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} >= 70100 65CWARNEXTRA+= -Wno-error=stringop-overflow 66.endif 67.if ${COMPILER_VERSION} >= 70200 68CWARNEXTRA+= -Wno-error=memset-elt-size 69.endif 70.if ${COMPILER_VERSION} >= 80000 71CWARNEXTRA+= -Wno-error=packed-not-aligned 72.endif 73.else 74# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 75CWARNEXTRA?= -Wno-uninitialized 76# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 77# the few files that are already known to generate cast-qual warnings. 78NO_WCAST_QUAL= -Wno-cast-qual 79NO_WNONNULL= -Wno-nonnull 80.endif 81.endif 82 83# This warning is utter nonsense 84CWARNFLAGS+= -Wno-format-zero-length 85 86# External compilers may not support our format extensions. Allow them 87# to be disabled. WARNING: format checking is disabled in this case. 88.if ${MK_FORMAT_EXTENSIONS} == "no" 89FORMAT_EXTENSIONS= -Wno-format 90.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 91FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 92.else 93FORMAT_EXTENSIONS= -fformat-extensions 94.endif 95 96# 97# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 98# and above adds code to the entry and exit point of every function to align the 99# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 100# per function call. While the 16-byte alignment may benefit micro benchmarks, 101# it is probably an overall loss as it makes the code bigger (less efficient 102# use of code cache tag lines) and uses more stack (less efficient use of data 103# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 104# operations inside the kernel itself. These operations are exclusively 105# reserved for user applications. 106# 107# gcc: 108# Setting -mno-mmx implies -mno-3dnow 109# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 110# 111# clang: 112# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 113# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 114# 115.if ${MACHINE_CPUARCH} == "i386" 116CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 117CFLAGS.clang+= -mno-aes -mno-avx 118CFLAGS+= -mno-mmx -mno-sse -msoft-float 119INLINE_LIMIT?= 8000 120.endif 121 122.if ${MACHINE_CPUARCH} == "arm" 123INLINE_LIMIT?= 8000 124.endif 125 126.if ${MACHINE_CPUARCH} == "aarch64" 127# We generally don't want fpu instructions in the kernel. 128CFLAGS += -mgeneral-regs-only 129# Reserve x18 for pcpu data 130CFLAGS += -ffixed-x18 131INLINE_LIMIT?= 8000 132.endif 133 134# 135# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 136# point registers within the kernel. We also specify the "medium" code model, 137# which generates code suitable for a 2GiB addressing range located at any 138# offset, allowing modules to be located anywhere in the 64-bit address space. 139# Note that clang and GCC refer to this code model as "medium" and "medany" 140# respectively. 141# 142.if ${MACHINE_CPUARCH} == "riscv" 143CFLAGS+= -march=rv64imafdc -mabi=lp64 144CFLAGS.clang+= -mcmodel=medium 145CFLAGS.gcc+= -mcmodel=medany 146INLINE_LIMIT?= 8000 147 148.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 149CFLAGS+= -mno-relax 150.endif 151.endif 152 153# 154# For sparc64 we want the medany code model so modules may be located 155# anywhere in the 64-bit address space. We also tell GCC to use floating 156# point emulation. This avoids using floating point registers for integer 157# operations which it has a tendency to do. 158# 159.if ${MACHINE_CPUARCH} == "sparc64" 160CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 161CFLAGS.gcc+= -mcmodel=medany -msoft-float 162INLINE_LIMIT?= 15000 163.endif 164 165# 166# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 167# operations inside the kernel itself. These operations are exclusively 168# reserved for user applications. 169# 170# gcc: 171# Setting -mno-mmx implies -mno-3dnow 172# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 173# 174# clang: 175# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 176# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 177# (-mfpmath= is not supported) 178# 179.if ${MACHINE_CPUARCH} == "amd64" 180CFLAGS.clang+= -mno-aes -mno-avx 181CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 182 -fno-asynchronous-unwind-tables 183INLINE_LIMIT?= 8000 184.endif 185 186# 187# For PowerPC we tell gcc to use floating point emulation. This avoids using 188# floating point registers for integer operations which it has a tendency to do. 189# Also explicitly disable Altivec instructions inside the kernel. 190# 191.if ${MACHINE_CPUARCH} == "powerpc" 192CFLAGS+= -mno-altivec -msoft-float 193INLINE_LIMIT?= 15000 194.endif 195 196.if ${MACHINE_ARCH} == "powerpcspe" 197CFLAGS.gcc+= -mno-spe 198.endif 199 200# 201# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 202# DDB happy. ELFv2, if available, has some other efficiency benefits. 203# 204.if ${MACHINE_ARCH} == "powerpc64" 205.if ${COMPILER_VERSION} >= 40900 206CFLAGS.gcc+= -mabi=elfv2 207.else 208CFLAGS.gcc+= -mcall-aixdesc 209.endif 210CFLAGS.clang+= -mabi=elfv2 211.endif 212 213# 214# For MIPS we also tell gcc to use floating point emulation 215# 216.if ${MACHINE_CPUARCH} == "mips" 217CFLAGS+= -msoft-float 218INLINE_LIMIT?= 8000 219.endif 220 221# 222# GCC 3.0 and above like to do certain optimizations based on the 223# assumption that the program is linked against libc. Stop this. 224# 225CFLAGS+= -ffreestanding 226 227# 228# The C standard leaves signed integer overflow behavior undefined. 229# gcc and clang opimizers take advantage of this. The kernel makes 230# use of signed integer wraparound mechanics so we need the compiler 231# to treat it as a wraparound and not take shortcuts. 232# 233CFLAGS+= -fwrapv 234 235# 236# GCC SSP support 237# 238.if ${MK_SSP} != "no" && \ 239 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 240CFLAGS+= -fstack-protector 241.endif 242 243# 244# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 245# 246.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 247 ${MK_KERNEL_RETPOLINE} != "no" 248CFLAGS+= -mretpoline 249.endif 250 251# 252# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 253# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 254# cope well with DWARF 4, so force it to genereate DWARF2, which they 255# understand. Do this unconditionally as it is harmless when not needed, 256# but critical for these newer versions. 257# 258.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 259CFLAGS+= -gdwarf-2 260.endif 261 262CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 263CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 264CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 265 266# Tell bmake not to mistake standard targets for things to be searched for 267# or expect to ever be up-to-date. 268PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 269 beforelinking build build-tools buildfiles buildincludes \ 270 checkdpadd clean cleandepend cleandir cleanobj configure \ 271 depend distclean distribute exe \ 272 html includes install installfiles installincludes \ 273 obj objlink objs objwarn \ 274 realinstall regress \ 275 tags whereobj 276 277.PHONY: ${PHONY_NOTMAIN} 278.NOTMAIN: ${PHONY_NOTMAIN} 279 280CSTD= c99 281 282.if ${CSTD} == "k&r" 283CFLAGS+= -traditional 284.elif ${CSTD} == "c89" || ${CSTD} == "c90" 285CFLAGS+= -std=iso9899:1990 286.elif ${CSTD} == "c94" || ${CSTD} == "c95" 287CFLAGS+= -std=iso9899:199409 288.elif ${CSTD} == "c99" 289CFLAGS+= -std=iso9899:1999 290.else # CSTD 291CFLAGS+= -std=${CSTD} 292.endif # CSTD 293 294# Set target-specific linker emulation name. 295LD_EMULATION_aarch64=aarch64elf 296LD_EMULATION_amd64=elf_x86_64_fbsd 297LD_EMULATION_arm=armelf_fbsd 298LD_EMULATION_armv6=armelf_fbsd 299LD_EMULATION_armv7=armelf_fbsd 300LD_EMULATION_i386=elf_i386_fbsd 301LD_EMULATION_mips= elf32btsmip_fbsd 302LD_EMULATION_mipshf= elf32btsmip_fbsd 303LD_EMULATION_mips64= elf64btsmip_fbsd 304LD_EMULATION_mips64hf= elf64btsmip_fbsd 305LD_EMULATION_mipsel= elf32ltsmip_fbsd 306LD_EMULATION_mipselhf= elf32ltsmip_fbsd 307LD_EMULATION_mips64el= elf64ltsmip_fbsd 308LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 309LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 310LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 311LD_EMULATION_powerpc= elf32ppc_fbsd 312LD_EMULATION_powerpcspe= elf32ppc_fbsd 313LD_EMULATION_powerpc64= elf64ppc_fbsd 314LD_EMULATION_riscv64= elf64lriscv 315LD_EMULATION_sparc64= elf64_sparc_fbsd 316LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 317