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.if ${COMPILER_VERSION} < 30500 43# XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives 44CLANG_NO_IAS34= -no-integrated-as 45.endif 46.endif 47 48.if ${COMPILER_TYPE} == "gcc" 49.if ${COMPILER_VERSION} >= 40800 50# Catch-all for all the things that are in our tree, but for which we're 51# not yet ready for this compiler. 52NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 53CWARNEXTRA?= -Wno-error=address \ 54 -Wno-error=aggressive-loop-optimizations \ 55 -Wno-error=array-bounds \ 56 -Wno-error=attributes \ 57 -Wno-error=cast-qual \ 58 -Wno-error=enum-compare \ 59 -Wno-error=inline \ 60 -Wno-error=maybe-uninitialized \ 61 -Wno-error=overflow \ 62 -Wno-error=sequence-point \ 63 -Wno-error=unused-but-set-variable 64.if ${COMPILER_VERSION} >= 60100 65CWARNEXTRA+= -Wno-error=misleading-indentation \ 66 -Wno-error=nonnull-compare \ 67 -Wno-error=shift-overflow \ 68 -Wno-error=tautological-compare 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.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 82.endif 83.endif 84 85# External compilers may not support our format extensions. Allow them 86# to be disabled. WARNING: format checking is disabled in this case. 87.if ${MK_FORMAT_EXTENSIONS} == "no" 88FORMAT_EXTENSIONS= -Wno-format 89.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 90FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 91.else 92FORMAT_EXTENSIONS= -fformat-extensions 93.endif 94 95# 96# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 97# and above adds code to the entry and exit point of every function to align the 98# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 99# per function call. While the 16-byte alignment may benefit micro benchmarks, 100# it is probably an overall loss as it makes the code bigger (less efficient 101# use of code cache tag lines) and uses more stack (less efficient use of data 102# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 103# operations inside the kernel itself. These operations are exclusively 104# reserved for user applications. 105# 106# gcc: 107# Setting -mno-mmx implies -mno-3dnow 108# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 109# 110# clang: 111# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 112# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 113# 114.if ${MACHINE_CPUARCH} == "i386" 115CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 116CFLAGS.clang+= -mno-aes -mno-avx 117CFLAGS+= -mno-mmx -mno-sse -msoft-float 118INLINE_LIMIT?= 8000 119.endif 120 121.if ${MACHINE_CPUARCH} == "arm" 122INLINE_LIMIT?= 8000 123.endif 124 125.if ${MACHINE_CPUARCH} == "aarch64" 126# We generally don't want fpu instructions in the kernel. 127CFLAGS += -mgeneral-regs-only 128# Reserve x18 for pcpu data 129CFLAGS += -ffixed-x18 130INLINE_LIMIT?= 8000 131.endif 132 133.if ${MACHINE_CPUARCH} == "riscv" 134CFLAGS.gcc+= -mcmodel=medany -march=rv64imafd -mabi=lp64 135INLINE_LIMIT?= 8000 136.endif 137 138# 139# For sparc64 we want the medany code model so modules may be located 140# anywhere in the 64-bit address space. We also tell GCC to use floating 141# point emulation. This avoids using floating point registers for integer 142# operations which it has a tendency to do. 143# 144.if ${MACHINE_CPUARCH} == "sparc64" 145CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 146CFLAGS.gcc+= -mcmodel=medany -msoft-float 147INLINE_LIMIT?= 15000 148.endif 149 150# 151# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 152# operations inside the kernel itself. These operations are exclusively 153# reserved for user applications. 154# 155# gcc: 156# Setting -mno-mmx implies -mno-3dnow 157# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 158# 159# clang: 160# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 161# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 162# (-mfpmath= is not supported) 163# 164.if ${MACHINE_CPUARCH} == "amd64" 165CFLAGS.clang+= -mno-aes -mno-avx 166CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 167 -fno-asynchronous-unwind-tables 168INLINE_LIMIT?= 8000 169.endif 170 171# 172# For PowerPC we tell gcc to use floating point emulation. This avoids using 173# floating point registers for integer operations which it has a tendency to do. 174# Also explicitly disable Altivec instructions inside the kernel. 175# 176.if ${MACHINE_CPUARCH} == "powerpc" 177CFLAGS+= -mno-altivec -msoft-float 178INLINE_LIMIT?= 15000 179.endif 180 181.if ${MACHINE_ARCH} == "powerpcspe" 182CFLAGS.gcc+= -mno-spe 183.endif 184 185# 186# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 187# DDB happy. ELFv2, if available, has some other efficiency benefits. 188# 189.if ${MACHINE_ARCH} == "powerpc64" 190.if ${COMPILER_VERSION} >= 40900 191CFLAGS.gcc+= -mabi=elfv2 192.else 193CFLAGS.gcc+= -mcall-aixdesc 194.endif 195CFLAGS.clang+= -mabi=elfv2 196.endif 197 198# 199# For MIPS we also tell gcc to use floating point emulation 200# 201.if ${MACHINE_CPUARCH} == "mips" 202CFLAGS+= -msoft-float 203INLINE_LIMIT?= 8000 204.endif 205 206# 207# GCC 3.0 and above like to do certain optimizations based on the 208# assumption that the program is linked against libc. Stop this. 209# 210CFLAGS+= -ffreestanding 211 212# 213# The C standard leaves signed integer overflow behavior undefined. 214# gcc and clang opimizers take advantage of this. The kernel makes 215# use of signed integer wraparound mechanics so we need the compiler 216# to treat it as a wraparound and not take shortcuts. 217# 218CFLAGS+= -fwrapv 219 220# 221# GCC SSP support 222# 223.if ${MK_SSP} != "no" && \ 224 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 225CFLAGS+= -fstack-protector 226.endif 227 228# 229# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 230# 231.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 232 ${MK_KERNEL_RETPOLINE} != "no" 233CFLAGS+= -mretpoline 234.endif 235 236# 237# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 238# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 239# cope well with DWARF 4, so force it to genereate DWARF2, which they 240# understand. Do this unconditionally as it is harmless when not needed, 241# but critical for these newer versions. 242# 243.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 244CFLAGS+= -gdwarf-2 245.endif 246 247CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 248CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 249 250# Tell bmake not to mistake standard targets for things to be searched for 251# or expect to ever be up-to-date. 252PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 253 beforelinking build build-tools buildfiles buildincludes \ 254 checkdpadd clean cleandepend cleandir cleanobj configure \ 255 depend distclean distribute exe \ 256 html includes install installfiles installincludes \ 257 obj objlink objs objwarn \ 258 realinstall regress \ 259 tags whereobj 260 261.PHONY: ${PHONY_NOTMAIN} 262.NOTMAIN: ${PHONY_NOTMAIN} 263 264CSTD= c99 265 266.if ${CSTD} == "k&r" 267CFLAGS+= -traditional 268.elif ${CSTD} == "c89" || ${CSTD} == "c90" 269CFLAGS+= -std=iso9899:1990 270.elif ${CSTD} == "c94" || ${CSTD} == "c95" 271CFLAGS+= -std=iso9899:199409 272.elif ${CSTD} == "c99" 273CFLAGS+= -std=iso9899:1999 274.else # CSTD 275CFLAGS+= -std=${CSTD} 276.endif # CSTD 277 278# Set target-specific linker emulation name. 279LD_EMULATION_aarch64=aarch64elf 280LD_EMULATION_amd64=elf_x86_64_fbsd 281LD_EMULATION_arm=armelf_fbsd 282LD_EMULATION_armv6=armelf_fbsd 283LD_EMULATION_armv7=armelf_fbsd 284LD_EMULATION_i386=elf_i386_fbsd 285LD_EMULATION_mips= elf32btsmip_fbsd 286LD_EMULATION_mipshf= elf32btsmip_fbsd 287LD_EMULATION_mips64= elf64btsmip_fbsd 288LD_EMULATION_mips64hf= elf64btsmip_fbsd 289LD_EMULATION_mipsel= elf32ltsmip_fbsd 290LD_EMULATION_mipselhf= elf32ltsmip_fbsd 291LD_EMULATION_mips64el= elf64ltsmip_fbsd 292LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 293LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 294LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 295LD_EMULATION_powerpc= elf32ppc_fbsd 296LD_EMULATION_powerpcspe= elf32ppc_fbsd 297LD_EMULATION_powerpc64= elf64ppc_fbsd 298LD_EMULATION_riscv64= elf64lriscv 299LD_EMULATION_sparc64= elf64_sparc_fbsd 300LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 301