Make the instructions for syscall list generation match Makefile and
refer to `update-syscall-lists'; there has been no `update-arch-syscall'
target. Also use single quotes around the command to stick to the ASCII
character set.
Fixes 4cf0d22305 ("Linux: Add tables with system call numbers").
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
To provide a y2038 safe interface a new symbol __shmctl64 is added
and __shmctl is change to call it instead (it adds some extra buffer
copying for the 32 bit time_t implementation).
Two new structures are added:
1. kernel_shmid64_ds: used internally only on 32-bit architectures
to issue the syscall. A handful of architectures (hppa, i386,
mips, powerpc32, and sparc32) require specific implementations
due to their kernel ABI.
2. shmid_ds64: this is only for __TIMESIZE != 64 to use along with
the 64-bit shmctl. It is different than the kernel struct because
the exported 64-bit time_t might require different alignment
depending on the architecture ABI.
So the resulting implementation does:
1. For 64-bit architectures it assumes shmid_ds already contains
64-bit time_t fields and will result in just the __shmctl symbol
using the __shmctl64 code. The shmid_ds argument is passed as-is
to the syscall.
2. For 32-bit architectures with default 64-bit time_t (newer ABIs
such riscv32 or arc), it will also result in only one exported
symbol but with the required high/low time handling.
3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t
support we follow the already set way to provide one symbol with
64-bit time_t support and implement the 32-bit time_t support
using of the 64-bit one.
The default 32-bit symbol will allocate and copy the shmid_ds
over multiple buffers, but this should be deprecated in favor
of the __shmctl64 anyway.
Checked on i686-linux-gnu and x86_64-linux-gnu. I also did some sniff
tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and
sparc64.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Each architecture overrides the struct msqid_ds which its required
kernel ABI one.
Checked on x86_64-linux-gnu and some bases sysvipc tests on hppa,
mips, mipsle, mips64, mips64le, sparc64, sparcv9, powerpc64le,
powerpc64, and powerpc.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This will allow us to have architectures specify their own version.
Not semantic changes expected. Checked with a build against the
all affected ABIs.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
To provide a y2038 safe interface a new symbol __msgctl64 is added
and __msgctl is change to call it instead (it adds some extra buffer
coping for the 32 bit time_t implementation).
Two new structures are added:
1. kernel_msqid64_ds: used internally only on 32-bit architectures
to issue the syscall. A handful of architectures (hppa, i386, mips,
powerpc32, and sparc32) require specific implementations due to
their kernel ABI.
2. msqid_ds64: this is only for __TIMESIZE != 64 to use along with
the 64-bit msgctl. It is different than the kernel struct because
the exported 64-bit time_t might require different alignment
depending on the architecture ABI.
So the resulting implementation does:
1. For 64-bit architectures it assumes msqid_ds already contains
64-bit time_t fields and will result in just the __msgctl symbol
using the __msgctl64 code. The msgid_ds argument is passed as-is
to the syscall.
2. For 32-bit architectures with default 64-bit time_t (newer ABIs
such riscv32 or arc), it will also result in only one exported
symbol but with the required high/low time handling.
3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t
support we follow the already set way to provide one symbol with
64-bit time_t support and implement the 32-bit time_t support using
the 64-bit time_t.
The default 32-bit symbol will allocate and copy the msqid_ds
over multiple buffers, but this should be deprecated in favor
of the __msgctl64 anyway.
Checked on i686-linux-gnu and x86_64-linux-gnu. I also did some sniff
tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and
sparc64.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Each architecture overrides the struct msqid_ds which its required
kernel ABI one.
Checked on x86_64-linux-gnu and some bases sysvipc tests on hppa,
mips, mipsle, mips64, mips64le, sparc64, sparcv9, powerpc64le,
powerpc64, and powerpc.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
This will allow us to have architectures specify their own version.
Not semantic changes expected. Checked with a build against the
all affected ABIs.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Different than others 64-bit time_t syscalls, the SysIPC interface
does not provide a new set of syscall for y2038 safeness. Instead it
uses unused fields in semid_ds structure to return the high bits for
the timestamps.
To provide a y2038 safe interface a new symbol __semctl64 is added
and __semctl is change to call it instead (it adds some extra buffer
copying for the 32 bit time_t implementation).
Two new structures are added:
1. kernel_semid64_ds: used internally only on 32-bit architectures
to issue the syscall. A handful of architectures (hppa, i386,
mips, powerpc32, sparc32) require specific implementations due
their kernel ABI.
2. semid_ds64: this is only for __TIMESIZE != 64 to use along with
the 64-bit semctl. It is different than the kernel struct because
the exported 64-bit time_t might require different alignment
depending on the architecture ABI.
So the resulting implementation does:
1. For 64-bit architectures it assumes semid_ds already contains
64-bit time_t fields and will result in just the __semctl symbol
using the __semctl64 code. The semid_ds argument is passed as-is
to the syscall.
2. For 32-bit architectures with default 64-bit time_t (newer ABIs
such riscv32 or arc), it will also result in only one exported
symbol but with the required high/low handling.
It might be possible to optimize it further to avoid the
kernel_semid64_ds to semun transformation if the exported ABI
for the architectures matches the expected kernel ABI, but the
implementation is already complex enough and don't think this
should be a hotspot in any case.
3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t
support we follow the already set way to provide one symbol with
64-bit time_t support and implement the 32-bit time_t support
using the 64-bit one.
The default 32-bit symbol will allocate and copy the semid_ds
over multiple buffers, but this should be deprecated in favor
of the __semctl64 anyway.
Checked on i686-linux-gnu and x86_64-linux-gnu. I also did some sniff
tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and
sparc64.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Vineet Gupta <vgupta@synopsys.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
On some targets static TLS surplus area can be used opportunistically
for dynamically loaded modules such that the TLS access then becomes
faster (TLSDESC and powerpc TLS optimization). However we don't want
all surplus TLS to be used for this optimization because dynamically
loaded modules with initial-exec model TLS can only use surplus TLS.
The new contract for surplus static TLS use is:
- libc.so can have up to 192 bytes of IE TLS,
- other system libraries together can have up to 144 bytes of IE TLS.
- Some "optional" static TLS is available for opportunistic use.
The optional TLS is now tunable: rtld.optional_static_tls, so users
can directly affect the allocated static TLS size. (Note that module
unloading with dlclose does not reclaim static TLS. After the optional
TLS runs out, TLS access is no longer optimized to use static TLS.)
The default setting of rtld.optional_static_tls is 512 so the surplus
TLS is 3*192 + 4*144 + 512 = 1664 by default, the same as before.
Fixes BZ #25051.
Tested on aarch64-linux-gnu and x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The new static TLS surplus size computation is
surplus_tls = 192 * (nns-1) + 144 * nns + 512
where nns is controlled via the rtld.nns tunable. This commit
accounts audit modules too so nns = rtld.nns + audit modules.
rtld.nns should only include the namespaces required by the
application, namespaces for audit modules are accounted on top
of that so audit modules don't use up the static TLS that is
reserved for the application. This allows loading many audit
modules without tuning rtld.nns or using up static TLS, and it
fixes
FAIL: elf/tst-auditmany
Note that DL_NNS is currently a hard upper limit for nns, and
if rtld.nns + audit modules go over the limit that's a fatal
error. By default rtld.nns is 4 which allows 12 audit modules.
Counting the audit modules is based on existing audit string
parsing code, we cannot use GLRO(dl_naudit) before the modules
are actually loaded.
TLS_STATIC_SURPLUS is 1664 bytes currently which is not enough to
support DL_NNS (== 16) number of dynamic link namespaces, if we
assume 192 bytes of TLS are reserved for libc use and 144 bytes
are reserved for other system libraries that use IE TLS.
A new tunable is introduced to control the number of supported
namespaces and to adjust the surplus static TLS size as follows:
surplus_tls = 192 * (rtld.nns-1) + 144 * rtld.nns + 512
The default is rtld.nns == 4 and then the surplus TLS size is the
same as before, so the behaviour is unchanged by default. If an
application creates more namespaces than the rtld.nns setting
allows, then it is not guaranteed to work, but the limit is not
checked. So existing usage will continue to work, but in the
future if an application creates more than 4 dynamic link
namespaces then the tunable will need to be set.
In this patch DL_NNS is a fixed value and provides a maximum to
the rtld.nns setting.
Static linking used fixed 2048 bytes surplus TLS, this is changed
so the same contract is used as for dynamic linking. With static
linking DL_NNS == 1 so rtld.nns tunable is forced to 1, so by
default the surplus TLS is reduced to 144 + 512 = 656 bytes. This
change is not expected to cause problems.
Tested on aarch64-linux-gnu and x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
this means that *always* libnsl is only built as shared library for
backward compatibility and the NSS modules libnss_nis and libnss_nisplus
are not built at all, libnsl's headers aren't installed.
This compatibility is kept only for architectures and ABIs that have
been added in or before version 2.28.
Replacement implementations based on TIRPC, which additionally support
IPv6, are available from <https://github.com/thkukuk/>.
This change does not affect libnss_compat which does not depended
on libnsl since 2.27 and thus can be used without NIS.
libnsl code depends on Sun RPC, e.g. on --enable-obsolete-rpc (installed
libnsl headers use installed Sun RPC headers), which will be removed in
the following commit.
RETURN_ADDRESS is used at several places in glibc to mean a valid
code address of the call site, but with pac-ret it may contain a
pointer authentication code (PAC), so its definition is adjusted.
This is gcc PR target/94891: __builtin_return_address should not
expose signed pointers to user code where it can cause ABI issues.
In glibc RETURN_ADDRESS is only changed if it is built with pac-ret.
There is no detection for the specific gcc issue because it is
hard to test and the additional xpac does not cause problems.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Currently gcc -pg -mbranch-protection=pac-ret passes signed return
address to _mcount, so _mcount now has to always strip pac from the
frompc since that's from user code that may be built with pac-ret.
This is gcc PR target/94791: signed pointers should not escape and get
passed across extern call boundaries, since that's an ABI break, but
because existing gcc has this issue we work it around in glibc until
that is resolved. This is compatible with a fixed gcc and it is a nop
on systems without PAuth support. The bug was introduced in gcc-7 with
-msign-return-address=non-leaf|all support which in gcc-9 got renamed
to -mbranch-protection=pac-ret|pac-ret+leaf|standard.
strip_pac uses inline asm instead of __builtin_aarch64_xpaclri since
that is not a documented api and not available in all supported gccs.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use return address signing in assembly files for functions that save
LR when pac-ret is enabled in the compiler.
The GNU property note for PAC-RET is not meaningful to the dynamic
linker so it is not strictly required, but it may be used to track
the security property of binaries. (The PAC-RET property is only set
if BTI is set too because BTI implies working GNU property support.)
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Return address signing requires unwinder support, which is
present in libgcc since >=gcc-7, however due to bugs the
support may be broken in <gcc-10 (and similarly there may
be issues in custom unwinders), so pac-ret is not always
safe to use. So in assembly code glibc should only use
pac-ret if the compiler uses it too. Unfortunately there
is no predefined feature macro for it set by the compiler
so pac-ret is inferred from the code generation.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
When glibc is built with branch protection (i.e. with a gcc configured
with --enable-standard-branch-protection), all glibc binaries should
be BTI compatible and marked as such.
It is easy to link BTI incompatible objects by accident and this is
silent currently which is usually not the expectation, so this is
changed into a link error. (There is no linker flag for failing on
BTI incompatible inputs so all warnings are turned into fatal errors
outside the test system when building glibc with branch protection.)
Unfortunately, outlined atomic functions are not BTI compatible in
libgcc (PR libgcc/96001), so to build glibc with current gcc use
'CC=gcc -mno-outline-atomics', this should be fixed in libgcc soon
and then glibc can be built and tested without such workarounds.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Binaries can opt-in to using BTI via an ELF object file marking.
The dynamic linker has to then mprotect the executable segments
with PROT_BTI. In case of static linked executables or in case
of the dynamic linker itself, PROT_BTI protection is done by the
operating system.
On AArch64 glibc uses PT_GNU_PROPERTY instead of PT_NOTE to check
the properties of a binary because PT_NOTE can be unreliable with
old linkers (old linkers just append the notes of input objects
together and add them to the output without checking them for
consistency which means multiple incompatible GNU property notes
can be present in PT_NOTE).
BTI property is handled in the loader even if glibc is not built
with BTI support, so in theory user code can be BTI protected
independently of glibc. In practice though user binaries are not
marked with the BTI property if glibc has no support because the
static linked libc objects (crt files, libc_nonshared.a) are
unmarked.
This patch relies on Linux userspace API that is not yet in a
linux release but in v5.8-rc1 so scheduled to be in Linux 5.8.
Co-authored-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Tailcalls must use x16 or x17 for the indirect branch instruction
to be compatible with code that uses BTI c at function entries.
(Other forms of indirect branches can only land on BTI j.)
Also added a BTI c at the ELF entry point of rtld, this is not
strictly necessary since the kernel does not use indirect branch
to get there, but it seems safest once building glibc itself with
BTI is supported.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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.
