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f39b4f8899
freebsd-skq/sys/conf/kern.pre.mk
John Baldwin f39b4f8899 Work around lld's inability to handle undefined weak symbols on risc-v. 
lld on RISC-V is not yet able to handle undefined weak symbols for
non-PIC code in the code model (medany/medium) used by the RISC-V
kernel.

Both GCC and clang emit an auipc / addi pair of instructions to
generate an address relative to the current PC with a 31-bit offset.
Undefined weak symbols need to have an address of 0, but the kernel
runs with PC values much greater than 2^31, so there is no way to
construct a NULL pointer as a PC-relative value.  The bfd linker
rewrites the instruction pair to use lui / addi with values of 0 to
force a NULL pointer address.  (There are similar cases for 'ld'
becoming auipc / ld that bfd rewrites to lui / ld with an address of
0.)

To work around this, compile the kernel with -fPIE when using lld.
This does not make the kernel position-independent, but it does
force the compiler to indirect address lookups through GOT entries
(so auipc / ld against a GOT entry to fetch the address).  This
adds extra memory indirections for global symbols, so should be
disabled once lld is finally fixed.

A few 'la' instructions in locore that depend on PC-relative
addressing to load physical addresses before paging is enabled have to
use auipc / addi and not indirect via GOT entries, so change those to
use 'lla' which always uses auipc / addi for both PIC and non-PIC.

Submitted by:	jrtc27
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D23064
2020-01-07 23:18:31 +00:00

351 lines
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Makefile
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# $FreeBSD$
# Part of a unified Makefile for building kernels. This part contains all
# of the definitions that need to be before %BEFORE_DEPEND.
# Allow user to configure things that only effect src tree builds.
# Note: This is duplicated from src.sys.mk to ensure that we include
# /etc/src.conf when building the kernel. Kernels can be built without
# the rest of /usr/src, but they still always process SRCCONF even though
# the normal mechanisms to prevent that (compiling out of tree) won't
# work. To ensure they do work, we have to duplicate thee few lines here.
SRCCONF?= /etc/src.conf
.if (exists(${SRCCONF}) || ${SRCCONF} != "/etc/src.conf") && !target(_srcconf_included_)
.include "${SRCCONF}"
_srcconf_included_:
.endif
.include <bsd.own.mk>
.include <bsd.compiler.mk>
.include "kern.opts.mk"
# The kernel build always occurs in the object directory which is .CURDIR.
.if ${.MAKE.MODE:Unormal:Mmeta}
.MAKE.MODE+= curdirOk=yes
.endif
# The kernel build always expects .OBJDIR=.CURDIR.
.OBJDIR: ${.CURDIR}
.if defined(NO_OBJWALK) || ${MK_AUTO_OBJ} == "yes"
NO_OBJWALK= t
NO_MODULES_OBJ= t
.endif
.if !defined(NO_OBJWALK)
_obj= obj
.endif
# Can be overridden by makeoptions or /etc/make.conf
KERNEL_KO?= kernel
KERNEL?= kernel
KODIR?= /boot/${KERNEL}
LDSCRIPT_NAME?= ldscript.$M
LDSCRIPT?= $S/conf/${LDSCRIPT_NAME}
M= ${MACHINE}
AWK?= awk
CP?= cp
NM?= nm
OBJCOPY?= objcopy
SIZE?= size
.if defined(DEBUG)
_MINUS_O= -O
CTFFLAGS+= -g
.else
.if ${MACHINE_CPUARCH} == "powerpc"
_MINUS_O= -O # gcc miscompiles some code at -O2
.else
_MINUS_O= -O2
.endif
.endif
.if ${MACHINE_CPUARCH} == "amd64"
.if ${COMPILER_TYPE} == "clang"
COPTFLAGS?=-O2 -pipe
.else
COPTFLAGS?=-O2 -frename-registers -pipe
.endif
.else
COPTFLAGS?=${_MINUS_O} -pipe
.endif
.if !empty(COPTFLAGS:M-O[23s]) && empty(COPTFLAGS:M-fno-strict-aliasing)
COPTFLAGS+= -fno-strict-aliasing
.endif
.if !defined(NO_CPU_COPTFLAGS)
COPTFLAGS+= ${_CPUCFLAGS}
.endif
NOSTDINC= -nostdinc
INCLUDES= ${NOSTDINC} ${INCLMAGIC} -I. -I$S -I$S/contrib/ck/include
CFLAGS= ${COPTFLAGS} ${DEBUG}
CFLAGS+= ${INCLUDES} -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h
CFLAGS_PARAM_INLINE_UNIT_GROWTH?=100
CFLAGS_PARAM_LARGE_FUNCTION_GROWTH?=1000
.if ${MACHINE_CPUARCH} == "mips"
CFLAGS_ARCH_PARAMS?=--param max-inline-insns-single=1000 -DMACHINE_ARCH='"${MACHINE_ARCH}"'
.endif
CFLAGS.gcc+= -fno-common -fms-extensions -finline-limit=${INLINE_LIMIT}
CFLAGS.gcc+= --param inline-unit-growth=${CFLAGS_PARAM_INLINE_UNIT_GROWTH}
CFLAGS.gcc+= --param large-function-growth=${CFLAGS_PARAM_LARGE_FUNCTION_GROWTH}
CFLAGS.gcc+= -fms-extensions
.if defined(CFLAGS_ARCH_PARAMS)
CFLAGS.gcc+=${CFLAGS_ARCH_PARAMS}
.endif
.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} < 50000
WERROR?= -Wno-error
.else
WERROR?= -Werror
.endif
# XXX LOCORE means "don't declare C stuff" not "for locore.s".
ASM_CFLAGS= -x assembler-with-cpp -DLOCORE ${CFLAGS} ${ASM_CFLAGS.${.IMPSRC:T}}
.if defined(PROFLEVEL) && ${PROFLEVEL} >= 1
CFLAGS+= -DGPROF
CFLAGS.gcc+= -falign-functions=16
.if ${PROFLEVEL} >= 2
CFLAGS+= -DGPROF4 -DGUPROF
PROF= -pg
.if ${COMPILER_TYPE} == "gcc"
PROF+= -mprofiler-epilogue
.endif
.else
PROF= -pg
.endif
.endif
DEFINED_PROF= ${PROF}
KCSAN_ENABLED!= grep KCSAN opt_global.h || true ; echo
.if !empty(KCSAN_ENABLED)
SAN_CFLAGS+= -fsanitize=thread
.endif
KUBSAN_ENABLED!= grep KUBSAN opt_global.h || true ; echo
.if !empty(KUBSAN_ENABLED)
SAN_CFLAGS+= -fsanitize=undefined
.endif
COVERAGE_ENABLED!= grep COVERAGE opt_global.h || true ; echo
.if !empty(COVERAGE_ENABLED)
.if ${COMPILER_TYPE} == "clang" || \
(${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 80100)
SAN_CFLAGS+= -fsanitize-coverage=trace-pc,trace-cmp
.else
SAN_CFLAGS+= -fsanitize-coverage=trace-pc
.endif
.endif
CFLAGS+= ${SAN_CFLAGS}
GCOV_ENABLED!= grep GCOV opt_global.h || true ; echo
.if !empty(GCOV_ENABLED)
.if ${COMPILER_TYPE} == "gcc"
GCOV_CFLAGS+= -fprofile-arcs -ftest-coverage
.endif
.endif
CFLAGS+= ${GCOV_CFLAGS}
# Put configuration-specific C flags last (except for ${PROF}) so that they
# can override the others.
CFLAGS+= ${CONF_CFLAGS}
.if defined(LINKER_FEATURES) && ${LINKER_FEATURES:Mbuild-id}
LDFLAGS+= --build-id=sha1
.endif
.if (${MACHINE_CPUARCH} == "aarch64" || ${MACHINE_CPUARCH} == "amd64" || \
${MACHINE_CPUARCH} == "i386") && \
defined(LINKER_FEATURES) && ${LINKER_FEATURES:Mifunc} == ""
.error amd64/arm64/i386 kernel requires linker ifunc support
.endif
.if ${MACHINE_CPUARCH} == "amd64"
LDFLAGS+= -z max-page-size=2097152
.if ${LINKER_TYPE} != "lld"
LDFLAGS+= -z common-page-size=4096
.else
LDFLAGS+= -z notext -z ifunc-noplt
.endif
.endif
.if ${MACHINE_CPUARCH} == "riscv"
# Hack: Work around undefined weak symbols being out of range when linking with
# LLD (address is a PC-relative calculation, and BFD works around this by
# rewriting the instructions to generate an absolute address of 0); -fPIE
# avoids this since it uses the GOT for all extern symbols, which is overly
# inefficient for us. Drop once undefined weak symbols work with medany.
.if ${LINKER_TYPE} == "lld"
CFLAGS+= -fPIE
.endif
.endif
NORMAL_C= ${CC} -c ${CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
NORMAL_S= ${CC:N${CCACHE_BIN}} -c ${ASM_CFLAGS} ${WERROR} ${.IMPSRC}
PROFILE_C= ${CC} -c ${CFLAGS} ${WERROR} ${.IMPSRC}
NORMAL_C_NOWERROR= ${CC} -c ${CFLAGS} ${PROF} ${.IMPSRC}
NORMAL_M= ${AWK} -f $S/tools/makeobjops.awk ${.IMPSRC} -c ; \
${CC} -c ${CFLAGS} ${WERROR} ${PROF} ${.PREFIX}.c
NORMAL_FW= uudecode -o ${.TARGET} ${.ALLSRC}
NORMAL_FWO= ${LD} -b binary --no-warn-mismatch -d -warn-common -r \
-m ${LD_EMULATION} -o ${.TARGET} ${.ALLSRC:M*.fw}
# for ZSTD in the kernel (include zstd/lib/freebsd before other CFLAGS)
ZSTD_C= ${CC} -c -DZSTD_HEAPMODE=1 -I$S/contrib/zstd/lib/freebsd ${CFLAGS} -I$S/contrib/zstd/lib -I$S/contrib/zstd/lib/common ${WERROR} -Wno-inline -Wno-missing-prototypes ${PROF} -U__BMI__ ${.IMPSRC}
# https://github.com/facebook/zstd/commit/812e8f2a [zstd 1.4.1]
# "Note that [GCC] autovectorization still does not do a good job on the
# optimized version, so it's turned off via attribute and flag. I found
# that neither attribute nor command-line flag were entirely successful in
# turning off vectorization, which is why there were both."
.if ${COMPILER_TYPE} == "gcc"
ZSTD_DECOMPRESS_BLOCK_FLAGS= -fno-tree-vectorize
.endif
# Common for dtrace / zfs
CDDL_CFLAGS= -DFREEBSD_NAMECACHE -nostdinc -I$S/cddl/compat/opensolaris -I$S/cddl/contrib/opensolaris/uts/common -I$S -I$S/cddl/contrib/opensolaris/common ${CFLAGS} -Wno-unknown-pragmas -Wno-missing-prototypes -Wno-undef -Wno-strict-prototypes -Wno-cast-qual -Wno-parentheses -Wno-redundant-decls -Wno-missing-braces -Wno-uninitialized -Wno-unused -Wno-inline -Wno-switch -Wno-pointer-arith -Wno-unknown-pragmas
CDDL_CFLAGS+= -include $S/cddl/compat/opensolaris/sys/debug_compat.h
CDDL_C= ${CC} -c ${CDDL_CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
# Special flags for managing the compat compiles for ZFS
ZFS_CFLAGS= -DBUILDING_ZFS -I$S/cddl/contrib/opensolaris/uts/common/fs/zfs
ZFS_CFLAGS+= -I$S/cddl/contrib/opensolaris/uts/common/fs/zfs/lua
ZFS_CFLAGS+= -I$S/cddl/contrib/opensolaris/uts/common/zmod
ZFS_CFLAGS+= -I$S/cddl/contrib/opensolaris/common/lz4
ZFS_CFLAGS+= -I$S/cddl/contrib/opensolaris/common/zfs
ZFS_CFLAGS+= ${CDDL_CFLAGS}
ZFS_ASM_CFLAGS= -x assembler-with-cpp -DLOCORE ${ZFS_CFLAGS}
ZFS_C= ${CC} -c ${ZFS_CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
ZFS_S= ${CC} -c ${ZFS_ASM_CFLAGS} ${WERROR} ${.IMPSRC}
# Special flags for managing the compat compiles for DTrace
DTRACE_CFLAGS= -DBUILDING_DTRACE ${CDDL_CFLAGS} -I$S/cddl/dev/dtrace -I$S/cddl/dev/dtrace/${MACHINE_CPUARCH}
.if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
DTRACE_CFLAGS+= -I$S/cddl/contrib/opensolaris/uts/intel -I$S/cddl/dev/dtrace/x86
.endif
DTRACE_CFLAGS+= -I$S/cddl/contrib/opensolaris/common/util -I$S -DDIS_MEM -DSMP
DTRACE_ASM_CFLAGS= -x assembler-with-cpp -DLOCORE ${DTRACE_CFLAGS}
DTRACE_C= ${CC} -c ${DTRACE_CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
DTRACE_S= ${CC} -c ${DTRACE_ASM_CFLAGS} ${WERROR} ${.IMPSRC}
# Special flags for managing the compat compiles for DTrace/FBT
FBT_CFLAGS= -DBUILDING_DTRACE -nostdinc -I$S/cddl/dev/fbt/${MACHINE_CPUARCH} -I$S/cddl/dev/fbt -I$S/cddl/compat/opensolaris -I$S/cddl/contrib/opensolaris/uts/common -I$S ${CDDL_CFLAGS}
.if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
FBT_CFLAGS+= -I$S/cddl/dev/fbt/x86
.endif
FBT_C= ${CC} -c ${FBT_CFLAGS} ${WERROR} ${PROF} ${.IMPSRC}
.if ${MK_CTF} != "no"
NORMAL_CTFCONVERT= ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
.elif ${MAKE_VERSION} >= 5201111300
NORMAL_CTFCONVERT=
.else
NORMAL_CTFCONVERT= @:
.endif
# Linux Kernel Programming Interface C-flags
LINUXKPI_INCLUDES= -I$S/compat/linuxkpi/common/include
LINUXKPI_C= ${NORMAL_C} ${LINUXKPI_INCLUDES}
# Infiniband C flags. Correct include paths and omit errors that linux
# does not honor.
OFEDINCLUDES= -I$S/ofed/include -I$S/ofed/include/uapi ${LINUXKPI_INCLUDES}
OFEDNOERR= -Wno-cast-qual -Wno-pointer-arith
OFEDCFLAGS= ${CFLAGS:N-I*} -DCONFIG_INFINIBAND_USER_MEM \
${OFEDINCLUDES} ${CFLAGS:M-I*} ${OFEDNOERR}
OFED_C_NOIMP= ${CC} -c -o ${.TARGET} ${OFEDCFLAGS} ${WERROR} ${PROF}
OFED_C= ${OFED_C_NOIMP} ${.IMPSRC}
# mlxfw C flags.
MLXFW_C= ${OFED_C_NOIMP} \
-I${SRCTOP}/sys/contrib/xz-embedded/freebsd \
-I${SRCTOP}/sys/contrib/xz-embedded/linux/lib/xz \
${.IMPSRC}
GEN_CFILES= $S/$M/$M/genassym.c ${MFILES:T:S/.m$/.c/}
SYSTEM_CFILES= config.c env.c hints.c vnode_if.c
SYSTEM_DEP= Makefile ${SYSTEM_OBJS}
SYSTEM_OBJS= locore.o ${MDOBJS} ${OBJS}
SYSTEM_OBJS+= ${SYSTEM_CFILES:.c=.o}
SYSTEM_OBJS+= hack.pico
MD_ROOT_SIZE_CONFIGURED!= grep MD_ROOT_SIZE opt_md.h || true ; echo
.if ${MFS_IMAGE:Uno} != "no"
.if empty(MD_ROOT_SIZE_CONFIGURED)
SYSTEM_OBJS+= embedfs_${MFS_IMAGE:T:R}.o
.endif
.endif
SYSTEM_LD_BASECMD= \
${LD} -m ${LD_EMULATION} -Bdynamic -T ${LDSCRIPT} ${_LDFLAGS} \
--no-warn-mismatch --warn-common --export-dynamic \
--dynamic-linker /red/herring -X
SYSTEM_LD= @${SYSTEM_LD_BASECMD} -o ${.TARGET} ${SYSTEM_OBJS} vers.o
SYSTEM_LD_TAIL= @${OBJCOPY} --strip-symbol gcc2_compiled. ${.TARGET} ; \
${SIZE} ${.TARGET} ; chmod 755 ${.TARGET}
SYSTEM_DEP+= ${LDSCRIPT}
# Calculate path for .m files early, if needed.
.if !defined(NO_MODULES) && !defined(__MPATH) && !make(install) && \
(empty(.MAKEFLAGS:M-V) || defined(NO_SKIP_MPATH))
__MPATH!=find ${S:tA}/ -name \*_if.m
.endif
# MKMODULESENV is set here so that port makefiles can augment
# them.
MKMODULESENV+= MAKEOBJDIRPREFIX=${.OBJDIR}/modules KMODDIR=${KODIR}
MKMODULESENV+= MACHINE_CPUARCH=${MACHINE_CPUARCH}
MKMODULESENV+= MACHINE=${MACHINE} MACHINE_ARCH=${MACHINE_ARCH}
MKMODULESENV+= MODULES_EXTRA="${MODULES_EXTRA}" WITHOUT_MODULES="${WITHOUT_MODULES}"
MKMODULESENV+= ARCH_FLAGS="${ARCH_FLAGS}"
.if (${KERN_IDENT} == LINT)
MKMODULESENV+= ALL_MODULES=LINT
.endif
.if defined(MODULES_OVERRIDE)
MKMODULESENV+= MODULES_OVERRIDE="${MODULES_OVERRIDE}"
.endif
.if defined(DEBUG)
MKMODULESENV+= DEBUG_FLAGS="${DEBUG}"
.endif
.if !defined(NO_MODULES)
MKMODULESENV+= __MPATH="${__MPATH}"
.endif
# Architecture and output format arguments for objcopy to convert image to
# object file
.if ${MFS_IMAGE:Uno} != "no"
.if empty(MD_ROOT_SIZE_CONFIGURED)
.if !defined(EMBEDFS_FORMAT.${MACHINE_ARCH})
EMBEDFS_FORMAT.${MACHINE_ARCH}!= awk -F'"' '/OUTPUT_FORMAT/ {print $$2}' ${LDSCRIPT}
.if empty(EMBEDFS_FORMAT.${MACHINE_ARCH})
.undef EMBEDFS_FORMAT.${MACHINE_ARCH}
.endif
.endif
.if !defined(EMBEDFS_ARCH.${MACHINE_ARCH})
EMBEDFS_ARCH.${MACHINE_ARCH}!= sed -n '/OUTPUT_ARCH/s/.*(\(.*\)).*/\1/p' ${LDSCRIPT}
.if empty(EMBEDFS_ARCH.${MACHINE_ARCH})
.undef EMBEDFS_ARCH.${MACHINE_ARCH}
.endif
.endif
EMBEDFS_FORMAT.arm?= elf32-littlearm
EMBEDFS_FORMAT.armv6?= elf32-littlearm
EMBEDFS_FORMAT.armv7?= elf32-littlearm
EMBEDFS_FORMAT.aarch64?= elf64-littleaarch64
EMBEDFS_FORMAT.mips?= elf32-tradbigmips
EMBEDFS_FORMAT.mipsel?= elf32-tradlittlemips
EMBEDFS_FORMAT.mips64?= elf64-tradbigmips
EMBEDFS_FORMAT.mips64el?= elf64-tradlittlemips
EMBEDFS_FORMAT.riscv64?= elf64-littleriscv
.endif
.endif
# Detect kernel config options that force stack frames to be turned on.
DDB_ENABLED!= grep DDB opt_ddb.h || true ; echo
DTR_ENABLED!= grep KDTRACE_FRAME opt_kdtrace.h || true ; echo
HWPMC_ENABLED!= grep HWPMC opt_hwpmc_hooks.h || true ; echo
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