freebsd-skq/stand/i386/Makefile.inc
Dimitry Andric a2037dba7e Link stand/i386 components using a linker script
LLD 10.0.0 changed the behavior of the -Ttext option, so that using
-Ttext=0x0 now causes linking of the loaders to fail with:

ld: error: output file too large: 18446744073707016908 bytes

I reported this in https://bugs.llvm.org/show_bug.cgi?id=44715, and
initially reverted the upstream change in r357259 to work around it.

However, after some discussion with Fangrui Song in the upstream ticket,
I think we can classify this as an unfortunate interaction between using
-Ttext=0 in combination with --no-rosegment.  (We added the latter
in r332090, because btxld does not correctly handle input with more
than 2 PT_LOAD segments.)

Fangrui suggested to use a linker script instead, and Warner was already
attempting this in r305353, but had to revert it due to "crypto-using
boot problems" (not sure what those were :).

This review updates the stand/i386/boot.ldscript to handle more
sections, inserts some symbols like _edata and such that we use in
libsa, and also discards any .interp section.

It uses ORG which is defined on the linker command line using
--defsym ORG=value to set the start of all the sections.

Reviewed by:	imp
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D23952
2020-03-04 21:01:22 +00:00

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944 B
Makefile

# Common defines for all of stand/i386/
#
# $FreeBSD$
.include "bsd.linker.mk"
LOADER_ADDRESS?=0x200000
LDFLAGS+= -nostdlib
LDFLAGS.lld+= -Wl,--no-rosegment
MK_PIE:= no
# BTX components
BTXDIR= ${BOOTOBJ}/i386/btx
BTXLDR= ${BTXDIR}/btxldr/btxldr
BTXKERN= ${BTXDIR}/btx/btx
BTXCRT= ${BTXDIR}/lib/crt0.o
BTXSRC= ${BOOTSRC}/i386/btx
BTXLIB= ${BTXSRC}/lib
CFLAGS+= -I${BTXLIB}
# compact binary with no padding between text, data, bss
LDSCRIPT= ${BOOTSRC}/i386/boot.ldscript
LDFLAGS_ORG= -Wl,--defsym,ORG=${ORG},-T,${LDSCRIPT}
LDFLAGS_BIN= -e start ${LDFLAGS_ORG} -Wl,-N,-S,--oformat,binary
.if ${LINKER_FEATURES:Mbuild-id} != ""
LDFLAGS_BIN+= -Wl,--build-id=none
.endif
LD_FLAGS_BIN= -static -N --gc-sections
.if ${MACHINE_CPUARCH} == "amd64"
DO32=1
.endif
.if defined(LOADER_FIREWIRE_SUPPORT)
MK_LOADER_FIREWIRE=yes
.warning "LOADER_FIREWIRE_SUPPORT deprecated, please move to WITH_LOADER_FIREWIRE"
.endif
.include "../Makefile.inc"