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ARM TLS descriptors support.

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This commit is contained in:
Nathan Sidwell 2011-03-05 03:39:15 +00:00 committed by Joseph Myers
parent 57d366bd22
commit 3447f0d785
10 changed files with 588 additions and 2 deletions
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20
ChangeLog.arm
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@ -1,3 +1,23 @@
2011-03-05 Nathan Sidwell <nathan@codesourcery.com>
Glauber de Oliveira Costa <glommer@gmail.com>
* sysdeps/arm/dl-tlsdesc.h: New.
* sysdeps/arm/dl-tls.h (struct dl_tls_index): Make non-anonymous.
* sysdeps/arm/Makefile: Add tlsdesc, dl-tlsdesc for elf
subdirectory.
* sysdeps/arm/tlsdesc.c: New.
* sysdeps/arm/dl-machine.h: #include sysdeps and dl-tlsdesc.h.
(elf_machine_runtime_setup): Record dl_tlsdesc_lazy_resolver
address.
(elf_machine_type_class): Check R_ARM_TLS_DESC.
(elf_machine_rel): Add R_ARM_TLS_DESC case.
(elf_machine_lazy_rel): Likewise.
* sysdeps/arm/dl-tlsdesc.S: New.
* sysdeps/arm/bits/linkmap.h (struct link_map_machine): Add
tlsdesc_table field.
* sysdeps/arm/tlsdesc.sym: New.
* sysdeps/arm/dl-lookupcfg.h: New.
2011-02-16 Manjunath Matti <manjunath81@gmail.com>
* sysdeps/arm/sysdep.h (CALL_MCOUNT): Use __gnu_mcount_nc

9
sysdeps/arm/Makefile Normal file
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@ -0,0 +1,9 @@
ifeq ($(subdir),elf)
sysdep-dl-routines += tlsdesc dl-tlsdesc
sysdep_routines += tlsdesc dl-tlsdesc
sysdep-rtld-routines += tlsdesc dl-tlsdesc
endif
ifeq ($(subdir),csu)
gen-as-const-headers += tlsdesc.sym
endif

1
sysdeps/arm/bits/linkmap.h
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@ -1,4 +1,5 @@
struct link_map_machine
{
Elf32_Addr plt; /* Address of .plt */
void *tlsdesc_table; /* Address of TLS descriptor hash table. */
};

28
sysdeps/arm/dl-lookupcfg.h Normal file
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@ -0,0 +1,28 @@
/* Configuration of lookup functions.
Copyright (C) 2006, 2010 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. */
#define DL_UNMAP_IS_SPECIAL
#include_next <dl-lookupcfg.h>
struct link_map;
extern void internal_function _dl_unmap (struct link_map *map);
#define DL_UNMAP(map) _dl_unmap (map)

56
sysdeps/arm/dl-machine.h
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@ -25,6 +25,7 @@
#include <sys/param.h>
#include <tls.h>
#include <dl-tlsdesc.h>
#define CLEAR_CACHE(BEG,END) \
INTERNAL_SYSCALL_ARM (cacheflush, , 3, (BEG), (END), 0)
@ -127,6 +128,11 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
the offset on the stack, and then jump to the resolved address. */
got[2] = (Elf32_Addr) &_dl_runtime_resolve;
}
if (l->l_info[ADDRIDX (DT_TLSDESC_GOT)] && lazy)
*(Elf32_Addr*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_GOT)]) + l->l_addr)
= (Elf32_Addr) &_dl_tlsdesc_lazy_resolver;
return lazy;
}
@ -239,7 +245,8 @@ _dl_start_user:\n\
#if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD)
# define elf_machine_type_class(type) \
((((type) == R_ARM_JUMP_SLOT || (type) == R_ARM_TLS_DTPMOD32 \
|| (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32) \
|| (type) == R_ARM_TLS_DTPOFF32 || (type) == R_ARM_TLS_TPOFF32 \
|| (type) == R_ARM_TLS_DESC) \
* ELF_RTYPE_CLASS_PLT) \
| (((type) == R_ARM_COPY) * ELF_RTYPE_CLASS_COPY))
#else
@ -421,6 +428,39 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
*reloc_addr += value;
break;
}
case R_ARM_TLS_DESC:
{
struct tlsdesc volatile *td =
(struct tlsdesc volatile *)reloc_addr;
# ifndef RTLD_BOOTSTRAP
if (! sym)
td->entry = _dl_tlsdesc_undefweak;
else
# endif
{
value = sym->st_value + td->argument.value;
# ifndef RTLD_BOOTSTRAP
# ifndef SHARED
CHECK_STATIC_TLS (map, sym_map);
# else
if (!TRY_STATIC_TLS (map, sym_map))
{
td->argument.pointer
= _dl_make_tlsdesc_dynamic (sym_map, value);
td->entry = _dl_tlsdesc_dynamic;
}
else
# endif
# endif
{
td->argument.value = value + sym_map->l_tls_offset;
td->entry = _dl_tlsdesc_return;
}
}
}
break;
case R_ARM_PC24:
{
Elf32_Sword addend;
@ -612,6 +652,20 @@ elf_machine_lazy_rel (struct link_map *map,
else
*reloc_addr = map->l_mach.plt;
}
#ifdef USE_TLS
else if (__builtin_expect (r_type == R_ARM_TLS_DESC, 1))
{
struct tlsdesc volatile *td =
(struct tlsdesc volatile *)reloc_addr;
/* The linker must have given us the parameter we need in the
first GOT entry, and left the second one empty. We fill the
last with the resolver address */
assert (td->entry == 0);
td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)])
+ map->l_addr);
}
#endif
else
_dl_reloc_bad_type (map, r_type, 1);
}

2
sysdeps/arm/dl-tls.h
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@ -19,7 +19,7 @@
/* Type used for the representation of TLS information in the GOT. */
typedef struct
typedef struct dl_tls_index
{
unsigned long int ti_module;
unsigned long int ti_offset;

222
sysdeps/arm/dl-tlsdesc.S Normal file
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@ -0,0 +1,222 @@
/* Thread-local storage handling in the ELF dynamic linker. ARM version.
Copyright (C) 2006, 2010 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 <sysdep.h>
#include <tls.h>
#include "tlsdesc.h"
#ifdef __USE_BX__
#define BX(x) bx x
#else
#define BX(x) mov pc, x
#endif
.text
@ emit debug information with cfi
@ use arm-specific pseudos for unwinding itself
.cfi_sections .debug_frame
#ifdef USE_TLS
.hidden _dl_tlsdesc_return
.global _dl_tlsdesc_return
.type _dl_tlsdesc_return,#function
cfi_startproc
.fnstart
.align 2
_dl_tlsdesc_return:
ldr r0, [r0]
BX (lr)
.fnend
cfi_endproc
.size _dl_tlsdesc_return, .-_dl_tlsdesc_return
.hidden _dl_tlsdesc_undefweak
.global _dl_tlsdesc_undefweak
.type _dl_tlsdesc_undefweak,#function
cfi_startproc
.fnstart
.align 2
_dl_tlsdesc_undefweak:
@ Are we allowed a misaligned stack pointer calling read_tp?
.save {lr}
stmdb sp!, {lr}
cfi_adjust_cfa_offset (4)
cfi_rel_offset (lr,0)
bl __aeabi_read_tp
rsb r0, r0, #0
ldmia sp!, {lr}
cfi_adjust_cfa_offset (-4)
cfi_restore (lr)
BX (lr)
cfi_endproc
.fnend
.size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
#ifdef SHARED
.hidden _dl_tlsdesc_dynamic
.global _dl_tlsdesc_dynamic
.type _dl_tlsdesc_dynamic,#function
/*
The assembly code that follows is a rendition of the following
C code, hand-optimized a little bit.
ptrdiff_t
_dl_tlsdesc_dynamic(struct tlsdesc *tdp)
{
struct tlsdesc_dynamic_arg *td = tdp->argument.pointer;
dtv_t *dtv = (dtv_t *)THREAD_DTV();
if (__builtin_expect (td->gen_count <= dtv[0].counter
&& dtv[td->tlsinfo.ti_module].pointer.val
!= TLS_DTV_UNALLOCATED,
1))
return dtv[td->tlsinfo.ti_module].pointer.val +
td->tlsinfo.ti_offset - __builtin_thread_pointer();
return __tls_get_addr (&td->tlsinfo) - __builtin_thread_pointer();
}
*/
cfi_startproc
.fnstart
.align 2
_dl_tlsdesc_dynamic:
/* Our calling convention is to clobber r0, r1 and the processor
flags. All others that are modified must be saved */
.save {r2,r3,r4,lr}
stmdb sp!, {r2,r3,r4,lr}
cfi_adjust_cfa_offset (16)
cfi_rel_offset (r2,0)
cfi_rel_offset (r3,4)
cfi_rel_offset (r4,8)
cfi_rel_offset (lr,12)
ldr r1, [r0] /* td */
bl __aeabi_read_tp
mov r4, r0 /* r4 = tp */
ldr r0, [r0]
ldr r2, [r1, #8] /* gen_count */
ldr r3, [r0]
cmp r2, r3
bhi 1f
ldr r3, [r1]
ldr r2, [r0, r3, lsl #3]
cmn r2, #1
ldrne r3, [r1, #4]
addne r3, r2, r3
rsbne r0, r4, r3
bne 2f
1: mov r0, r1
bl __tls_get_addr
rsb r0, r4, r0
2: ldmia sp!, {r2,r3,r4, lr}
cfi_adjust_cfa_offset (-16)
cfi_restore (lr)
cfi_restore (r4)
cfi_restore (r3)
cfi_restore (r2)
BX (lr)
.fnend
cfi_endproc
.size _dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
#endif /* SHARED */
/* lazy resolved for tls descriptors. */
.hidden _dl_tlsdesc_lazy_resolver
.global _dl_tlsdesc_lazy_resolver
.type _dl_tlsdesc_lazy_resolver,#function
cfi_startproc
.fnstart
.align 2
_dl_tlsdesc_lazy_resolver:
/* r0 points at the tlsdesc,
r1 points at the GOT
r2 was pushed by the trampoline and used as a temp,
we need to pop it here.
We push the remaining call-clobbered registers here, and also
R1 -- to keep the stack correctly aligned. */
/* Tell the unwinder that r2 has already been pushed. */
.save {r2}
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r2, 0)
.save {r0,r1,r3,ip,lr}
stmdb sp!, {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (20)
cfi_rel_offset (r0, 0)
cfi_rel_offset (r1, 4)
cfi_rel_offset (r3, 8)
cfi_rel_offset (ip, 12)
cfi_rel_offset (lr, 16)
bl _dl_tlsdesc_lazy_resolver_fixup
ldmia sp!, {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (-20)
cfi_restore (lr)
cfi_restore (ip)
cfi_restore (r3)
cfi_restore (r1)
cfi_restore (r0)
ldmia sp!, {r2}
cfi_adjust_cfa_offset (-4)
cfi_restore (r2)
ldr r1, [r0, #4]
BX (r1)
.fnend
cfi_endproc
.size _dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
/* Holder for lazy tls descriptors being resolve in another thread.
Same ABI as the lazy resolver itself. */
.hidden _dl_tlsdesc_resolve_hold
.global _dl_tlsdesc_resolve_hold
.type _dl_tlsdesc_resolve_hold,#function
cfi_startproc
.fnstart
.align 2
_dl_tlsdesc_resolve_hold:
/* Tell the unwinder that r2 has already been pushed. */
.save {r2}
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r2, 0)
.save {r0,r1,r3,ip,lr}
stmdb sp!, {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (20)
cfi_rel_offset (r0, 0)
cfi_rel_offset (r1, 4)
cfi_rel_offset (r3, 8)
cfi_rel_offset (ip, 12)
cfi_rel_offset (lr, 16)
adr r2, _dl_tlsdesc_resolve_hold
bl _dl_tlsdesc_resolve_hold_fixup
ldmia sp!, {r0, r1, r3, ip, lr}
cfi_adjust_cfa_offset (-20)
cfi_restore (lr)
cfi_restore (ip)
cfi_restore (r3)
cfi_restore (r1)
cfi_restore (r0)
ldmia sp!, {r2}
cfi_adjust_cfa_offset (-4)
cfi_restore (r2)
ldr r1, [r0, #4]
BX (r1)
.fnend
cfi_endproc
.size _dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
#endif /* USE_TLS */

69
sysdeps/arm/dl-tlsdesc.h Normal file
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@ -0,0 +1,69 @@
/* Thread-local storage descriptor handling in the ELF dynamic linker.
ARM version.
Copyright (C) 2005, 2010 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; witout 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 _ARM_DL_TLSDESC_H
# define _ARM_DL_TLSDESC_H 1
/* Use this to access DT_TLSDESC_PLT and DT_TLSDESC_GOT. */
#ifndef ADDRIDX
# define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
+ DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
#endif
/* Type used to represent a TLS descriptor in the GOT. */
struct tlsdesc
{
union
{
void *pointer;
long value;
} argument;
ptrdiff_t (*entry)(struct tlsdesc *);
};
typedef struct dl_tls_index
{
unsigned long int ti_module;
unsigned long int ti_offset;
} tls_index;
/* Type used as the argument in a TLS descriptor for a symbol that
needs dynamic TLS offsets. */
struct tlsdesc_dynamic_arg
{
tls_index tlsinfo;
size_t gen_count;
};
extern ptrdiff_t attribute_hidden
_dl_tlsdesc_return(struct tlsdesc *),
_dl_tlsdesc_undefweak(struct tlsdesc *),
_dl_tlsdesc_resolve_hold(struct tlsdesc *),
_dl_tlsdesc_lazy_resolver(struct tlsdesc *);
# ifdef SHARED
extern void *_dl_make_tlsdesc_dynamic (struct link_map *map, size_t ti_offset);
extern ptrdiff_t attribute_hidden
_dl_tlsdesc_dynamic(struct tlsdesc *);
# endif
#endif

164
sysdeps/arm/tlsdesc.c Normal file
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@ -0,0 +1,164 @@
/* Manage TLS descriptors. ARM version.
Copyright (C) 2005, 2010 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>
#ifdef USE_TLS
/* This function is used to lazily resolve TLS_DESC REL relocations
Besides the TLS descriptor itself, we get the module's got address
as the second parameter. */
void
attribute_hidden
_dl_tlsdesc_lazy_resolver_fixup (struct tlsdesc volatile *td,
Elf32_Addr *got)
{
struct link_map *l = (struct link_map *)got[1];
lookup_t result;
unsigned long value;
if (_dl_tlsdesc_resolve_early_return_p
(td, (void*)(D_PTR (l, l_info[ADDRIDX (DT_TLSDESC_PLT)]) + l->l_addr)))
return;
if (td->argument.value & 0x80000000)
{
/* A global symbol, this is the symbol index. */
/* The code below was borrowed from _dl_fixup(). */
const Elf_Symndx symndx = td->argument.value ^ 0x80000000;
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[symndx];
/* 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[symndx] & 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);
if (sym)
value = sym->st_value;
else
{
td->entry = _dl_tlsdesc_undefweak;
goto done;
}
}
else
{
/* We already found the symbol. The module (and therefore its load
address) is also known. */
result = l;
value = sym->st_value;
}
}
else
{
/* A local symbol, this is the offset within our tls section.
*/
value = td->argument.value;
result = l;
}
#ifndef SHARED
CHECK_STATIC_TLS (l, result);
#else
if (!TRY_STATIC_TLS (l, result))
{
td->argument.pointer = _dl_make_tlsdesc_dynamic (result, value);
td->entry = _dl_tlsdesc_dynamic;
}
else
#endif
{
td->argument.value = value + result->l_tls_offset;
td->entry = _dl_tlsdesc_return;
}
done:
_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_hidden
_dl_tlsdesc_resolve_hold_fixup (struct tlsdesc volatile *td,
void *caller)
{
/* Maybe we're lucky and can return early. */
if (caller != 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
/* _dl_unmap is only called for dlopen()ed libraries, for which
calling free() is safe, or before we've completed the initial
relocation, in which case calling free() is probably pointless,
but still safe. */
if (map->l_mach.tlsdesc_table)
htab_delete (map->l_mach.tlsdesc_table);
#endif
}
#endif

19
sysdeps/arm/tlsdesc.sym Normal file
View File

@ -0,0 +1,19 @@
#include <stddef.h>
#include <sysdep.h>
#include <tls.h>
#include <link.h>
#include <dl-tlsdesc.h>
--
-- Abuse tls.h macros to derive offsets relative to the thread register.
#if defined USE_TLS
TLSDESC_ARG offsetof(struct tlsdesc, argument.pointer)
TLSDESC_GEN_COUNT offsetof(struct tlsdesc_dynamic_arg, gen_count)
TLSDESC_MODID offsetof(struct tlsdesc_dynamic_arg, tlsinfo.ti_module)
TLSDESC_MODOFF offsetof(struct tlsdesc_dynamic_arg, tlsinfo.ti_offset)
#endif