Re: [PATCH v11 0/7] Support DT_RELR relative relocation format

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 22/04/2022 16:01, H.J. Lu wrote:
> Changes in v11:
> 
> 1. Replace 
> 
> if (!(map)->l_info[DT_RELR])
> 
> with
> 
> if ((map)->l_info[DT_RELR] == NULL)
> 
> 2. Add a space to --disable-default-dt-relr option.
> 3. Compile extra DT_RELR tests with $(no-stack-protector).
> 4. Add DT_RELR related macros to scripts/glibcelf.py.
> 
> Changes in v10:
> 
> 1. Don't check GLIBC_PRIVATE definition for DT_RELR in ld.so since ld.so
> has no DT_NEEDED entry.
> 
> Changes in v9:
> 
> 1. A DT_RELR shared library without DT_NEEDED works.
> 2. A DT_RELR shared library without DT_VERNEED works.
> 3. A DT_RELR shared library without libc.so on DT_NEEDED works.
> 
> Changes in v8:
> 
> 1. Remove the out-of-date comments in _dl_check_map_versions.
> 2. Change "long" to "long int".
> 3. Update the DT_RELR NEWS entry.
> 
> Changes in v7:
> 
> 1. Add GLIBC_ABI_DT_RELR support before adding DT_RELR support.
> 2. Update the DT_RELR NEWS entry.
> 3. Misc fixes.
> 
> Changes in v6:
> 
> 1. Move ELF_DYNAMIC_DO_RELR before ELF_DYNAMIC_DO_REL.
> 
> Changes in v5:
> 
> 1. Update NEWS entry with the linker option, -z pack-relative-relocs.
> 2. Remove elf/libc-abi-version.exp and use $(READELF) to check
> GLIBC_ABI_DT_RELR.
> 
> Changes in v4:
> 
> 1. Always enable GLIBC_ABI_DT_RELR check.
> 2. Use $(OBJDUMP) instead of $(NM) for GLIBC_ABI_DT_RELR check. 
> 
> Changes in v3:
> 
> 1. Don't define SUPPORT_DT_RELR.
> 2. Enable DT_RELR in glibc shared libraries and position independent
> executables (PIE) automatically if linker supports -z pack-relative-relocs.
> 
> Changes in v2:
> 
> 1. Enable DT_RELR for all targets.
> 2. Issue an error if there is a DT_RELR entry without GLIBC_ABI_DT_RELR
> dependency nor GLIBC_PRIVATE definition.
> 
> Fangrui Song (1):
>   elf: Support DT_RELR relative relocation format [BZ #27924]

The patchset looks ok, the only piece that I think it does not add much and
it would be better to be dropped is the '--disable-default-dt-relr' support.

As we discussed in the weekly patchset call, having less configure switches
is desirable and this specific option will most likely not be used.