This new section in the manual provides recommendations for
use of glibc in environments with higher integrity requirements.
It's reflecting both current implementation shortcomings, and
challenges we inherit from ELF and psABI requirements.
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Starting with commit
59974938fe
elf/rtld: Count skipped environment variables for enable_secure
The new testcase elf/tst-tunables-enable_secure-env segfaults on s390 (31bit).
There _start parses the auxiliary vector for some additional checks.
Therefore it skips over the zeros after the environment variables ...
0x7fffac20: 0x7fffbd17 0x7fffbd32 0x7fffbd69 0x00000000
------------------------------------------------^^^last environment variable
... and then it parses the auxiliary vector and stops at AT_NULL.
0x7fffac30: 0x00000000 0x00000021 0x00000000 0x00000000
--------------------------------^^^AT_SYSINFO_EHDR--------------^^^AT_NULL
----------------^^^newp-----------------------------------------^^^oldp
Afterwards it tries to access AT_PHDR which points to somewhere and segfaults.
Due to not incorporating the skip_env variable in the computation of oldp
when shuffling down the auxv in rtld.c, it just copies one entry with AT_NULL
and value 0x00000021 and stops the loop. In reality we have skipped
GLIBC_TUNABLES environment variable (=> skip_env=1). Thus we should copy from
here:
0x7fffac40: 0x00000021 0x7ffff000 0x00000010 0x007fffff
----------------^^^fixed-oldp
This patch fixes the computation of oldp when shuffling down auxiliary vector.
It also adds some checks in the testcase. Those checks also fail on
s390x (64bit) and x86_64 without the fix.
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Adhemerval noticed that the gettimeofday() and 32-bit clock_gettime()
vDSO calls won't be used by glibc on hppa, so there is no need to
declare them. Both syscalls will be emulated by utilizing return values
of the 64-bit clock_gettime() vDSO instead.
Signed-off-by: Helge Deller <deller@gmx.de>
Suggested-by: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
The clang open fortify wrapper from 4228baef1a added
a restriction where open with 3 arguments where flags do not
contain O_CREAT or O_TMPFILE are handled as invalid. They are
not invalid, since the third argument is ignored, and the gcc
wrapper also allows it.
Checked x86_64-linux-gnu and with a yocto build for some affected
packages.
Tested-by: “Khem Raj <raj.khen@gmail.com>”
By default, if the C++ toolchain lacks support for static linking,
configure fails to find the C++ header files and the glibc build fails.
The --disable-static-c++-link-check option allows the glibc build to
finish, but static C++ tests will fail if the C++ toolchain doesn't
have the necessary static C++ libraries which may not be easily installed.
Add --disable-static-c++-tests option to skip the static C++ link check
and tests. This fixes BZ #31797.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
The current minimum GCC version of glibc build is GCC 6.2 or newer. But
building i686 glibc with GCC 6.4 on Fedora 40 failed since the C++ header
files couldn't be found which was caused by the static C++ link check
failure due to missing __divmoddi4 which was referenced in i686 libc.a
and added to GCC 7. Add --disable-static-c++-link-check configure option
to disable the static C++ link test. The newly built i686 libc.a can be
used by GCC 6.4 to create static C++ tests. This fixes BZ #31412.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Extend the list of MAP_* macros to include all macros available
to the average program (gcc -E -dM | grep MAP_*)
Extend the list of errno codes.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
MIPSr6 has MADDF.s/MADDF.d instructions, which are fused.
In MIPS ISA, double support can be subsetted. Only FMAF is enabled
for this case.
* sysdeps/mips/fpu/math-use-builtins-fma.h
Signed-off-by: YunQiang Su <syq@gcc.gnu.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
It turns out that quite a few applications use bundled mallocs that
have been built to use global-dynamic TLS (instead of the recommended
initial-exec TLS). The previous workaround from
commit afe42e935b ("elf: Avoid some
free (NULL) calls in _dl_update_slotinfo") does not fix all
encountered cases unfortunatelly.
This change avoids the TLS generation update for recursive use
of TLS from a malloc that was called during a TLS update. This
is possible because an interposed malloc has a fixed module ID and
TLS slot. (It cannot be unloaded.) If an initially-loaded module ID
is encountered in __tls_get_addr and the dynamic linker is already
in the middle of a TLS update, use the outdated DTV, thus avoiding
another call into malloc. It's still necessary to update the
DTV to the most recent generation, to get out of the slow path,
which is why the check for recursion is needed.
The bookkeeping is done using a global counter instead of per-thread
flag because TLS access in the dynamic linker is tricky.
All this will go away once the dynamic linker stops using malloc
for TLS, likely as part of a change that pre-allocates all TLS
during pthread_create/dlopen.
Fixes commit d2123d6827 ("elf: Fix slow
tls access after dlopen [BZ #19924]").
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
The conditionals for several mtrace-based tests in catgets, elf, libio,
malloc, misc, nptl, posix, and stdio-common were incorrect leading to
test failures when bootstrapping glibc without perl.
The correct conditional for mtrace-based tests requires three checks:
first checking for run-built-tests, then build-shared, and lastly that
PERL is not equal to "no" (missing perl).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This will make it easier to add tests later; see also the test section
in malloc/Makefile that inspires this.
Signed-off-by: Michel Lind <salimma@fedoraproject.org>
Suggested-by: Arjun Shankar <arjun@redhat.com>
Reviewed-by: Arjun Shankar <arjun@redhat.com>
Current 'non_temporal_threshold' set to 'non_temporal_threshold_lowbound'
on Zhaoxin processors without ERMS. The default
'non_temporal_threshold_lowbound' is too small for the KH-40000 and KX-7000
Zhaoxin processors, this patch updates the value to
'shared / cachesize_non_temporal_divisor'.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This patch optimizes large size copy using normal store when src > dst
and overlap. Make it the same as the logic in memmove-vec-unaligned-erms.S.
Current memmove-ssse3 use '__x86_shared_cache_size_half' as the non-
temporal threshold, this patch updates that value to
'__x86_shared_non_temporal_threshold'. Currently, the
__x86_shared_non_temporal_threshold is cpu-specific, and different CPUs
will have different values based on the related nt-benchmark results.
However, in memmove-ssse3, the nontemporal threshold uses
'__x86_shared_cache_size_half', which sounds unreasonable.
The performance is not changed drastically although shows overall
improvements without any major regressions or gains.
Results on Zhaoxin KX-7000:
bench-memcpy geometric_mean(N=20) New / Original: 0.999
bench-memcpy-random geometric_mean(N=20) New / Original: 0.999
bench-memcpy-large geometric_mean(N=20) New / Original: 0.978
bench-memmove geometric_mean(N=20) New / Original: 1.000
bench-memmmove-large geometric_mean(N=20) New / Original: 0.962
Results on Intel Core i5-6600K:
bench-memcpy geometric_mean(N=20) New / Original: 1.001
bench-memcpy-random geometric_mean(N=20) New / Original: 0.999
bench-memcpy-large geometric_mean(N=20) New / Original: 1.001
bench-memmove geometric_mean(N=20) New / Original: 0.995
bench-memmmove-large geometric_mean(N=20) New / Original: 0.936
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Fix code formatting under the Zhaoxin branch and add comments for
different Zhaoxin models.
Unaligned AVX load are slower on KH-40000 and KX-7000, so disable
the AVX_Fast_Unaligned_Load.
Enable Prefer_No_VZEROUPPER and Fast_Unaligned_Load features to
use sse2_unaligned version of memset,strcpy and strcat.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Qualcom's new core, oryon-1, has a different characteristics for
memset than the current versions of memset. For non-zero, larger
sizes, using GPRs rather than the SIMD stores is ~30% faster.
For even larger sizes, using the nontemporal stores is needed
not to polute the L1/L2 caches.
For zero values, using `dc zva` should be used. Since we
know the size will always be 64 bytes, we don't need to figure
out the size there.
I started with the emag memset and added back the `dc zva` code.
Changes since v1:
* v3: Fix comment formating
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Qualcomm's new core (oryon-1) has a different performance characteristic
than other cores. For memcpy, it is faster to use the GPRs to
do the copy for large sizes (2x faster). For even larger sizes,
it is better to use the nontemporal load/store instructions so
we don't pollute the L1/L2 caches.
For smaller sizes, the characteristic are very similar to
other cores.
I used the thunderx memcpy as a starting point and expanded from there.
Changes since v1:
* v2: Fix ordering in Makefile.
* v3: Fix comment grammar about the ldnp/stnp instructions.
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The fcntl.h fortify wrapper for clang added by 86889e22db
missed the __fortify_clang_overload_arg and and also added the
mode argument for the __fortify_function_error_function function,
which leads clang to be able to correct resolve which overloaded
function it should emit.
Checked on x86_64-linux-gnu.
Reported-by: Khem Raj <raj.khem@gmail.com>
Tested-by: Khem Raj <raj.khem@gmail.com>
The mqueue.h fortify wrapper for clang added by c23107effb
is not fully correct, where correct 4 argument usage are not
being correctly handled. For instance, while building socat 1.8
with a yocto clang based system shows:
./socat-1.8.0.0/xio-posixmq.c:119:8: error: 'mq_open' is unavailable: mq_open can be called either with 2 or 4 arguments
119 | mqd = mq_open(name, oflag, opt_mode, NULL);
| ^
[...] /usr/include/bits/mqueue2.h:66:8: note: 'mq_open' has been explicitly marked unavailable here
66 | __NTH (mq_open (const char *__name, int __oflag, mode_t mode,
| ^
1 error generated.
The correct way to define the wrapper is to set invalid usage
with __fortify_clang_unavailable (for the case with 5 or more
arguments), followed by the expected ones. This fix make mq_open
similar to current open wrappers.
[1] http://www.dest-unreach.org/socat/
Reported-by: Khem Raj <raj.khem@gmail.com>
Acked-by: Khem Raj <raj.khem@gmail.com>
With gcc 14, I get this warning/werror when building the localedata tests:
tests-mbwc/tsp_common.c: In function ‘result.constprop.isra’:
tests-mbwc/tsp_common.c:55:43: error: ‘%s’ directive writing up to 92 bytes into a region of size between 0 and 114 [-Werror=format-overflow=]
55 | sprintf (result_rec, "%s:%s:%d:%d:%d:%c:%s\n", func, loc, rec_no, seq_no,
| ^~
In file included from ../include/bits/stdio2.h:1,
from ../libio/stdio.h:980,
from ../include/stdio.h:14,
from tests-mbwc/tsp_common.c:10:
In function ‘sprintf’,
inlined from ‘result.constprop.isra’ at tests-mbwc/tsp_common.c:55:3:
../libio/bits/stdio2.h:30:10: note: ‘__builtin___sprintf_chk’ output between 20 and 234 bytes into a destination of size 132
30 | return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
31 | __glibc_objsize (__s), __fmt,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
32 | __va_arg_pack ());
| ~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
This patch now gets rid of using sprintf and the result_rec buffer and just
prints to fp directly.
The test does not necessarily trigger the crash, depending on memcmp
behavior. A crash was observed in __memcmp_ia32 on i686 builds.
Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
* manual/string.texi: For strnlen (s, maxlen), do not say that s must
be of size maxlen, as it can be smaller if it is null-terminated.
This should help avoid confusion such as seen in
<https://lists.gnu.org/r/bug-gnulib/2024-06/msg00280.html>.
Mention that strnlen and wcsnlen have been in POSIX since
POSIX.1-2008.
This recently came up during a cleanup to remove misaligned accesses
from the RISC-V port.
Link: https://sourceware.org/pipermail/libc-alpha/2022-June/139961.html
Suggested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Fangrui Song <maskray@google.com>
asm volatile ("movfcsr2gr $t0, $fcsr0" ::: "$t0");
asm volatile ("st.d $t0, %0" :"=m"(restore_fcsr));
generate to the following instructions with -Og flag:
movfcsr2gr $t0, $zero
addi.d $t0, $sp, 2047(0x7ff)
addi.d $t0, $t0, 77(0x4d)
st.w $t0, $t0, 0
fcsr0 register and restore_fcsr variable are both stored in t0 register.
Change to:
asm volatile ("movfcsr2gr %0, $fcsr0" :"=r"(restore_fcsr));
to avoid restore_fcsr address in t0.
Comparing float value using memcmp because float value cannot be
directly compared for equality.
Put LOAD_REGISTER_FCSR and SAVE_REGISTER_FCC after LOAD_REGISTER_FLOAT.
Some float instructions may change fcsr register.
If the pidfd_spawn/pidfd_spawnp helper process succeeds, but evecve
fails for some reason (either with an invalid/non-existent, memory
allocation, etc.) the resulting pidfd is never closed, nor returned
to caller (so it can call close).
Since the process creation failed, it should be up to posix_spawn to
also, close the file descriptor in this case (similar to what it
does to reap the process).
This patch also changes the waitpid with waitid (P_PIDFD) for pidfd
case, to avoid a possible pid re-use.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The atomic_spin_nop() macro can be used to run arch-specific
code in the body of a spin loop to potentially improve efficiency.
RISC-V's Zihintpause extension includes a PAUSE instruction for
this use-case, which is encoded as a HINT, which means that it
behaves like a NOP on systems that don't implement Zihintpause.
Binutils supports Zihintpause since 2.36, so this patch uses
the ".insn" directive to keep the code compatible with older
toolchains.
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
MIPSr6 has MADDF.s/MADDF.d instructions, which are fused.
In MIPS ISA, double support can be subsetted. Only FMAF is enabled
for this case.
* sysdeps/mips/fpu/math-use-builtins-fma.h
Signed-off-by: YunQiang Su <syq@gcc.gnu.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The upcoming parisc (hppa) v6.11 Linux kernel will include vDSO
support for gettimeofday(), clock_gettime() and clock_gettime64()
syscalls for 32- and 64-bit userspace.
The patch below adds the necessary glue code for glibc.
Signed-off-by: Helge Deller <deller@gmx.de>
Changes in v2:
- add vsyscalls for 64-bit too
The walk benchmarks don't measure anything useful - memory is not initialized
properly so doing a single walk in 32MB just measures reading the 4KB zero
page for reads and clear_page overhead for writes. The memset variants don't
even manage to do a walk in the 32MB region due to using incorrect pointer
increments... Neither is it clear why it is walking backwards since this
won't confuse modern prefetchers. If you fix the benchmark and print the
bandwidth, the results are identical for all sizes larger than ~1KB since it
is just testing memory bandwidth of a single 32MB block. This case is already
tested by the large benchmark, so overall it doesn't seem useful to keep these.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The previous version expanded $0 and $@ twice.
The new version defines a q no-op shell command. The Perl syntax
error is masked by the eval Perl function. The q { … } construct
is executed by the shell without errors because the q shell function
was defined, but treated as a non-expanding quoted string by Perl,
effectively hiding its context from the Perl interpreter. As before
the script is read by require instead of executed directly, to avoid
infinite recursion because the #! line contains /bin/sh.
Introduce the “fatal” function to produce diagnostics that are not
suppressed by “do”. Use “do” instead of “require” because it has
fewer requirements on the executed script than “require”.
Prefix relative paths with './' because “do” (and “require“ before)
searches for the script in @INC if the path is relative and does not
start with './'. Use $_ to make the trampoline shorter.
Add an Emacs mode marker to indentify the script as a Perl script.
The test is not a run-time check, so update the description.
Also use readelf -W for a more stable output format and fix
an LC_ALL typo.
This avoids garbled configure messages:
checking for s390-specific static PIE requirements (runtime check)... 0x0000000000000017 (JMPREL) 0x280
yes
Based on a -march=x86-64-v4 -mfpmath=sse build, with and without
--disable-multi-arch, running on a Zen 4 CPU. Also used different
-march=x8i6-64-v… settings.
Generation of the Perl script does not depend on Perl, so we can
always install it even if $(PERL) is not set during the build.
Change the malloc/mtrace.pl text substition not to rely on $(PERL).
Instead use PATH at run time to find the Perl interpreter. The Perl
interpreter cannot execute directly a script that starts with
“#! /bin/sh”: it always executes it with /bin/sh. There is no
perl command line switch to disable this behavior. Instead, use
the Perl require function to execute the script. The additional
shift calls remove the “.” shell arguments. Perl interprets the
“.” as a string concatenation operator, making the expression
syntactically valid.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
HWCAP value is overwritten at the first comparison of the LASX case.
The second comparison at LSX get incorrect result.
Change to use t0 to save HWCAP value, and use t1 to save comparison
result.
