setcontext returns to the specified context via an indirect jump,
so there should be a BTI j.
In case of getcontext (and all other returns_twice functions) the
compiler adds BTI j at the call site, but swapcontext is a normal
c call that is currently not handled specially by the compiler.
So we change swapcontext such that the saved context returns to a
local address that has BTI j and then swapcontext returns to the
caller via a normal RET. For this we save the original return
address in the slot for x1 of the context because x1 need not be
preserved by swapcontext but it is restored when the context saved
by swapcontext is resumed.
The alternative fix (which is done on x86) would make swapcontext
special in the compiler so BTI j is emitted at call sites, on
x86 there is an indirect_return attribute for this, on AArch64
we would have to use returns_twice. It was decided against because
such fix may need user code updates: the attribute has to be added
when swapcontext is called via a function pointer and it breaks
always_inline functions with swapcontext.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To enable building glibc with branch protection, assembly code
needs BTI landing pads and ELF object file markings in the form
of a GNU property note.
The landing pads are unconditionally added to all functions that
may be indirectly called. When the code segment is not mapped
with PROT_BTI these instructions are nops. They are kept in the
code when BTI is not supported so that the layout of performance
critical code is unchanged across configurations.
The GNU property notes are only added when there is support for
BTI in the toolchain, because old binutils does not handle the
notes right. (Does not know how to merge them nor to put them in
PT_GNU_PROPERTY segment instead of PT_NOTE, and some versions
of binutils emit warnings about the unknown GNU property. In
such cases the produced libc binaries would not have valid
ELF marking so BTI would not be enabled.)
Note: functions using ENTRY or ENTRY_ALIGN now start with an
additional BTI c, so alignment of the following code changes,
but ENTRY_ALIGN_AND_PAD was fixed so there is no change to the
existing code layout. Some string functions may need to be
tuned for optimal performance after this commit.
Co-authored-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The compiler can add required elf markings based on CFLAGS
but the assembler cannot, so using C code for empty files
creates less of a maintenance problem.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Check BTI support in the compiler and linker. The check also
requires READELF that understands the BTI GNU property note.
It is expected to succeed with gcc >=gcc-9 configured with
--enable-standard-branch-protection and binutils >=binutils-2.33.
Note: passing -mbranch-protection=bti in CFLAGS when building glibc
may not be enough to get a glibc that supports BTI because crtbegin*
and crtend* provided by the compiler needs to be BTI compatible too.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Using C code allows the compiler to add target specific object file
markings based on CFLAGS.
The arm specific abi-note.S is removed and similar object file fix
up will be avoided on AArch64 with standard branch protection.
Add generic code to handle PT_GNU_PROPERTY notes. Invalid
content is ignored, _dl_process_pt_gnu_property is always called
after PT_LOAD segments are mapped and it has no failure modes.
Currently only one NT_GNU_PROPERTY_TYPE_0 note is handled, which
contains target specific properties: the _dl_process_gnu_property
hook is called for each property.
The old _dl_process_pt_note and _rtld_process_pt_note differ in how
the program header is read. The old _dl_process_pt_note is called
before PT_LOAD segments are mapped and _rtld_process_pt_note is called
after PT_LOAD segments are mapped. The old _rtld_process_pt_note is
removed and _dl_process_pt_note is always called after PT_LOAD
segments are mapped and now it has no failure modes.
The program headers are scanned backwards so that PT_NOTE can be
skipped if PT_GNU_PROPERTY exists.
Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Unsigned branch instructions could be used for r2 to fix the wrong
behavior when a negative length is passed to memcpy.
This commit fixes the armv7 version.
Unsigned branch instructions could be used for r2 to fix the wrong
behavior when a negative length is passed to memcpy and memmove.
This commit fixes the generic arm implementation of memcpy amd memmove.
The strerrorname_np returns error number name (e.g. "EINVAL" for EINVAL)
while strerrordesc_np returns string describing error number (e.g
"Invalid argument" for EINVAL). Different than strerror,
strerrordesc_np does not attempt to translate the return description,
both functions return NULL for an invalid error number.
They should be used instead of sys_errlist and sys_nerr, both are
thread and async-signal safe. These functions are GNU extensions.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The sigabbrev_np returns the abbreviated signal name (e.g. "HUP" for
SIGHUP) while sigdescr_np returns the string describing the error
number (e.g "Hangup" for SIGHUP). Different than strsignal,
sigdescr_np does not attempt to translate the return description and
both functions return NULL for an invalid signal number.
They should be used instead of sys_siglist or sys_sigabbrev and they
are both thread and async-signal safe. They are added as GNU
extensions on string.h header (same as strsignal).
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Use snprintf instead of mempcpy plus itoa_word and remove unused
definitions. There is no potential for infinite recursion because
snprintf only use strerror_r for the %m specifier.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The buffer allocation uses the same strategy of strsignal.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
If the thread is terminated then __libc_thread_freeres will free the
storage via __glibc_tls_internal_free.
It is only within the calling thread that this matters. It makes
strerror MT-safe.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The per-thread state is refactored two use two strategies:
1. The default one uses a TLS structure, which will be placed in the
static TLS space (using __thread keyword).
2. Linux allocates via struct pthread and access it through THREAD_*
macros.
The default strategy has the disadvantage of increasing libc.so static
TLS consumption and thus decreasing the possible surplus used in
some scenarios (which might be mitigated by BZ#25051 fix).
It is used only on Hurd, where accessing the thread storage in the in
single thread case is not straightforward (afaiu, Hurd developers could
correct me here).
The fallback static allocation used for allocation failure is also
removed: defining its size is problematic without synchronizing with
translated messages (to avoid partial translation) and the resulting
usage is not thread-safe.
Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The __NSIG_WORDS value is based on minimum number of words to hold
the maximum number of signals supported by the architecture.
This patch also adds __NSIG_BYTES, which is the number of bytes
required to represent the supported number of signals. It is used in
syscalls which takes a sigset_t.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The symbol is deprecated by strerror since its usage imposes some issues
such as copy relocations.
Its internal name is also changed to _sys_errlist_internal to avoid
static linking usage. The compat code is also refactored by removing
the over enginered errlist-compat.c generation from manual entried and
extra comment token in linker script file. It disantangle the code
generation from manual and simplify both Linux and Hurd compat code.
The definitions from errlist.c are moved to errlist.h and a new test
is added to avoid a new errno entry without an associated one in manual.
Checked on x86_64-linux-gnu and i686-linux-gnu. I also run a check-abi
on all affected platforms.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The symbol was deprecated by strsignal and its usage imposes issues
such as copy relocations.
Its internal name is changed to __sys_siglist and __sys_sigabbrev to
avoid static linking usage. The compat code is also refactored, since
both Linux and Hurd usage the same strategy: export the same array with
different object sizes.
The libSegfault change avoids calling strsignal on the SIGFAULT signal
handler (the current usage is already sketchy, adding a call that
potentially issue locale internal function is even sketchier).
Checked on x86_64-linux-gnu and i686-linux-gnu. I also run a check-abi
on all affected platforms.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
It refactor how signals are defined by each architecture. Instead of
include a generic header (bits/signum-generic.h) and undef non-default
values in an arch specific header (bits/signum.h) the new scheme uses a
common definition (bits/signum-generic.h) and each architectures add
its specific definitions on a new header (bits/signum-arch.h).
For Linux it requires copy some system default definitions to alpha,
hppa, and sparc. They are historical values and newer ports uses
the generic Linux signum-arch.h.
For Hurd the BSD signum is removed and moved to a new header (it is
used currently only on Hurd).
Checked on a build against all affected ABIs.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Add x86_rep_movsb_threshold and x86_rep_stosb_threshold to tunables
to update thresholds for "rep movsb" and "rep stosb" at run-time.
Note that the user specified threshold for "rep movsb" smaller than
the minimum threshold will be ignored.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
In TS 18661-1, getpayload had an unspecified return value for a
non-NaN argument, while C2x requires the return value -1 in that case.
This patch implements the return value of -1. I don't think this is
worth having a new symbol version that's an alias of the old one,
although occasionally we do that in such cases where the new function
semantics are a refinement of the old ones (to avoid programs relying
on the new semantics running on older glibc versions but not behaving
as intended).
Tested for x86_64 and x86; also ran math/ tests for aarch64 and
powerpc.
An extension called extended feature disable (XFD) is an extension added
for Intel AMX to the XSAVE feature set that allows an operating system
to enable a feature while preventing specific user threads from using
the feature.
The variable is placed in libc.so, and it can be true only in
an outer libc, not libcs loaded via dlmopen or static dlopen.
Since thread creation from inner namespaces does not work,
pthread_create can update __libc_single_threaded directly.
Using __libc_early_init and its initial flag, implementation of this
variable is very straightforward. A future version may reset the flag
during fork (but not in an inner namespace), or after joining all
threads except one.
Reviewed-by: DJ Delorie <dj@redhat.com>
These tests validate that rseq is registered from various execution
contexts (main thread, destructor, other threads, other threads created
from destructor, forked process (without exec), pthread_atfork handlers,
pthread setspecific destructors, signal handlers, atexit handlers).
tst-rseq.c only links against libc.so, testing registration of rseq in
a non-multithreaded environment.
tst-rseq-nptl.c also links against libpthread.so, testing registration
of rseq in a multithreaded environment.
See the Linux kernel selftests for extensive rseq stress-tests.
When available, use the cpu_id field from __rseq_abi on Linux to
implement sched_getcpu(). Fall-back on the vgetcpu vDSO if unavailable.
Benchmarks:
x86-64: Intel E5-2630 v3@2.40GHz, 16-core, hyperthreading
glibc sched_getcpu(): 13.7 ns (baseline)
glibc sched_getcpu() using rseq: 2.5 ns (speedup: 5.5x)
inline load cpuid from __rseq_abi TLS: 0.8 ns (speedup: 17.1x)
Register rseq TLS for each thread (including main), and unregister for
each thread (excluding main). "rseq" stands for Restartable Sequences.
See the rseq(2) man page proposed here:
https://lkml.org/lkml/2018/9/19/647
Those are based on glibc master branch commit 3ee1e0ec5c.
The rseq system call was merged into Linux 4.18.
The TLS_STATIC_SURPLUS define is increased to leave additional room for
dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working.
The increase (76 bytes) is larger than 32 bytes because it has not been
increased in quite a while. The cost in terms of additional TLS storage
is quite significant, but it will also obscure some initial-exec-related
dlopen failures.
The time argument is NULL in this case, and attempt to convert it
leads to a null pointer dereference.
This fixes commit d2e3b697da
("y2038: linux: Provide __settimeofday64 implementation").
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch updates the kernel version in the test tst-mman-consts.py
to 5.7. (There are no new constants covered by this test in 5.7 that
need any other header changes; there's a new MREMAP_DONTUNMAP, but
this test doesn't yet cover MREMAP_*.)
Tested with build-many-glibcs.py.
1. Add the directories to hold POWER10 files.
2. Add support to select POWER10 libraries based on AT_PLATFORM.
3. Let submachine=power10 be set automatically.
* hurd/hurdselect.c: Include <sysdep-cancel.h>.
(_hurd_select): Surround call to __mach_msg with enabling async cancel.
* sysdeps/mach/hurd/accept4.c: Include <sysdep-cancel.h>.
(__libc_accept4): Surround call to __socket_accept with enabling async cancel,
and use HURD_DPORT_USE_CANCEL instead of HURD_DPORT_USE.
* sysdeps/mach/hurd/connect.c: Include <sysdep-cancel.h>.
(__connect): Surround call to __file_name_lookup and __socket_connect
with enabling async cancel, and use HURD_DPORT_USE_CANCEL instead of
HURD_DPORT_USE.
* sysdeps/mach/hurd/fdatasync.c: Include <sysdep-cancel.h>.
(fdatasync): Surround call to __file_sync with enabling async cancel, and use
HURD_DPORT_USE_CANCEL instead of HURD_DPORT_USE.
* sysdeps/mach/hurd/fsync.c: Include <sysdep-cancel.h>.
(fsync): Surround call to __file_sync with enabling async cancel, and use
HURD_DPORT_USE_CANCEL instead of HURD_DPORT_USE.
* sysdeps/mach/hurd/ioctl.c: Include <sysdep-cancel.h>.
(__ioctl): When request is TIOCDRAIN, surround call to send_rpc with enabling
async cancel, and use HURD_DPORT_USE_CANCEL instead of HURD_DPORT_USE.
* sysdeps/mach/hurd/msync.c: Include <sysdep-cancel.h>.
(msync): Surround call to __vm_object_sync with enabling async cancel.
* sysdeps/mach/hurd/sigsuspend.c: Include <sysdep-cancel.h>.
(__sigsuspend): Surround call to __mach_msg with enabling async cancel.
* sysdeps/mach/hurd/sigwait.c: Include <sysdep-cancel.h>.
(__sigwait): Surround wait code with enabling async cancel.
* sysdeps/mach/msync.c: Include <sysdep-cancel.h>.
(msync): Surround call to __vm_msync with enabling async cancel.
* sysdeps/mach/sleep.c: Include <sysdep-cancel.h>.
(__sleep): Surround call to __mach_msg with enabling async cancel.
* sysdeps/mach/usleep.c: Include <sysdep-cancel.h>.
(usleep): Surround call to __vm_msync with enabling async cancel.
and add _nocancel variant.
* sysdeps/mach/hurd/Makefile [io] (sysdep_routines): Add fcntl_nocancel.
* sysdeps/mach/hurd/fcntl.c [NOCANCEL]: Include <not-cancel.h>.
[!NOCANCEL]: Include <sysdep-cancel.h>.
(__libc_fcntl) [!NOCANCEL]: Surround __file_record_lock call with enabling async cancel, and use HURD_FD_PORT_USE_CANCEL instead of HURD_FD_PORT_USE.
* sysdeps/mach/hurd/fcntl_nocancel.c: New file, defines __fcntl_nocancel by including fcntl.c.
* sysdeps/mach/hurd/not-cancel.h (__fcntl64_nocancel): Replace macro with
__fcntl_nocancel declaration with hidden proto, and make
__fcntl64_nocancel call __fcntl_nocancel.
and add _nocancel variant.
* sysdeps/mach/hurd/Makefile [io] (sysdep_routines): Add wait4_nocancel.
* sysdeps/mach/hurd/wait4.c: Include <sysdep-cancel.h>
(__wait4): Surround __proc_wait with enabling async cancel, and use
__USEPORT_CANCEL instead of __USEPORT.
* sysdeps/mach/hurd/wait4_nocancel.c: New file, contains previous
implementation of __wait4.
* sysdeps/mach/hurd/not-cancel.h (__waitpid_nocancel): Replace macro with
__wait4_nocancel declaration with hidden proto, and make
__waitpid_nocancel call __wait4_nocancel.
HURD_*PORT_USE link fd and port with a stack-stored structure, so on
thread cancel we need to cleanup this.
* hurd/fd-cleanup.c: New file.
* hurd/port-cleanup.c (_hurd_port_use_cleanup): New function.
* hurd/Makefile (routines): Add fd-cleanup.
* sysdeps/hurd/include/hurd.h (__USEPORT_CANCEL): New macro.
* sysdeps/hurd/include/hurd/fd.h (_hurd_fd_port_use_data): New
structure.
(_hurd_fd_port_use_cleanup): New prototype.
(HURD_DPORT_USE_CANCEL, HURD_FD_PORT_USE_CANCEL): New macros.
* sysdeps/hurd/include/hurd/port.h (_hurd_port_use_data): New structure.
(_hurd_port_use_cleanup): New prototype.
(HURD_PORT_USE_CANCEL): New macro.
* hurd/hurd/fd.h (HURD_FD_PORT_USE): Also refer to HURD_FD_PORT_USE_CANCEL.
* hurd/hurd.h (__USEPORT): Also refer to __USEPORT_CANCEL.
* hurd/hurd/port.h (HURD_PORT_USE): Also refer to HURD_PORT_USE_CANCEL.
* hurd/fd-read.c (_hurd_fd_read): Call HURD_FD_PORT_USE_CANCEL instead
of HURD_FD_PORT_USE.
* hurd/fd-write.c (_hurd_fd_write): Likewise.
* sysdeps/mach/hurd/send.c (__send): Call HURD_DPORT_USE_CANCEL instead
of HURD_DPORT_USE.
* sysdeps/mach/hurd/sendmsg.c (__libc_sendmsg): Likewise.
* sysdeps/mach/hurd/sendto.c (__sendto): Likewise.
* sysdeps/mach/hurd/recv.c (__recv): Likewise.
* sysdeps/mach/hurd/recvfrom.c (__recvfrom): Likewise.
* sysdeps/mach/hurd/recvmsg.c (__libc_recvmsg): Call __USEPORT_CANCEL
instead of __USEPORT, and HURD_DPORT_USE_CANCEL instead of
HURD_DPORT_USE.
This adds sysdeps/htl/libc-lock.h which augments sysdeps/mach/libc-lock.h with
the htl-aware cleanup handling. Otherwise inclusion of libc-lock.h
without libc-lockP.h would keep only the mach-aware handling.
This also fixes cleanup getting called when the binary is
statically-linked without libpthread.
* sysdeps/htl/libc-lockP.h (__libc_cleanup_region_start,
__libc_cleanup_end, __libc_cleanup_region_end,
__pthread_get_cleanup_stack): Move to...
* sysdeps/htl/libc-lock.h: ... new file.
(__libc_cleanup_region_start): Always set handler and arg.
(__libc_cleanup_end): Always call the cleanup handler.
(__libc_cleanup_push, __libc_cleanup_pop): New macros.
These only need exactly to use __libc_ptf_call.
* sysdeps/htl/flockfile.c: Include <libc-lockP.h> instead of
<libc-lock.h>
* sysdeps/htl/ftrylockfile.c: Include <libc-lockP.h> instead of
<errno.h>, <pthread.h>, <stdio-lock.h>
* sysdeps/htl/funlockfile.c: Include <libc-lockP.h> instead of
<pthread.h> and <stdio-lock.h>
Like hurd_thread_cancel does.
* sysdeps/mach/hurd/htl/pt-docancel.c: Include <hurd/signal.h>
(__pthread_do_cancel): Lock target thread's critical_section_lock and ss
lock around thread mangling.
Intel Advanced Matrix Extensions (Intel AMX) is a new programming
paradigm consisting of two components: a set of 2-dimensional registers
(tiles) representing sub-arrays from a larger 2-dimensional memory image,
and accelerators able to operate on tiles. Intel AMX is an extensible
architecture. New accelerators can be added and the existing accelerator
may be enhanced to provide higher performance. The initial features are
AMX-BF16, AMX-TILE and AMX-INT8, which are usable only if the operating
system supports both XTILECFG state and XTILEDATA state.
Add AMX-BF16, AMX-TILE and AMX-INT8 support to HAS_CPU_FEATURE and
CPU_FEATURE_USABLE.
It turned out that an 256b-mvc instruction which depends on the
result of a previous 256b-mvc instruction is counterproductive.
Therefore this patch adjusts the 256b-loop by storing the
first byte with stc and setting the remaining 255b with mvc.
Now the 255b-mvc instruction depends on the stc instruction.
This patch introduces an extra loop without pfd instructions
as it turned out that the pfd instructions are usefull
for copies >=64KB but are counterproductive for smaller copies.
