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.if ${COMPILER_VERSION} >= 90100 74CWARNEXTRA+= -Wno-address-of-packed-member 75.endif 76.else 77# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 78CWARNEXTRA?= -Wno-uninitialized 79# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 80# the few files that are already known to generate cast-qual warnings. 81NO_WCAST_QUAL= -Wno-cast-qual 82NO_WNONNULL= -Wno-nonnull 83.endif 84.endif 85 86# This warning is utter nonsense 87CWARNFLAGS+= -Wno-format-zero-length 88 89# External compilers may not support our format extensions. Allow them 90# to be disabled. WARNING: format checking is disabled in this case. 91.if ${MK_FORMAT_EXTENSIONS} == "no" 92FORMAT_EXTENSIONS= -Wno-format 93.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 94FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 95.else 96FORMAT_EXTENSIONS= -fformat-extensions 97.endif 98 99# 100# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 101# and above adds code to the entry and exit point of every function to align the 102# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 103# per function call. While the 16-byte alignment may benefit micro benchmarks, 104# it is probably an overall loss as it makes the code bigger (less efficient 105# use of code cache tag lines) and uses more stack (less efficient use of data 106# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 107# operations inside the kernel itself. These operations are exclusively 108# reserved for user applications. 109# 110# gcc: 111# Setting -mno-mmx implies -mno-3dnow 112# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 113# 114# clang: 115# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 116# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 117# 118.if ${MACHINE_CPUARCH} == "i386" 119CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 120CFLAGS.clang+= -mno-aes -mno-avx 121CFLAGS+= -mno-mmx -mno-sse -msoft-float 122INLINE_LIMIT?= 8000 123.endif 124 125.if ${MACHINE_CPUARCH} == "arm" 126INLINE_LIMIT?= 8000 127.endif 128 129.if ${MACHINE_CPUARCH} == "aarch64" 130# We generally don't want fpu instructions in the kernel. 131CFLAGS += -mgeneral-regs-only 132# Reserve x18 for pcpu data 133CFLAGS += -ffixed-x18 134INLINE_LIMIT?= 8000 135.endif 136 137# 138# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 139# point registers within the kernel. We also specify the "medium" code model, 140# which generates code suitable for a 2GiB addressing range located at any 141# offset, allowing modules to be located anywhere in the 64-bit address space. 142# Note that clang and GCC refer to this code model as "medium" and "medany" 143# respectively. 144# 145.if ${MACHINE_CPUARCH} == "riscv" 146CFLAGS+= -march=rv64imafdc -mabi=lp64 147CFLAGS.clang+= -mcmodel=medium 148CFLAGS.gcc+= -mcmodel=medany 149INLINE_LIMIT?= 8000 150 151.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 152CFLAGS+= -mno-relax 153.endif 154.endif 155 156# 157# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 158# operations inside the kernel itself. These operations are exclusively 159# reserved for user applications. 160# 161# gcc: 162# Setting -mno-mmx implies -mno-3dnow 163# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 164# 165# clang: 166# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 167# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 168# (-mfpmath= is not supported) 169# 170.if ${MACHINE_CPUARCH} == "amd64" 171CFLAGS.clang+= -mno-aes -mno-avx 172CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 173 -fno-asynchronous-unwind-tables 174INLINE_LIMIT?= 8000 175.endif 176 177# 178# For PowerPC we tell gcc to use floating point emulation. This avoids using 179# floating point registers for integer operations which it has a tendency to do. 180# Also explicitly disable Altivec instructions inside the kernel. 181# 182.if ${MACHINE_CPUARCH} == "powerpc" 183CFLAGS+= -mno-altivec -msoft-float 184INLINE_LIMIT?= 15000 185.endif 186 187.if ${MACHINE_ARCH} == "powerpcspe" 188CFLAGS.gcc+= -mno-spe 189.endif 190 191# 192# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 193# DDB happy. ELFv2, if available, has some other efficiency benefits. 194# 195.if ${MACHINE_ARCH} == "powerpc64" 196.if ${COMPILER_VERSION} >= 40900 197CFLAGS.gcc+= -mabi=elfv2 198.else 199CFLAGS.gcc+= -mcall-aixdesc 200.endif 201CFLAGS.clang+= -mabi=elfv2 202.endif 203 204# 205# For MIPS we also tell gcc to use floating point emulation 206# 207.if ${MACHINE_CPUARCH} == "mips" 208CFLAGS+= -msoft-float 209INLINE_LIMIT?= 8000 210.endif 211 212# 213# GCC 3.0 and above like to do certain optimizations based on the 214# assumption that the program is linked against libc. Stop this. 215# 216CFLAGS+= -ffreestanding 217 218# 219# The C standard leaves signed integer overflow behavior undefined. 220# gcc and clang opimizers take advantage of this. The kernel makes 221# use of signed integer wraparound mechanics so we need the compiler 222# to treat it as a wraparound and not take shortcuts. 223# 224CFLAGS+= -fwrapv 225 226# 227# GCC SSP support 228# 229.if ${MK_SSP} != "no" && \ 230 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 231CFLAGS+= -fstack-protector 232.endif 233 234# 235# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 236# 237.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 238 ${MK_KERNEL_RETPOLINE} != "no" 239CFLAGS+= -mretpoline 240.endif 241 242# 243# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 244# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 245# cope well with DWARF 4, so force it to genereate DWARF2, which they 246# understand. Do this unconditionally as it is harmless when not needed, 247# but critical for these newer versions. 248# 249.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 250CFLAGS+= -gdwarf-2 251.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# Set target-specific linker emulation name. 286LD_EMULATION_aarch64=aarch64elf 287LD_EMULATION_amd64=elf_x86_64_fbsd 288LD_EMULATION_arm=armelf_fbsd 289LD_EMULATION_armv6=armelf_fbsd 290LD_EMULATION_armv7=armelf_fbsd 291LD_EMULATION_i386=elf_i386_fbsd 292LD_EMULATION_mips= elf32btsmip_fbsd 293LD_EMULATION_mipshf= elf32btsmip_fbsd 294LD_EMULATION_mips64= elf64btsmip_fbsd 295LD_EMULATION_mips64hf= elf64btsmip_fbsd 296LD_EMULATION_mipsel= elf32ltsmip_fbsd 297LD_EMULATION_mipselhf= elf32ltsmip_fbsd 298LD_EMULATION_mips64el= elf64ltsmip_fbsd 299LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 300LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 301LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 302LD_EMULATION_powerpc= elf32ppc_fbsd 303LD_EMULATION_powerpcspe= elf32ppc_fbsd 304LD_EMULATION_powerpc64= elf64ppc_fbsd 305LD_EMULATION_riscv64= elf64lriscv 306LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 307