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authorUlrich Drepper <drepper@redhat.com>2008-05-13 05:41:30 +0000
committerUlrich Drepper <drepper@redhat.com>2008-05-13 05:41:30 +0000
commitc9ff0187a63b6bc535c9febd2c2eb1c5a843b2c1 (patch)
tree4d30dab17b7e46a98332aafbe886e62aa78228de /elf
parenta3636e8b89a7c565b1141d56055a6a07a053792c (diff)
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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.
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-conflict.c9
-rw-r--r--elf/dl-reloc.c42
-rw-r--r--elf/dynamic-link.h27
-rw-r--r--elf/elf.h22
-rw-r--r--elf/tlsdeschtab.h157
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