Introduce TLS descriptors for i386 and x86_64.

	* include/inline-hashtab.h: New file, copied from 2005's
	libiberty, with fix for memory leak imported afterwards by
	Glauber de Oliveira Costa.
	* elf/tlsdeschtab.h: New file.
	* elf/dl-reloc.c (_dl_try_allocate_static_tls): Extract from...
	(_dl_allocate_static_tls): ... here.  Rearrange failure path.
	(CHECK_STATIC_TLS): Move to...
	* elf/dynamic-link.h: ... this file.
	(TRY_STATIC_TLS): New macro.
	* elf/dl-conflict.c (CHECK_STATIC_TLS, TRY_STATIC_TLS): Override.
	* elf/elf.h (R_386_TLS_GOTDESC, R_386_TLS_DESC_CALL,
	R_386_TLS_DESC): Define.
	(R_X86_64_PC64, R_X86_GOTOFF64, R_X86_64_GOTPC32): Merge from
	binutils.
	(R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL,
	R_X86_64_TLSDESC): Define.
	(R_386_NUM, R_X86_64_NUM): Adjust.
	* sysdeps/i386/Makefile (sysdep-dl-routines, sysdep_routines,
	systep-rtld-routines): Add tlsdesc and dl-tlsdesc for elf subdir.
	(gen-as-const-headers): Add tlsdesc.sym to csu subdir.
	* sysdeps/i386/dl-lookupcfg.h: New file.  Introduce _dl_unmap to
	release tlsdesc_table.
	* sysdeps/i386/dl-machine.h: Include dl-tlsdesc.h.
	(elf_machine_type_class): Mark R_386_TLS_DESC as PLT class.
	(elf_machine_rel): Handle R_386_TLS_DESC.
	(elf_machine_rela): Likewise.
	(elf_machine_lazy_rel): Likewise.
	(elf_machine_lazy_rela): Likewise.
	* sysdeps/i386/dl-tls.h (struct dl_tls_index): Name it.
	* sysdeps/i386/dl-tlsdesc.S: New file.
	* sysdeps/i386/dl-tlsdesc.h: New file.
	* sysdeps/i386/tlsdesc.c: New file.
	* sysdeps/i386/tlsdesc.sym: New file.
	* sysdeps/i386/bits/linkmap.h (struct link_map_machine): Add
	tlsdesc_table.
	* sysdeps/x86_64/Makefile (sysdep-dl-routines, sysdep_routines,
	systep-rtld-routines): Add tlsdesc and dl-tlsdesc for elf subdir.
	(gen-as-const-headers): Add tlsdesc.sym to csu subdir.
	* sysdeps/x86_64/dl-lookupcfg.h: New file.  Introduce _dl_unmap to
	release tlsdesc_table.
	* sysdeps/x86_64/dl-machine.h: Include dl-tlsdesc.h.
	(elf_machine_runtime_setup): Set up lazy TLSDESC GOT entry.
	(elf_machine_type_class): Mark R_X86_64_TLSDESC as PLT class.
	(elf_machine_rel): Handle R_X86_64_TLSDESC.
	(elf_machine_rela): Likewise.
	(elf_machine_lazy_rel): Likewise.
	* sysdeps/x86_64/dl-tls.h (struct dl_tls_index): Name it.
	(__tls_get_addr): Do not declare for non-shared compiles.
	* sysdeps/x86_64/dl-tlsdesc.S: New file.
	* sysdeps/x86_64/dl-tlsdesc.h: New file.
	* sysdeps/x86_64/tlsdesc.c: New file.
	* sysdeps/x86_64/tlsdesc.sym: New file.
	* sysdeps/x86_64/bits/linkmap.h (struct link_map_machine): Add
	tlsdesc_table for both 32- and 64-bit structs.

5 files changed, 229 insertions, 28 deletions

diff --git a/elf/dl-conflict.c b/elf/dl-conflict.c
index 9b49e77..b730105 100644
--- a/elf/dl-conflict.c
+++ b/elf/dl-conflict.c
@@ -1,5 +1,5 @@
 /* Resolve conflicts against already prelinked libraries.
-   Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Jakub Jelinek <jakub@redhat.com>, 2001.
 
@@ -44,7 +44,6 @@ _dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
     /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code.  */
 #define RESOLVE_MAP(ref, version, flags) (*ref = NULL, NULL)
 #define RESOLVE(ref, version, flags) (*ref = NULL, 0)
-#define CHECK_STATIC_TLS(ref_map, sym_map) ((void) 0)
 #define RESOLVE_CONFLICT_FIND_MAP(map, r_offset) \
   do {									      \
     while ((resolve_conflict_map->l_map_end < (ElfW(Addr)) (r_offset))	      \
@@ -61,6 +60,12 @@ _dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
 
 #include "dynamic-link.h"
 
+    /* Override these, defined in dynamic-link.h.  */
+#undef CHECK_STATIC_TLS
+#define CHECK_STATIC_TLS(ref_map, sym_map) ((void) 0)
+#undef TRY_STATIC_TLS
+#define TRY_STATIC_TLS(ref_map, sym_map) (0)
+
     GL(dl_num_cache_relocations) += conflictend - conflict;
 
     for (; conflict < conflictend; ++conflict)
diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
index e9784c2..a303cb4 100644
--- a/elf/dl-reloc.c
+++ b/elf/dl-reloc.c
@@ -1,5 +1,5 @@
 /* Relocate a shared object and resolve its references to other loaded objects.
-   Copyright (C) 1995-2004, 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1995-2004, 2005, 2006, 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
@@ -43,9 +43,9 @@
    This function intentionally does not return any value but signals error
    directly, as static TLS should be rare and code handling it should
    not be inlined as much as possible.  */
-void
-internal_function __attribute_noinline__
-_dl_allocate_static_tls (struct link_map *map)
+int
+internal_function
+_dl_try_allocate_static_tls (struct link_map *map)
 {
   /* If we've already used the variable with dynamic access, or if the
      alignment requirements are too high, fail.  */
@@ -53,8 +53,7 @@ _dl_allocate_static_tls (struct link_map *map)
       || map->l_tls_align > GL(dl_tls_static_align))
     {
     fail:
-      _dl_signal_error (0, map->l_name, NULL, N_("\
-cannot allocate memory in static TLS block"));
+      return -1;
     }
 
 #if TLS_TCB_AT_TP
@@ -108,6 +107,20 @@ cannot allocate memory in static TLS block"));
     }
   else
     map->l_need_tls_init = 1;
+
+  return 0;
+}
+
+void
+internal_function __attribute_noinline__
+_dl_allocate_static_tls (struct link_map *map)
+{
+  if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
+      || _dl_try_allocate_static_tls (map))
+    {
+      _dl_signal_error (0, map->l_name, NULL, N_("\
+cannot allocate memory in static TLS block"));
+    }
 }
 
 /* Initialize static TLS area and DTV for current (only) thread.
@@ -248,23 +261,6 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
 	     l->l_lookup_cache.value = _lr; }))				      \
      : l)
 
-    /* This macro is used as a callback from elf_machine_rel{a,} when a
-       static TLS reloc is about to be performed.  Since (in dl-load.c) we
-       permit dynamic loading of objects that might use such relocs, we
-       have to check whether each use is actually doable.  If the object
-       whose TLS segment the reference resolves to was allocated space in
-       the static TLS block at startup, then it's ok.  Otherwise, we make
-       an attempt to allocate it in surplus space on the fly.  If that
-       can't be done, we fall back to the error that DF_STATIC_TLS is
-       intended to produce.  */
-#define CHECK_STATIC_TLS(map, sym_map)					\
-    do {								\
-      if (__builtin_expect ((sym_map)->l_tls_offset == NO_TLS_OFFSET	\
-			    || ((sym_map)->l_tls_offset			\
-				== FORCED_DYNAMIC_TLS_OFFSET), 0))	\
-	_dl_allocate_static_tls (sym_map);				\
-    } while (0)
-
 #include "dynamic-link.h"
 
     ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 7eb9a36..c34cbcd 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -1,5 +1,5 @@
 /* Inline functions for dynamic linking.
-   Copyright (C) 1995-2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1995-2005, 2006, 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
@@ -17,6 +17,31 @@
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */
 
+/* This macro is used as a callback from elf_machine_rel{a,} when a
+   static TLS reloc is about to be performed.  Since (in dl-load.c) we
+   permit dynamic loading of objects that might use such relocs, we
+   have to check whether each use is actually doable.  If the object
+   whose TLS segment the reference resolves to was allocated space in
+   the static TLS block at startup, then it's ok.  Otherwise, we make
+   an attempt to allocate it in surplus space on the fly.  If that
+   can't be done, we fall back to the error that DF_STATIC_TLS is
+   intended to produce.  */
+#define CHECK_STATIC_TLS(map, sym_map)					\
+    do {								\
+      if (__builtin_expect ((sym_map)->l_tls_offset == NO_TLS_OFFSET	\
+			    || ((sym_map)->l_tls_offset			\
+				== FORCED_DYNAMIC_TLS_OFFSET), 0))	\
+	_dl_allocate_static_tls (sym_map);				\
+    } while (0)
+
+#define TRY_STATIC_TLS(map, sym_map)					\
+    (__builtin_expect ((sym_map)->l_tls_offset				\
+		       != FORCED_DYNAMIC_TLS_OFFSET, 1)			\
+     && (__builtin_expect ((sym_map)->l_tls_offset != NO_TLS_OFFSET, 1)	\
+	 || _dl_try_allocate_static_tls (sym_map) == 0))
+
+int internal_function _dl_try_allocate_static_tls (struct link_map *map);
+
 #include <elf.h>
 #include <assert.h>
 
diff --git a/elf/elf.h b/elf/elf.h
index 928e9ec..269de52 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -1159,8 +1159,17 @@ typedef struct
 #define R_386_TLS_DTPMOD32 35		/* ID of module containing symbol */
 #define R_386_TLS_DTPOFF32 36		/* Offset in TLS block */
 #define R_386_TLS_TPOFF32  37		/* Negated offset in static TLS block */
+/* 38? */
+#define R_386_TLS_GOTDESC  39		/* GOT offset for TLS descriptor.  */
+#define R_386_TLS_DESC_CALL 40		/* Marker of call through TLS
+					   descriptor for
+					   relaxation.  */
+#define R_386_TLS_DESC     41		/* TLS descriptor containing
+					   pointer to code and to
+					   argument, returning the TLS
+					   offset for the symbol.  */
 /* Keep this the last entry.  */
-#define R_386_NUM	   38
+#define R_386_NUM	   42
 
 /* SUN SPARC specific definitions.  */
 
@@ -2557,8 +2566,17 @@ typedef Elf32_Addr Elf32_Conflict;
 #define R_X86_64_GOTTPOFF	22	/* 32 bit signed PC relative offset
 					   to GOT entry for IE symbol */
 #define R_X86_64_TPOFF32	23	/* Offset in initial TLS block */
+#define R_X86_64_PC64		24	/* PC relative 64 bit */
+#define R_X86_64_GOTOFF64	25	/* 64 bit offset to GOT */
+#define R_X86_64_GOTPC32	26	/* 32 bit signed pc relative
+					   offset to GOT */
+/* 27 .. 33 */
+#define R_X86_64_GOTPC32_TLSDESC 34	/* GOT offset for TLS descriptor.  */
+#define R_X86_64_TLSDESC_CALL   35	/* Marker for call through TLS
+					   descriptor.  */
+#define R_X86_64_TLSDESC        36	/* TLS descriptor.  */
 
-#define R_X86_64_NUM		24
+#define R_X86_64_NUM		37
 
 
 /* AM33 relocations.  */
diff --git a/elf/tlsdeschtab.h b/elf/tlsdeschtab.h
new file mode 100644
index 0000000..c3cbc3f
--- /dev/null
+++ b/elf/tlsdeschtab.h
@@ -0,0 +1,157 @@
+/* Hash table for TLS descriptors.
+   Copyright (C) 2005, 2008 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Alexandre Oliva  <aoliva@redhat.com>
+
+   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.  */
+
+#ifndef TLSDESCHTAB_H
+# define TLSDESCHTAB_H 1
+
+# ifdef SHARED
+
+#  include <inline-hashtab.h>
+
+inline static int
+hash_tlsdesc (void *p)
+{
+  struct tlsdesc_dynamic_arg *td = p;
+
+  /* We know all entries are for the same module, so ti_offset is the
+     only distinguishing entry.  */
+  return td->tlsinfo.ti_offset;
+}
+
+inline static int
+eq_tlsdesc (void *p, void *q)
+{
+  struct tlsdesc_dynamic_arg *tdp = p, *tdq = q;
+
+  return tdp->tlsinfo.ti_offset == tdq->tlsinfo.ti_offset;
+}
+
+inline static int
+map_generation (struct link_map *map)
+{
+  size_t idx = map->l_tls_modid;
+  struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
+
+  /* Find the place in the dtv slotinfo list.  */
+  do
+    {
+      /* Does it fit in the array of this list element?  */
+      if (idx < listp->len)
+	{
+	  /* We should never get here for a module in static TLS, so
+	     we can assume that, if the generation count is zero, we
+	     still haven't determined the generation count for this
+	     module.  */
+	  if (listp->slotinfo[idx].gen)
+	    return listp->slotinfo[idx].gen;
+	  else
+	    break;
+	}
+      idx -= listp->len;
+      listp = listp->next;
+    }
+  while (listp != NULL);
+
+  /* If we get to this point, the module still hasn't been assigned an
+     entry in the dtv slotinfo data structures, and it will when we're
+     done with relocations.  At that point, the module will get a
+     generation number that is one past the current generation, so
+     return exactly that.  */
+  return GL(dl_tls_generation) + 1;
+}
+
+void *
+internal_function
+_dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset)
+{
+  struct hashtab *ht;
+  void **entry;
+  struct tlsdesc_dynamic_arg *td, test;
+
+  /* FIXME: We could use a per-map lock here, but is it worth it?  */
+  __rtld_lock_lock_recursive (GL(dl_load_lock));
+
+  ht = map->l_mach.tlsdesc_table;
+  if (! ht)
+    {
+      ht = htab_create ();
+      if (! ht)
+	{
+	  __rtld_lock_unlock_recursive (GL(dl_load_lock));
+	  return 0;
+	}
+      map->l_mach.tlsdesc_table = ht;
+    }
+
+  test.tlsinfo.ti_module = map->l_tls_modid;
+  test.tlsinfo.ti_offset = ti_offset;
+  entry = htab_find_slot (ht, &test, 1, hash_tlsdesc, eq_tlsdesc);
+  if (*entry)
+    {
+      td = *entry;
+      __rtld_lock_unlock_recursive (GL(dl_load_lock));
+      return td;
+    }
+
+  *entry = td = malloc (sizeof (struct tlsdesc_dynamic_arg));
+  /* This may be higher than the map's generation, but it doesn't
+     matter much.  Worst case, we'll have one extra DTV update per
+     thread.  */
+  td->gen_count = map_generation (map);
+  td->tlsinfo = test.tlsinfo;
+
+  __rtld_lock_unlock_recursive (GL(dl_load_lock));
+  return td;
+}
+
+# endif /* SHARED */
+
+/* The idea of the following two functions is to stop multiple threads
+   from attempting to resolve the same TLS descriptor without busy
+   waiting.  Ideally, we should be able to release the lock right
+   after changing td->entry, and then using say a condition variable
+   or a futex wake to wake up any waiting threads, but let's try to
+   avoid introducing such dependencies.  */
+
+inline static int
+_dl_tlsdesc_resolve_early_return_p (struct tlsdesc volatile *td, void *caller)
+{
+  if (caller != td->entry)
+    return 1;
+
+  __rtld_lock_lock_recursive (GL(dl_load_lock));
+  if (caller != td->entry)
+    {
+      __rtld_lock_unlock_recursive (GL(dl_load_lock));
+      return 1;
+    }
+
+  td->entry = _dl_tlsdesc_resolve_hold;
+
+  return 0;
+}
+
+inline static void
+_dl_tlsdesc_wake_up_held_fixups (void)
+{
+  __rtld_lock_unlock_recursive (GL(dl_load_lock));
+}
+
+#endif