From dd8f8da99d7a0d93f517a07e150d8abd47386d7c Mon Sep 17 00:00:00 2001 From: Stefan Liebler Date: Wed, 6 Jul 2016 15:22:35 +0200 Subject: S390: Use DT_JUMPREL in prelink undo code. On s390, the current prelink undo code in elf_machine_lazy_rel() has the requirement, that the plt stubs use the first got slots after the 3 reserved ones. In case of undoing prelink, the plt got slots are reset to the correct addresses whithin the corresponding plt-stub. Therefore the address is calculated by the address of the first plt-stub-address which was written by prelink (see l->l_mach.plt) to got[1] and index of current relocation multiplied with 32 (=size of one plt slot). The index was calculated with ¤t-got-slot - &got[3]. This patch removes the requirement, that the plt-got-slots are starting at got[3]. The index is now calculated with ¤t-reloc - &reloc[0]. The first struct Elf64_Rela is stored at DT_JMPREL. This patch is needed to prepare for partial relro support. Ulrich Weigand suggested this approach to use DT_JMPREL - Thanks. ChangeLog: * sysdeps/s390/linkmap.h (struct link_map_machine): Remove member gotplt and add member jmprel. * sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup): Setup member jmprel with DT_JMPREL instead of gotplt with &got[3]. (elf_machine_lazy_rel): Calculate address with reloc and jmprel. * sysdeps/s390/s390-64/dl-machine.h: Likewise. --- sysdeps/s390/s390-32/dl-machine.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'sysdeps/s390/s390-32/dl-machine.h') diff --git a/sysdeps/s390/s390-32/dl-machine.h b/sysdeps/s390/s390-32/dl-machine.h index ec0ae4a..0a58897 100644 --- a/sysdeps/s390/s390-32/dl-machine.h +++ b/sysdeps/s390/s390-32/dl-machine.h @@ -109,7 +109,7 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) if (got[1]) { l->l_mach.plt = got[1] + l->l_addr; - l->l_mach.gotplt = (Elf32_Addr) &got[3]; + l->l_mach.jmprel = (const Elf32_Rela *) D_PTR (l, l_info[DT_JMPREL]); } got[1] = (Elf32_Addr) l; /* Identify this shared object. */ @@ -506,9 +506,7 @@ elf_machine_lazy_rel (struct link_map *map, if (__builtin_expect (map->l_mach.plt, 0) == 0) *reloc_addr += l_addr; else - *reloc_addr = - map->l_mach.plt - + (((Elf32_Addr) reloc_addr) - map->l_mach.gotplt) * 8; + *reloc_addr = map->l_mach.plt + (reloc - map->l_mach.jmprel) * 32; } else if (__glibc_likely (r_type == R_390_IRELATIVE)) { -- cgit v1.1