HardenedBSD/sys/conf/kern.mk
2024-10-31 18:01:48 -06:00

322 lines
11 KiB
Makefile

#
# Warning flags for compiling the kernel and components of the kernel:
#
CWARNFLAGS?= -Wall -Wstrict-prototypes \
-Wmissing-prototypes -Wpointer-arith -Wcast-qual \
-Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
-Wmissing-include-dirs -fdiagnostics-show-option \
-Wno-unknown-pragmas -Wswitch \
${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
.if ${COMPILER_VERSION} >= 100000
NO_WMISLEADING_INDENTATION= -Wno-misleading-indentation
.endif
.if ${COMPILER_VERSION} >= 130000
NO_WUNUSED_BUT_SET_VARIABLE= -Wno-unused-but-set-variable
.endif
.if ${COMPILER_VERSION} >= 140000
NO_WBITWISE_INSTEAD_OF_LOGICAL= -Wno-bitwise-instead-of-logical
.endif
.if ${COMPILER_VERSION} >= 150000
NO_WSTRICT_PROTOTYPES= -Wno-strict-prototypes
NO_WDEPRECATED_NON_PROTOTYPE= -Wno-deprecated-non-prototype
.endif
# 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
.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=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-error=unused-function
.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 \
-Wno-alloc-size-larger-than \
-Wno-error=alloca-larger-than=
.if ${COMPILER_VERSION} >= 120100
CWARNEXTRA+= -Wno-error=nonnull \
-Wno-dangling-pointer \
-Wno-zero-length-bounds
NO_WINFINITE_RECURSION= -Wno-infinite-recursion
NO_WSTRINGOP_OVERREAD= -Wno-stringop-overread
.endif
.endif
# GCC produces false positives for functions that switch on an
# enum (GCC bug 87950)
CWARNFLAGS+= -Wno-return-type
.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 ${COMPILER_TYPE} == "clang" || \
(${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 120100)
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+= -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
# Build with BTI+PAC
CFLAGS += -mbranch-protection=standard
.if ${LINKER_FEATURES:Mbti-report}
LDFLAGS += -Wl,-zbti-report=error
.endif
# TODO: support outline atomics
CFLAGS += -mno-outline-atomics
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, we include the F and D extensions
# in -march so we can have limited floating point support in context switching
# code. 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=rv64imafdch
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:Mpowerpc64*} != "" && \
${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} < 160000
CFLAGS+= -mabi=elfv2
.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"
KERN_SSP_CFLAG?= -fstack-protector-strong
CFLAGS+= ${KERN_SSP_CFLAG}
.endif
.if defined(MK_RETPOLINE) && ${MK_RETPOLINE} != "no"
CFLAGS+= -mretpoline
.endif
.if !defined(TRIVIAL_VAR_AUTO_INIT_ZERO_SAFE)
CFLAGS+= -ftrivial-auto-var-init=uninitialized
.endif
#
# Some newer toolchains default to DWARF 5, which isn't supported by some build
# tools yet.
#
.if (${CFLAGS:M-g} != "" || ${CFLAGS:M-g[0-3]} != "") && ${CFLAGS:M-gdwarf*} == ""
CFLAGS+= -gdwarf-4
.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?= gnu99
# c99/gnu99 is the minimum C standard version supported for kernel build
.if ${CSTD} == "k&r" || ${CSTD} == "c89" || ${CSTD} == "c90" || \
${CSTD} == "c94" || ${CSTD} == "c95"
.error "Only c99/gnu99 or later is supported"
.else # CSTD
CFLAGS+= -std=${CSTD}
.endif # CSTD
NOSAN_CFLAGS= ${CFLAGS:N-fsanitize*:N-fno-sanitize*:N-fasan-shadow-offset*}
# 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".
.if ${COMPILER_TYPE} == "clang"
# Note: Clang does not like relative paths for ld so we map ld.lld -> lld.
.if ${COMPILER_VERSION} >= 120000
CCLDFLAGS+= --ld-path=${LD:[1]:S/^ld.//1W}
.else
CCLDFLAGS+= -fuse-ld=${LD:[1]:S/^ld.//1W}
.endif
.else
# GCC does not support an absolute path for -fuse-ld so we just print this
# warning instead and let the user add the required symlinks.
# However, we can avoid this warning if -B is set appropriately (e.g. for
# CROSS_TOOLCHAIN=...-gcc).
.if !(${LD:[1]:T} == "ld" && ${CC:tw:M-B${LD:[1]:H}/})
.warning LD (${LD}) is not the default linker for ${CC} but -fuse-ld= is not supported
.endif
.endif
.endif
# Set target-specific linker emulation name.
LD_EMULATION_aarch64=aarch64elf
LD_EMULATION_amd64=elf_x86_64_fbsd
LD_EMULATION_arm=armelf_fbsd
LD_EMULATION_armv7=armelf_fbsd
LD_EMULATION_i386=elf_i386_fbsd
LD_EMULATION_powerpc= elf32ppc_fbsd
LD_EMULATION_powerpcspe= elf32ppc_fbsd
LD_EMULATION_powerpc64= elf64ppc_fbsd
LD_EMULATION_powerpc64le= elf64lppc_fbsd
LD_EMULATION_riscv64= elf64lriscv
LD_EMULATION=${LD_EMULATION_${MACHINE_ARCH}}