Updated to fedora-glibc-20080515T0735 cvs/fedora-glibc-2_8_90-1

1 files changed, 269 insertions, 0 deletions

diff --git a/sysdeps/i386/tlsdesc.c b/sysdeps/i386/tlsdesc.c
new file mode 100644
index 0000000000..28287d574b
--- /dev/null
+++ b/sysdeps/i386/tlsdesc.c
@@ -0,0 +1,269 @@
+/* Manage TLS descriptors.  i386 version.
+   Copyright (C) 2005, 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <link.h>
+#include <ldsodefs.h>
+#include <elf/dynamic-link.h>
+#include <tls.h>
+#include <dl-tlsdesc.h>
+#include <tlsdeschtab.h>
+
+/* The following 4 functions take an entry_check_offset argument.
+   It's computed by the caller as an offset between its entry point
+   and the call site, such that by adding the built-in return address
+   that is implicitly passed to the function with this offset, we can
+   easily obtain the caller's entry point to compare with the entry
+   point given in the TLS descriptor.  If it's changed, we want to
+   return immediately.  */
+
+/* This function is used to lazily resolve TLS_DESC REL relocations
+   that reference the *ABS* segment in their own link maps.  The
+   argument is the addend originally stored there.  */
+
+void
+__attribute__ ((regparm (3))) attribute_hidden
+_dl_tlsdesc_resolve_abs_plus_addend_fixup (struct tlsdesc volatile *td,
+					   struct link_map *l,
+					   ptrdiff_t entry_check_offset)
+{
+  ptrdiff_t addend = (ptrdiff_t) td->arg;
+
+  if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0)
+					  - entry_check_offset))
+    return;
+
+#ifndef SHARED
+  CHECK_STATIC_TLS (l, l);
+#else
+  if (!TRY_STATIC_TLS (l, l))
+    {
+      td->arg = _dl_make_tlsdesc_dynamic (l, addend);
+      td->entry = _dl_tlsdesc_dynamic;
+    }
+  else
+#endif
+    {
+      td->arg = (void*) (addend - l->l_tls_offset);
+      td->entry = _dl_tlsdesc_return;
+    }
+
+  _dl_tlsdesc_wake_up_held_fixups ();
+}
+
+/* This function is used to lazily resolve TLS_DESC REL relocations
+   that originally had zero addends.  The argument location, that
+   originally held the addend, is used to hold a pointer to the
+   relocation, but it has to be restored before we call the function
+   that applies relocations.  */
+
+void
+__attribute__ ((regparm (3))) attribute_hidden
+_dl_tlsdesc_resolve_rel_fixup (struct tlsdesc volatile *td,
+			       struct link_map *l,
+			       ptrdiff_t entry_check_offset)
+{
+  const ElfW(Rel) *reloc = td->arg;
+
+  if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0)
+					  - entry_check_offset))
+    return;
+
+  /* The code below was borrowed from _dl_fixup(),
+     except for checking for STB_LOCAL.  */
+  const ElfW(Sym) *const symtab
+    = (const void *) D_PTR (l, l_info[DT_SYMTAB]);
+  const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
+  const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)];
+  lookup_t result;
+
+   /* Look up the target symbol.  If the normal lookup rules are not
+      used don't look in the global scope.  */
+  if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL
+      && __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)
+    {
+      const struct r_found_version *version = NULL;
+
+      if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
+	{
+	  const ElfW(Half) *vernum =
+	    (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);
+	  ElfW(Half) ndx = vernum[ELFW(R_SYM) (reloc->r_info)] & 0x7fff;
+	  version = &l->l_versions[ndx];
+	  if (version->hash == 0)
+	    version = NULL;
+	}
+
+      result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym,
+				    l->l_scope, version, ELF_RTYPE_CLASS_PLT,
+				    DL_LOOKUP_ADD_DEPENDENCY, NULL);
+    }
+  else
+    {
+      /* We already found the symbol.  The module (and therefore its load
+	 address) is also known.  */
+      result = l;
+    }
+
+  if (!sym)
+    {
+      td->arg = 0;
+      td->entry = _dl_tlsdesc_undefweak;
+    }
+  else
+    {
+#  ifndef SHARED
+      CHECK_STATIC_TLS (l, result);
+#  else
+      if (!TRY_STATIC_TLS (l, result))
+	{
+	  td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value);
+	  td->entry = _dl_tlsdesc_dynamic;
+	}
+      else
+#  endif
+	{
+	  td->arg = (void*)(sym->st_value - result->l_tls_offset);
+	  td->entry = _dl_tlsdesc_return;
+	}
+    }
+
+  _dl_tlsdesc_wake_up_held_fixups ();
+}
+
+/* This function is used to lazily resolve TLS_DESC RELA relocations.
+   The argument location is used to hold a pointer to the relocation.  */
+
+void
+__attribute__ ((regparm (3))) attribute_hidden
+_dl_tlsdesc_resolve_rela_fixup (struct tlsdesc volatile *td,
+				struct link_map *l,
+				ptrdiff_t entry_check_offset)
+{
+  const ElfW(Rela) *reloc = td->arg;
+
+  if (_dl_tlsdesc_resolve_early_return_p (td, __builtin_return_address (0)
+					  - entry_check_offset))
+    return;
+
+  /* The code below was borrowed from _dl_fixup(),
+     except for checking for STB_LOCAL.  */
+  const ElfW(Sym) *const symtab
+    = (const void *) D_PTR (l, l_info[DT_SYMTAB]);
+  const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
+  const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)];
+  lookup_t result;
+
+   /* Look up the target symbol.  If the normal lookup rules are not
+      used don't look in the global scope.  */
+  if (ELFW(ST_BIND) (sym->st_info) != STB_LOCAL
+      && __builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)
+    {
+      const struct r_found_version *version = NULL;
+
+      if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
+	{
+	  const ElfW(Half) *vernum =
+	    (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);
+	  ElfW(Half) ndx = vernum[ELFW(R_SYM) (reloc->r_info)] & 0x7fff;
+	  version = &l->l_versions[ndx];
+	  if (version->hash == 0)
+	    version = NULL;
+	}
+
+      result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym,
+				    l->l_scope, version, ELF_RTYPE_CLASS_PLT,
+				    DL_LOOKUP_ADD_DEPENDENCY, NULL);
+    }
+  else
+    {
+      /* We already found the symbol.  The module (and therefore its load
+	 address) is also known.  */
+      result = l;
+    }
+
+  if (!sym)
+    {
+      td->arg = (void*) reloc->r_addend;
+      td->entry = _dl_tlsdesc_undefweak;
+    }
+  else
+    {
+#  ifndef SHARED
+      CHECK_STATIC_TLS (l, result);
+#  else
+      if (!TRY_STATIC_TLS (l, result))
+	{
+	  td->arg = _dl_make_tlsdesc_dynamic (result, sym->st_value
+					      + reloc->r_addend);
+	  td->entry = _dl_tlsdesc_dynamic;
+	}
+      else
+#  endif
+	{
+	  td->arg = (void*) (sym->st_value - result->l_tls_offset
+			     + reloc->r_addend);
+	  td->entry = _dl_tlsdesc_return;
+	}
+    }
+
+  _dl_tlsdesc_wake_up_held_fixups ();
+}
+
+/* This function is used to avoid busy waiting for other threads to
+   complete the lazy relocation.  Once another thread wins the race to
+   relocate a TLS descriptor, it sets the descriptor up such that this
+   function is called to wait until the resolver releases the
+   lock.  */
+
+void
+__attribute__ ((regparm (3))) attribute_hidden
+_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td,
+				struct link_map *l __attribute__((__unused__)),
+				ptrdiff_t entry_check_offset)
+{
+  /* Maybe we're lucky and can return early.  */
+  if (__builtin_return_address (0) - entry_check_offset != td->entry)
+    return;
+
+  /* Locking here will stop execution until the running resolver runs
+     _dl_tlsdesc_wake_up_held_fixups(), releasing the lock.
+
+     FIXME: We'd be better off waiting on a condition variable, such
+     that we didn't have to hold the lock throughout the relocation
+     processing.  */
+  __rtld_lock_lock_recursive (GL(dl_load_lock));
+  __rtld_lock_unlock_recursive (GL(dl_load_lock));
+}
+
+
+/* Unmap the dynamic object, but also release its TLS descriptor table
+   if there is one.  */
+
+void
+internal_function
+_dl_unmap (struct link_map *map)
+{
+  __munmap ((void *) (map)->l_map_start,
+	    (map)->l_map_end - (map)->l_map_start);
+
+#if SHARED
+  if (map->l_mach.tlsdesc_table)
+    htab_delete (map->l_mach.tlsdesc_table);
+#endif
+}