Preserve SSE registers in runtime relocations on x86-64.

SSE registers are used for passing parameters and must be preserved
in runtime relocations.  This is inside ld.so enforced through the
tests in tst-xmmymm.sh.  But the malloc routines used after startup
come from libc.so and can be arbitrarily complex.  It's overkill
to save the SSE registers all the time because of that.  These calls
are rare.  Instead we save them on demand.  The new infrastructure
put in place in this patch makes this possible and efficient.

2 files changed, 21 insertions, 0 deletions

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 1d68d67a35..56724c9b4d 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -380,6 +380,10 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
 		  if (size * 3 <= tab->n_elements * 4)
 		    {
 		      /* Expand the table.  */
+#ifdef RTLD_CHECK_FOREIGN_CALL
+		      /* This must not happen during runtime relocations.  */
+		      assert (!RTLD_CHECK_FOREIGN_CALL);
+#endif
 		      size_t newsize = _dl_higher_prime_number (size + 1);
 		      struct unique_sym *newentries
 			= calloc (sizeof (struct unique_sym), newsize);
@@ -405,6 +409,11 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash,
 		}
 	      else
 		{
+#ifdef RTLD_CHECK_FOREIGN_CALL
+		  /* This must not happen during runtime relocations.  */
+		  assert (!RTLD_CHECK_FOREIGN_CALL);
+#endif
+
 #define INITIAL_NUNIQUE_SYM_TABLE 31
 		  size = INITIAL_NUNIQUE_SYM_TABLE;
 		  entries = calloc (sizeof (struct unique_sym), size);
@@ -600,6 +609,10 @@ add_dependency (struct link_map *undef_map, struct link_map *map, int flags)
 	  unsigned int max
 	    = undef_map->l_reldepsmax ? undef_map->l_reldepsmax * 2 : 10;
 
+#ifdef RTLD_PREPARE_FOREIGN_CALL
+	  RTLD_PREPARE_FOREIGN_CALL;
+#endif
+
 	  newp = malloc (sizeof (*newp) + max * sizeof (struct link_map *));
 	  if (newp == NULL)
 	    {
diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c
index 0eb7d4e3b9..a52120d121 100644
--- a/elf/dl-runtime.c
+++ b/elf/dl-runtime.c
@@ -111,6 +111,10 @@ _dl_fixup (
 	  flags |= DL_LOOKUP_GSCOPE_LOCK;
 	}
 
+#ifdef RTLD_ENABLE_FOREIGN_CALL
+      RTLD_ENABLE_FOREIGN_CALL;
+#endif
+
       result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, l->l_scope,
 				    version, ELF_RTYPE_CLASS_PLT, flags, NULL);
 
@@ -118,6 +122,10 @@ _dl_fixup (
       if (!RTLD_SINGLE_THREAD_P)
 	THREAD_GSCOPE_RESET_FLAG ();
 
+#ifdef RTLD_FINALIZE_FOREIGN_CALL
+      RTLD_FINALIZE_FOREIGN_CALL;
+#endif
+
       /* Currently result contains the base load address (or link map)
 	 of the object that defines sym.  Now add in the symbol
 	 offset.  */