benchmarks, 98# it is probably an overall loss as it makes the code bigger (less efficient 99# use of code cache tag lines) and uses more stack (less efficient use of data 100# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 101# operations inside the kernel itself. These operations are exclusively 102# reserved for user applications. 103# 104# gcc: 105# Setting -mno-mmx implies -mno-3dnow 106# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 107# 108# clang: 109# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 110# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 111# 112.if ${MACHINE_CPUARCH} == "i386" 113CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 114CFLAGS.clang+= -mno-aes -mno-avx 115CFLAGS+= -mno-mmx -mno-sse -msoft-float 116INLINE_LIMIT?= 8000 117.endif 118 119.if ${MACHINE_CPUARCH} == "arm" 120INLINE_LIMIT?= 8000 121.endif 122 123.if ${MACHINE_CPUARCH} == "aarch64" 124# We generally don't want fpu instructions in the kernel. 125CFLAGS += -mgeneral-regs-only 126# Reserve x18 for pcpu data 127CFLAGS += -ffixed-x18 128INLINE_LIMIT?= 8000 129.endif 130 131# 132# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 133# point registers within the kernel. We also specify the "medium" code model, 134# which generates code suitable for a 2GiB addressing range located at any 135# offset, allowing modules to be located anywhere in the 64-bit address space. 136# Note that clang and GCC refer to this code model as "medium" and "medany" 137# respectively. 138# 139.if ${MACHINE_CPUARCH} == "riscv" 140CFLAGS+= -march=rv64imafdc -mabi=lp64 141CFLAGS.clang+= -mcmodel=medium 142CFLAGS.gcc+= -mcmodel=medany 143INLINE_LIMIT?= 8000 144.endif 145 146# 147# For sparc64 we want the medany code model so modules may be located 148# anywhere in the 64-bit address space. We also tell GCC to use floating 149# point emulation. This avoids using floating point registers for integer 150# operations which it has a tendency to do. 151# 152.if ${MACHINE_CPUARCH} == "sparc64" 153CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 154CFLAGS.gcc+= -mcmodel=medany -msoft-float 155INLINE_LIMIT?= 15000 156.endif 157 158# 159# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 160# operations inside the kernel itself. These operations are exclusively 161# reserved for user applications. 162# 163# gcc: 164# Setting -mno-mmx implies -mno-3dnow 165# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 166# 167# clang: 168# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 169# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 170# (-mfpmath= is not supported) 171# 172.if ${MACHINE_CPUARCH} == "amd64" 173CFLAGS.clang+= -mno-aes -mno-avx 174CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 175 -fno-asynchronous-unwind-tables 176INLINE_LIMIT?= 8000 177.endif 178 179# 180# For PowerPC we tell gcc to use floating point emulation. This avoids using 181# floating point registers for integer operations which it has a tendency to do. 182# Also explicitly disable Altivec instructions inside the kernel. 183# 184.if ${MACHINE_CPUARCH} == "powerpc" 185CFLAGS+= -mno-altivec -msoft-float 186INLINE_LIMIT?= 15000 187.endif 188 189.if ${MACHINE_ARCH} == "powerpcspe" 190CFLAGS.gcc+= -mno-spe 191.endif 192 193# 194# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 195# DDB happy. ELFv2, if available, has some other efficiency benefits. 196# 197.if ${MACHINE_ARCH} == "powerpc64" 198.if ${COMPILER_VERSION} >= 40900 199CFLAGS.gcc+= -mabi=elfv2 200.else 201CFLAGS.gcc+= -mcall-aixdesc 202.endif 203CFLAGS.clang+= -mabi=elfv2 204.endif 205 206# 207# For MIPS we also tell gcc to use floating point emulation 208# 209.if ${MACHINE_CPUARCH} == "mips" 210CFLAGS+= -msoft-float 211INLINE_LIMIT?= 8000 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" && \ 232 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 233CFLAGS+= -fstack-protector 234.endif 235 236# 237# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 238# 239.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 240 ${MK_KERNEL_RETPOLINE} != "no" 241CFLAGS+= -mretpoline 242.endif 243 244# 245# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 246# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 247# cope well with DWARF 4, so force it to genereate DWARF2, which they 248# understand. Do this unconditionally as it is harmless when not needed, 249# but critical for these newer versions. 250# 251.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 252CFLAGS+= -gdwarf-2 253.endif 254 255CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 256CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 257CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 258 259# Tell bmake not to mistake standard targets for things to be searched for 260# or expect to ever be up-to-date. 261PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 262 beforelinking build build-tools buildfiles buildincludes \ 263 checkdpadd clean cleandepend cleandir cleanobj configure \ 264 depend distclean distribute exe \ 265 html includes install installfiles installincludes \ 266 obj objlink objs objwarn \ 267 realinstall regress \ 268 tags whereobj 269 270.PHONY: ${PHONY_NOTMAIN} 271.NOTMAIN: ${PHONY_NOTMAIN} 272 273CSTD= c99 274 275.if ${CSTD} == "k&r" 276CFLAGS+= -traditional 277.elif ${CSTD} == "c89" || ${CSTD} == "c90" 278CFLAGS+= -std=iso9899:1990 279.elif ${CSTD} == "c94" || ${CSTD} == "c95" 280CFLAGS+= -std=iso9899:199409 281.elif ${CSTD} == "c99" 282CFLAGS+= -std=iso9899:1999 283.else # CSTD 284CFLAGS+= -std=${CSTD} 285.endif # CSTD 286 287# Set target-specific linker emulation name. 288LD_EMULATION_aarch64=aarch64elf 289LD_EMULATION_amd64=elf_x86_64_fbsd 290LD_EMULATION_arm=armelf_fbsd 291LD_EMULATION_armv6=armelf_fbsd 292LD_EMULATION_armv7=armelf_fbsd 293LD_EMULATION_i386=elf_i386_fbsd 294LD_EMULATION_mips= elf32btsmip_fbsd 295LD_EMULATION_mipshf= elf32btsmip_fbsd 296LD_EMULATION_mips64= elf64btsmip_fbsd 297LD_EMULATION_mips64hf= elf64btsmip_fbsd 298LD_EMULATION_mipsel= elf32ltsmip_fbsd 299LD_EMULATION_mipselhf= elf32ltsmip_fbsd 300LD_EMULATION_mips64el= elf64ltsmip_fbsd 301LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 302LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 303LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 304LD_EMULATION_powerpc= elf32ppc_fbsd 305LD_EMULATION_powerpcspe= elf32ppc_fbsd 306LD_EMULATION_powerpc64= elf64ppc_fbsd 307LD_EMULATION_riscv64= elf64lriscv 308LD_EMULATION_sparc64= elf64_sparc_fbsd 309LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 310