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 -Wno-format-zero-length 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# 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.if ${MACHINE_CPUARCH} == "riscv" 132CFLAGS.gcc+= -mcmodel=medany -march=rv64imafdc -mabi=lp64 133INLINE_LIMIT?= 8000 134.endif 135 136# 137# For sparc64 we want the medany code model so modules may be located 138# anywhere in the 64-bit address space. We also tell GCC to use floating 139# point emulation. This avoids using floating point registers for integer 140# operations which it has a tendency to do. 141# 142.if ${MACHINE_CPUARCH} == "sparc64" 143CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 144CFLAGS.gcc+= -mcmodel=medany -msoft-float 145INLINE_LIMIT?= 15000 146.endif 147 148# 149# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 150# operations inside the kernel itself. These operations are exclusively 151# reserved for user applications. 152# 153# gcc: 154# Setting -mno-mmx implies -mno-3dnow 155# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 156# 157# clang: 158# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 159# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 160# (-mfpmath= is not supported) 161# 162.if ${MACHINE_CPUARCH} == "amd64" 163CFLAGS.clang+= -mno-aes -mno-avx 164CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 165 -fno-asynchronous-unwind-tables 166INLINE_LIMIT?= 8000 167.endif 168 169# 170# For PowerPC we tell gcc to use floating point emulation. This avoids using 171# floating point registers for integer operations which it has a tendency to do. 172# Also explicitly disable Altivec instructions inside the kernel. 173# 174.if ${MACHINE_CPUARCH} == "powerpc" 175CFLAGS+= -mno-altivec -msoft-float 176INLINE_LIMIT?= 15000 177.endif 178 179.if ${MACHINE_ARCH} == "powerpcspe" 180CFLAGS.gcc+= -mno-spe 181.endif 182 183# 184# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 185# DDB happy. ELFv2, if available, has some other efficiency benefits. 186# 187.if ${MACHINE_ARCH} == "powerpc64" 188.if ${COMPILER_VERSION} >= 40900 189CFLAGS.gcc+= -mabi=elfv2 190.else 191CFLAGS.gcc+= -mcall-aixdesc 192.endif 193CFLAGS.clang+= -mabi=elfv2 194.endif 195 196# 197# For MIPS we also tell gcc to use floating point emulation 198# 199.if ${MACHINE_CPUARCH} == "mips" 200CFLAGS+= -msoft-float 201INLINE_LIMIT?= 8000 202.endif 203 204# 205# GCC 3.0 and above like to do certain optimizations based on the 206# assumption that the program is linked against libc. Stop this. 207# 208CFLAGS+= -ffreestanding 209 210# 211# The C standard leaves signed integer overflow behavior undefined. 212# gcc and clang opimizers take advantage of this. The kernel makes 213# use of signed integer wraparound mechanics so we need the compiler 214# to treat it as a wraparound and not take shortcuts. 215# 216CFLAGS+= -fwrapv 217 218# 219# GCC SSP support 220# 221.if ${MK_SSP} != "no" && \ 222 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 223CFLAGS+= -fstack-protector 224.endif 225 226# 227# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 228# 229.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 230 ${MK_KERNEL_RETPOLINE} != "no" 231CFLAGS+= -mretpoline 232.endif 233 234# 235# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 236# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 237# cope well with DWARF 4, so force it to genereate DWARF2, which they 238# understand. Do this unconditionally as it is harmless when not needed, 239# but critical for these newer versions. 240# 241.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 242CFLAGS+= -gdwarf-2 243.endif 244 245CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 246CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 247 248# Tell bmake not to mistake standard targets for things to be searched for 249# or expect to ever be up-to-date. 250PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 251 beforelinking build build-tools buildfiles buildincludes \ 252 checkdpadd clean cleandepend cleandir cleanobj configure \ 253 depend distclean distribute exe \ 254 html includes install installfiles installincludes \ 255 obj objlink objs objwarn \ 256 realinstall regress \ 257 tags whereobj 258 259.PHONY: ${PHONY_NOTMAIN} 260.NOTMAIN: ${PHONY_NOTMAIN} 261 262CSTD= c99 263 264.if ${CSTD} == "k&r" 265CFLAGS+= -traditional 266.elif ${CSTD} == "c89" || ${CSTD} == "c90" 267CFLAGS+= -std=iso9899:1990 268.elif ${CSTD} == "c94" || ${CSTD} == "c95" 269CFLAGS+= -std=iso9899:199409 270.elif ${CSTD} == "c99" 271CFLAGS+= -std=iso9899:1999 272.else # CSTD 273CFLAGS+= -std=${CSTD} 274.endif # CSTD 275 276# Set target-specific linker emulation name. 277LD_EMULATION_aarch64=aarch64elf 278LD_EMULATION_amd64=elf_x86_64_fbsd 279LD_EMULATION_arm=armelf_fbsd 280LD_EMULATION_armv6=armelf_fbsd 281LD_EMULATION_armv7=armelf_fbsd 282LD_EMULATION_i386=elf_i386_fbsd 283LD_EMULATION_mips= elf32btsmip_fbsd 284LD_EMULATION_mipshf= elf32btsmip_fbsd 285LD_EMULATION_mips64= elf64btsmip_fbsd 286LD_EMULATION_mips64hf= elf64btsmip_fbsd 287LD_EMULATION_mipsel= elf32ltsmip_fbsd 288LD_EMULATION_mipselhf= elf32ltsmip_fbsd 289LD_EMULATION_mips64el= elf64ltsmip_fbsd 290LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 291LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 292LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 293LD_EMULATION_powerpc= elf32ppc_fbsd 294LD_EMULATION_powerpcspe= elf32ppc_fbsd 295LD_EMULATION_powerpc64= elf64ppc_fbsd 296LD_EMULATION_riscv64= elf64lriscv 297LD_EMULATION_sparc64= elf64_sparc_fbsd 298LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 299