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. However, for kernels supporting hardware 143# float (FPE), we have to include that in the march so we can have limited 144# floating point support in context switching needed for that. This is different 145# than userland where we use a hard-float ABI (lp64d). 146# 147# We also specify the "medium" code model, which generates code suitable for a 148# 2GiB addressing range located at any offset, allowing modules to be located 149# anywhere in the 64-bit address space. Note that clang and GCC refer to this 150# code model as "medium" and "medany" respectively. 151# 152.if ${MACHINE_CPUARCH} == "riscv" 153.if ${MACHINE_ARCH:Mriscv*sf} 154CFLAGS+= -march=rv64imac 155.else 156CFLAGS+= -march=rv64imafdc 157.endif 158CFLAGS+= -mabi=lp64 159CFLAGS.clang+= -mcmodel=medium 160CFLAGS.gcc+= -mcmodel=medany 161INLINE_LIMIT?= 8000 162 163.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 164CFLAGS+= -mno-relax 165.endif 166.endif 167 168# 169# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 170# operations inside the kernel itself. These operations are exclusively 171# reserved for user applications. 172# 173# gcc: 174# Setting -mno-mmx implies -mno-3dnow 175# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 176# 177# clang: 178# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 179# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 180# (-mfpmath= is not supported) 181# 182.if ${MACHINE_CPUARCH} == "amd64" 183CFLAGS.clang+= -mno-aes -mno-avx 184CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 185 -fno-asynchronous-unwind-tables 186INLINE_LIMIT?= 8000 187.endif 188 189# 190# For PowerPC we tell gcc to use floating point emulation. This avoids using 191# floating point registers for integer operations which it has a tendency to do. 192# Also explicitly disable Altivec instructions inside the kernel. 193# 194.if ${MACHINE_CPUARCH} == "powerpc" 195CFLAGS+= -mno-altivec -msoft-float 196INLINE_LIMIT?= 15000 197.endif 198 199.if ${MACHINE_ARCH} == "powerpcspe" 200CFLAGS.gcc+= -mno-spe 201.endif 202 203# 204# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 205# DDB happy. ELFv2, if available, has some other efficiency benefits. 206# 207.if ${MACHINE_ARCH} == "powerpc64" 208.if ${COMPILER_VERSION} >= 40900 209CFLAGS.gcc+= -mabi=elfv2 210.else 211CFLAGS.gcc+= -mcall-aixdesc 212.endif 213CFLAGS.clang+= -mabi=elfv2 214.endif 215 216# 217# For MIPS we also tell gcc to use floating point emulation 218# 219.if ${MACHINE_CPUARCH} == "mips" 220CFLAGS+= -msoft-float 221INLINE_LIMIT?= 8000 222.endif 223 224# 225# GCC 3.0 and above like to do certain optimizations based on the 226# assumption that the program is linked against libc. Stop this. 227# 228CFLAGS+= -ffreestanding 229 230# 231# The C standard leaves signed integer overflow behavior undefined. 232# gcc and clang opimizers take advantage of this. The kernel makes 233# use of signed integer wraparound mechanics so we need the compiler 234# to treat it as a wraparound and not take shortcuts. 235# 236CFLAGS+= -fwrapv 237 238# 239# GCC SSP support 240# 241.if ${MK_SSP} != "no" && \ 242 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 243CFLAGS+= -fstack-protector 244.endif 245 246# 247# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 248# 249.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 250 ${MK_KERNEL_RETPOLINE} != "no" 251CFLAGS+= -mretpoline 252.endif 253 254# 255# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 256# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 257# cope well with DWARF 4, so force it to genereate DWARF2, which they 258# understand. Do this unconditionally as it is harmless when not needed, 259# but critical for these newer versions. 260# 261.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 262CFLAGS+= -gdwarf-2 263.endif 264 265CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 266CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} 267CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 268 269# Tell bmake not to mistake standard targets for things to be searched for 270# or expect to ever be up-to-date. 271PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 272 beforelinking build build-tools buildfiles buildincludes \ 273 checkdpadd clean cleandepend cleandir cleanobj configure \ 274 depend distclean distribute exe \ 275 html includes install installfiles installincludes \ 276 obj objlink objs objwarn \ 277 realinstall regress \ 278 tags whereobj 279 280.PHONY: ${PHONY_NOTMAIN} 281.NOTMAIN: ${PHONY_NOTMAIN} 282 283CSTD= c99 284 285.if ${CSTD} == "k&r" 286CFLAGS+= -traditional 287.elif ${CSTD} == "c89" || ${CSTD} == "c90" 288CFLAGS+= -std=iso9899:1990 289.elif ${CSTD} == "c94" || ${CSTD} == "c95" 290CFLAGS+= -std=iso9899:199409 291.elif ${CSTD} == "c99" 292CFLAGS+= -std=iso9899:1999 293.else # CSTD 294CFLAGS+= -std=${CSTD} 295.endif # CSTD 296 297# Set target-specific linker emulation name. 298LD_EMULATION_aarch64=aarch64elf 299LD_EMULATION_amd64=elf_x86_64_fbsd 300LD_EMULATION_arm=armelf_fbsd 301LD_EMULATION_armv6=armelf_fbsd 302LD_EMULATION_armv7=armelf_fbsd 303LD_EMULATION_i386=elf_i386_fbsd 304LD_EMULATION_mips= elf32btsmip_fbsd 305LD_EMULATION_mipshf= elf32btsmip_fbsd 306LD_EMULATION_mips64= elf64btsmip_fbsd 307LD_EMULATION_mips64hf= elf64btsmip_fbsd 308LD_EMULATION_mipsel= elf32ltsmip_fbsd 309LD_EMULATION_mipselhf= elf32ltsmip_fbsd 310LD_EMULATION_mips64el= elf64ltsmip_fbsd 311LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 312LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 313LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 314LD_EMULATION_powerpc= elf32ppc_fbsd 315LD_EMULATION_powerpcspe= elf32ppc_fbsd 316LD_EMULATION_powerpc64= elf64ppc_fbsd 317LD_EMULATION_riscv64= elf64lriscv 318LD_EMULATION_riscv64sf= elf64lriscv 319LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 320