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 41CLANG_NO_IAS= -no-integrated-as 42.endif 43 44.if ${COMPILER_TYPE} == "gcc" 45.if ${COMPILER_VERSION} >= 40800 46# Catch-all for all the things that are in our tree, but for which we're 47# not yet ready for this compiler. 48NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 49CWARNEXTRA?= -Wno-error=address \ 50 -Wno-error=aggressive-loop-optimizations \ 51 -Wno-error=array-bounds \ 52 -Wno-error=attributes \ 53 -Wno-error=cast-qual \ 54 -Wno-error=enum-compare \ 55 -Wno-error=inline \ 56 -Wno-error=maybe-uninitialized \ 57 -Wno-error=overflow \ 58 -Wno-error=sequence-point \ 59 -Wno-unused-but-set-variable 60.if ${COMPILER_VERSION} >= 60100 61CWARNEXTRA+= -Wno-error=misleading-indentation \ 62 -Wno-error=nonnull-compare \ 63 -Wno-error=shift-overflow \ 64 -Wno-error=tautological-compare 65.endif 66.if ${COMPILER_VERSION} >= 70200 67CWARNEXTRA+= -Wno-error=memset-elt-size 68.endif 69.if ${COMPILER_VERSION} >= 80000 70CWARNEXTRA+= -Wno-error=packed-not-aligned 71.endif 72.else 73# For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars. 74CWARNEXTRA?= -Wno-uninitialized 75# GCC 4.2 doesn't have -Wno-error=cast-qual, so just disable the warning for 76# the few files that are already known to generate cast-qual warnings. 77NO_WCAST_QUAL= -Wno-cast-qual 78.endif 79.endif 80 81# External compilers may not support our format extensions. Allow them 82# to be disabled. WARNING: format checking is disabled in this case. 83.if ${MK_FORMAT_EXTENSIONS} == "no" 84FORMAT_EXTENSIONS= -Wno-format 85.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 86FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 87.else 88FORMAT_EXTENSIONS= -fformat-extensions 89.endif 90 91# 92# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 93# and above adds code to the entry and exit point of every function to align the 94# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 95# per function call. While the 16-byte alignment may benefit micro benchmarks, 96# it is probably an overall loss as it makes the code bigger (less efficient 97# use of code cache tag lines) and uses more stack (less efficient use of data 98# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 99# operations inside the kernel itself. These operations are exclusively 100# reserved for user applications. 101# 102# gcc: 103# Setting -mno-mmx implies -mno-3dnow 104# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 105# 106# clang: 107# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 108# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 109# 110.if ${MACHINE_CPUARCH} == "i386" 111CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 112CFLAGS.clang+= -mno-aes -mno-avx 113CFLAGS+= -mno-mmx -mno-sse -msoft-float 114INLINE_LIMIT?= 8000 115.endif 116 117.if ${MACHINE_CPUARCH} == "arm" 118INLINE_LIMIT?= 8000 119.endif 120 121.if ${MACHINE_CPUARCH} == "aarch64" 122# We generally don't want fpu instructions in the kernel. 123CFLAGS += -mgeneral-regs-only 124# Reserve x18 for pcpu data 125CFLAGS += -ffixed-x18 126INLINE_LIMIT?= 8000 127.endif 128 129.if ${MACHINE_CPUARCH} == "riscv" 130CFLAGS.gcc+= -mcmodel=medany -march=rv64imafdc -mabi=lp64 131INLINE_LIMIT?= 8000 132.endif 133 134# 135# For sparc64 we want the medany code model so modules may be located 136# anywhere in the 64-bit address space. We also tell GCC to use floating 137# point emulation. This avoids using floating point registers for integer 138# operations which it has a tendency to do. 139# 140.if ${MACHINE_CPUARCH} == "sparc64" 141CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 142CFLAGS.gcc+= -mcmodel=medany -msoft-float 143INLINE_LIMIT?= 15000 144.endif 145 146# 147# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 148# operations inside the kernel itself. These operations are exclusively 149# reserved for user applications. 150# 151# gcc: 152# Setting -mno-mmx implies -mno-3dnow 153# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 154# 155# clang: 156# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 157# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 158# (-mfpmath= is not supported) 159# 160.if ${MACHINE_CPUARCH} == "amd64" 161CFLAGS.clang+= -mno-aes -mno-avx 162CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 163 -fno-asynchronous-unwind-tables 164INLINE_LIMIT?= 8000 165.endif 166 167# 168# For PowerPC we tell gcc to use floating point emulation. This avoids using 169# floating point registers for integer operations which it has a tendency to do. 170# Also explicitly disable Altivec instructions inside the kernel. 171# 172.if ${MACHINE_CPUARCH} == "powerpc" 173CFLAGS+= -mno-altivec -msoft-float 174INLINE_LIMIT?= 15000 175.endif 176 177.if ${MACHINE_ARCH} == "powerpcspe" 178CFLAGS.gcc+= -mno-spe 179.endif 180 181# 182# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 183# DDB happy. ELFv2, if available, has some other efficiency benefits. 184# 185.if ${MACHINE_ARCH} == "powerpc64" 186.if ${COMPILER_VERSION} >= 40900 187CFLAGS.gcc+= -mabi=elfv2 188.else 189CFLAGS.gcc+= -mcall-aixdesc 190.endif 191CFLAGS.clang+= -mabi=elfv2 192.endif 193 194# 195# For MIPS we also tell gcc to use floating point emulation 196# 197.if ${MACHINE_CPUARCH} == "mips" 198CFLAGS+= -msoft-float 199INLINE_LIMIT?= 8000 200.endif 201 202# 203# GCC 3.0 and above like to do certain optimizations based on the 204# assumption that the program is linked against libc. Stop this. 205# 206CFLAGS+= -ffreestanding 207 208# 209# The C standard leaves signed integer overflow behavior undefined. 210# gcc and clang opimizers take advantage of this. The kernel makes 211# use of signed integer wraparound mechanics so we need the compiler 212# to treat it as a wraparound and not take shortcuts. 213# 214CFLAGS+= -fwrapv 215 216# 217# GCC SSP support 218# 219.if ${MK_SSP} != "no" && \ 220 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 221CFLAGS+= -fstack-protector 222.endif 223 224# 225# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 226# 227.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 228 ${MK_KERNEL_RETPOLINE} != "no" 229CFLAGS+= -mretpoline 230.endif 231 232# 233# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 234# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 235# cope well with DWARF 4, so force it to genereate DWARF2, which they 236# understand. Do this unconditionally as it is harmless when not needed, 237# but critical for these newer versions. 238# 239.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 240CFLAGS+= -gdwarf-2 241.endif 242 243CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 244CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 245 246# Tell bmake not to mistake standard targets for things to be searched for 247# or expect to ever be up-to-date. 248PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 249 beforelinking build build-tools buildfiles buildincludes \ 250 checkdpadd clean cleandepend cleandir cleanobj configure \ 251 depend distclean distribute exe \ 252 html includes install installfiles installincludes \ 253 obj objlink objs objwarn \ 254 realinstall regress \ 255 tags whereobj 256 257.PHONY: ${PHONY_NOTMAIN} 258.NOTMAIN: ${PHONY_NOTMAIN} 259 260CSTD= c99 261 262.if ${CSTD} == "k&r" 263CFLAGS+= -traditional 264.elif ${CSTD} == "c89" || ${CSTD} == "c90" 265CFLAGS+= -std=iso9899:1990 266.elif ${CSTD} == "c94" || ${CSTD} == "c95" 267CFLAGS+= -std=iso9899:199409 268.elif ${CSTD} == "c99" 269CFLAGS+= -std=iso9899:1999 270.else # CSTD 271CFLAGS+= -std=${CSTD} 272.endif # CSTD 273 274# Set target-specific linker emulation name. 275LD_EMULATION_aarch64=aarch64elf 276LD_EMULATION_amd64=elf_x86_64_fbsd 277LD_EMULATION_arm=armelf_fbsd 278LD_EMULATION_armv6=armelf_fbsd 279LD_EMULATION_armv7=armelf_fbsd 280LD_EMULATION_i386=elf_i386_fbsd 281LD_EMULATION_mips= elf32btsmip_fbsd 282LD_EMULATION_mipshf= elf32btsmip_fbsd 283LD_EMULATION_mips64= elf64btsmip_fbsd 284LD_EMULATION_mips64hf= elf64btsmip_fbsd 285LD_EMULATION_mipsel= elf32ltsmip_fbsd 286LD_EMULATION_mipselhf= elf32ltsmip_fbsd 287LD_EMULATION_mips64el= elf64ltsmip_fbsd 288LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 289LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 290LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 291LD_EMULATION_powerpc= elf32ppc_fbsd 292LD_EMULATION_powerpcspe= elf32ppc_fbsd 293LD_EMULATION_powerpc64= elf64ppc_fbsd 294LD_EMULATION_riscv64= elf64lriscv 295LD_EMULATION_sparc64= elf64_sparc_fbsd 296LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 297