elf: Implement force_first handling in _dl_sort_maps_dfs (bug 28937)
The implementation in _dl_close_worker requires that the first
element of l_initfini is always this very map (“We are always the
zeroth entry, and since we don't include ourselves in the
dependency analysis start at 1.”). Rather than fixing that
assumption, this commit adds an implementation of the force_first
argument to the new dependency sorting algorithm. This also means
that the directly dlopen'ed shared object is always initialized last,
which is the least surprising behavior in the presence of cycles.
scripts/dso-ordering-test.py: Generate program run-time dependencies
The main program needs to depend on all shared objects, even objects
that have link-time dependencies among shared objects. Filtering
out shared objects that already have an link-time dependencies is not
necessary here; make will do this automatically.
Javier Pello [Mon, 5 Sep 2022 18:09:01 +0000 (20:09 +0200)]
elf: Fix hwcaps string size overestimation
Commit dad90d528259b669342757c37dedefa8577e2636 added glibc-hwcaps
support for LD_LIBRARY_PATH and, for this, it adjusted the total
string size required in _dl_important_hwcaps. However, in doing so
it inadvertently altered the calculation of the size required for
the power set strings, as the computation of the power set string
size depended on the first value assigned to the total variable,
which is later shifted, resulting in overallocation of string
space. Fix this now by using a different variable to hold the
string size required for glibc-hwcaps.
Alan Modra [Wed, 27 Apr 2022 05:09:10 +0000 (14:39 +0930)]
Use __ehdr_start rather than _begin in _dl_start_final
__ehdr_start is already used in rltld.c:dl_main, and can serve the
same purpose as _begin. Besides tidying the code, using linker
defined section relative symbols rather than "-defsym _begin=0" better
reflects the intent of _dl_start_final use of _begin, which is to
refer to the load address of ld.so rather than absolute address zero.
elf: Run tst-audit-tlsdesc, tst-audit-tlsdesc-dlopen everywhere
The test is valid for all TLS models, but we want to make a reasonable
effort to test the GNU2 model specifically. For example, aarch64
defaults to GNU2, but does not have -mtls-dialect=gnu2, and the test
was not run there.
Fixes early backport commit 577c2fc7f34eeaaa2ecec94108bb3f0417383a32
("elf: Call __libc_early_init for reused namespaces (bug 29528)");
it had a wrong conflict resolution.
nscd: Fix netlink cache invalidation if epoll is used [BZ #29415]
Processes cache network interface information such as whether IPv4 or IPv6
are enabled. This is only checked again if the "netlink timestamp" provided
by nscd changed, which is triggered by netlink socket activity.
However, in the epoll handler for the netlink socket, it was missed to
assign the new timestamp to the nscd database. The handler for plain poll
did that properly, copy that over.
This bug caused that e.g. processes which started before network
configuration got unusuable addresses from getaddrinfo, like IPv6 only even
though only IPv4 is available:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/1041
It's a bit hard to reproduce, so I verified this by checking the timestamp
on calls to __check_pf manually. Without this patch it's stuck at 1, now
it's increasing on network changes as expected.
Apply asm redirections in wchar.h before first use
Similar to d0fa09a770, but for wchar.h. Fixes [BZ #27087] by applying
all long double related asm redirections before using functions in
bits/wchar2.h.
Moves the function declarations from wcsmbs/bits/wchar2.h to a new file
wcsmbs/bits/wchar2-decl.h that will be included first in wcsmbs/wchar.h.
Tested with build-many-glibcs.py. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit c7509d49c4e8fa494120c5ead21338559dad16f5)
Florian Weimer [Fri, 26 Aug 2022 19:15:43 +0000 (21:15 +0200)]
elf: Call __libc_early_init for reused namespaces (bug 29528)
libc_map is never reset to NULL, neither during dlclose nor on a
dlopen call which reuses the namespace structure. As a result, if a
namespace is reused, its libc is not initialized properly. The most
visible result is a crash in the <ctype.h> functions.
To prevent similar bugs on namespace reuse from surfacing,
unconditionally initialize the chosen namespace to zero using memset.
Arjun Shankar [Tue, 2 Aug 2022 09:10:25 +0000 (11:10 +0200)]
socket: Check lengths before advancing pointer in CMSG_NXTHDR
The inline and library functions that the CMSG_NXTHDR macro may expand
to increment the pointer to the header before checking the stride of
the increment against available space. Since C only allows incrementing
pointers to one past the end of an array, the increment must be done
after a length check. This commit fixes that and includes a regression
test for CMSG_FIRSTHDR and CMSG_NXTHDR.
The Linux, Hurd, and generic headers are all changed.
Tested on Linux on armv7hl, i686, x86_64, aarch64, ppc64le, and s390x.
stdlib: Remove attr_write from mbstows if dst is NULL [BZ: 29265]
Incorrectly called `__mbstowcs_chk` in the NULL __dst case which is
incorrect as in the NULL __dst case we are explicitly skipping
the objsize checks.
As well, remove the `__always_inline` attribute which exists in
`__fortify_function`. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 220b83d83d32aa9e6f5659e2fa2a63a0024c3e4a)
Joseph Myers [Tue, 2 Aug 2022 21:05:07 +0000 (21:05 +0000)]
Update syscall lists for Linux 5.19
Linux 5.19 has no new syscalls, but enables memfd_secret in the uapi
headers for RISC-V. Update the version number in syscall-names.list
to reflect that it is still current for 5.19 and regenerate the
arch-syscall.h headers with build-many-glibcs.py update-syscalls.
malloc: Simplify implementation of __malloc_assert
It is prudent not to run too much code after detecting heap
corruption, and __fxprintf is really complex. The line number
and file name do not carry much information, so it is not included
in the error message. (__libc_message only supports %s formatting.)
The function name and assertion should provide some context.
Apply asm redirections in stdio.h before first use [BZ #27087]
Compilers may not be able to apply asm redirections to functions after
these functions are used for the first time, e.g. clang 13.
Fix [BZ #27087] by applying all long double-related asm redirections
before using functions in bits/stdio.h.
However, as these asm redirections depend on the declarations provided
by libio/bits/stdio2.h, this header was split in 2:
- libio/bits/stdio2-decl.h contains all function declarations;
- libio/bits/stdio2.h remains with the remaining contents, including
redirections.
This also adds the access attribute to __vsnprintf_chk that was missing.
Noah Goldstein [Wed, 29 Jun 2022 23:07:15 +0000 (16:07 -0700)]
x86: Move mem{p}{mov|cpy}_{chk_}erms to its own file
The primary memmove_{impl}_unaligned_erms implementations don't
interact with this function. Putting them in same file both
wastes space and unnecessarily bloats a hot code section.
Noah Goldstein [Wed, 29 Jun 2022 23:07:05 +0000 (16:07 -0700)]
x86: Move and slightly improve memset_erms
Implementation wise:
1. Remove the VZEROUPPER as memset_{impl}_unaligned_erms does not
use the L(stosb) label that was previously defined.
2. Don't give the hotpath (fallthrough) to zero size.
Code positioning wise:
Move memset_{chk}_erms to its own file. Leaving it in between the
memset_{impl}_unaligned both adds unnecessary complexity to the
file and wastes space in a relatively hot cache section.
Noah Goldstein [Wed, 15 Jun 2022 17:41:28 +0000 (10:41 -0700)]
x86: Cleanup bounds checking in large memcpy case
1. Fix incorrect lower-bound threshold in L(large_memcpy_2x).
Previously was using `__x86_rep_movsb_threshold` and should
have been using `__x86_shared_non_temporal_threshold`.
2. Avoid reloading __x86_shared_non_temporal_threshold before
the L(large_memcpy_4x) bounds check.
3. Document the second bounds check for L(large_memcpy_4x)
more clearly.
Noah Goldstein [Wed, 15 Jun 2022 17:41:29 +0000 (10:41 -0700)]
x86: Add bounds `x86_non_temporal_threshold`
The lower-bound (16448) and upper-bound (SIZE_MAX / 16) are assumed
by memmove-vec-unaligned-erms.
The lower-bound is needed because memmove-vec-unaligned-erms unrolls
the loop aggressively in the L(large_memset_4x) case.
The upper-bound is needed because memmove-vec-unaligned-erms
right-shifts the value of `x86_non_temporal_threshold` by
LOG_4X_MEMCPY_THRESH (4) which without a bound may overflow.
The lack of lower-bound can be a correctness issue. The lack of
upper-bound cannot.
Noah Goldstein [Tue, 14 Jun 2022 20:50:11 +0000 (13:50 -0700)]
x86: Fix misordered logic for setting `rep_movsb_stop_threshold`
Move the setting of `rep_movsb_stop_threshold` to after the tunables
have been collected so that the `rep_movsb_stop_threshold` (which
is used to redirect control flow to the non_temporal case) will
use any user value for `non_temporal_threshold` (set using
glibc.cpu.x86_non_temporal_threshold)
Noah Goldstein [Fri, 3 Jun 2022 23:52:37 +0000 (18:52 -0500)]
x86: ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST expect no transactions
Give fall-through path to `vzeroupper` and taken-path to `vzeroall`.
Generally even on machines with RTM the expectation is the
string-library functions will not be called in transactions. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit c28db9cb29a7d6cf3ce08fd8445e6b7dea03f35b)
Changed how the page cross case aligned string (rdi) in
rawmemchr. This was incompatible with how
`L(cross_page_continue)` expected the pointer to be aligned and
would cause rawmemchr to read data start started before the
beginning of the string. What it would read was in valid memory
but could count CHAR matches resulting in an incorrect return
value.
This commit fixes that issue by essentially reverting the changes to
the L(page_cross) case as they didn't really matter.
Test cases added and all pass with the new code (and where confirmed
to fail with the old code). Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 2c9af8421d2b4a7fcce163e7bc81a118d22fd346)
Noah Goldstein [Tue, 7 Jun 2022 04:11:32 +0000 (21:11 -0700)]
x86: Optimize memrchr-avx2.S
The new code:
1. prioritizes smaller user-arg lengths more.
2. optimizes target placement more carefully
3. reuses logic more
4. fixes up various inefficiencies in the logic. The biggest
case here is the `lzcnt` logic for checking returns which
saves either a branch or multiple instructions.
The total code size saving is: 306 bytes
Geometric Mean of all benchmarks New / Old: 0.760
Regressions:
There are some regressions. Particularly where the length (user arg
length) is large but the position of the match char is near the
beginning of the string (in first VEC). This case has roughly a
10-20% regression.
This is because the new logic gives the hot path for immediate matches
to shorter lengths (the more common input). This case has roughly
a 15-45% speedup.
Noah Goldstein [Tue, 7 Jun 2022 04:11:31 +0000 (21:11 -0700)]
x86: Optimize memrchr-evex.S
The new code:
1. prioritizes smaller user-arg lengths more.
2. optimizes target placement more carefully
3. reuses logic more
4. fixes up various inefficiencies in the logic. The biggest
case here is the `lzcnt` logic for checking returns which
saves either a branch or multiple instructions.
The total code size saving is: 263 bytes
Geometric Mean of all benchmarks New / Old: 0.755
Regressions:
There are some regressions. Particularly where the length (user arg
length) is large but the position of the match char is near the
beginning of the string (in first VEC). This case has roughly a
20% regression.
This is because the new logic gives the hot path for immediate matches
to shorter lengths (the more common input). This case has roughly
a 35% speedup.
Noah Goldstein [Tue, 7 Jun 2022 04:11:30 +0000 (21:11 -0700)]
x86: Optimize memrchr-sse2.S
The new code:
1. prioritizes smaller lengths more.
2. optimizes target placement more carefully.
3. reuses logic more.
4. fixes up various inefficiencies in the logic.
The total code size saving is: 394 bytes
Geometric Mean of all benchmarks New / Old: 0.874
Regressions:
1. The page cross case is now colder, especially re-entry from the
page cross case if a match is not found in the first VEC
(roughly 50%). My general opinion with this patch is this is
acceptable given the "coldness" of this case (less than 4%) and
generally performance improvement in the other far more common
cases.
2. There are some regressions 5-15% for medium/large user-arg
lengths that have a match in the first VEC. This is because the
logic was rewritten to optimize finds in the first VEC if the
user-arg length is shorter (where we see roughly 20-50%
performance improvements). It is not always the case this is a
regression. My intuition is some frontend quirk is partially
explaining the data although I haven't been able to find the
root cause.
This code does not change any existing functionality.
There is no difference in the objdump of libc.so before and after this
patch. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit dd5c483b2598f411428df4d8864c15c4b8a3cd68)
Noah Goldstein [Tue, 7 Jun 2022 04:11:27 +0000 (21:11 -0700)]
x86: Create header for VEC classes in x86 strings library
This patch does not touch any existing code and is only meant to be a
tool for future patches so that simple source files can more easily be
maintained to target multiple VEC classes.
There is no difference in the objdump of libc.so before and after this
patch. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 8a780a6b910023e71f3173f37f0793834c047554)
Adding a 512-bit EVEX version of strstr. The algorithm works as follows:
(1) We spend a few cycles at the begining to peek into the needle. We
locate an edge in the needle (first occurance of 2 consequent distinct
characters) and also store the first 64-bytes into a zmm register.
(2) We search for the edge in the haystack by looking into one cache
line of the haystack at a time. This avoids having to read past a page
boundary which can cause a seg fault.
(3) If an edge is found in the haystack we first compare the first
64-bytes of the needle (already stored in a zmm register) before we
proceed with a full string compare performed byte by byte.
Benchmarking results: (old = strstr_sse2_unaligned, new = strstr_avx512)
Geometric mean of all benchmarks: new / old = 0.66
Difficult skiptable(0) : new / old = 0.02
Difficult skiptable(1) : new / old = 0.01
Difficult 2-way : new / old = 0.25
Difficult testing first 2 : new / old = 1.26
Difficult skiptable(0) : new / old = 0.05
Difficult skiptable(1) : new / old = 0.06
Difficult 2-way : new / old = 0.26
Difficult testing first 2 : new / old = 1.05
Difficult skiptable(0) : new / old = 0.42
Difficult skiptable(1) : new / old = 0.24
Difficult 2-way : new / old = 0.21
Difficult testing first 2 : new / old = 1.04 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 5082a287d5e9a1f9cb98b7c982a708a3684f1d5c)
x86: Remove __mmask intrinsics in strstr-avx512.c
The intrinsics are not available before GCC7 and using standard
operators generates code of equivalent or better quality.
H.J. Lu [Sat, 21 May 2022 02:21:48 +0000 (19:21 -0700)]
x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOT
According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT
and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we
can ignore their r_addends.
Sunil K Pandey [Mon, 28 Feb 2022 00:39:47 +0000 (16:39 -0800)]
x86_64: Implement evex512 version of strlen, strnlen, wcslen and wcsnlen
This patch implements following evex512 version of string functions.
Perf gain for evex512 version is up to 50% as compared to evex,
depending on length and alignment.
Placeholder function, not used by any processor at the moment.
- String length function using 512 bit vectors.
- String N length using 512 bit vectors.
- Wide string length using 512 bit vectors.
- Wide string N length using 512 bit vectors.
Both symbols are marked as legacy in POSIX.1-2001 and removed on
POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE
or _DEFAULT_SOURCE.
GCC also replaces bcopy with a memmove and bzero with memset on default
configuration (to actually get a bzero libc call the code requires
to omit string.h inclusion and built with -fno-builtin), so it is
highly unlikely programs are actually calling libc bzero symbol.
On a recent Linux distro (Ubuntu 22.04), there is no bzero calls
by the installed binaries.
$ cat count_bstring.sh
#!/bin/bash
files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done`
total=0
for file in $files; do
symbols=`objdump -R $file 2>&1`
if [ $? -eq 0 ]; then
ncalls=`echo $symbols | grep -w $1 | wc -l`
((total=total+ncalls))
if [ $ncalls -gt 0 ]; then
echo "$file: $ncalls"
fi
fi
done
echo "TOTAL=$total"
$ ./count_bstring.sh bzero
TOTAL=0
linux: Fix mq_timereceive check for 32 bit fallback code (BZ 29304)
On success, mq_receive() and mq_timedreceive() return the number of
bytes in the received message, so it requires to check if the value
is larger than 0.
Sam James [Sun, 5 Jun 2022 03:57:10 +0000 (04:57 +0100)]
nss: handle stat failure in check_reload_and_get (BZ #28752)
Skip the chroot test if the database isn't loaded
correctly (because the chroot test uses some
existing DB state).
The __stat64_time64 -> fstatat call can fail if
running under an (aggressive) seccomp filter,
like Firefox seems to use.
This manifested in a crash when using glib built
with FAM support with such a Firefox build.
Suggested-by: DJ Delorie <dj@redhat.com> Signed-off-by: Sam James <sam@gentoo.org> Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit ace9e3edbca62d978b1e8f392d8a5d78500272d9)
Sam James [Sun, 5 Jun 2022 03:57:09 +0000 (04:57 +0100)]
nss: add assert to DB_LOOKUP_FCT (BZ #28752)
It's interesting if we have a null action list,
so an assert is worthwhile.
Suggested-by: DJ Delorie <dj@redhat.com> Signed-off-by: Sam James <sam@gentoo.org> Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit 3fdf0a205b622e40fa7e3c4ed1e4ed4d5c6c5380)
Since ad43cac44a the generic code already shuffles the argv/envp/auxv
on the stack to remove the ld.so own arguments and thus _dl_skip_args
is always 0. So there is no need to adjust the argc or argv.
Checked with qemu-user that arguments are correctly passed on both
constructors and main program.
Different than other architectures, hppa creates an unrelated stack
frame where ld.so argc/argv adjustments done by ad43cac44a6860eaefc
is not done on the argc/argv saved/restore by _dl_start_user.
Instead load _dl_argc and _dl_argv directlty instead of adjust them
using _dl_skip_args value.
powerpc: Fix VSX register number on __strncpy_power9 [BZ #29197]
__strncpy_power9 initializes VR 18 with zeroes to be used throughout the
code, including when zero-padding the destination string. However, the
v18 reference was mistakenly being used for stxv and stxvl, which take a
VSX vector as operand. The code ended up using the uninitialized VSR 18
register by mistake.
Both occurrences have been changed to use the proper VSX number for VR 18
(i.e. VSR 50).
Arjun Shankar [Tue, 24 May 2022 15:57:36 +0000 (17:57 +0200)]
Fix deadlock when pthread_atfork handler calls pthread_atfork or dlclose
In multi-threaded programs, registering via pthread_atfork,
de-registering implicitly via dlclose, or running pthread_atfork
handlers during fork was protected by an internal lock. This meant
that a pthread_atfork handler attempting to register another handler or
dlclose a dynamically loaded library would lead to a deadlock.
This commit fixes the deadlock in the following way:
During the execution of handlers at fork time, the atfork lock is
released prior to the execution of each handler and taken again upon its
return. Any handler registrations or de-registrations that occurred
during the execution of the handler are accounted for before proceeding
with further handler execution.
If a handler that hasn't been executed yet gets de-registered by another
handler during fork, it will not be executed. If a handler gets
registered by another handler during fork, it will not be executed
during that particular fork.
The possibility that handlers may now be registered or deregistered
during handler execution means that identifying the next handler to be
run after a given handler may register/de-register others requires some
bookkeeping. The fork_handler struct has an additional field, 'id',
which is assigned sequentially during registration. Thus, handlers are
executed in ascending order of 'id' during 'prepare', and descending
order of 'id' during parent/child handler execution after the fork.
Two tests are included:
* tst-atfork3: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This test exercises calling dlclose from prepare, parent, and child
handlers.
* tst-atfork4: This test exercises calling pthread_atfork and dlclose
from the prepare handler.
Noah Goldstein [Tue, 15 Feb 2022 14:18:15 +0000 (08:18 -0600)]
x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #29127]
Re-cherry-pick commit c627209832 for strcmp-avx2.S change which was
omitted in intial cherry pick because at the time this bug was not
present on release branch.
Fixes BZ #29127.
In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
call strcmp-avx2 and wcscmp-avx2 respectively. This would have
not checks around vzeroupper and would trigger spurious
aborts. This commit fixes that.
test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
AVX2 machines with and without RTM.
commit e938c0274 "Don't add access size hints to fortifiable functions"
converted a few '__attr_access ((...))' into '__fortified_attr_access (...)'
calls.
But one of conversions had double parentheses of '__fortified_attr_access (...)'.
Noticed as a gnat6 build failure:
/<<NIX>>-glibc-2.34-210-dev/include/bits/string_fortified.h:110:50: error: macro "__fortified_attr_access" requires 3 arguments, but only 1 given
The change fixes parentheses.
This is seen when using compilers that do not support
__builtin___stpncpy_chk, e.g. gcc older than 4.7, clang older than 2.6
or some compiler not derived from gcc or clang.
Signed-off-by: Sergei Trofimovich <slyich@gmail.com> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 5a5f94af0542f9a35aaa7992c18eb4e2403a29b9)
Szabolcs Nagy [Fri, 15 Jun 2018 15:14:58 +0000 (16:14 +0100)]
rtld: Use generic argv adjustment in ld.so [BZ #23293]
When an executable is invoked as
./ld.so [ld.so-args] ./exe [exe-args]
then the argv is adujusted in ld.so before calling the entry point of
the executable so ld.so args are not visible to it. On most targets
this requires moving argv, env and auxv on the stack to ensure correct
stack alignment at the entry point. This had several issues:
- The code for this adjustment on the stack is written in asm as part
of the target specific ld.so _start code which is hard to maintain.
- The adjustment is done after _dl_start returns, where it's too late
to update GLRO(dl_auxv), as it is already readonly, so it points to
memory that was clobbered by the adjustment. This is bug 23293.
- _environ is also wrong in ld.so after the adjustment, but it is
likely not used after _dl_start returns so this is not user visible.
- _dl_argv was updated, but for this it was moved out of relro, which
changes security properties across targets unnecessarily.
This patch introduces a generic _dl_start_args_adjust function that
handles the argument adjustments after ld.so processed its own args
and before relro protection is applied.
The same algorithm is used on all targets, _dl_skip_args is now 0, so
existing target specific adjustment code is no longer used. The bug
affects aarch64, alpha, arc, arm, csky, ia64, nios2, s390-32 and sparc,
other targets don't need the change in principle, only for consistency.
The GNU Hurd start code relied on _dl_skip_args after dl_main returned,
now it checks directly if args were adjusted and fixes the Hurd startup
data accordingly.
Follow up patches can remove _dl_skip_args and DL_ARGV_NOT_RELRO.
Tested on aarch64-linux-gnu and cross tested on i686-gnu.
Stefan Liebler [Tue, 17 May 2022 14:12:18 +0000 (16:12 +0200)]
S390: Enable static PIE
This commit enables static PIE on 64bit. On 31bit, static PIE is
not supported.
A new configure check in sysdeps/s390/s390-64/configure.ac also performs
a minimal test for requirements in ld:
Ensure you also have those patches for:
- binutils (ld)
- "[PR ld/22263] s390: Avoid dynamic TLS relocs in PIE"
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=26b1426577b5dcb32d149c64cca3e603b81948a9
(Tested by configure check above)
Otherwise there will be a R_390_TLS_TPOFF relocation, which fails to
be processed in _dl_relocate_static_pie() as static TLS map is not setup.
- "s390: Add DT_JMPREL pointing to .rela.[i]plt with static-pie"
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d942d8db12adf4c9e5c7d9ed6496a779ece7149e
(We can't test it in configure as we are not able to link a static PIE
executable if the system glibc lacks static PIE support)
Otherwise there won't be DT_JMPREL, DT_PLTRELA, DT_PLTRELASZ entries
and the IFUNC symbols are not processed, which leads to crashes.
- kernel (the mentioned links to the commits belong to 5.19 merge window):
- "s390/mmap: increase stack/mmap gap to 128MB"
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=f2f47d0ef72c30622e62471903ea19446ea79ee2
- "s390/vdso: move vdso mapping to its own function"
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=57761da4dc5cd60bed2c81ba0edb7495c3c740b8
- "s390/vdso: map vdso above stack"
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=9e37a2e8546f9e48ea76c839116fa5174d14e033
- "s390/vdso: add vdso randomization"
https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=features&id=41cd81abafdc4e58a93fcb677712a76885e3ca25
(We can't test the kernel of the target system)
Otherwise if /proc/sys/kernel/randomize_va_space is turned off (0),
static PIE executables like ldconfig will crash. While startup sbrk is
used to enlarge the HEAP. Unfortunately the underlying brk syscall fails
as there is not enough space after the HEAP. Then the address of the TLS
image is invalid and the following memcpy in __libc_setup_tls() leads
to a segfault.
If /proc/sys/kernel/randomize_va_space is activated (default: 2), there
is enough space after HEAP.
- glibc
- "Linux: Define MMAP_CALL_INTERNAL"
https://sourceware.org/git/?p=glibc.git;a=commit;h=c1b68685d438373efe64e5f076f4215723004dfb
- "i386: Remove OPTIMIZE_FOR_GCC_5 from Linux libc-do-syscall.S"
https://sourceware.org/git/?p=glibc.git;a=commit;h=6e5c7a1e262961adb52443ab91bd2c9b72316402
- "i386: Honor I386_USE_SYSENTER for 6-argument Linux system calls"
https://sourceware.org/git/?p=glibc.git;a=commit;h=60f0f2130d30cfd008ca39743027f1e200592dff
- "ia64: Always define IA64_USE_NEW_STUB as a flag macro"
https://sourceware.org/git/?p=glibc.git;a=commit;h=18bd9c3d3b1b6a9182698c85354578d1d58e9d64
- "Linux: Implement a useful version of _startup_fatal"
https://sourceware.org/git/?p=glibc.git;a=commit;h=a2a6bce7d7e52c1c34369a7da62c501cc350bc31
- "Linux: Introduce __brk_call for invoking the brk system call"
https://sourceware.org/git/?p=glibc.git;a=commit;h=b57ab258c1140bc45464b4b9908713e3e0ee35aa
- "csu: Implement and use _dl_early_allocate during static startup"
https://sourceware.org/git/?p=glibc.git;a=commit;h=f787e138aa0bf677bf74fa2a08595c446292f3d7
The mentioned patch series by Florian Weimer avoids the mentioned failing
sbrk syscall by falling back to mmap.
This commit also adjusts startup code in start.S to be ready for static PIE.
We have to add a wrapper function for main as we are not allowed to use
GOT relocations before __libc_start_main is called.
(Compare also to:
- commit 14d886edbd3d80b771e1c42fbd9217f9074de9c6
"aarch64: fix start code for static pie"
- commit 3d1d79283e6de4f7c434cb67fb53a4fd28359669
"aarch64: fix static pie enabled libc when main is in a shared library"
)
Florian Weimer [Wed, 4 May 2022 13:37:21 +0000 (15:37 +0200)]
Linux: Define MMAP_CALL_INTERNAL
Unlike MMAP_CALL, this avoids a TCB dependency for an errno update
on failure.
<mmap_internal.h> cannot be included as is on several architectures
due to the definition of page_unit, so introduce a separate header
file for the definition of MMAP_CALL and MMAP_CALL_INTERNAL,
<mmap_call.h>.
Fangrui Song [Tue, 19 Apr 2022 22:52:27 +0000 (15:52 -0700)]
elf: Remove __libc_init_secure
After 73fc4e28b9464f0e13edc719a5372839970e7ddb,
__libc_enable_secure_decided is always 0 and a statically linked
executable may overwrite __libc_enable_secure without considering
AT_SECURE.
The __libc_enable_secure has been correctly initialized in _dl_aux_init,
so just remove __libc_enable_secure_decided and __libc_init_secure.
This allows us to remove some startup_get*id functions from 22b79ed7f413cd980a7af0cf258da5bf82b6d5e5.
Florian Weimer [Fri, 11 Feb 2022 18:03:04 +0000 (19:03 +0100)]
Linux: Include <dl-auxv.h> in dl-sysdep.c only for SHARED
Otherwise, <dl-auxv.h> on POWER ends up being included twice,
once in dl-sysdep.c, once in dl-support.c. That leads to a linker
failure due to multiple definitions of _dl_cache_line_size.
The revert is necessary because the reverted commit introduced an
early memset call on aarch64, which leads to crash due to lack of TCB
initialization.
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.
Geometric Mean of all benchmarks New / Old: 0.755
See email for all results.
Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit c966099cdc3e0fdf92f63eac09b22fa7e5f5f02d)
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.
Geometric Mean of all benchmarks New / Old: 0.832
See email for all results.
Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit df7e295d18ffa34f629578c0017a9881af7620f6)
The new code unrolls the main loop slightly without adding too much
overhead and minimizes the comparisons for the search CHAR.
Geometric Mean of all benchmarks New / Old: 0.741
See email for all results.
Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 5307aa9c1800f36a64c183c091c9af392c1fa75c)
This is because A) the checks in range [65, 96] are now unrolled 2x
and B) because smaller values <= 16 are now given a hotter path. By
contrast the SSE4 version has a branch for Size = 80. The unrolled
version has get better performance for returns which need both
comparisons.
As well, out of microbenchmark environments that are not full
predictable the branch will have a real-cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 7cbc03d03091d5664060924789afe46d30a5477e)
New code save size (-303 bytes) and has significantly better
performance.
geometric_mean(N=20) of page cross cases New / Original: 0.634 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 8804157ad9da39631703b92315460808eac86b0c)
Noah Goldstein [Fri, 25 Mar 2022 22:13:33 +0000 (17:13 -0500)]
x86: Small improvements for wcslen
Just a few QOL changes.
1. Prefer `add` > `lea` as it has high execution units it can run
on.
2. Don't break macro-fusion between `test` and `jcc`
3. Reduce code size by removing gratuitous padding bytes (-90
bytes).
geometric_mean(N=20) of all benchmarks New / Original: 0.959
Noah Goldstein [Wed, 23 Mar 2022 21:57:46 +0000 (16:57 -0500)]
x86: Remove AVX str{n}casecmp
The rational is:
1. SSE42 has nearly identical logic so any benefit is minimal (3.4%
regression on Tigerlake using SSE42 versus AVX across the
benchtest suite).
2. AVX2 version covers the majority of targets that previously
prefered it.
3. The targets where AVX would still be best (SnB and IVB) are
becoming outdated.
projects / thirdparty / glibc.git / log
