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[binutils-gdb] S/390: Disable relocation sort against code sections.
- From: Andreas Krebbel <krebbel at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 14 Mar 2015 10:46:38 -0000
- Subject: [binutils-gdb] S/390: Disable relocation sort against code sections.
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b9005ba76ee501a809f2657b04bb2f2590829fa3
commit b9005ba76ee501a809f2657b04bb2f2590829fa3
Author: Andreas Krebbel <krebbel@linux.vnet.ibm.com>
Date: Sat Mar 14 11:45:05 2015 +0100
S/390: Disable relocation sort against code sections.
When downgrading from GD to IE model we rewrite the call to
__tls_get_offset to a 64 bit load instruction. This relies on the fact
that the additional relocation for the call target has already been
executed when doing the rewrite.
f1018: e3 20 d0 00 00 04 lg %r2,0(%r13)
f101e: c0 e5 00 00 00 00 brasl %r14,f101e <__res_init+0x1e>
f101e: R_390_TLS_GDCALL __libc_resp
f1020: R_390_PLT32DBL __tls_get_offset+0x2
0000000f1020 39f6c00000014 R_390_PLT32DBL 0000000000000000 __tls_get_offset + 2
0000000f101e 3afb700000026 R_390_TLS_GDCALL 0000000000000008 __libc_resp + 0
Due to the reloc sorting the order changed an the PLT32DBL reloc is
executed after the rewrite and overwrites part of the load instruction
with garbage.
bfd/
2015-03-14 Andreas Krebbel <krebbel@linux.vnet.ibm.com>
* elf-s390-common.c (elf_s390_elf_sort_relocs_p): Don't sort
relocs against code sections.
* elf32-s390.c: Define elf_backend_sort_relocs_p.
* elf64-s390.c: Likewise.
Diff:
---
bfd/ChangeLog | 7 +++++++
bfd/elf-s390-common.c | 12 ++++++++++++
bfd/elf32-s390.c | 1 +
bfd/elf64-s390.c | 1 +
4 files changed, 21 insertions(+)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 68b8549..06f13b2 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2015-03-14 Andreas Krebbel <krebbel@linux.vnet.ibm.com>
+
+ * elf-s390-common.c (elf_s390_elf_sort_relocs_p): Don't sort
+ relocs against code sections.
+ * elf32-s390.c: Define elf_backend_sort_relocs_p.
+ * elf64-s390.c: Likewise.
+
2015-03-11 Alan Modra <amodra@gmail.com>
* elf32-ppc.c (ppc_elf_get_synthetic_symtab): Examine stubs in
diff --git a/bfd/elf-s390-common.c b/bfd/elf-s390-common.c
index 6fd1027..462da16 100644
--- a/bfd/elf-s390-common.c
+++ b/bfd/elf-s390-common.c
@@ -242,3 +242,15 @@ elf_s390_add_symbol_hook (bfd *abfd,
return TRUE;
}
+
+/* Whether to sort relocs output by ld -r or ld --emit-relocs, by
+ r_offset. Don't do so for code sections. We want to keep ordering
+ of GDCALL / PLT32DBL for TLS optimizations as is. On the other
+ hand, elf-eh-frame.c processing requires .eh_frame relocs to be
+ sorted. */
+
+static bfd_boolean
+elf_s390_elf_sort_relocs_p (asection *sec)
+{
+ return (sec->flags & SEC_CODE) == 0;
+}
diff --git a/bfd/elf32-s390.c b/bfd/elf32-s390.c
index f5403e2..0127eab 100644
--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -4028,6 +4028,7 @@ elf32_s390_merge_private_bfd_data (bfd *ibfd, bfd *obfd)
#define elf_backend_grok_prstatus elf_s390_grok_prstatus
#define elf_backend_plt_sym_val elf_s390_plt_sym_val
#define elf_backend_add_symbol_hook elf_s390_add_symbol_hook
+#define elf_backend_sort_relocs_p elf_s390_elf_sort_relocs_p
#define bfd_elf32_mkobject elf_s390_mkobject
#define elf_backend_object_p elf_s390_object_p
diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c
index e002f06..f06b58a 100644
--- a/bfd/elf64-s390.c
+++ b/bfd/elf64-s390.c
@@ -3840,6 +3840,7 @@ const struct elf_size_info s390_elf64_size_info =
#define elf_backend_init_index_section _bfd_elf_init_1_index_section
#define elf_backend_plt_sym_val elf_s390_plt_sym_val
#define elf_backend_add_symbol_hook elf_s390_add_symbol_hook
+#define elf_backend_sort_relocs_p elf_s390_elf_sort_relocs_p
#define bfd_elf64_mkobject elf_s390_mkobject
#define elf_backend_object_p elf_s390_object_p