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| author | H.J. Lu <hjl.tools@gmail.com> | 2022-01-03 06:50:20 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2022-01-12 06:04:29 -0800 |
| commit | 6a91be866619c592762cd7e9b034a9f7ad27ef37 (patch) | |
| tree | 0e6f3c1cb84ecdee20857f3ba3f2087bf0425e06 /ld/ld.texi | |
| parent | e2cbf4df83fe57892a6aaedf737b84baa6321fa7 (diff) | |
| download | binutils-gdb-6a91be866619c592762cd7e9b034a9f7ad27ef37.tar.gz | |
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.
Diffstat (limited to 'ld/ld.texi')
| -rw-r--r-- | ld/ld.texi | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/ld/ld.texi b/ld/ld.texi index edcf1772855..1b42c6b562a 100644 --- a/ld/ld.texi +++ b/ld/ld.texi @@ -1430,6 +1430,15 @@ called. @item origin Specify that the object requires @samp{$ORIGIN} handling in paths. +@item pack-relative-relocs +@itemx nopack-relative-relocs +Generate compact relative relocation in position-independent executable +and shared library. It adds @code{DT_RELR}, @code{DT_RELRSZ} and +@code{DT_RELRENT} entries to the dynamic section. It is ignored when +building position-dependent executable and relocatable output. +@option{nopack-relative-relocs} is the default, which disables compact +relative relocation. Supported for i386 and x86-64. + @item relro @itemx norelro Create an ELF @code{PT_GNU_RELRO} segment header in the object. This |