[PATCH v4 06/10] elf: Avoid RELATIVE relocation for _dl_sysinfo

[Szabolcs Nagy]

From: "H.J. Lu" <hjl.tools@gmail.com>

In static PIE, set the default _dl_sysinfo in _dl_aux_init, instead of
using the RELATIVE relocation to intialize it.

This is needed for fixing bug 27072 on x86.
---
 elf/dl-support.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/elf/dl-support.c b/elf/dl-support.c
index 384080dd80..5acd59290f 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -200,7 +200,12 @@ struct dl_scope_free_list *_dl_scope_free_list;
 
 #ifdef NEED_DL_SYSINFO
 /* Needed for improved syscall handling on at least x86/Linux.  */
-uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
+uintptr_t _dl_sysinfo
+/* NB: Avoid RELATIVE relocation in static PIE.  */
+# ifndef BUILD_PIE_DEFAULT
+  = DL_SYSINFO_DEFAULT
+# endif
+;
 #endif
 #ifdef NEED_DL_SYSINFO_DSO
 /* Address of the ELF headers in the vsyscall page.  */
@@ -238,6 +243,11 @@ _dl_aux_init (ElfW(auxv_t) *av)
   uid_t uid = 0;
   gid_t gid = 0;
 
+#if defined NEED_DL_SYSINFO && BUILD_PIE_DEFAULT
+  /* NB: Avoid RELATIVE relocation in static PIE.  */
+  GL(dl_sysinfo) = DL_SYSINFO_DEFAULT;
+#endif
+
   _dl_auxv = av;
   for (; av->a_type != AT_NULL; ++av)
     switch (av->a_type)
-- 
2.17.1