Lazy tlsdesc initialization is no longer used in the dynamic linker
so all related code can be removed.
* sysdeps/arm/dl-machine.h (elf_machine_runtime_setup): Remove
DT_TLSDESC_GOT initialization.
* sysdeps/arm/dl-tlsdesc.S (_dl_tlsdesc_lazy_resolver): Remove.
(_dl_tlsdesc_resolve_hold): Likewise.
* sysdeps/aarch64/dl-tlsdesc.h (_dl_tlsdesc_lazy_resolver): Remove.
(_dl_tlsdesc_resolve_hold): Likewise.
* sysdeps/aarch64/tlsdesc.c (_dl_tlsdesc_lazy_resolver_fixup): Remove.
(_dl_tlsdesc_resolve_hold_fixup): Likewise.
Follow up to
https://sourceware.org/ml/libc-alpha/2015-11/msg00272.html
Always do tls descriptor initialization at load time during relocation
processing (as if DF_BIND_NOW were set for the binary) to avoid barriers
at every tls access. This patch mimics bind-now semantics in the lazy
relocation code of the arm target (elf_machine_lazy_rel).
Ideally the static linker should be updated too to not emit tlsdesc
relocs in DT_REL*, so elf_machine_lazy_rel is not called on them at all.
[BZ #18572]
* sysdeps/arm/dl-machine.h (elf_machine_lazy_rel): Do symbol binding
non-lazily for R_ARM_TLS_DESC.
This patch reverts
commit 9c82da17b5
Author: Maciej W. Rozycki <macro@codesourcery.com>
Date: 2014-07-17 19:22:05 +0100
[BZ #17078] ARM: R_ARM_TLS_DESC prelinker support
This only implemented support for the lazy binding case (and thus
closed the bugzilla ticket prematurely), however tlsdesc on arm is
not correct with lazy binding because there is a data race between
the lazy initialization code and tlsdesc resolver functions.
Lazy initialization of tlsdesc entries will be removed from arm to
fix the data races and thus this half-finished prelinker support
is no longer useful.
[BZ #17078]
* sysdeps/arm/dl-machine.h (elf_machine_rela): Remove the
R_ARM_TLS_DESC case.
(elf_machine_lazy_rel): Remove the prelink check.
Since arm can't convert access _DYNAMIC via GOT, which needs dynamic
relocation, to PC-relative at link-time, don't check _DYNAMIC in
elf_machine_load_address.
* sysdeps/arm/dl-machine.h (elf_machine_load_address): Don't
check _DYNAMIC.
When --enable-static-pie is used to configure glibc, we need to use
_dl_relocate_static_pie to compute load address in static PIE.
* sysdeps/arm/dl-machine.h (elf_machine_load_address): Use
_dl_relocate_static_pie instead of _dl_start to compute load
address in static PIE. Return 0 if _DYNAMIC is undefined for
static executable.
There is bug report that ld.so in GLIBC 2.24 built by Binutils 2.29 will crash
on arm-linux-gnueabihf. This is confirmed, and the details is at:
https://sourceware.org/bugzilla/show_bug.cgi?id=21725.
As analyzed in the PR, the old code was with the assumption that assembler
won't set bit0 of thumb function address if it comes from PC-relative
instructions and the calculation can be finished during assembling. This
assumption however does not hold after PR gas/21458.
* sysdeps/arm/dl-machine.h (elf_machine_load_address): Also strip bit 0
of pcrel_address under Thumb mode.
ELFv2 functions with localentry:0 are those with a single entry point,
ie. global entry == local entry, that have no requirement on r2 or
r12 and guarantee r2 is unchanged on return. Such an external
function can be called via the PLT without saving r2 or restoring it
on return, avoiding a common load-hit-store for small functions.
This patch implements the ld.so changes necessary for this
optimization. ld.so needs to check that an optimized plt call
sequence is in fact calling a function implemented with localentry:0,
end emit a fatal error otherwise.
The elf/testobj6.c change is to stop "error while loading shared
libraries: expected localentry:0 `preload'" when running
elf/preloadtest, which we'd get otherwise.
* elf/elf.h (PPC64_OPT_LOCALENTRY): Define.
* sysdeps/alpha/dl-machine.h (elf_machine_fixup_plt): Add
refsym and sym parameters. Adjust callers.
* sysdeps/aarch64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/arm/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/generic/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/hppa/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/i386/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/ia64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/m68k/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/microblaze/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/mips/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/nios2/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/powerpc/powerpc32/dl-machine.h (elf_machine_fixup_plt):
Likewise.
* sysdeps/s390/s390-32/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/s390/s390-64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sh/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sparc/sparc32/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/tile/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/x86_64/dl-machine.h (elf_machine_fixup_plt): Likewise.
* sysdeps/powerpc/powerpc64/dl-machine.c (_dl_error_localentry): New.
(_dl_reloc_overflow): Increase buffser size. Formatting.
* sysdeps/powerpc/powerpc64/dl-machine.h (ppc64_local_entry_offset):
Delete reloc param, add refsym and sym. Check optimized plt
call stubs for localentry:0 functions. Adjust callers.
(elf_machine_fixup_plt, elf_machine_plt_conflict): Add refsym
and sym parameters. Adjust callers.
(_dl_reloc_overflow): Move attribute.
(_dl_error_localentry): Declare.
* elf/dl-runtime.c (_dl_fixup): Save original sym. Pass
refsym and sym to elf_machine_fixup_plt.
* elf/testobj6.c (preload): Call printf.
When building on i686, x86_64, and arm, and with NDEBUG, or --with-cpu
there are various variables and functions which are unused based on
these settings.
This patch marks all such variables with __attribute__((unused)) to
avoid the compiler warnings when building with the aformentioned
options.
Continuing the removal of the obsolete INTDEF / INTUSE mechanism, this
patch eliminates its use for _dl_init. Since _dl_init was already
declared with hidden visibility, creating a second hidden alias for it
was completely pointless, so this patch replaces all uses of
_dl_init_internal with plain _dl_init instead of using hidden_proto /
hidden_def (which are only needed when you want a hidden alias for a
non-hidden symbol; it's quite possible there are cases where they are
used but don't need to be because the symbol in question is not part
of the public ABI and is only used within a single library, so using
attributes_hidden instead would suffice).
Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.
[BZ #14132]
* elf/dl-init.c (_dl_init): Don't use INTDEF.
* sysdeps/aarch64/dl-machine.h (RTLD_START): Use _dl_init instead
of _dl_init_internal.
* sysdeps/alpha/dl-machine.h (RTLD_START): Likewise.
* sysdeps/arm/dl-machine.h (RTLD_START): Likewise.
* sysdeps/hppa/dl-machine.h (RTLD_START): Likewise.
* sysdeps/i386/dl-machine.h (RTLD_START): Likewise.
* sysdeps/ia64/dl-machine.h (RTLD_START): Likewise.
* sysdeps/m68k/dl-machine.h (RTLD_START): Likewise.
* sysdeps/microblaze/dl-machine.h (RTLD_START): Likewise.
* sysdeps/mips/dl-machine.h (RTLD_START): Likewise.
* sysdeps/powerpc/powerpc32/dl-start.S (_start): Likewise.
* sysdeps/s390/s390-32/dl-machine.h (RTLD_START): Likewise.
* sysdeps/s390/s390-64/dl-machine.h (RTLD_START): Likewise.
* sysdeps/sh/dl-machine.h (RTLD_START): Likewise.
* sysdeps/sparc/sparc32/dl-machine.h (RTLD_START): Likewise.
* sysdeps/sparc/sparc64/dl-machine.h (RTLD_START): Likewise.
* sysdeps/tile/dl-start.S (_start): Likewise.
* sysdeps/x86_64/dl-machine.h (RTLD_START): Likewise.
* sysdeps/x86_64/x32/dl-machine.h (RTLD_START): Likewise.
This is a change to the dynamic linker to add prelinker support for the
R_ARM_TLS_DESC relocation. Two cases can be considered here, the usual
one where lazy binding is in use and the less frequent one, where
immediate binding is requested via the use of the DF_BIND_NOW dynamic
flag (e.g. by using the GNU linker's "-z now" option).
This change only handles the first case. In this scenario the prelinker
does what the dynamic linker would do, that is it preinitialises
R_ARM_TLS_DESC relocations with a pointer to the lazy specialization as
provided with the DT_TLSDESC_PLT dynamic tag. A conflict is
additionally created and in the conflict resolution path the dynamic
linker complements the work by initialising the object's pointer as
indicated by the DT_TLSDESC_GOT dynamic tag to the linker's internal
lazy specialization worker function and also providing the associated
link map in the second entry of the GOT. This step is required, because
if prelinking is successful at the run time, then the dynamic linker's
elf_machine_runtime_setup() function isn't called that would normally do
so.
The second case remains unresolved, because support for that scenario
has not been implemented in the prelinker. In this case the lazy
specialization is unavailable and the DT_TLSDESC_PLT dynamic tag is not
present.
The prelinker could assume the common case of static specialization and
resolve the relocation, but that would require the exposure of dynamic
linker's specialization worker function. Furthermore the dynamic linker
would have to handle the relocation in the conflict resolution path and
see if the dynamic specialization should be used instead. This however
would require access to data structures currently not made available to
the conflict resolution path and therefore a redesign of this part of
the dynamic linker.
Alternatively the prelinker could defer all processing to the dynamic
linker's conflict resolution path, but that would require similar access
to the said data structures.
Therefore the prelinker issues an error instead and the dynamic linker
has assertions to check that DT_TLSDESC_PLT and DT_TLSDESC_GOT are in
use in its conflict resolution path.
This change resolves all TLS failures in the prelinker testsuite, as
noted in the bug report, as well as the small test case provided there.
Unfortunately we don't seem to have any hooks to factor in the prelinker
(if present on a system) to testing, so at this time this fix has to
rely on using the prelinker test suite and enabling TLS descriptors
there for coverage.
[BZ #17078]
* sysdeps/arm/dl-machine.h (elf_machine_rela)
[RESOLVE_CONFLICT_FIND_MAP]: Handle R_ARM_TLS_DESC relocation.
(elf_machine_lazy_rel): Handle prelinked R_ARM_TLS_DESC entries.
This fixes the calculation of R_ARM_TLS_DESC relocations for lazy global
symbol references, i.e. created with `-z lazy' in effect with the static
linker, where immediate resolution is requested with LD_BIND_NOW.
This patch fixes what I believe to be a bug in the handling of
R_ARM_IRELATIVE RELA relocations. At present, these are handled the
same as REL relocations: i.e. the addend is loaded from the relocation
address. Most of the time this isn't a problem because RELA relocations
aren't used on ARM (GNU/Linux at least) anyway, but it causes problems
with prelink, which uses RELA on all targets for its conflict table.
(Support for ifunc prelinking requires a prelink patch, not yet posted.)
Anyway, this patch works, though I'm not 100% sure if it is correct: I
notice that this code path received attention last year:
https://sourceware.org/ml/libc-ports/2013-07/msg00000.html
I'm not sure under what circumstances that patch would have had an
effect, nor if my patch conflicts with that case.
No regressions using Mentor's usual glibc cross-testing infrastructure.
[BZ #16888]
* sysdeps/arm/dl-machine.h (elf_machine_rela): Fix R_ARM_IRELATIVE
handling.
I've moved the ARM port from ports to the main sysdeps hierarchy.
Beyond the README update, the move of the files was simply
git mv ports/sysdeps/arm sysdeps/arm
git mv ports/sysdeps/unix/arm sysdeps/unix/arm
git mv ports/sysdeps/unix/sysv/linux/arm sysdeps/unix/sysv/linux/arm
and in addition to the ChangeLog entries here, I put a note at the top
of ports/ChangeLog.arm similar to that at the top of
ChangeLog.powerpc. There is deliberately no NEWS change, as I think
it makes the most sense to put in a general note above all ports
having moved if we can achieve that for 2.20.
Tested that disassembly of installed shared libraries for arm is the
same before and after this patch, except for data (not instructions)
in ld.so (there are assertions in sysdeps/arm/dl-machine.h, and the
path by which that file is found, and so by which it appears in the
assertion message, changes as a result of the move).
* sysdeps/arm: Move directory from ports/sysdeps/arm.
* sysdeps/unix/arm: Move directory from ports/sysdeps/unix/arm.
* sysdeps/unix/sysv/linux/arm: Move directory from
ports/sysdeps/unix/sysv/linux/arm.
* README: Update listing for arm-*-linux-gnueabi.
ports/ChangeLog.arm:
* sysdeps/arm: Move directory to ../sysdeps/arm.
* sysdeps/unix/arm: Move directory to ../sysdeps.arm.
* sysdeps/unix/sysv/linux/arm: Move directory to
../sysdeps/unix/sysv/linux/arm.
Use it instead of __THUMB_INTERWORK__. Make RETINSTR take
only a condition and a register.
* sysdeps/arm/dl-machine.h: Use __USE_BX__ instead of
__THUMB_INTERWORK__.
(_dl_start_user): Use BX.
* sysdeps/arm/strlen.S: Use DO_RET.
* sysdeps/unix/arm/brk.S, sysdeps/unix/arm/fork.S,
sysdeps/unix/arm/sysdep.S, sysdeps/unix/arm/sysdep.h: Likewise.
* sysdeps/unix/sysv/linux/arm/clone.S,
sysdeps/unix/sysv/linux/arm/mmap.S,
sysdeps/unix/sysv/linux/arm/mmap64.S,
sysdeps/unix/sysv/linux/arm/socket.S,
sysdeps/unix/sysv/linux/arm/sysdep.h,
sysdeps/unix/sysv/linux/arm/vfork.S: Update uses of RETINSTR.
2004-04-29 Philip Blundell <pb@nexus.co.uk>
* sysdeps/arm/dl-machine.h (RTLD_START): Avoid unnecessary GOT
entries.
[BZ #140]
* sysdeps/unix/sysv/linux/sys/sysctl.h: Remove linux/compiler.h
include.
(_LINUX_KERNEL_H, _LINUX_TYPES_H, _LINUX_LIST_H): Only define if not
yet defined, #undef back after including linux/sysctl.h if defined
here.
(__LINUX_COMPILER_H, __user): Define if not yet defined, #undef
back after including linux/sysctl.h if defined here.
2004-04-22 Philip Blundell <philb@gnu.org>
* sysdeps/arm/dl-machine.h (elf_machine_rela): Don't use INTUSE
when calling _dl_signal_error.
(elf_machine_rel): Likewise.
2003-09-17 Philip Blundell <philb@gnu.org>
* sysdeps/unix/sysv/linux/arm/vfork.S: Branch to fork if
libpthread is loaded. Elide backwards compatibility code when not
required.
* sysdeps/arm/dl-machine.h (elf_machine_rela): Handle R_ARM_COPY.
2002-11-15 Roland McGrath <roland@redhat.com>
* math/Makefile (libm-calls): Change s_ldexp to m_ldexp.
* Makerules ($(+sysdir_pfx)sysd-rules): Emit pattern rules for m_%.[Sc]
from sysdeps/.../s_%.[Sc] with commands $(+make-include-of-dep).
(+make-include-of-dep): New canned sequence.
* stdlib/canonicalize.c (__realpath): Check for malloc failure.
From Dmitry V. Levin <ldv@altlinux.org>.
2001-12-11 Jakub Jelinek <jakub@redhat.com>
* elf/Makefile (dl-routines): Add conflict.
(rtld-ldscript-in, rtld-ldscript, rtld-parms): Remove.
(ld.so): Add _begin local symbol.
* elf/elf.h (DT_VALTAGIDX, DT_VALNUM, DT_ADDRTAGIDX, DT_ADDRNUM):
Define.
* elf/dl-deps.c (_dl_build_local_scope): New.
(_dl_map_object_deps): If LD_TRACE_PRELINKING, compute local scopes
of all libraries.
* elf/do-rel.h (VALIDX): Define.
(elf_dynamic_do_rel): If ELF_MACHINE_PLT_REL is defined, don't do
lazy binding for RELA. If DT_GNU_PRELINKED, DT_RELACOUNT relocations
can be skipped.
* elf/dl-conflict.c: New file.
* elf/dl-lookup.c (_dl_debug_bindings): New.
(_dl_lookup_symbol): Use _dl_debug_bindings. Reference_name is always
non-NULL.
(_dl_lookup_symbol_skip): Likewise.
(_dl_lookup_versioned_symbol): Likewise.
(_dl_lookup_versioned_symbol_skip): Likewise.
* elf/dl-runtime.c (PLTREL): If ELF_MACHINE_PLT_REL is defined,
define to ElfW(Rel).
* elf/dynamic-link.h (elf_get_dynamic_info): Record selected dynamic
tags in the DT_VALRNGLO..DT_VALRNGHI and DT_ADDRRNGLO..DT_ADDRRNGHI
ranges.
Don't adjust address dynamic tags if l_addr is 0.
* elf/rtld.c (_dl_trace_prelink, _dl_trace_prelink_map): New variables.
(_dl_start): Skip ELF_DYNAMIC_RELOCATE if ld.so is prelinked.
(VALIDX, ADDRIDX): Define.
(_dl_start_final): Initialize _dl_rtld_map's l_map_start and l_map_end.
(dl_main): Print library list for LD_TRACE_PRELINKING.
If prelinking information can be used, skip relocating libraries and
call _dl_resolve_conflicts instead.
(process_envvars): Handle LD_TRACE_PRELINKING envvar.
* elf/dl-load.c (_dl_map_object): Don't create fake libs
if LD_TRACE_PRELINKING.
* include/link.h (struct link_map) [l_info]: Add DT_VALNUM
+ DT_ADDRNUM.
* sysdeps/generic/ldsodefs.h (_dl_trace_prelink_map): New declaration.
(DL_DEBUG_PRELINK): Define.
(_dl_resolve_conflicts): Add prototype.
* sysdeps/alpha/dl-machine.h (elf_machine_runtime_setup): Reinitialize
.plt for prelinked libraries where prelinking info cannot be used.
(elf_machine_rela): If relocating R_ALPHA_JMP_SLOT in .gnu.conflict
section, use RESOLVE_CONFLICT_FIND_MAP to find out reloc's link_map.
* sysdeps/arm/bits/link.h: New file.
* sysdeps/arm/dl-machine.h (elf_machine_runtime_setup): Save original
content of .got[1].
(ELF_MACHINE_NO_RELA): Only define if RTLD_BOOTSTRAP.
(ELF_MACHINE_PLT_REL): Define.
(elf_machine_rela, elf_machine_rela_relative): New.
(elf_machine_lazy_rel): Reinitialize R_ARM_JUMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
* sysdeps/i386/bits/link.h: New file.
* sysdeps/i386/dl-machine.h (elf_machine_runtime_setup): Save original
content of .got[1].
(ELF_MACHINE_NO_RELA): Only define if RTLD_BOOTSTRAP.
(ELF_MACHINE_PLT_REL): Define.
(elf_machine_rela, elf_machine_rela_relative): New.
(elf_machine_lazy_rel): Reinitialize R_386_JUMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
* sysdeps/powerpc/dl-machine.h (elf_machine_rela): If relocating
conflicts, skip finaladdr computation. Use RESOLVE_CONFLICT_FIND_MAP
to find out map for R_PPC_JMP_SLOT relocs.
* sysdeps/sparc/sparc32/dl-machine.h (VALIDX): Define.
(OPCODE_BA): Define.
(elf_machine_runtime_setup): Reinitialize .plt for prelinked
libraries where prelinking info cannot be used.
(sparc_fixup_plt): Renamed from elf_machine_fixup_plt.
(elf_machine_fixup_plt): Call sparc_fixup_plt.
(elf_machine_rela): Set value to 0 if relocating conflicts.
Call sparc_fixup_plt for R_SPARC_JMP_SLOT.
* sysdeps/sparc/sparc64/dl-machine.h (VALIDX): Define.
(sparc64_fixup_plt): Fix a typo.
(elf_machine_rela): Set value to 0 if relocating conflicts.
Handle R_SPARC_JMP_SLOT relocs when relocating conflicts.
(elf_machine_runtime_setup): Reinitialize .plt for prelinked
libraries where prelinking info cannot be used.
* sysdeps/sh/bits/link.h: New file.
* sysdeps/sh/dl-machine.h (elf_machine_runtime_setup): Save original
content of .got[1].
(elf_machine_lazy_rel): Reinitialize R_SH_JMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
* sysdeps/s390/s390-32/bits/link.h: New file.
* sysdeps/s390/s390-32/dl-machine.h (elf_machine_runtime_setup):
Save original content of .got[1].
(elf_machine_lazy_rel): Reinitialize R_390_JMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
* sysdeps/s390/s390-64/bits/link.h: New file.
* sysdeps/s390/s390-64/dl-machine.h (elf_machine_runtime_setup):
Save original content of .got[1].
(elf_machine_lazy_rel): Reinitialize R_390_JMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
* sysdeps/x86_64/bits/link.h: New file.
* sysdeps/x86_64/dl-machine.h (elf_machine_runtime_setup):
Save original content of .got[1].
(elf_machine_lazy_rel): Reinitialize R_X86_64_JMP_SLOT address instead
of adjusting it if prelinked and prelinking cannot be used.
2001-09-08 Ben Collins <bcollins@debian.org>
* sysdeps/arm/dl-machine.h (elf_machine_rel): Fix thinko in
usage of RESOLVE() (r_type, not reloc->r_type).
2001-08-11 Ulrich Drepper <drepper@redhat.com>
* malloc/malloc.c (ptmalloc_init): Don't call getenv five times.
Instead use new function next_env_entry which iterates over the
environment once.
* sysdeps/arm/dl-machine.h (elf_machine_runtime_setup): Only set
_dl_profile_map for the right object.
* elf/dl-reloc.c (_dl_relocate_object): Allocate l_reloc_result
only if consider_profiling is != 0, not if _dl_profile != NULL.
* sysdeps/generic/dl-environ.c (_dl_next_ld_env_entry): Optimize a bit.
Now returns pointer to first character set "LD_".
* elf/rtld.c (process_envvars): Adjust for change above.
* sysdeps/unix/sysv/linux/dl-librecon.h (EXTRA_LD_ENVVARS): Likewise.
* sysdeps/unix/sysv/linux/i386/dl-librecon.h (EXTRA_LD_ENVVARS):
Likewise.
2001-08-10 Wolfram Gloger <wg@malloc.de>
* malloc/malloc.c (grow_heap): Use mmap() rather than mprotect()
to allocate new memory, for better performance with Linux-2.4.x.
