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authorStefan Liebler <stli@linux.vnet.ibm.com>2016-07-06 15:22:35 +0200
committerStefan Liebler <stli@linux.vnet.ibm.com>2016-07-06 15:22:35 +0200
commitdd8f8da99d7a0d93f517a07e150d8abd47386d7c (patch)
tree6ef2b2ed5ea18773028cbc06939f5dad6aab070d /sysdeps
parentb95a6ebb931a8df8604ef3b52eea8f324bc08e92 (diff)
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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 &current-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 &current-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.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/s390/linkmap.h4
-rw-r--r--sysdeps/s390/s390-32/dl-machine.h6
-rw-r--r--sysdeps/s390/s390-64/dl-machine.h6
3 files changed, 6 insertions, 10 deletions
diff --git a/sysdeps/s390/linkmap.h b/sysdeps/s390/linkmap.h
index fc1fba3..283615b 100644
--- a/sysdeps/s390/linkmap.h
+++ b/sysdeps/s390/linkmap.h
@@ -2,12 +2,12 @@
struct link_map_machine
{
Elf64_Addr plt; /* Address of .plt + 0x2e */
- Elf64_Addr gotplt; /* Address of .got + 0x18 */
+ const Elf64_Rela *jmprel; /* Address of first JMP_SLOT reloc */
};
#else
struct link_map_machine
{
Elf32_Addr plt; /* Address of .plt + 0x2c */
- Elf32_Addr gotplt; /* Address of .got + 0x0c */
+ const Elf32_Rela *jmprel; /* Address of first JMP_SLOT reloc */
};
#endif
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))
{
diff --git a/sysdeps/s390/s390-64/dl-machine.h b/sysdeps/s390/s390-64/dl-machine.h
index 9ee7c92..6e5ee1e 100644
--- a/sysdeps/s390/s390-64/dl-machine.h
+++ b/sysdeps/s390/s390-64/dl-machine.h
@@ -98,7 +98,7 @@ 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 = (Elf64_Addr) &got[3];
+ l->l_mach.jmprel = (const Elf64_Rela *) D_PTR (l, l_info[DT_JMPREL]);
}
got[1] = (Elf64_Addr) l; /* Identify this shared object. */
@@ -460,9 +460,7 @@ 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
- + (((Elf64_Addr) reloc_addr) - map->l_mach.gotplt) * 4;
+ *reloc_addr = map->l_mach.plt + (reloc - map->l_mach.jmprel) * 32;
}
else if (__glibc_likely (r_type == R_390_IRELATIVE))
{