backends: aarch64 can have _GLOBAL_OFFSET_TABLE_ point anywhere in .got.

When building with relro aarch64 splits .got in a writable and read-only
part. _GLOBAL_OFFSET_TABLE_ points to the first writable symbol, not the
start of .got.

https://bugzilla.redhat.com/show_bug.cgi?id=1201778

Signed-off-by: Mark Wielaard <mjw@redhat.com>

diff --git a/backends/ChangeLog b/backends/ChangeLog
index 818e8d5d9d32bf04488af4c9166501c310b5a1fb..0a47b75ec33aec1871cee26dee2391725df64f6f 100644 (file)
--- a/backends/ChangeLog
+++ b/backends/ChangeLog
@@ -1,3 +1,8 @@
+2015-03-23  Mark Wielaard  <mjw@redhat.com>
+
+       * aarch64_symbol.c (aarch64_check_special_symbol): Accept
+       _GLOBAL_OFFSET_TABLE_ pointing anywhere in .got.
+
 2015-03-09  Mark Wielaard  <mjw@redhat.com>
 
        * aarch64_reloc.def (COPY): Add DYN.

diff --git a/backends/aarch64_symbol.c b/backends/aarch64_symbol.c
index 3fdc9cf8bead297794fcfcff03435984cda76a59..76999e4b1c9749ff93c6a90fe7ad3e59db54aa50 100644 (file)
--- a/backends/aarch64_symbol.c
+++ b/backends/aarch64_symbol.c
@@ -1,5 +1,5 @@
 /* AArch64 specific symbolic name handling.
-   Copyright (C) 2013 Red Hat, Inc.
+   Copyright (C) 2013, 2015 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -56,8 +56,11 @@ aarch64_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type)
     }
 }
 
-/* If this is the _GLOBAL_OFFSET_TABLE_ symbol, then it should point to
-   .got[0] even if there is a .got.plt section.  */
+/* If this is the _GLOBAL_OFFSET_TABLE_ symbol, then it should point in
+   the .got even if there is a .got.plt section.
+   https://sourceware.org/ml/libc-ports/2013-06/msg00057.html
+   https://bugzilla.redhat.com/show_bug.cgi?id=1201778
+ */
 bool
 aarch64_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
                               const char *name, const GElf_Shdr *destshdr)
@@ -66,7 +69,8 @@ aarch64_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
       && strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
     {
       const char *sname = elf_strptr (elf, ehdr->e_shstrndx, destshdr->sh_name);
-      if (sname != NULL && strcmp (sname, ".got.plt") == 0)
+      if (sname != NULL
+         && (strcmp (sname, ".got") == 0 || strcmp (sname, ".got.plt") == 0))
        {
          Elf_Scn *scn = NULL;
          while ((scn = elf_nextscn (elf, scn)) != NULL)
@@ -77,7 +81,8 @@ aarch64_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
                {
                  sname = elf_strptr (elf, ehdr->e_shstrndx, shdr->sh_name);
                  if (sname != NULL && strcmp (sname, ".got") == 0)
-                   return sym->st_value == shdr->sh_addr;
+                   return (sym->st_value >= shdr->sh_addr
+                           && sym->st_value < shdr->sh_addr + shdr->sh_size);
                }
            }
        }