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Linux 6.5 adds a new AArch64 HWCAP2 value, HWCAP2_MOPS. Add it to
glibc's bits/hwcap.h.
Tested with build-many-glibcs.py for aarch64-linux-gnu.
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Linux 6.5 adds a constant SCM_PIDFD (recall that the non-uapi
linux/socket.h, where this constant is added, is in fact a header
providing many constants that are part of the kernel/userspace
interface). This shows up that SCM_SECURITY, from the same set of
definitions and added in Linux 2.6.17, is also missing from glibc,
although glibc has the first two constants from this set, SCM_RIGHTS
and SCM_CREDENTIALS; add both missing constants to glibc.
Tested for x86_64.
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Linux 6.5 adds a constant AT_HANDLE_FID; add it to glibc. Because
this is a flag for the function name_to_handle_at declared in
bits/fcntl-linux.h, put the flag there rather than alongside other
AT_* flags in (OS-independent) fcntl.h.
Tested for x86_64.
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With GCC 14 on 32-bit x86 the compiler emits a maybe-uninitialized
warning:
../sysdeps/ieee754/dbl-64/k_rem_pio2.c: In function '__kernel_rem_pio2':
../sysdeps/ieee754/dbl-64/k_rem_pio2.c:364:20: error: 'fq' may be used uninitialized [-Werror=maybe-uninitialized]
364 | y[0] = fq[0]; y[1] = fq[1]; y[2] = fw;
| ~~^~~
This is similar to the warning that is suppressed in the other branch of
the switch. Help the compiler knowing that the variable is always
initialized, which also makes the suppression obsolete.
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This commit refactors `strrchr-evex` and `strrchr-evex512` to use a
common implementation: `strrchr-evex-base.S`.
The motivation is `strrchr-evex` needed to be refactored to not use
64-bit masked registers in preperation for AVX10.
Once vec-width masked register combining was removed, the EVEX and
EVEX512 implementations can easily be implemented in the same file
without any major overhead.
The net result is performance improvements (measured on TGL) for both
`strrchr-evex` and `strrchr-evex512`. Although, note there are some
regressions in the test suite and it may be many of the cases that
make the total-geomean of improvement/regression across bench-strrchr
are cold. The point of the performance measurement is to show there
are no major regressions, but the primary motivation is preperation
for AVX10.
Benchmarks where taken on TGL:
https://www.intel.com/content/www/us/en/products/sku/213799/intel-core-i711850h-processor-24m-cache-up-to-4-80-ghz/specifications.html
EVEX geometric_mean(N=5) of all benchmarks New / Original : 0.74
EVEX512 geometric_mean(N=5) of all benchmarks New / Original: 0.87
Full check passes on x86.
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* Transpose table layout for improved memory access
* Use half-vector special comparisons for AdvSIMD
* Improve register use near special-case branches
- Due to the presence of a function call, return value would get
mov-d out of x0 in order to facilitate PCS. By moving the final
computation after the branch this can be avoided
Also change SVE routines to use overloaded intrinsics for readability.
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Use overloaded intrinsics for readability. Codegen does not
change, however while we're bringing the routines up-to-date with
recent improvements to other routines in AOR it is worth copying
this change over as well.
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Saves a mov by ensuring return value does not need to be moved out of
the way before special-case branch. Also change to use overloaded
intrinsics.
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* Update ULP comment reflecting a new observed max in [-pi/2, pi/2]
* Use the same polynomial in AdvSIMD and SVE, rather than FTRIG instructions
* Improve register use near special-case branch
Also use overloaded intrinsics for SVE.
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When -D_FORTIFY_SOURCE=2 was given during compilation,
sprintf and similar functions will check if their
first argument is in read-only memory and exit with
*** %n in writable segment detected ***
otherwise. To check if the memory is read-only, glibc
reads frpm the file "/proc/self/maps". If opening this
file fails due to too many open files (EMFILE), glibc
will now ignore this error.
Fixes [BZ #30932]
Signed-off-by: Volker Weißmann <volker.weissmann@gmx.de>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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GLIBC_TUNABLES scrubbing happens earlier than envvar scrubbing and some
tunables are required to propagate past setxid boundary, like their
env_alias. Rely on tunable scrubbing to clean out GLIBC_TUNABLES like
before, restoring behaviour in glibc 2.37 and earlier.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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Linux v5.10 added a mount option MS_NOSYMFOLLOW, which was added to
glibc in commit 0ca21427d950755b.
Add the corresponding statfs/statvfs flag bit, ST_NOSYMFOLLOW.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Read directly into the mips_abiflags struct rather than reading the
entire segment and using alloca when the passed buffer is not big enough.
Checked with build-many-glibcs.py on mips-linux-gnu
Tested-by: Ying Huang <ying.huang@oss.cipunited.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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This commit add support for the new AVX10 cpu features:
https://cdrdv2-public.intel.com/784267/355989-intel-avx10-spec.pdf
We add checks for:
- `AVX10`: Check if AVX10 is present.
- `AVX10_{X,Y,Z}MM`: Check if a given vec class has AVX10 support.
`make check` passes and cpuid output was checked against GNR/DMR on an
emulator.
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These are useless on x86_64, and __NGREG was actually wrong with them.
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On powerpc, SET_RESTORE_ROUND uses inline assembly to optimize the
prologue get/save/set rounding mode operations for POWER9 and
later by using 'mffscrn' where possible, this was introduced by
commit f1c56cdff09f650ad721fae026eb6a3651631f3d.
GCC version 14 onwards supports builtins as __builtin_set_fpscr_rn
which now returns the FPSCR fields in a double. This feature is
available on Power9 when the __SET_FPSCR_RN_RETURNS_FPSCR__ macro
is defined.
GCC commit ef3bbc69d15707e4db6e2f198c621effb636cc26 adds
this feature.
Changes are done to use __builtin_set_fpscr_rn instead of mffscrn
or mffscrni in __fe_mffscrn(rn).
Suggested-by: Carl Love <cel@us.ibm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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AT_EMPTY_PATH is a requirement to implement fstat over fstatat,
however it does not prevent the kernel to read the path argument.
It is not an issue, but on x86-64 with SMAP-capable CPUs the kernel is
forced to perform expensive user memory access. After that regular
lookup is performed which adds even more overhead.
Instead, issue the fstat syscall directly on LFS fstat implementation
(32 bit architectures will still continue to use statx, which is
required to have 64 bit time_t support). it should be even a
small performance gain on non x86_64, since there is no need
to handle the path argument.
Checked on x86_64-linux-gnu.
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Remove the unnecessary extra checks for sin (-0.0) from vector sin/sinf,
improving performance. Passes regress.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
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This allows us to avoid some #ifdef SHARED conditionals.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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This patch fixes a very recently added leak in getaddrinfo.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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This reverts commit a53451559dc9cce765ea5bcbb92c4007e058e92b.
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This patch updates the kernel version in the tests tst-mman-consts.py
and tst-pidfd-consts.py to 6.5. (There are no new constants covered
by these tests in 6.5 that need any other header changes;
tst-mount-consts.py was updated separately along with a header
constant addition.)
Tested with build-many-glibcs.py.
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Key Points:
1. On lasx & lsx platforms, We must use _dl_runtime_{profile, resolve}_{lsx, lasx}
to save vector registers.
2. Via "tunables", users can choose str/mem_{lasx,lsx,unaligned} functions with
`export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,...`.
Note: glibc.cpu.hwcaps doesn't affect _dl_runtime_{profile, resolve}_{lsx, lasx}
selection.
Usage Notes:
1. Only valid inputs: LASX, LSX, UAL. Case-sensitive, comma-separated, no spaces.
2. Example: `export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL` turns on LASX & UAL.
Unmentioned features turn off. With default ifunc: lasx > lsx > unaligned >
aligned > generic, effect is: lasx > unaligned > aligned > generic; lsx off.
3. Incorrect GLIBC_TUNABLES settings will show error messages.
For example: On lsx platforms, you cannot enable lasx features. If you do
that, you will get error messages.
4. Valid input examples:
- GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX: lasx > aligned > generic.
- GLIBC_TUNABLES=glibc.cpu.hwcaps=LSX,UAL: lsx > unaligned > aligned > generic.
- GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL,LASX,UAL,LSX,LASX,UAL: Repetitions
allowed but not recommended. Results in: lasx > lsx > unaligned > aligned >
generic.
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When an NSS plugin only implements the _gethostbyname2_r and
_getcanonname_r callbacks, getaddrinfo could use memory that was freed
during tmpbuf resizing, through h_name in a previous query response.
The backing store for res->at->name when doing a query with
gethostbyname3_r or gethostbyname2_r is tmpbuf, which is reallocated in
gethosts during the query. For AF_INET6 lookup with AI_ALL |
AI_V4MAPPED, gethosts gets called twice, once for a v6 lookup and second
for a v4 lookup. In this case, if the first call reallocates tmpbuf
enough number of times, resulting in a malloc, th->h_name (that
res->at->name refers to) ends up on a heap allocated storage in tmpbuf.
Now if the second call to gethosts also causes the plugin callback to
return NSS_STATUS_TRYAGAIN, tmpbuf will get freed, resulting in a UAF
reference in res->at->name. This then gets dereferenced in the
getcanonname_r plugin call, resulting in the use after free.
Fix this by copying h_name over and freeing it at the end. This
resolves BZ #30843, which is assigned CVE-2023-4806.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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Change to put magic number to .rodata section in memmove-lsx, and use
pcalau12i and %pc_lo12 with vld to get the data.
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According to glibc strrchr microbenchmark test results, this implementation
could reduce the runtime time as following:
Name Percent of rutime reduced
strrchr-lasx 10%-50%
strrchr-lsx 0%-50%
strrchr-aligned 5%-50%
Generic strrchr is implemented by function strlen + memrchr, the lasx version
will compare with generic strrchr implemented by strlen-lasx + memrchr-lasx,
the lsx version will compare with generic strrchr implemented by strlen-lsx +
memrchr-lsx, the aligned version will compare with generic strrchr implemented
by strlen-aligned + memrchr-generic.
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According to glibc strcpy and stpcpy microbenchmark test results(changed
to use generic_strcpy and generic_stpcpy instead of strlen + memcpy),
comparing with the generic version, this implementation could reduce the
runtime as following:
Name Percent of rutime reduced
strcpy-aligned 8%-45%
strcpy-unaligned 8%-48%, comparing with the aligned version, unaligned
version takes less instructions to copy the tail of data
which length is less than 8. it also has better performance
in case src and dest cannot be both aligned with 8bytes
strcpy-lsx 20%-80%
strcpy-lasx 15%-86%
stpcpy-aligned 6%-43%
stpcpy-unaligned 8%-48%
stpcpy-lsx 10%-80%
stpcpy-lasx 10%-87%
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This patch adds the MOVE_MOUNT_BENEATH constant from Linux 6.5 to
glibc's sys/mount.h and updates tst-mount-consts.py to reflect these
constants being up to date with that Linux kernel version.
Tested with build-many-glibcs.py.
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Linux 6.5 has one new syscall, cachestat, and also enables the
cacheflush syscall for hppa. Update syscall-names.list and regenerate
the arch-syscall.h headers with build-many-glibcs.py update-syscalls.
Tested with build-many-glibcs.py.
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Needed since gcc-10 enabled -fno-common by default.
[In use in Gentoo since gcc-10, no problems observed.
Also discussed with and reviewed by Jessica Clarke from
Debian. Andreas]
Bug: https://bugs.gentoo.org/723268
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Signed-off-by: Sergei Trofimovich <slyich@gmail.com>
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
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Use a fixed size array instead. The maximum number of arguments
is set by macro tricks.
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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The current implementation of dlclose (and process exit) re-sorts the
link maps before calling ELF destructors. Destructor order is not the
reverse of the constructor order as a result: The second sort takes
relocation dependencies into account, and other differences can result
from ambiguous inputs, such as cycles. (The force_first handling in
_dl_sort_maps is not effective for dlclose.) After the changes in
this commit, there is still a required difference due to
dlopen/dlclose ordering by the application, but the previous
discrepancies went beyond that.
A new global (namespace-spanning) list of link maps,
_dl_init_called_list, is updated right before ELF constructors are
called from _dl_init.
In dl_close_worker, the maps variable, an on-stack variable length
array, is eliminated. (VLAs are problematic, and dlclose should not
call malloc because it cannot readily deal with malloc failure.)
Marking still-used objects uses the namespace list directly, with
next and next_idx replacing the done_index variable.
After marking, _dl_init_called_list is used to call the destructors
of now-unused maps in reverse destructor order. These destructors
can call dlopen. Previously, new objects do not have l_map_used set.
This had to change: There is no copy of the link map list anymore,
so processing would cover newly opened (and unmarked) mappings,
unloading them. Now, _dl_init (indirectly) sets l_map_used, too.
(dlclose is handled by the existing reentrancy guard.)
After _dl_init_called_list traversal, two more loops follow. The
processing order changes to the original link map order in the
namespace. Previously, dependency order was used. The difference
should not matter because relocation dependencies could already
reorder link maps in the old code.
The changes to _dl_fini remove the sorting step and replace it with
a traversal of _dl_init_called_list. The l_direct_opencount
decrement outside the loader lock is removed because it appears
incorrect: the counter manipulation could race with other dynamic
loader operations.
tst-audit23 needs adjustments to the changes in LA_ACT_DELETE
notifications. The new approach for checking la_activity should
make it clearer that la_activty calls come in pairs around namespace
updates.
The dependency sorting test cases need updates because the destructor
order is always the opposite order of constructor order, even with
relocation dependencies or cycles present.
There is a future cleanup opportunity to remove the now-constant
force_first and for_fini arguments from the _dl_sort_maps function.
Fixes commit 1df71d32fe5f5905ffd5d100e5e9ca8ad62 ("elf: Implement
force_first handling in _dl_sort_maps_dfs (bug 28937)").
Reviewed-by: DJ Delorie <dj@redhat.com>
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Commit 5f828ff824e3b7cd1 ("io: Fix F_GETLK, F_SETLK, and F_SETLKW for
powerpc64") fixed an issue with the value of the lock constants on
powerpc64 when not using __USE_FILE_OFFSET64, but it ended-up also
changing the value when using __USE_FILE_OFFSET64 causing an API change.
Fix that by also checking that define, restoring the pre
4d0fe291aed3a476a commit values:
Default values:
- F_GETLK: 5
- F_SETLK: 6
- F_SETLKW: 7
With -D_FILE_OFFSET_BITS=64:
- F_GETLK: 12
- F_SETLK: 13
- F_SETLKW: 14
At the same time, it has been noticed that there was no test for io lock
with __USE_FILE_OFFSET64, so just add one.
Tested on x86_64-linux-gnu, i686-linux-gnu and
powerpc64le-unknown-linux-gnu.
Resolves: BZ #30804.
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
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Use a scratch_buffer rather than alloca to avoid potential stack
overflow.
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XTheadBb has similar instructions like Zbb, which allow optimized
string processing:
* th.ff0: find-first zero is a CLZ instruction.
* th.tstnbz: Similar like orc.b, but with a bit-inverted result.
The instructions are documented here:
https://github.com/T-head-Semi/thead-extension-spec/tree/master/xtheadbb
These instructions can be found in the T-Head C906 and the C910.
Tested with the string tests.
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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This code is generally unused in practice since there don't seem to be
any NSS modules that only implement _nss_MOD_gethostbyname2_r and not
_nss_MOD_gethostbyname3_r.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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This interface allows to obtain the associated process ID from the
process file descriptor. It is done by parsing the procps fdinfo
information. Its prototype is:
pid_t pidfd_getpid (int fd)
It returns the associated pid or -1 in case of an error and sets the
errno accordingly. The possible errno values are those from open, read,
and close (used on procps parsing), along with:
- EBADF if the FD is negative, does not have a PID associated, or if
the fdinfo fields contain a value larger than pid_t.
- EREMOTE if the PID is in a separate namespace.
- ESRCH if the process is already terminated.
Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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Returning a pidfd allows a process to keep a race-free handle for a
child process, otherwise, the caller will need to either use pidfd_open
(which still might be subject to TOCTOU) or keep the old racy interface
base on pid_t.
To correct use pifd_spawn, the kernel must support not only returning
the pidfd with clone/clone3 but also waitid (P_PIDFD) (added on Linux
5.4). If kernel does not support the waitid, pidfd return ENOSYS.
It avoids the need to racy workarounds, such as reading the procfs
fdinfo to get the pid to use along with other wait interfaces.
These interfaces are similar to the posix_spawn and posix_spawnp, with
the only difference being it returns a process file descriptor (int)
instead of a process ID (pid_t). Their prototypes are:
int pidfd_spawn (int *restrict pidfd,
const char *restrict file,
const posix_spawn_file_actions_t *restrict facts,
const posix_spawnattr_t *restrict attrp,
char *const argv[restrict],
char *const envp[restrict])
int pidfd_spawnp (int *restrict pidfd,
const char *restrict path,
const posix_spawn_file_actions_t *restrict facts,
const posix_spawnattr_t *restrict attrp,
char *const argv[restrict_arr],
char *const envp[restrict_arr]);
A new symbol is used instead of a posix_spawn extension to avoid
possible issues with language bindings that might track the return
argument lifetime. Although on Linux pid_t and int are interchangeable,
POSIX only states that pid_t should be a signed integer.
Both symbols reuse the posix_spawn posix_spawn_file_actions_t and
posix_spawnattr_t, to void rehash posix_spawn API or add a new one. It
also means that both interfaces support the same attribute and file
actions, and a new flag or file action on posix_spawn is also added
automatically for pidfd_spawn.
Also, using posix_spawn plumbing allows the reusing of most of the
current testing with some changes:
- waitid is used instead of waitpid since it is a more generic
interface.
- tst-posix_spawn-setsid.c is adapted to take into consideration that
the caller can check for session id directly. The test now spawns
itself and writes the session id as a file instead.
- tst-spawn3.c need to know where pidfd_spawn is used so it keeps an
extra file description unused.
Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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These functions allow to posix_spawn and posix_spawnp to use
CLONE_INTO_CGROUP with clone3, allowing the child process to
be created in a different cgroup version 2. These are GNU
extensions that are available only for Linux, and also only
for the architectures that implement clone3 wrapper
(HAVE_CLONE3_WRAPPER).
To create a process on a different cgroupv2, one can use the:
posix_spawnattr_t attr;
posix_spawnattr_init (&attr);
posix_spawnattr_setflags (&attr, POSIX_SPAWN_SETCGROUP);
posix_spawnattr_setcgroup_np (&attr, cgroup);
posix_spawn (...)
Similar to other posix_spawn flags, POSIX_SPAWN_SETCGROUP control
whether the cgroup file descriptor will be used or not with
clone3.
There is no fallback if either clone3 does not support the flag
or if the architecture does not provide the clone3 wrapper, in
this case posix_spawn returns EOPNOTSUPP.
Checked on x86_64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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Not all architectures added clone3 syscall.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
Checked on mips64el-linux-gnueabihf, mips64el-n32-linux-gnu, and
mipsel-linux-gnu.
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It follows the internal signature:
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
Checked on arm-linux-gnueabihf.
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We can easily directly ask the kernel with vm_region rather than
assuming a one-page stack.
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In short: __tls_get_addr checks the global generation counter and if
the current dtv is older then _dl_update_slotinfo updates dtv up to the
generation of the accessed module. So if the global generation is newer
than generation of the module then __tls_get_addr keeps hitting the
slow dtv update path. The dtv update path includes a number of checks
to see if any update is needed and this already causes measurable tls
access slow down after dlopen.
It may be possible to detect up-to-date dtv faster. But if there are
many modules loaded (> TLS_SLOTINFO_SURPLUS) then this requires at
least walking the slotinfo list.
This patch tries to update the dtv to the global generation instead, so
after a dlopen the tls access slow path is only hit once. The modules
with larger generation than the accessed one were not necessarily
synchronized before, so additional synchronization is needed.
This patch uses acquire/release synchronization when accessing the
generation counter.
Note: in the x86_64 version of dl-tls.c the generation is only loaded
once, since relaxed mo is not faster than acquire mo load.
I have not benchmarked this. Tested by Adhemerval Zanella on aarch64,
powerpc, sparc, x86 who reported that it fixes the performance issue
of bug 19924.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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The old Intel software developer manual specified that the low byte of
EAX of CPUID leaf 2 returned 1 which indicated the number of rounds of
CPUDID leaf 2 was needed to retrieve the complete cache information. The
newer Intel manual has been changed to that it should always return 1
and be ignored. If the lower byte isn't 1, CPUID leaf 2 can't be used.
In this case, we ignore CPUID leaf 2 and use CPUID leaf 4 instead. If
CPUID leaf 4 doesn't contain the cache information, cache information
isn't available at all. This addresses BZ #30643.
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According to glibc memcmp microbenchmark test results(Add generic
memcmp), this implementation have performance improvement
except the length is less than 3, details as below:
Name Percent of time reduced
memcmp-lasx 16%-74%
memcmp-lsx 20%-50%
memcmp-aligned 5%-20%
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