binutils-gdb/ld/emulparams/elf_i386.sh
H.J. Lu 6a91be8666 ld: Initial DT_RELR support
Add a -z pack-relative-relocs option to enable DT_RELR and create a
relr.dyn section for DT_RELR.  DT_RELR is implemented with the linker
relaxation infrastructure, but it doesn't require the --relax option
enabled.  -z pack-relative-relocs implies -z combreloc.  -z nocombreloc
implies -z nopack-relative-relocs.

-z pack-relative-relocs is chosen over the similar option in lld,
--pack-dyn-relocs=relr, to implement a glibc binary lockout mechanism
with a special glibc version symbol, to avoid random crashes of DT_RELR
binaries with the existing glibc binaries.

bfd/

	* elf-bfd.h (elf_link_hash_table): Add srelrdyn.
	* elflink.c (_bfd_elf_link_create_dynamic_sections): Create a
	.relr.dyn section for DT_RELR.

include/

	* bfdlink.h (bfd_link_info): Add enable_dt_relr.

ld/

	* News: Mention -z pack-relative-relocs and
	-z nopack-relative-relocs.
	* ld.texi: Document -z pack-relative-relocs and
	-z nopack-relative-relocs.
	* ldelf.c (ldelf_after_parse): Disable DT_RELR if not building
	PIE nor shared library.  Add 3 spare dynamic tags for DT_RELR,
	DT_RELRSZ and DT_RELRENT.
	* ldlang.c (lang_relax_sections): Also enable relaxation if
	DT_RELR is enabled.
	* emulparams/elf32_x86_64.sh: Source dt-relr.sh.
	* emulparams/elf_i386.sh: Likewise.
	* emulparams/elf_x86_64.sh: Likewise.
	* emulparams/dt-relr.sh: New file.
	* scripttempl/elf.sc: Support .relr.dyn.
2022-01-12 06:04:29 -08:00

43 lines
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source_sh ${srcdir}/emulparams/plt_unwind.sh
source_sh ${srcdir}/emulparams/extern_protected_data.sh
source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
source_sh ${srcdir}/emulparams/call_nop.sh
source_sh ${srcdir}/emulparams/cet.sh
source_sh ${srcdir}/emulparams/x86-report-relative.sh
source_sh ${srcdir}/emulparams/x86-64-level.sh
source_sh ${srcdir}/emulparams/static.sh
source_sh ${srcdir}/emulparams/dt-relr.sh
SCRIPT_NAME=elf
OUTPUT_FORMAT="elf32-i386"
NO_RELA_RELOCS=yes
TEXT_START_ADDR=0x08048000
MAXPAGESIZE="CONSTANT (MAXPAGESIZE)"
COMMONPAGESIZE="CONSTANT (COMMONPAGESIZE)"
ARCH=i386
MACHINE=
TEMPLATE_NAME=elf
EXTRA_EM_FILE="elf-x86"
GENERATE_SHLIB_SCRIPT=yes
GENERATE_PIE_SCRIPT=yes
NO_SMALL_DATA=yes
SEPARATE_GOTPLT="SIZEOF (.got.plt) >= 12 ? 12 : 0"
IREL_IN_PLT=
# These sections are placed right after .plt section.
OTHER_PLT_SECTIONS="
.plt.got ${RELOCATING-0} : { *(.plt.got) }
.plt.sec ${RELOCATING-0} : { *(.plt.sec) }
"
# Linux modify the default library search path to first include
# a 32-bit specific directory.
case "$target" in
x86_64*-linux* | i[3-7]86*-linux*)
case "$EMULATION_NAME" in
*i386*)
LIBPATH_SUFFIX=32
LIBPATH_SUFFIX_SKIP=64
;;
esac
;;
esac