To support Intel Control-flow Enforcement Technology (CET) run-time
control:
1. An architecture specific field in the writable ld.so namespace is
needed to indicate if CET features are enabled at run-time.
2. An architecture specific field in struct link_map is needed if
CET features are enabled in an ELF module.
This patch adds dl-procruntime.c to the writable ld.so namespace and
link_map.h to struct link_map.
Tested with build-many-glibcs.py.
* elf/dl-support.c: Include <dl-procruntime.c>.
* include/link.h: Include <link_map.h>.
* sysdeps/generic/dl-procruntime.c: New file.
* sysdeps/generic/link_map.h: Likewise.
* sysdeps/generic/ldsodefs.h: Include <dl-procruntime.c> in
the writable ld.so namespace.
res_hnok rejected some host names used on the Internet, such as
www-.example.com. res_hnok and res_dnok failed to perform basic syntax
checking on DNS domain names.
Also fix res_mailok, res_ownok.
Verify that sizes, alignments and field offsets of jmp_buf as well as
sigjmp_buf are unchanged regardless how struct __jmp_buf_tag is defined.
Since jmp_buf is target specific, jmp_buf-macros.h is added for each
Linux target. A new target must provides its own jmp_buf-macros.h.
TODO: Hurd needs to provide a jmp_buf-macros.h.
Tested with build-many-glibcs.py.
* include/setjmp.h [!_ISOMAC]: Include <stddef.h> and
<jmp_buf-macros.h>.
[!_ISOMAC] (STR_HELPER): New.
[!_ISOMAC] (STR): Likewise.
[!_ISOMAC] (TEST_SIZE): Likewise.
[!_ISOMAC] (TEST_ALIGN): Likewise.
[!_ISOMAC] (TEST_OFFSET): Likewise.
[!_ISOMAC] Add _Static_assert to check sizes, alignments and
field offsets of jmp_buf as well as sigjmp_buf.
* sysdeps/unix/sysv/linux/aarch64/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/alpha/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/arm/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/hppa/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/i386/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/ia64/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/m68k/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/microblaze/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/nios2/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/sh/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/jmp_buf-macros.h:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/jmp_buf-macros.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/jmp_buf-macros.h: Likewise.
Continuing the preparation for additional _FloatN / _FloatNx type
support, this patch adds support to type-generic strtod tests.
GEN_STRTOD_TEST_FOREACH and STRTOD_TEST_FOREACH are made to handle the
full set of such types. tst-strtod-round-skeleton.c is updated for
those types it can handle without needing changes to the generator
(i.e. those types that have already-handled formats).
Tested for x86_64.
* stdlib/tst-strtod.h (F16): New macro.
(F32): Likewise.
(F64): Likewise.
(F32X): Likewise.
(F64X): Likewise.
(F128X): Likewise.
(IF_FLOAT16): Likewise.
(IF_FLOAT32): Likewise.
(IF_FLOAT64): Likewise.
(IF_FLOAT32X): Likewise.
(IF_FLOAT64X): Likewise.
(IF_FLOAT128X): Likewise.
(GEN_TEST_STRTOD_FOREACH): Conditionally call macros for _Float16,
_Float32, _Float64, _Float32x, _Float64x and _Float128x.
(STRTOD_TEST_FOREACH): Likewise.
* stdlib/tst-strtod-round-skeleton.c (CHOOSE_f32): New macro.
(CHOOSE_f64): Likewise.
(CHOOSE_f32x): Likewise.
(CHOOSE_f64x): Likewise.
This patch adds two new internal defines to set the internal
pthread_mutex_t layout required by the supported ABIS:
1. __PTHREAD_MUTEX_NUSERS_AFTER_KIND which control whether to define
__nusers fields before or after __kind. The preferred value for
is 0 for new ports and it sets __nusers before __kind.
2. __PTHREAD_MUTEX_USE_UNION which control whether internal __spins and
__list members will be place inside an union for linuxthreads
compatibility. The preferred value is 0 for ports and it sets
to not use an union to define both fields.
It fixes the wrong offsets value for __kind value on x86_64-linux-gnu-x32.
Checked with a make check run-built-tests=no on all afected ABIs.
[BZ #22298]
* nptl/allocatestack.c (allocate_stack): Check if
__PTHREAD_MUTEX_HAVE_PREV is non-zero, instead if
__PTHREAD_MUTEX_HAVE_PREV is defined.
* nptl/descr.h (pthread): Likewise.
* nptl/nptl-init.c (__pthread_initialize_minimal_internal):
Likewise.
* nptl/pthread_create.c (START_THREAD_DEFN): Likewise.
* sysdeps/nptl/fork.c (__libc_fork): Likewise.
* sysdeps/nptl/pthread.h (PTHREAD_MUTEX_INITIALIZER): Likewise.
* sysdeps/nptl/bits/thread-shared-types.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
defines.
(__pthread_internal_list): Check __PTHREAD_MUTEX_USE_UNION instead
of __WORDSIZE for internal layout.
(__pthread_mutex_s): Check __PTHREAD_MUTEX_NUSERS_AFTER_KIND instead
of __WORDSIZE for internal __nusers layout and __PTHREAD_MUTEX_USE_UNION
instead of __WORDSIZE whether to use an union for __spins and __list
fields.
(__PTHREAD_MUTEX_HAVE_PREV): Define also for __PTHREAD_MUTEX_USE_UNION
case.
* sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION): New
defines.
* sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/arm/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/mips/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/s390/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/sh/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/tile/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
* sysdeps/x86/nptl/bits/pthreadtypes-arch.h
(__PTHREAD_MUTEX_NUSERS_AFTER_KIND, __PTHREAD_MUTEX_USE_UNION):
Likewise.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch adds a new build test to check for internal fields
offsets for user visible internal field. Although currently
the only field which is statically initialized to a non zero value
is pthread_mutex_t.__data.__kind value, the tests also check the
offset of __kind, __spins, __elision (if supported), and __list
internal member. A internal header (pthread-offset.h) is added
to each major ABI with the reference value.
Checked on x86_64-linux-gnu and with a build check for all affected
ABIs (aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
hppa-linux-gnu, i686-linux-gnu, ia64-linux-gnu, m68k-linux-gnu,
microblaze-linux-gnu, mips64-linux-gnu, mips64-n32-linux-gnu,
mips-linux-gnu, powerpc64le-linux-gnu, powerpc-linux-gnu,
s390-linux-gnu, s390x-linux-gnu, sh4-linux-gnu, sparc64-linux-gnu,
sparcv9-linux-gnu, tilegx-linux-gnu, tilegx-linux-gnu-x32,
tilepro-linux-gnu, x86_64-linux-gnu, and x86_64-linux-x32).
* nptl/pthreadP.h (ASSERT_PTHREAD_STRING,
ASSERT_PTHREAD_INTERNAL_OFFSET): New macro.
* nptl/pthread_mutex_init.c (__pthread_mutex_init): Add build time
checks for internal pthread_mutex_t offsets.
* sysdeps/aarch64/nptl/pthread-offsets.h
(__PTHREAD_MUTEX_NUSERS_OFFSET, __PTHREAD_MUTEX_KIND_OFFSET,
__PTHREAD_MUTEX_SPINS_OFFSET, __PTHREAD_MUTEX_ELISION_OFFSET,
__PTHREAD_MUTEX_LIST_OFFSET): New macro.
* sysdeps/alpha/nptl/pthread-offsets.h: Likewise.
* sysdeps/arm/nptl/pthread-offsets.h: Likewise.
* sysdeps/hppa/nptl/pthread-offsets.h: Likewise.
* sysdeps/i386/nptl/pthread-offsets.h: Likewise.
* sysdeps/ia64/nptl/pthread-offsets.h: Likewise.
* sysdeps/m68k/nptl/pthread-offsets.h: Likewise.
* sysdeps/microblaze/nptl/pthread-offsets.h: Likewise.
* sysdeps/mips/nptl/pthread-offsets.h: Likewise.
* sysdeps/nios2/nptl/pthread-offsets.h: Likewise.
* sysdeps/powerpc/nptl/pthread-offsets.h: Likewise.
* sysdeps/s390/nptl/pthread-offsets.h: Likewise.
* sysdeps/sh/nptl/pthread-offsets.h: Likewise.
* sysdeps/sparc/nptl/pthread-offsets.h: Likewise.
* sysdeps/tile/nptl/pthread-offsets.h: Likewise.
* sysdeps/x86_64/nptl/pthread-offsets.h: Likewise.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Update strcasestr-power8 to use power8 version of strnlen for
calculating length.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
This patch simplifies sighold a bit by removing an extra sigprocmask
and using SIG_BLOCK (which union of the current set and the set argument).
Checked on x86_64-linux-gnu.
* signal/sighold.c (sighold): Optimize implementation.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>
This patch simplify Linux sigqueue implementation by assuming
__NR_rt_sigqueueinfo existence due minimum kernel requirement
(it pre-dates Linux git inclusion for Linux 2.6.12).
Checked on x86_64-linux-gnu.
* sysdeps/unix/sysv/linux/sigqueue.c (__sigqueue): Asssume
__NR_rt_sigqueueinfo.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>
This patch simplifies sig{timed}wait{info} by:
- Assuming __NR_rt_sigtimedwait existence on all architectures due minimum
kernel version requirement (it pre-dates Linux git inclusion for Linux
2.6.12).
- Call __sigtimedwait on both sigwait and sigwaitinfo.
- Now that sigwait is based on an internal sigtimedwait call and it is
present of both libc.so and libpthread.so we need to add an external
private definition of __sigtimedwait for libpthread.so call.
Checked on x86_64-linux-gnu.
* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
__sigtimedwait.
* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
assume __NR_rt_sigtimedwait.
* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
and add LIBC_CANCEL_HANDLED for cancellation marking.
* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>
This patch refactor ARM memchr ifunc selector to a C implementation.
No functional change is expected, including ifunc resolution rules.
It also reorganize the ifunc options code:
1. The memchr_impl.S is renamed to memchr_neon.S and multiple
compilation options (which route to armv6t2/memchr one) is
removed. The code to build if __ARM_NEON__ is defined is
also simplified.
2. A memchr_noneon is added (which as build along previous ifunc
resolution) and includes the armv6t2 direct.
3. Same as 2. for loader object.
Alongside the aforementioned changes, it also some cleanus:
- Internal memchr definition (__GI_memcpy) is now a hidden
symbol.
- No need to create hidden definition for the ifunc variants.
Checked on armv7-linux-gnueabihf and with a build for arm-linux-gnueabi,
arm-linux-gnueabihf with and without multiarch support and with both
GCC 7.1 and GCC mainline.
* sysdeps/arm/armv7/multiarch/Makefile [$(subdir) = string]
(sysdeps_routines): Add memchr_noneon.
* sysdeps/arm/armv7/multiarch/ifunc-memchr.h: New file.
* sysdeps/arm/armv7/multiarch/memchr_noneon.S: Likewise.
* sysdeps/arm/armv7/multiarch/rtld-memchr.S: Likewise.
* sysdeps/arm/armv7/multiarch/memchr.S: Remove file.
* sysdeps/arm/armv7/multiarch/memchr.c: New file.
* sysdeps/arm/armv7/multiarch/memchr_impl.S: Move to ...
* sysdeps/arm/armv7/multiarch/memchr_neon.S: ... here.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch refactor ARM memcpy ifunc selector to a C implementation.
No functional change is expected, including ifunc resolution rules.
It also adds some cleanup:
- Internal memcpy hidden definition (__GI_memcpy) is now a hidden
symbol.
- No need to create hidden definition for the ifunc variants.
Checked on armv7-linux-gnueabihf and with a build for arm-linux-gnueabi,
arm-linux-gnueabihf with and without multiarch support and with both
GCC 7.1 and GCC mainline. I also checked with the some possible
multiarch different configurations that trigger different memcpy
buids (__ARM_NEON__ && !__SOFT_FP__, !__ARM_NEON__ && !__SOFT_FP__, and
!__ARM_NEON__ && __SOFT_FP__).
* sysdeps/arm/arm-ifunc.h: New file.
* sysdeps/arm/armv7/multiarch/ifunc-memcpy.h: Likewise.
* sysdeps/arm/armv7/multiarch/memcpy.c: Likewise.
* sysdeps/arm/armv7/multiarch/memcpy_arm.S: Likewise.
* sysdeps/arm/armv7/multiarch/rtld-memcpy.S: Likewise.
* sysdeps/arm/armv7/multiarch/memcpy_neon.S [!__ARM_NEON__]
(__memcpy_neon): Avoid create hidden alias.
* sysdeps/arm/armv7/multiarch/memcpy_vfp.S [!__ARM_NEON_]
(__memcpy_vfp): Likewise.
* sysdeps/arm/armv7/multiarch/Makefile [$(subdir) = string]
(sysdep_routines): Add memcpy_arm.
* sysdeps/arm/armv7/multiarch/memcpy.S: Remove file.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
When multi-lib GCC is used to build glibc, the search order of GCC driver
for crt*.o is -B*/`gcc -print-multi-directory`, the installed diretory,
-B*/. This patch adds multi-lib support to csu/Makefile so that
-B/glibc-build-directory/csu/ will pick up the newly built crt*.o.
Tested on x86-64 for i686 and x32.
[BZ #22362]
* Makerules (make-link-multidir): New.
* config.make.in (multidir): New.
* configure.ac (libc_cv_multidir): New. AC_SUBST.
* configure: Regenerated.
* csu/Makefile [$(multidir) != .](multilib-extra-objs): New.
[$(multidir) != .](extra-objs): Add $(multilib-extra-objs).
[$(multidir) != .]($(addprefix $(objpfx)$(multidir)/, $(install-lib))):
New target.
The powerpc bits/floatn.h declares _Float128 support to be present
when the compiler supports it for powerpc64le. However, in the case
where -mlong-double-64 is used, __MATH_TG does not actually support
_Float128; it only supports _Float128 in the distinct-long-double
case.
This shows up as a build failure when building glibc mainline with GCC
mainline, given the recently added sanity check in math.h for
configurations supported by __MATH_TG, as the compat code for
-mlong-double-64 fails to build. However, the bug was logically
present before that change (including in 2.26), just less visible.
This patch fixes the build failure by declaring _Float128 to be
unsupported in that case. (Of course this can't actually stop users
calling the type-generic macros with _Float128 arguments with
-mlong-double-64, just as they could be called with other unsupported
types on other platforms, but perhaps makes it less likely by making
all the type-specific _Float128 interfaces invisible in that case.)
Tested compilation for powerpc64le with build-many-glibcs.py.
[BZ #22402]
* sysdeps/powerpc/bits/floatn.h: Include <bits/long-double.h>.
[__NO_LONG_DOUBLE_MATH] (__HAVE_FLOAT128): Define to 0.
Continuing the preparation for additional _FloatN / _FloatNx type
support, this patch prepares __MATH_TG to handle more such types.
Various unhandled cases, which do not correspond to any current glibc
configuration, have explicit #errors added. _Float32 and _Float64x
are then handled appropriately in the _Generic case, which is the only
one, other than the cases where use of sizeof is sufficient, where
they should ever be explicit types at the language level instead of
typedefs. There is no need to handle _Float64 or _Float32x explicitly
there because the default case calling a double function is correct
for those types.
Tested for x86_64.
* math/math.h [__HAVE_DISTINCT_FLOAT16
|| __HAVE_DISTINCT_FLOAT32 || __HAVE_DISTINCT_FLOAT64
|| __HAVE_DISTINCT_FLOAT32X || __HAVE_DISTINCT_FLOAT64X
|| __HAVE_DISTINCT_FLOAT128X]: Use #error.
[__NO_LONG_DOUBLE_MATH && __HAVE_DISTINCT_FLOAT128]: Likewise.
[__HAVE_DISTINCT_FLOAT128 && !__HAVE_GENERIC_SELECTION
&& __HAVE_FLOATN_NOT_TYPEDEF]: Likewise.
[__HAVE_DISTINCT_FLOAT128 && __HAVE_GENERIC_SELECTION]
(__MATH_TG_F32): New macro.
[__HAVE_DISTINCT_FLOAT128 && __HAVE_GENERIC_SELECTION]
(__MATH_TG_F64X): Likewise.
[__HAVE_DISTINCT_FLOAT128 && __HAVE_GENERIC_SELECTION]
(__MATH_TG): Use __MATH_TG_F32 and __MATH_TG_F64X.
Continuing the preparation for additional _FloatN / _FloatNx type
support, this patch improves how <tgmath.h> handles such types.
Use of #error is added for cases of distinct types that are not
supported by the header, to indicate that additional work on the
header would be needed if, for example, _Float16 support were added to
glibc. Given that #error, types with the same format as other types
are handled automatically by the sizeof-based logic, so the only case
needing special handling is that where _Float64x exists, has the same
format as _Float128, does not have the same format as long double, and
is not a typedef for _Float128. In this case (which will apply for
powerpc64le once _Float64x support is added to glibc), the
__builtin_types_compatible_p calls testing for _Float128 need
corresponding calls testing for _Float64x, which this patch adds.
Tested for x86_64.
* math/tgmath.h [__HAVE_DISTINCT_FLOAT16
|| __HAVE_DISTINCT_FLOAT32 || __HAVE_DISTINCT_FLOAT64
|| __HAVE_DISTINCT_FLOAT32X || __HAVE_DISTINCT_FLOAT64X
|| __HAVE_DISTINCT_FLOAT128X]: Use #error.
[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_F128): Handle _Float64x
the same as _Float128.
[__HAVE_DISTINCT_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
&& __HAVE_FLOAT64X && !__HAVE_FLOAT64X_LONG_DOUBLE
&& __HAVE_FLOATN_NOT_TYPEDEF] (__TGMATH_CF128): Likewise.
Using the cache hierarchy linesize minimum in CTR_EL0.
See the comment within the code for rationale.
* sysdeps/unix/sysv/linux/aarch64/sysconf.c: New file.
Remove some load/store instructions from the dynamic tlsdesc resolver
fast path. This gives around 20% faster tls access in dlopened shared
libraries (assuming glibc ran out of static tls space).
* sysdeps/aarch64/dl-tlsdesc.S (_dl_tlsdesc_dynamic): Optimize.
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.
Always do TLS descriptor initialization at load time during relocation
processing to avoid barriers at every TLS access. In non-dlopened shared
libraries the overhead of tls access vs static global access is > 3x
bigger when lazy initialization is used (_dl_tlsdesc_return_lazy)
compared to bind-now (_dl_tlsdesc_return) so the barriers dominate tls
access performance.
TLSDESC relocs are in DT_JMPREL which are processed at load time using
elf_machine_lazy_rel which is only supposed to do lightweight
initialization using the DT_TLSDESC_PLT trampoline (the trampoline code
jumps to the entry point in DT_TLSDESC_GOT which does the lazy tlsdesc
initialization at runtime). This patch changes elf_machine_lazy_rel
in aarch64 to do the symbol binding and initialization as if DF_BIND_NOW
was set, so the non-lazy code path of elf/do-rel.h was replicated.
The static linker could be changed to emit TLSDESC relocs in DT_REL*,
which are processed non-lazily, but the goal of this patch is to always
guarantee bind-now semantics, even if the binary was produced with an
old linker, so the barriers can be dropped in tls descriptor functions.
After this change the synchronizing ldar instructions can be dropped
as well as the lazy initialization machinery including the DT_TLSDESC_GOT
setup.
I believe this should be done on all targets, including ones where no
barrier is needed for lazy initialization. There is very little gain in
optimizing for large number of symbolic tlsdesc relocations which is an
extremely uncommon case. And currently the tlsdesc entries are only
readonly protected with -z now and some hardennings against writable
JUMPSLOT relocs don't work for TLSDESC so they are a security hazard.
(But to fix that the static linker has to be changed.)
* sysdeps/aarch64/dl-machine.h (elf_machine_lazy_rel): Do symbol
binding and initialization non-lazily for R_AARCH64_TLSDESC.
These static functions are not needed if a target does not do lazy
tlsdesc initialization.
* elf/tlsdeschtab.h (_dl_tls_resolve_early_return_p): Mark unused.
(_dl_tlsdesc_wake_up_held_fixups): Likewise.
