Update ifunc-memset.h/ifunc-wmemset.h to select the function optimized
with AVX512 instructions using ZMM16-ZMM31 registers to avoid RTM abort
with usable AVX512VL and AVX512BW since VZEROUPPER isn't needed at
function exit.
At function exit, AVX optimized string/memory functions have VZEROUPPER
which triggers RTM abort. When such functions are called inside a
transactionally executing RTM region, RTM abort causes severe performance
degradation. Add tests to verify that string/memory functions won't
cause RTM abort in RTM region.
Since VZEROUPPER triggers RTM abort while VZEROALL won't, select AVX
optimized string/memory functions with
xtest
jz 1f
vzeroall
ret
1:
vzeroupper
ret
at function exit on processors with usable RTM, but without 256-bit EVEX
instructions to avoid VZEROUPPER inside a transactionally executing RTM
region.
Update ifunc-memcmp.h to select the function optimized with 256-bit EVEX
instructions using YMM16-YMM31 registers to avoid RTM abort with usable
AVX512VL, AVX512BW and MOVBE since VZEROUPPER isn't needed at function
exit.
Update ifunc-memset.h/ifunc-wmemset.h to select the function optimized
with 256-bit EVEX instructions using YMM16-YMM31 registers to avoid RTM
abort with usable AVX512VL and AVX512BW since VZEROUPPER isn't needed at
function exit.
Update ifunc-memmove.h to select the function optimized with 256-bit EVEX
instructions using YMM16-YMM31 registers to avoid RTM abort with usable
AVX512VL since VZEROUPPER isn't needed at function exit.
Update ifunc-strcpy.h to select the function optimized with 256-bit EVEX
instructions using YMM16-YMM31 registers to avoid RTM abort with usable
AVX512VL and AVX512BW since VZEROUPPER isn't needed at function exit.
Update ifunc-avx2.h, strchr.c, strcmp.c, strncmp.c and wcsnlen.c to
select the function optimized with 256-bit EVEX instructions using
YMM16-YMM31 registers to avoid RTM abort with usable AVX512VL, AVX512BW
and BMI2 since VZEROUPPER isn't needed at function exit.
For strcmp/strncmp, prefer AVX2 strcmp/strncmp if Prefer_AVX2_STRCMP
is set.
1. Set Prefer_No_VZEROUPPER if RTM is usable to avoid RTM abort triggered
by VZEROUPPER inside a transactionally executing RTM region.
2. Since to compare 2 32-byte strings, 256-bit EVEX strcmp requires 2
loads, 3 VPCMPs and 2 KORDs while AVX2 strcmp requires 1 load, 2 VPCMPEQs,
1 VPMINU and 1 VPMOVMSKB, AVX2 strcmp is faster than EVEX strcmp. Add
Prefer_AVX2_STRCMP to prefer AVX2 strcmp family functions.
The tests are refactored to use a common skeleton that handles whether
the underlying filesystem supports 64 bit time, skips 64 bit time
tests when the TU only supports 32 bit, and also skip 64 bit time
tests larger than 32 unsigned int (y2106) if the system does not
support it (MIPSn64 on kernels without statx support).
Checked on x86_64-linux-gnu and i686-linux-gnu. I also checked
on a mips64el-linux-gnu with 4.1.4 and 5.10.0-4-5kc-malta kernel
to verify if the y2106 are indeed skipped.
MIPSn64 kernel ABI for legacy stat uses unsigned 32 bit for second
timestamp, which limits the maximum value to y2106. This patch
make mips64 use statx as for 32-bit architectures.
Thie __cp_stat64_t64_statx is open coded, its usage is solely on
fstatat64 and it avoid the need to redefine the name for mips64
(which will call __cp_stat64_statx since its does not use
__stat64_t64 internally).
If the minimum kernel supports statx there is no need to call the
fallback stat legacy syscalls.
The statx is also called on compat xstat syscall, but different
than the fstatat it calls no fallback and it is assumed to be
always present.
Checked on powerpc-linux-gnu (with and without --enable-kernel=4.11)
and on powerpc64-linux-gnu.
It makes fstatat use __NR_statx, which fix the s390 issue with
missing nanoxsecond support on compat stat syscalls (at least
on recent kernels) and limits the statx call to only one function
(which simplifies the __ASSUME_STATX support).
Checked on i686-linux-gnu and on powerpc-linux-gnu.
1. Support GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVE.
2. Disable all features which depend on XSAVE:
a. If OSXSAVE is disabled by glibc tunables. Or
b. If both XSAVE and XSAVEC aren't usable.
The Linux version already target the current thread by using tgkill
along with getpid and gettid.
For arm, libpthread does not do a intra PLT since it will call the
raise from libc.
Checked on x86_64-linux-gnu.
The libc version is identical and built with same flags. The libc
version is set as the default version.
The libpthread compat symbol requires to mask it when building the
loader object otherwise ld might complain about a missing
versioned symbol (as for alpha).
Checked on x86_64-linux-gnu.
The libc version is identical and built with same flags. Both aarch64
and nios2 also requires to export __send and tt was done previously with
the HAVE_INTERNAL_SEND_SYMBOL (which forced the symbol creation).
All __send callers are internal to libc and the original issue that
required the symbol export was due a missing libc_hidden_def. So
a compat symbol is added for __send and the libc_hidden_def is
defined regardless.
Checked on x86_64-linux-gnu and i686-linux-gnu.
This is a target hook for memory tagging, the original was a naive
implementation. Uses the same algorithm as __libc_mtag_tag_region,
but with instructions that also zero the memory. This was not
benchmarked on real cpu, but expected to be faster than the naive
implementation.
This is a target hook for memory tagging, the original was a naive
implementation. The optimized version relies on "dc gva" to tag 64
bytes at a time for large allocations and optimizes small cases without
adding too many branches. This was not benchmarked on real cpu, but
expected to be faster than the naive implementation.
This is a common operation when heap tagging is enabled, so inline the
instruction instead of using an extern call.
The .inst directive is used instead of the name of the instruction (or
acle intrinsics) because malloc.c is not compiled for armv8.5-a+memtag
architecture, runtime cpu support detection is used.
Prototypes are removed from the comments as they were not always
correct.
The memset api is suboptimal and does not provide much benefit. Memory
tagging only needs a zeroing memset (and only for memory that's sized
and aligned to multiples of the tag granule), so change the internal
api and the target hooks accordingly. This is to simplify the
implementation of the target hook.
Reviewed-by: DJ Delorie <dj@redhat.com>
Use inline functions instead of macros, because macros can cause unused
variable warnings and type conversion issues. We assume these functions
may appear in the code but only in dead code paths (hidden by a runtime
check), so it's important that they can compile with correct types, but
if they are actually used that should be an error.
Currently the hooks are only used when USE_MTAG is true which only
happens on aarch64 and then the aarch64 specific code is used not this
generic header. However followup refactoring will allow the hooks to
be used with !USE_MTAG.
Note: the const qualifier in the comment was wrong: changing tags is a
write operation.
Reviewed-by: DJ Delorie <dj@redhat.com>
The arch13 memmove variant is currently selected by the ifunc selector
if the Miscellaneous-Instruction-Extensions Facility 3 facility bit
is present, but the function is also using vector instructions.
If the vector support is not present, one is receiving an operation
exception.
Therefore this patch also checks for vector support in the ifunc
selector and in ifunc-impl-list.c.
Just to be sure, the configure check is now also testing an arch13
vector instruction and an arch13 Miscellaneous-Instruction-Extensions
Facility 3 instruction.
This essentially folds compat_symbol_unique functionality into
compat_symbol.
This change eliminates the need for intermediate aliases for defining
multiple symbol versions, for both compat_symbol and versioned_symbol.
Some binutils versions do not suport multiple versions per symbol on
some targets, so aliases are automatically introduced, similar to what
compat_symbol_unique did. To reduce symbol table sizes, a configure
check is added to avoid these aliases if they are not needed.
The new mechanism works with data symbols as well as function symbols,
due to the way an assembler-level redirect is used. It is not
compatible with weak symbols for old binutils versions, which is why
the definition of __malloc_initialize_hook had to be changed. This
is not a loss of functionality because weak symbols do not matter
to dynamic linking.
The placeholder symbol needs repeating in nptl/libpthread-compat.c
now that compat_symbol is used, but that seems more obvious than
introducing yet another macro.
A subtle difference was that compat_symbol_unique made the symbol
global automatically. compat_symbol does not do this, so static
had to be removed from the definition of
__libpthread_version_placeholder.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
A subsequent change will require including <config.h> for defining
symbol_version_reference. <libc-symbol.h> should not include
<config.h> for _ISOMAC, so it cannot define symbol_version_reference
anymore, but symbol_version_reference is needed <shlib-compat.h> even
for _ISOMAC. Moving the definition of symbol_version_reference to a
separate file <libc-symver.h> makes it possible to use a single
definition for both cases.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2b47727c68 ("posix: Consolidate register-atfork") introduced a fork.h
header to declare the atfork unregister hook, but was missing adding it
for htl.
This fixes tst-atfork2.
During critical sections, signal handling is deferred and thus RPCs return
EINTR, even if SA_RESTART is set. We thus have to restart the whole critical
section in that case.
This also adds HURD_CRITICAL_UNLOCK in the cases where one wants to
break the section in the middle.
This change adds new test to assess sigtimedwait's timeout related
functionality - the sigset_t is configured for SIGUSR1, which will
not be triggered, so sigtimedwait just waits for timeout.
To be more specific - two use cases are checked:
- if sigtimedwait times out immediately when passed struct timespec has
zero values of tv_nsec and tv_sec.
- if sigtimedwait times out after timeout specified in passed argument
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This code provides test to check if time on target machine is properly
read via ntp_gettime syscall.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
After this patch applied the ntp_gettimex function is always declared
in the sys/timex.h header. Currently it is not when __REDIRECT_NTH is
defined (i.e. in ARM 32 bit port).
The generic implementation basically handle the system agnostic logic
(filtering out the invalid signals) while the __libc_sigaction is
the function with implements the system and architecture bits.
Checked on x86_64-linux-gnu and i686-linux-gnu.
