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| author | Fangrui Song <maskray@google.com> | 2022-03-08 17:17:05 -0800 |
|---|---|---|
| committer | Fangrui Song <maskray@google.com> | 2022-03-08 17:17:05 -0800 |
| commit | 1c6cc29baf9a4c7129ab2e94b0d4022bfa4f3299 (patch) | |
| tree | 008312335cd84ecfcc73c38b72ba836d06e3ca2f /elf/get-dynamic-info.h | |
| parent | edc696a73a7cb07b1aa68792a845a98d036ee7eb (diff) | |
| download | glibc-1c6cc29baf9a4c7129ab2e94b0d4022bfa4f3299.tar.gz glibc-1c6cc29baf9a4c7129ab2e94b0d4022bfa4f3299.tar.xz glibc-1c6cc29baf9a4c7129ab2e94b0d4022bfa4f3299.zip | |
elf: Support DT_RELR relative relocation format [BZ #27924] maskray/relr
PIE and shared objects usually have many relative relocations. In
2017/2018, SHT_RELR/DT_RELR was proposed on
https://groups.google.com/g/generic-abi/c/bX460iggiKg/m/GxjM0L-PBAAJ
("Proposal for a new section type SHT_RELR") and is a pre-standard. RELR
usually takes 3% or smaller space than R_*_RELATIVE relocations. The
virtual memory size of a mostly statically linked PIE is typically 5~10%
smaller.
This patch adds ELF_DYNAMIC_DO_RELR to ELF_DYNAMIC_RELOCATE.
ELF_DYNAMIC_DO_RELR is ordered before ELF_DYNAMIC_DO_REL[A] so that ifunc
resolvers that require relocated got entries have them relocated. This is
needed for ppc64 according to Alan Modra.
Diffstat (limited to 'elf/get-dynamic-info.h')
| -rw-r--r-- | elf/get-dynamic-info.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h index 6c2ccd6db4..6c2a3a12b1 100644 --- a/elf/get-dynamic-info.h +++ b/elf/get-dynamic-info.h @@ -89,6 +89,7 @@ elf_get_dynamic_info (struct link_map *l, bool bootstrap, # if ! ELF_MACHINE_NO_REL ADJUST_DYN_INFO (DT_REL); # endif + ADJUST_DYN_INFO (DT_RELR); ADJUST_DYN_INFO (DT_JMPREL); ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM)); ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH)); @@ -113,6 +114,8 @@ elf_get_dynamic_info (struct link_map *l, bool bootstrap, if (info[DT_REL] != NULL) assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel))); #endif + if (info[DT_RELR] != NULL) + assert (info[DT_RELRENT]->d_un.d_val == sizeof (ElfW(Relr))); if (bootstrap || static_pie_bootstrap) { assert (info[DT_RUNPATH] == NULL); |