diff options
Diffstat (limited to 'sys/conf/kern.mk')
| -rw-r--r-- | sys/conf/kern.mk | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk new file mode 100644 index 000000000000..de5286688e13 --- /dev/null +++ b/sys/conf/kern.mk @@ -0,0 +1,312 @@ +# $FreeBSD$ + +# +# Warning flags for compiling the kernel and components of the kernel: +# +CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \ + -Wmissing-prototypes -Wpointer-arith -Wcast-qual \ + -Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \ + -Wmissing-include-dirs -fdiagnostics-show-option \ + -Wno-unknown-pragmas \ + ${CWARNEXTRA} +# +# The following flags are next up for working on: +# -Wextra + +# Disable a few warnings for clang, since there are several places in the +# kernel where fixing them is more trouble than it is worth, or where there is +# a false positive. +.if ${COMPILER_TYPE} == "clang" +NO_WCONSTANT_CONVERSION= -Wno-error-constant-conversion +NO_WSHIFT_COUNT_NEGATIVE= -Wno-shift-count-negative +NO_WSHIFT_COUNT_OVERFLOW= -Wno-shift-count-overflow +NO_WSELF_ASSIGN= -Wno-self-assign +NO_WUNNEEDED_INTERNAL_DECL= -Wno-error-unneeded-internal-declaration +NO_WSOMETIMES_UNINITIALIZED= -Wno-error-sometimes-uninitialized +NO_WCAST_QUAL= -Wno-error-cast-qual +NO_WTAUTOLOGICAL_POINTER_COMPARE= -Wno-tautological-pointer-compare +# Several other warnings which might be useful in some cases, but not severe +# enough to error out the whole kernel build. Display them anyway, so there is +# some incentive to fix them eventually. +CWARNEXTRA?= -Wno-error-tautological-compare -Wno-error-empty-body \ + -Wno-error-parentheses-equality -Wno-error-unused-function \ + -Wno-error-pointer-sign +CWARNEXTRA+= -Wno-error-shift-negative-value +CWARNEXTRA+= -Wno-address-of-packed-member +.if ${COMPILER_VERSION} >= 100000 +NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation +.endif +.endif # clang + +.if ${COMPILER_TYPE} == "gcc" +# Catch-all for all the things that are in our tree, but for which we're +# not yet ready for this compiler. +NO_WUNUSED_BUT_SET_VARIABLE = -Wno-unused-but-set-variable +CWARNEXTRA?= -Wno-error=address \ + -Wno-error=aggressive-loop-optimizations \ + -Wno-error=array-bounds \ + -Wno-error=attributes \ + -Wno-error=cast-qual \ + -Wno-error=enum-compare \ + -Wno-error=inline \ + -Wno-error=maybe-uninitialized \ + -Wno-error=misleading-indentation \ + -Wno-error=nonnull-compare \ + -Wno-error=overflow \ + -Wno-error=sequence-point \ + -Wno-error=shift-overflow \ + -Wno-error=tautological-compare \ + -Wno-unused-but-set-variable +.if ${COMPILER_VERSION} >= 70100 +CWARNEXTRA+= -Wno-error=stringop-overflow +.endif +.if ${COMPILER_VERSION} >= 70200 +CWARNEXTRA+= -Wno-error=memset-elt-size +.endif +.if ${COMPILER_VERSION} >= 80000 +CWARNEXTRA+= -Wno-error=packed-not-aligned +.endif +.if ${COMPILER_VERSION} >= 90100 +CWARNEXTRA+= -Wno-address-of-packed-member +.endif +.endif # gcc + +# This warning is utter nonsense +CWARNFLAGS+= -Wno-format-zero-length + +# External compilers may not support our format extensions. Allow them +# to be disabled. WARNING: format checking is disabled in this case. +.if ${MK_FORMAT_EXTENSIONS} == "no" +FORMAT_EXTENSIONS= -Wno-format +.elif ${COMPILER_TYPE} == "clang" +FORMAT_EXTENSIONS= -D__printf__=__freebsd_kprintf__ +.else +FORMAT_EXTENSIONS= -fformat-extensions +.endif + +# +# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95 +# and above adds code to the entry and exit point of every function to align the +# stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack +# per function call. While the 16-byte alignment may benefit micro benchmarks, +# it is probably an overall loss as it makes the code bigger (less efficient +# use of code cache tag lines) and uses more stack (less efficient use of data +# cache tag lines). Explicitly prohibit the use of FPU, SSE and other SIMD +# operations inside the kernel itself. These operations are exclusively +# reserved for user applications. +# +# gcc: +# Setting -mno-mmx implies -mno-3dnow +# Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3 +# +# clang: +# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa +# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 +# +.if ${MACHINE_CPUARCH} == "i386" +CFLAGS.gcc+= -mno-align-long-strings -mpreferred-stack-boundary=2 +CFLAGS.clang+= -mno-aes -mno-avx +CFLAGS+= -mno-mmx -mno-sse -msoft-float +INLINE_LIMIT?= 8000 +.endif + +.if ${MACHINE_CPUARCH} == "arm" +INLINE_LIMIT?= 8000 +.endif + +.if ${MACHINE_CPUARCH} == "aarch64" +# We generally don't want fpu instructions in the kernel. +CFLAGS += -mgeneral-regs-only +# Reserve x18 for pcpu data +CFLAGS += -ffixed-x18 +INLINE_LIMIT?= 8000 +.endif + +# +# For RISC-V we specify the soft-float ABI (lp64) to avoid the use of floating +# point registers within the kernel. However, for kernels supporting hardware +# float (FPE), we have to include that in the march so we can have limited +# floating point support in context switching needed for that. This is different +# than userland where we use a hard-float ABI (lp64d). +# +# We also specify the "medium" code model, which generates code suitable for a +# 2GiB addressing range located at any offset, allowing modules to be located +# anywhere in the 64-bit address space. Note that clang and GCC refer to this +# code model as "medium" and "medany" respectively. +# +.if ${MACHINE_CPUARCH} == "riscv" +CFLAGS+= -march=rv64imafdc +CFLAGS+= -mabi=lp64 +CFLAGS.clang+= -mcmodel=medium +CFLAGS.gcc+= -mcmodel=medany +INLINE_LIMIT?= 8000 + +.if ${LINKER_FEATURES:Mriscv-relaxations} == "" +CFLAGS+= -mno-relax +.endif +.endif + +# +# For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD +# operations inside the kernel itself. These operations are exclusively +# reserved for user applications. +# +# gcc: +# Setting -mno-mmx implies -mno-3dnow +# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387 +# +# clang: +# Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa +# Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42 +# (-mfpmath= is not supported) +# +.if ${MACHINE_CPUARCH} == "amd64" +CFLAGS.clang+= -mno-aes -mno-avx +CFLAGS+= -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \ + -fno-asynchronous-unwind-tables +INLINE_LIMIT?= 8000 +.endif + +# +# For PowerPC we tell gcc to use floating point emulation. This avoids using +# floating point registers for integer operations which it has a tendency to do. +# Also explicitly disable Altivec instructions inside the kernel. +# +.if ${MACHINE_CPUARCH} == "powerpc" +CFLAGS+= -mno-altivec -msoft-float +INLINE_LIMIT?= 15000 +.endif + +.if ${MACHINE_ARCH} == "powerpcspe" +CFLAGS.gcc+= -mno-spe +.endif + +# +# Use dot symbols (or, better, the V2 ELF ABI) on powerpc64 to make +# DDB happy. ELFv2, if available, has some other efficiency benefits. +# +.if ${MACHINE_ARCH} == "powerpc64" +CFLAGS+= -mabi=elfv2 +.endif + +# +# For MIPS we also tell gcc to use floating point emulation +# +.if ${MACHINE_CPUARCH} == "mips" +CFLAGS+= -msoft-float +INLINE_LIMIT?= 8000 +.endif + +# +# GCC 3.0 and above like to do certain optimizations based on the +# assumption that the program is linked against libc. Stop this. +# +CFLAGS+= -ffreestanding + +# +# The C standard leaves signed integer overflow behavior undefined. +# gcc and clang opimizers take advantage of this. The kernel makes +# use of signed integer wraparound mechanics so we need the compiler +# to treat it as a wraparound and not take shortcuts. +# +CFLAGS+= -fwrapv + +# +# GCC SSP support +# +.if ${MK_SSP} != "no" && \ + ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips" +CFLAGS+= -fstack-protector +.endif + +# +# Retpoline speculative execution vulnerability mitigation (CVE-2017-5715) +# +.if defined(COMPILER_FEATURES) && ${COMPILER_FEATURES:Mretpoline} != "" && \ + ${MK_KERNEL_RETPOLINE} != "no" +CFLAGS+= -mretpoline +.endif + +# +# Add -gdwarf-2 when compiling -g. The default starting in clang v3.4 +# and gcc 4.8 is to generate DWARF version 4. However, our tools don't +# cope well with DWARF 4, so force it to genereate DWARF2, which they +# understand. Do this unconditionally as it is harmless when not needed, +# but critical for these newer versions. +# +.if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == "" +CFLAGS+= -gdwarf-2 +.endif + +CFLAGS+= ${CWARNFLAGS:M*} ${CWARNFLAGS.${.IMPSRC:T}} +CFLAGS+= ${CWARNFLAGS.${COMPILER_TYPE}} +CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}} + +# Tell bmake not to mistake standard targets for things to be searched for +# or expect to ever be up-to-date. +PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \ + beforelinking build build-tools buildfiles buildincludes \ + checkdpadd clean cleandepend cleandir cleanobj configure \ + depend distclean distribute exe \ + html includes install installfiles installincludes \ + obj objlink objs objwarn \ + realinstall regress \ + tags whereobj + +.PHONY: ${PHONY_NOTMAIN} +.NOTMAIN: ${PHONY_NOTMAIN} + +CSTD= c99 + +.if ${CSTD} == "k&r" +CFLAGS+= -traditional +.elif ${CSTD} == "c89" || ${CSTD} == "c90" +CFLAGS+= -std=iso9899:1990 +.elif ${CSTD} == "c94" || ${CSTD} == "c95" +CFLAGS+= -std=iso9899:199409 +.elif ${CSTD} == "c99" +CFLAGS+= -std=iso9899:1999 +.else # CSTD +CFLAGS+= -std=${CSTD} +.endif # CSTD + +# Please keep this if in sync with bsd.sys.mk +.if ${LD} != "ld" && (${CC:[1]:H} != ${LD:[1]:H} || ${LD:[1]:T} != "ld") +# Add -fuse-ld=${LD} if $LD is in a different directory or not called "ld". +# Note: Clang 12+ will prefer --ld-path= over -fuse-ld=. +.if ${COMPILER_TYPE} == "clang" +# Note: unlike bsd.sys.mk we can't use LDFLAGS here since that is used for the +# flags required when linking the kernel. We don't need those flags when +# building the vdsos. However, we do need -fuse-ld, so use ${CCLDFLAGS} instead. +# Note: Clang does not like relative paths in -fuse-ld so we map ld.lld -> lld. +CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W} +.else +# GCC does not support an absolute path for -fuse-ld so we just print this +# warning instead and let the user add the required symlinks. +.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported +.endif +.endif + +# Set target-specific linker emulation name. +LD_EMULATION_aarch64=aarch64elf +LD_EMULATION_amd64=elf_x86_64_fbsd +LD_EMULATION_arm=armelf_fbsd +LD_EMULATION_armv6=armelf_fbsd +LD_EMULATION_armv7=armelf_fbsd +LD_EMULATION_i386=elf_i386_fbsd +LD_EMULATION_mips= elf32btsmip_fbsd +LD_EMULATION_mipshf= elf32btsmip_fbsd +LD_EMULATION_mips64= elf64btsmip_fbsd +LD_EMULATION_mips64hf= elf64btsmip_fbsd +LD_EMULATION_mipsel= elf32ltsmip_fbsd +LD_EMULATION_mipselhf= elf32ltsmip_fbsd +LD_EMULATION_mips64el= elf64ltsmip_fbsd +LD_EMULATION_mips64elhf= elf64ltsmip_fbsd +LD_EMULATION_mipsn32= elf32btsmipn32_fbsd +LD_EMULATION_mipsn32el= elf32btsmipn32_fbsd # I don't think this is a thing that works +LD_EMULATION_powerpc= elf32ppc_fbsd +LD_EMULATION_powerpcspe= elf32ppc_fbsd +LD_EMULATION_powerpc64= elf64ppc_fbsd +LD_EMULATION_riscv64= elf64lriscv +LD_EMULATION_riscv64sf= elf64lriscv +LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}} |