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 44CLANG_NO_IAS= -no-integrated-as 45.if ${COMPILER_VERSION} < 30500 46# XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives 47CLANG_NO_IAS34= -no-integrated-as 48.endif 49.endif 50 51.if ${COMPILER_TYPE} == "gcc" 52.if ${COMPILER_VERSION} >= 40800 53# Catch-all for all the things that are in our tree, but for which we're 54# not yet ready for this compiler. 55NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable 56CWARNEXTRA?= -Wno-error=address \ 57 -Wno-error=aggressive-loop-optimizations \ 58 -Wno-error=array-bounds \ 59 -Wno-error=attributes \ 60 -Wno-error=cast-qual \ 61 -Wno-error=enum-compare \ 62 -Wno-error=inline \ 63 -Wno-error=maybe-uninitialized \ 64 -Wno-error=overflow \ 65 -Wno-error=sequence-point \ 66 -Wno-error=unused-but-set-variable 67.if ${COMPILER_VERSION} >= 60100 68CWARNEXTRA+= -Wno-error=misleading-indentation \ 69 -Wno-error=nonnull-compare \ 70 -Wno-error=shift-overflow \ 71 -Wno-error=tautological-compare 72.endif 73.if ${COMPILER_VERSION} >= 70200 74CWARNEXTRA+= -Wno-error=memset-elt-size 75.endif 76.if ${COMPILER_VERSION} >= 80000 77CWARNEXTRA+= -Wno-error=packed-not-aligned 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 85.endif 86.endif 87 88# This warning is utter nonsense 89CWARNFLAGS+= -Wno-format-zero-length 90 91# External compilers may not support our format extensions. Allow them 92# to be disabled. WARNING: format checking is disabled in this case. 93.if ${MK_FORMAT_EXTENSIONS} == "no" 94FORMAT_EXTENSIONS= -Wno-format 95.elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600 96FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ 97.else 98FORMAT_EXTENSIONS= -fformat-extensions 99.endif 100 101# 102# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 103# and above adds code to the entry and exit point of every function to align the 104# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack 105# per function call. While the 16-byte alignment may benefit micro benchmarks, 106# it is probably an overall loss as it makes the code bigger (less efficient 107# use of code cache tag lines) and uses more stack (less efficient use of data 108# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD 109# operations inside the kernel itself. These operations are exclusively 110# reserved for user applications. 111# 112# gcc: 113# Setting -mno-mmx implies -mno-3dnow 114# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 115# 116# clang: 117# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 118# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 119# 120.if ${MACHINE_CPUARCH} == "i386" 121CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 122CFLAGS.clang+= -mno-aes -mno-avx 123CFLAGS+= -mno-mmx -mno-sse -msoft-float 124INLINE_LIMIT?= 8000 125.endif 126 127.if ${MACHINE_CPUARCH} == "arm" 128INLINE_LIMIT?= 8000 129.endif 130 131.if ${MACHINE_CPUARCH} == "aarch64" 132# We generally don't want fpu instructions in the kernel. 133CFLAGS += -mgeneral-regs-only 134# Reserve x18 for pcpu data 135CFLAGS += -ffixed-x18 136INLINE_LIMIT?= 8000 137.endif 138 139# 140# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating 141# point registers within the kernel. We also specify the "medium" code model, 142# which generates code suitable for a 2GiB addressing range located at any 143# offset, allowing modules to be located anywhere in the 64-bit address space. 144# Note that clang and GCC refer to this code model as "medium" and "medany" 145# respectively. 146# 147.if ${MACHINE_CPUARCH} == "riscv" 148CFLAGS+= -march=rv64imafdc -mabi=lp64 149CFLAGS.clang+= -mcmodel=medium 150CFLAGS.gcc+= -mcmodel=medany 151INLINE_LIMIT?= 8000 152 153.if ${LINKER_FEATURES:Mriscv-relaxations} == "" 154CFLAGS+= -mno-relax 155.endif 156.endif 157 158# 159# For sparc64 we want the medany code model so modules may be located 160# anywhere in the 64-bit address space. We also tell GCC to use floating 161# point emulation. This avoids using floating point registers for integer 162# operations which it has a tendency to do. 163# 164.if ${MACHINE_CPUARCH} == "sparc64" 165CFLAGS.clang+= -mcmodel=large -fno-dwarf2-cfi-asm 166CFLAGS.gcc+= -mcmodel=medany -msoft-float 167INLINE_LIMIT?= 15000 168.endif 169 170# 171# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD 172# operations inside the kernel itself. These operations are exclusively 173# reserved for user applications. 174# 175# gcc: 176# Setting -mno-mmx implies -mno-3dnow 177# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 178# 179# clang: 180# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa 181# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 182# (-mfpmath= is not supported) 183# 184.if ${MACHINE_CPUARCH} == "amd64" 185CFLAGS.clang+= -mno-aes -mno-avx 186CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ 187 -fno-asynchronous-unwind-tables 188INLINE_LIMIT?= 8000 189.endif 190 191# 192# For PowerPC we tell gcc to use floating point emulation. This avoids using 193# floating point registers for integer operations which it has a tendency to do. 194# Also explicitly disable Altivec instructions inside the kernel. 195# 196.if ${MACHINE_CPUARCH} == "powerpc" 197CFLAGS+= -mno-altivec -msoft-float 198INLINE_LIMIT?= 15000 199.endif 200 201.if ${MACHINE_ARCH} == "powerpcspe" 202CFLAGS.gcc+= -mno-spe 203.endif 204 205# 206# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make 207# DDB happy. ELFv2, if available, has some other efficiency benefits. 208# 209.if ${MACHINE_ARCH} == "powerpc64" 210.if ${COMPILER_VERSION} >= 40900 211CFLAGS.gcc+= -mabi=elfv2 212.else 213CFLAGS.gcc+= -mcall-aixdesc 214.endif 215CFLAGS.clang+= -mabi=elfv2 216.endif 217 218# 219# For MIPS we also tell gcc to use floating point emulation 220# 221.if ${MACHINE_CPUARCH} == "mips" 222CFLAGS+= -msoft-float 223INLINE_LIMIT?= 8000 224.endif 225 226# 227# GCC 3.0 and above like to do certain optimizations based on the 228# assumption that the program is linked against libc. Stop this. 229# 230CFLAGS+= -ffreestanding 231 232# 233# The C standard leaves signed integer overflow behavior undefined. 234# gcc and clang opimizers take advantage of this. The kernel makes 235# use of signed integer wraparound mechanics so we need the compiler 236# to treat it as a wraparound and not take shortcuts. 237# 238CFLAGS+= -fwrapv 239 240# 241# GCC SSP support 242# 243.if ${MK_SSP} != "no" && \ 244 ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" 245CFLAGS+= -fstack-protector 246.endif 247 248# 249# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) 250# 251.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ 252 ${MK_KERNEL_RETPOLINE} != "no" 253CFLAGS+= -mretpoline 254.endif 255 256# 257# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 258# and gcc 4.8 is to generate DWARF version 4. However, our tools don't 259# cope well with DWARF 4, so force it to genereate DWARF2, which they 260# understand. Do this unconditionally as it is harmless when not needed, 261# but critical for these newer versions. 262# 263.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" 264CFLAGS+= -gdwarf-2 265.endif 266 267CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} 268CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} 269 270# Tell bmake not to mistake standard targets for things to be searched for 271# or expect to ever be up-to-date. 272PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ 273 beforelinking build build-tools buildfiles buildincludes \ 274 checkdpadd clean cleandepend cleandir cleanobj configure \ 275 depend distclean distribute exe \ 276 html includes install installfiles installincludes \ 277 obj objlink objs objwarn \ 278 realinstall regress \ 279 tags whereobj 280 281.PHONY: ${PHONY_NOTMAIN} 282.NOTMAIN: ${PHONY_NOTMAIN} 283 284CSTD= c99 285 286.if ${CSTD} == "k&r" 287CFLAGS+= -traditional 288.elif ${CSTD} == "c89" || ${CSTD} == "c90" 289CFLAGS+= -std=iso9899:1990 290.elif ${CSTD} == "c94" || ${CSTD} == "c95" 291CFLAGS+= -std=iso9899:199409 292.elif ${CSTD} == "c99" 293CFLAGS+= -std=iso9899:1999 294.else # CSTD 295CFLAGS+= -std=${CSTD} 296.endif # CSTD 297 298# Set target-specific linker emulation name. 299LD_EMULATION_aarch64=aarch64elf 300LD_EMULATION_amd64=elf_x86_64_fbsd 301LD_EMULATION_arm=armelf_fbsd 302LD_EMULATION_armv6=armelf_fbsd 303LD_EMULATION_armv7=armelf_fbsd 304LD_EMULATION_i386=elf_i386_fbsd 305LD_EMULATION_mips= elf32btsmip_fbsd 306LD_EMULATION_mipshf= elf32btsmip_fbsd 307LD_EMULATION_mips64= elf64btsmip_fbsd 308LD_EMULATION_mips64hf= elf64btsmip_fbsd 309LD_EMULATION_mipsel= elf32ltsmip_fbsd 310LD_EMULATION_mipselhf= elf32ltsmip_fbsd 311LD_EMULATION_mips64el= elf64ltsmip_fbsd 312LD_EMULATION_mips64elhf= elf64ltsmip_fbsd 313LD_EMULATION_mipsn32= elf32btsmipn32_fbsd 314LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works 315LD_EMULATION_powerpc= elf32ppc_fbsd 316LD_EMULATION_powerpcspe= elf32ppc_fbsd 317LD_EMULATION_powerpc64= elf64ppc_fbsd 318LD_EMULATION_riscv64= elf64lriscv 319LD_EMULATION_sparc64= elf64_sparc_fbsd 320LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} 321