The kernel actually verifies it, and a garbage value in the register
causes improper system call failures.
Fixes commit c1c0dea388 ("Linux: Remove epoll_create,
inotify_init from syscalls.list") and commit d1d23b1342
("Lninux: consolidate epoll_create implementation").
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This patch increases the value of SIGSTKSZ and MINSIGSTKSZ
for powerpc64 similar to the kernel commit
2f82ec19757f58549467db568c56e7dfff8af283 to allow
further expansion of the signal stack frame size.
This patch updates the kernel version in the tests tst-mman-consts.py,
tst-mount-consts.py and tst-pidfd-consts.py to 6.1. (There are no new
constants covered by these tests in 6.1 that need any other header
changes.)
Tested with build-many-glibcs.py.
vfprintf is entangled with vfwprintf (of course), __printf_fp,
__printf_fphex, __vstrfmon_l_internal, and the strfrom family of
functions. The latter use the internal snprintf functionality,
so vsnprintf is converted as well.
The simples conversion is __printf_fphex, followed by
__vstrfmon_l_internal and __printf_fp, and finally
__vfprintf_internal and __vfwprintf_internal. __vsnprintf_internal
and strfrom* are mostly consuming the new interfaces, so they
are comparatively simple.
__printf_fp is a public symbol, so the FILE *-based interface
had to preserved.
The __printf_fp rewrite does not change the actual binary-to-decimal
conversion algorithm, and digits are still not emitted directly to
the target buffer. However, the staging buffer now uses bytes
instead of wide characters, and one buffer copy is eliminated.
The changes are at least performance-neutral in my testing.
Floating point printing and snprintf improved measurably, so that
this Lua script
for i=1,5000000 do
print(i, i * math.pi)
end
runs about 5% faster for me. To preserve fprintf performance for
a simple "%d" format, this commit has some logic changes under
LABEL (unsigned_number) to avoid additional function calls. There
are certainly some very easy performance improvements here: binary,
octal and hexadecimal formatting can easily avoid the temporary work
buffer (the number of digits can be computed ahead-of-time using one
of the __builtin_clz* built-ins). Decimal formatting can use a
specialized version of _itoa_word for base 10.
The existing (inconsistent) width handling between strfmon and printf
is preserved here. __print_fp_buffer_1 would have to use
__translated_number_width to achieve ISO conformance for printf.
Test expectations in libio/tst-vtables-common.c are adjusted because
the internal staging buffer merges all virtual function calls into
one.
In general, stack buffer usage is greatly reduced, particularly for
unbuffered input streams. __printf_fp can still use a large buffer
in binary128 mode for %g, though.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Their presence causes stub warnings to be created on architectures
which do not implement them.
Fixes commit d1d23b1342 ("Lninux: consolidate
epoll_create implementation") and commit 842128f160
("Linux: consolidate inotify_init implementation").
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
8b8c768e3c ("Force use of -ffreestanding when checking for gnumach
headers") was passing -ffreestanding to CFLAGS only, but headers checks are
performed with the preprocessor, so we rather need to pass it to CPPFLAGS.
Without this ./configure assumes that we are in a fully hosted
environment, which might not be the case. After this patch, we can rely on
the freestanding header files provided by GCC such as stdint.h.
Message-Id: <Y5+0V9osFc/zXMq0@mars>
In the case of INCORRECT usage of `memcmp(a, b, N)` where `a` and `b`
are concurrently modified as `memcmp` runs, there can be a SIGSEGV
in `L(ret_nonzero_vec_end_0)` because the sequential logic
assumes that `(rdx - 32 + rax)` is a positive 32-bit integer.
To be clear, this change does not mean the usage of `memcmp` is
supported. The program behaviour is undefined (UB) in the
presence of data races, and `memcmp` is incorrect when the values
of `a` and/or `b` are modified concurrently (data race). This UB
may manifest itself as a SIGSEGV. That being said, if we can
allow the idiomatic use cases, like those in yottadb with
opportunistic concurrency control (OCC), to execute without a
SIGSEGV, at no cost to regular use cases, then we can aim to
minimize harm to those existing users.
The fix replaces a 32-bit `addl %edx, %eax` with the 64-bit variant
`addq %rdx, %rax`. The 1-extra byte of code size from using the
64-bit instruction doesn't contribute to overall code size as the
next target is aligned and has multiple bytes of `nop` padding
before it. As well all the logic between the add and `ret` still
fits in the same fetch block, so the cost of this change is
basically zero.
The relevant sequential logic can be seen in the following
pseudo-code:
```
/*
* rsi = a
* rdi = b
* rdx = len - 32
*/
/* cmp a[0:15] and b[0:15]. Since length is known to be [17, 32]
in this case, this check is also assumed to cover a[0:(31 - len)]
and b[0:(31 - len)]. */
movups (%rsi), %xmm0
movups (%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(END_NEQ)
/* cmp a[len-16:len-1] and b[len-16:len-1]. */
movups 16(%rsi, %rdx), %xmm0
movups 16(%rdi, %rdx), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(END_NEQ2)
ret
L(END2):
/* Position first mismatch. */
bsfl %eax, %eax
/* The sequential version is able to assume this value is a
positive 32-bit value because the first check included bytes in
range a[0:(31 - len)] and b[0:(31 - len)] so `eax` must be
greater than `31 - len` so the minimum value of `edx` + `eax` is
`(len - 32) + (32 - len) >= 0`. In the concurrent case, however,
`a` or `b` could have been changed so a mismatch in `eax` less or
equal than `(31 - len)` is possible (the new low bound is `(16 -
len)`. This can result in a negative 32-bit signed integer, which
when zero extended to 64-bits is a random large value this out
out of bounds. */
addl %edx, %eax
/* Crash here because 32-bit negative number in `eax` zero
extends to out of bounds 64-bit offset. */
movzbl 16(%rdi, %rax), %ecx
movzbl 16(%rsi, %rax), %eax
```
This fix is quite simple, just make the `addl %edx, %eax` 64 bit (i.e
`addq %rdx, %rax`). This prevents the 32-bit zero extension
and since `eax` is still a low bound of `16 - len` the `rdx + rax`
is bound by `(len - 32) - (16 - len) >= -16`. Since we have a
fixed offset of `16` in the memory access this must be in bounds.
A recent GCC change resulted in localplt test failures on sparc64
because of references to _Qp_fgt. This is analogous to all the other
floating-point symbols allowed in localplt.data, so it seems
appropriate to allow this one as well.
Tested with build-many-glibcs.py for sparc64-linux-gnu (GCC mainline),
where it fixes the test failure.
The generic (sysdeps/unix/sysv/linux/generic/bits/typesizes.h) and
default (bits/typesizes.h) differs in two fields:
bits/typesizes.h Linux generic
__NLINK_T_TYPE __UWORD_TYPE __U32_TYPE
__BLKSIZE_T_TYPE __SLONGWORD_TYPE __S32_TYPE
Sinceit leads to different C++ mangling names, the default typesize.h
is copied for the requires archtiectures and the generic is make the
default Linux one.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
It is currently used for csky, arc, nios2, and or1k. Newer 64 bit
architecture, like riscv32 and loongarch, reimplement it to override
F_GETLK64/F_SETLK64/F_SETLKW64.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
The includes chain is added on each architecture sysdep.h and
the __NR__llseek hack is moved to lseek.c and lseek64.c.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And disable if kernel does not support it.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And disable if kernel does not support it.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And disable if kernel does not support it.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And disable if kernel does not support it.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And disable if kernel does not support it.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
This is similar to other LFS consolidation, where the non-LFS is only
built if __OFF_T_MATCHES_OFF64_T is not defined and the LFS version
is aliased to non-LFS name if __OFF_T_MATCHES_OFF64_T is defined.
For non-LFS variant, use sendfile syscall if defined, otherwise use
sendfile64 plus the offset overflow check (as generic implementation).
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use unlink syscall if defined, otherwise use unlinkat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use symlink syscall if defined, otherwise use symlinkat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use rmdir syscall if defined, otherwise use unlinkat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use readlink syscall if defined, otherwise readlinkat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use mkdir syscall if defined, otherwise use mkdirat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use link syscall if defined, otherwise use linkat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use lchown syscall if defined, otherwise use fchownat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use inotify_init syscall if defined, otherwise use inotify_init1.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use epoll_create syscall if defined, otherwise use epoll_create1.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use dup2 syscall if defined, otherwise use dup3.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use chown syscall if defined, otherwise use fchownat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use chmod syscall if defined, otherwise use fchmodat.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Use the generic implementation as the default, since the syscall
is supported by all architectures.
Also cleanup some headers and remove the INTERNAL_SYSCALL_ERROR_P
usage (the INTERNAL_SYSCALL_CALL macro already returns an negative
value if an error occurs).
The linux syscall ABI returns long, so the generic syscall code for
linux should use long for the return value.
This fixes the truncation of the return value of the syscall function
when that does not fit into an int.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The assembler is not issued directly, but rather always through CC
wrapper. The binutils version check if done with LD instead.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Previously, getrandom would, each time it's called, traverse the file
system to find /dev/urandom, fetch some random data from it, then throw
away that port. This is quite slow, while calls to getrandom are
genrally expected to be fast.
Additionally, this means that getrandom can not work when /dev/urandom
is unavailable, such as inside a chroot that lacks one. User programs
expect calls to getrandom to work inside a chroot if they first call
getrandom outside of the chroot.
In particular, this is known to break the OpenSSH server, and in that
case the issue is exacerbated by the API of arc4random, which prevents
it from properly reporting errors, forcing glibc to abort on failure.
This causes sshd to just die once it tries to generate a random number.
Caching the random server port, in a manner similar to how socket
server ports are cached, both improves the performance and works around
the chroot issue.
Tested on i686-gnu with the following program:
pthread_barrier_t barrier;
void *worker(void*) {
pthread_barrier_wait(&barrier);
uint32_t sum = 0;
for (int i = 0; i < 10000; i++) {
sum += arc4random();
}
return (void *)(uintptr_t) sum;
}
int main() {
pthread_t threads[THREAD_COUNT];
pthread_barrier_init(&barrier, NULL, THREAD_COUNT);
for (int i = 0; i < THREAD_COUNT; i++) {
pthread_create(&threads[i], NULL, worker, NULL);
}
for (int i = 0; i < THREAD_COUNT; i++) {
void *retval;
pthread_join(threads[i], &retval);
printf("Thread %i: %lu\n", i, (unsigned long)(uintptr_t) retval);
}
In my totally unscientific benchmark, with this patch, this completes
in about 7 seconds, whereas previously it took about 50 seconds. This
program was also used to test that getrandom () doesn't explode if the
random server dies, but instead reopens the /dev/urandom anew. I have
also verified that with this patch, OpenSSH can once again accept
connections properly.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20221202135558.23781-1-bugaevc@gmail.com>
This patch cleans up the power4 strncmp optimization for powerpc64 which
is unlikely to be used anywhere.
Tested on ppc64le with and without --disable-multi-arch flag.
Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes strncpy for x32. Tested on x86-64 and x32. On x86-64,
libc.so is the same with and without the fix.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes strncat for x32. Tested on x86-64 and x32. On x86-64,
libc.so is the same with and without the fix.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Add inline assembler for the scalbn functions. Passes GLIBC regression.
GCC 13, LoongArch support ___builtin_scalbn{,f} with -fno-math-errno,
but only "libm" can use -fno-math-errno in GLIBC, and scalbn is in libc
instead of libm because __printf_fp calls it.
GCC 13 compiles these built-ins instead of generic
implementation for function logb.
Link: https://gcc.gnu.org/r13-3922
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
This patch is using the corresponding GCC builtin for logbf, logb,
logbl and logbf128 if the USE_FUNCTION_BUILTIN macros are defined to one
in math-use-builtins-function.h.
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
GCC 13 compiles these built-ins instead of generic
implementation for function llrint.
Link: https://gcc.gnu.org/r13-3920
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
This patch is using the corresponding GCC builtin for llrintf, llrint,
llrintl and llrintf128 if the USE_FUNCTION_BUILTIN macros are defined to one
in math-use-builtins-function.h.
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
GCC 13 compiles these built-ins instead of generic
implementation for function lrint.
Link: https://gcc.gnu.org/r13-3920
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
This patch is using the corresponding GCC builtin for lrintf, lrint,
lrintl and lrintf128 if the USE_FUNCTION_BUILTIN macros are defined to one
in math-use-builtins-function.h.
Co-Authored-By: Xi Ruoyao <xry111@xry111.site>
lld does not implement all the linker optimization to avoid the GOT
relocation as done by binutils (bfd/elf32-i386.c:elf_i386_convert_load_reloc).
The current 'movl main@GOT(%ebx), %eax' will then create a GOT
relocation when building with lld, which make static-pie status to
not being able to start the provided main function.
The change uses a __wrap_main local symbol, which in turn calls main
(similar as used by aarch64 and s390x).
Checked on i686-linux-gnu with binutils and lld.
Reviewed-by: Fangrui Song <maskray@google.com>
This patch fixes two problems with audit:
1. The DL_OFFSET_RV_VPCS offset was mixed up with DL_OFFSET_RG_VPCS,
resulting in x2 register value nulling in RG structure.
2. We need to preserve the x8 register before function call, but
don't have to save it's new value and restore it before return.
Anyway the final restore was using OFFSET_RV instead of OFFSET_RG value
which is wrong (althoug doesn't affect anything).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Currently glibc uses in_time_t_range to detects time_t overflow,
and if it occurs fallbacks to 64 bit syscall version.
The function name is confusing because internally time_t might be
either 32 bits or 64 bits (depending on __TIMESIZE).
This patch refactors the in_time_t_range by replacing it with
in_int32_t_range for the case to check if the 64 bit time_t syscall
should be used.
The in_time_t range is used to detect overflow of the
syscall return value.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use __builtin_{fma, fmaf} to implement function {fma, fmaf} instead of
the generic implementation.
* sysdeps/loongarch/fpu/math-use-builtins-fma.h: New file.
Old applications pass __IPC_64 as part of the command argument because
old glibc did not check for unknown commands, and passed through the
arguments directly to the kernel, without adding __IPC_64.
Applications need to continue doing that for old glibc compatibility,
so this commit enables this approach in current glibc.
For msgctl and shmctl, if no translation is required, make
direct system calls, as we did before the time64 changes. If
translation is required, mask __IPC_64 from the command argument.
For semctl, the union-in-vararg argument handling means that
translation is needed on all architectures.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
RISC-V architecture extends the cache information for level 3 cache
in AUX vector in Linux v.6.1-rc1. This patch supports sysconf to get
the level 3 cache information.
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Implemented:
wcscat-avx2 (+ 744 bytes
wcscpy-avx2 (+ 539 bytes)
wcpcpy-avx2 (+ 577 bytes)
wcsncpy-avx2 (+1108 bytes)
wcpncpy-avx2 (+1214 bytes)
wcsncat-avx2 (+1085 bytes)
Performance Changes:
Times are from N = 10 runs of the benchmark suite and are reported
as geometric mean of all ratios of New Implementation / Best Old
Implementation. Best Old Implementation was determined with the
highest ISA implementation.
wcscat-avx2 -> 0.975
wcscpy-avx2 -> 0.591
wcpcpy-avx2 -> 0.698
wcsncpy-avx2 -> 0.730
wcpncpy-avx2 -> 0.711
wcsncat-avx2 -> 0.954
Code Size Changes:
This change increase the size of libc.so by ~5.5kb bytes. For
reference the patch optimizing the normal strcpy family functions
decreases libc.so by ~5.2kb.
Full check passes on x86-64 and build succeeds for all ISA levels w/
and w/o multiarch.
Implemented:
wcscat-evex (+ 905 bytes)
wcscpy-evex (+ 674 bytes)
wcpcpy-evex (+ 709 bytes)
wcsncpy-evex (+1358 bytes)
wcpncpy-evex (+1467 bytes)
wcsncat-evex (+1213 bytes)
Performance Changes:
Times are from N = 10 runs of the benchmark suite and are reported
as geometric mean of all ratios of New Implementation / Best Old
Implementation. Best Old Implementation was determined with the
highest ISA implementation.
wcscat-evex -> 0.991
wcscpy-evex -> 0.587
wcpcpy-evex -> 0.695
wcsncpy-evex -> 0.719
wcpncpy-evex -> 0.694
wcsncat-evex -> 0.979
Code Size Changes:
This change increase the size of libc.so by ~6.3kb bytes. For
reference the patch optimizing the normal strcpy family functions
decreases libc.so by ~5.7kb.
Full check passes on x86-64 and build succeeds for all ISA levels w/
and w/o multiarch.
Optimizations are:
1. Use more overlapping stores to avoid branches.
2. Reduce how unrolled the aligning copies are (this is more of a
code-size save, its a negative for some sizes in terms of
perf).
3. For st{r|p}n{cat|cpy} re-order the branches to minimize the
number that are taken.
Performance Changes:
Times are from N = 10 runs of the benchmark suite and are
reported as geometric mean of all ratios of
New Implementation / Old Implementation.
strcat-avx2 -> 0.998
strcpy-avx2 -> 0.937
stpcpy-avx2 -> 0.971
strncpy-avx2 -> 0.793
stpncpy-avx2 -> 0.775
strncat-avx2 -> 0.962
Code Size Changes:
function -> Bytes New / Bytes Old -> Ratio
strcat-avx2 -> 685 / 1639 -> 0.418
strcpy-avx2 -> 560 / 903 -> 0.620
stpcpy-avx2 -> 592 / 939 -> 0.630
strncpy-avx2 -> 1176 / 2390 -> 0.492
stpncpy-avx2 -> 1268 / 2438 -> 0.520
strncat-avx2 -> 1042 / 2563 -> 0.407
Notes:
1. Because of the significant difference between the
implementations they are split into three files.
strcpy-avx2.S -> strcpy, stpcpy, strcat
strncpy-avx2.S -> strncpy
strncat-avx2.S > strncat
I couldn't find a way to merge them without making the
ifdefs incredibly difficult to follow.
Full check passes on x86-64 and build succeeds for all ISA levels w/
and w/o multiarch.
Optimizations are:
1. Use more overlapping stores to avoid branches.
2. Reduce how unrolled the aligning copies are (this is more of a
code-size save, its a negative for some sizes in terms of
perf).
3. Improve the loop a bit (similiar to what we do in strlen with
2x vpminu + kortest instead of 3x vpminu + kmov + test).
4. For st{r|p}n{cat|cpy} re-order the branches to minimize the
number that are taken.
Performance Changes:
Times are from N = 10 runs of the benchmark suite and are
reported as geometric mean of all ratios of
New Implementation / Old Implementation.
stpcpy-evex -> 0.922
strcat-evex -> 0.985
strcpy-evex -> 0.880
strncpy-evex -> 0.831
stpncpy-evex -> 0.780
strncat-evex -> 0.958
Code Size Changes:
function -> Bytes New / Bytes Old -> Ratio
strcat-evex -> 819 / 1874 -> 0.437
strcpy-evex -> 700 / 1074 -> 0.652
stpcpy-evex -> 735 / 1094 -> 0.672
strncpy-evex -> 1397 / 2611 -> 0.535
stpncpy-evex -> 1489 / 2691 -> 0.553
strncat-evex -> 1184 / 2832 -> 0.418
Notes:
1. Because of the significant difference between the
implementations they are split into three files.
strcpy-evex.S -> strcpy, stpcpy, strcat
strncpy-evex.S -> strncpy
strncat-evex.S > strncat
I couldn't find a way to merge them without making the
ifdefs incredibly difficult to follow.
2. All implementations can be made evex512 by including
"x86-evex512-vecs.h" at the top.
3. All implementations have an optional define:
`USE_EVEX_MASKED_STORE`
Setting to one uses evex-masked stores for handling short
strings. This saves code size and branches. It's disabled
for all implementations are the moment as there are some
serious drawbacks to masked stores in certain cases, but
that may be fixed on future architectures.
Full check passes on x86-64 and build succeeds for all ISA levels w/
and w/o multiarch.
Changes to generated code are:
1. In a few places use `vpcmpeqb` instead of `vpcmpneq` to save a
byte of code size.
2. Add a branch for length <= (VEC_SIZE * 6) as opposed to doing
the entire block of [VEC_SIZE * 4 + 1, VEC_SIZE * 8] in a
single basic-block (the space to add the extra branch without
changing code size is bought with the above change).
Change (2) has roughly a 20-25% speedup for sizes in [VEC_SIZE * 4 +
1, VEC_SIZE * 6] and negligible to no-cost for [VEC_SIZE * 6 + 1,
VEC_SIZE * 8]
From N=10 runs on Tigerlake:
align1,align2 ,length ,result ,New Time ,Cur Time ,New Time / Old Time
0 ,0 ,129 ,0 ,5.404 ,6.887 ,0.785
0 ,0 ,129 ,1 ,5.308 ,6.826 ,0.778
0 ,0 ,129 ,18446744073709551615 ,5.359 ,6.823 ,0.785
0 ,0 ,161 ,0 ,5.284 ,6.827 ,0.774
0 ,0 ,161 ,1 ,5.317 ,6.745 ,0.788
0 ,0 ,161 ,18446744073709551615 ,5.406 ,6.778 ,0.798
0 ,0 ,193 ,0 ,6.804 ,6.802 ,1.000
0 ,0 ,193 ,1 ,6.950 ,6.754 ,1.029
0 ,0 ,193 ,18446744073709551615 ,6.792 ,6.719 ,1.011
0 ,0 ,225 ,0 ,6.625 ,6.699 ,0.989
0 ,0 ,225 ,1 ,6.776 ,6.735 ,1.003
0 ,0 ,225 ,18446744073709551615 ,6.758 ,6.738 ,0.992
0 ,0 ,256 ,0 ,5.402 ,5.462 ,0.989
0 ,0 ,256 ,1 ,5.364 ,5.483 ,0.978
0 ,0 ,256 ,18446744073709551615 ,5.341 ,5.539 ,0.964
Rewriting with VMM API allows for memcmpeq-evex to be used with
evex512 by including "x86-evex512-vecs.h" at the top.
Complete check passes on x86-64.
The only change to the existing generated code is `tzcnt` -> `bsf` to
save a byte of code size here and there.
Rewriting with VMM API allows for memcmp-evex-movbe to be used with
evex512 by including "x86-evex512-vecs.h" at the top.
Complete check passes on x86-64.
Similar to ppoll, the poll.h header needs to redirect the poll call
to a proper fortified ppoll with 64 bit time_t support.
The implementation is straightforward, just need to add a similar
check as __poll_chk and call the 64 bit time_t ppoll version. The
debug fortify tests are also extended to cover 64 bit time_t for
affected ABIs.
Unfortunately it requires an aditional symbol, which makes backport
tricky. One possibility is to add a static inline version if compiler
supports is and call abort instead of __chk_fail, so fortified version
will call __poll64 in the end.
Another possibility is to just remove the fortify support for
_TIME_BITS=64.
Checked on i686-linux-gnu.
Changes from v1:
Use vec api for register.
Replace VPCMP with VPCMPEQ
Restructure and remove 1 unconditional jump.
Change page cross logic to use sall.
This patch implements following evex512 version of string functions.
evex512 version takes up to 30% less cycle as compared to evex,
depending on length and alignment.
- strrchr function using 512 bit vectors.
- wcsrchr function using 512 bit vectors.
Code size data:
strrchr-evex.o 879 byte
strrchr-evex512.o 601 byte (-32%)
wcsrchr-evex.o 882 byte
wcsrchr-evex512.o 572 byte (-35%)
Placeholder function, not used by any processor at the moment.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This makes it more likely that the compiler can compute the strlen
argument in _startup_fatal at compile time, which is required to
avoid a dependency on strlen this early during process startup.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
The old exception handling implementation used function interposition
to replace the dynamic loader implementation (no TLS support) with the
libc implementation (TLS support). This results in problems if the
link order between the dynamic loader and libc is reversed (bug 25486).
The new implementation moves the entire implementation of the
exception handling functions back into the dynamic loader, using
THREAD_GETMEM and THREAD_SETMEM for thread-local data support.
These depends on Hurd support for these macros, added in commit
b65a82e4e7 ("hurd: Add THREAD_GET/SETMEM/_NC").
One small obstacle is that the exception handling facilities are used
before the TCB has been set up, so a check is needed if the TCB is
available. If not, a regular global variable is used to store the
exception handling information.
Also rename dl-error.c to dl-catch.c, to avoid confusion with the
dlerror function.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Commit 6e8a0aac2f ("time: Fix overflow itimer tests on 32-bit
systems") changed in_time_t_range to assume a 32-bit time_t. This broke
fstatat on MIPSn64 that was using it with a 64-bit time_t due to
difference between stat and stat64. This commit fix that by adding a
MIPSn64 specific version, which bypasses the EOVERFLOW tests.
Resolves: BZ #29730
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
clang emits an warning when a double alias redirection is used, to warn
the the original symbol will be used even when weak definition is
overridden. However, this is a common pattern for weak_alias, where
multiple alias are set to same symbol.
Reviewed-by: Fangrui Song <maskray@google.com>
GCC 13 has added more _FloatN and _FloatNx versions of existing
<math.h> and <complex.h> built-in functions, for use in libstdc++-v3.
This breaks the glibc build because of how those functions are defined
as aliases to functions with the same ABI but different types. Add
appropriate -fno-builtin-* options for compiling relevant files, as
already done for the case of long double functions aliasing double
ones and based on the list of files used there.
I fixed some mistakes in that list of double files that I noticed
while implementing this fix, but there may well be more such
(harmless) cases, in this list or the new one (files that don't
actually exist or don't define the named functions as aliases so don't
need the options). I did try to exclude cases where glibc doesn't
define certain functions for _FloatN or _FloatNx types at all from the
new uses of -fno-builtin-* options. As with the options for double
files (see the commit message for commit
49348beafe, "Fix build with GCC 10 when
long double = double."), it's deliberate that the options are used
even if GCC currently doesn't have a built-in version of a given
functions, so providing some level of future-proofing against more
such built-in functions being added in future.
Tested with build-many-glibcs.py for aarch64-linux-gnu
powerpc-linux-gnu powerpc64le-linux-gnu x86_64-linux-gnu (compilers
and glibcs builds) with GCC mainline.
This patch improves following functionality
- Replace VPCMP with VPCMPEQ.
- Replace page cross check logic with sall.
- Remove extra lea from align_more.
- Remove uncondition loop jump.
- Use bsf to check max length in first vector.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
According to the specification of ISO/IEC TS 18661-1:2014,
The strfromd, strfromf, and strfroml functions are equivalent to
snprintf(s, n, format, fp) (7.21.6.5), except the format string contains only
the character %, an optional precision that does not contain an asterisk *, and
one of the conversion specifiers a, A, e, E, f, F, g, or G, which applies to
the type (double, float, or long double) indicated by the function suffix
(rather than by a length modifier). Use of these functions with any other 20
format string results in undefined behavior.
strfromf will convert the arguement with type float to double first.
According to the latest version of IEEE754 which is published in 2019,
Conversion of a quiet NaN from a narrower format to a wider format in the same
radix, and then back to the same narrower format, should not change the quiet
NaN payload in any way except to make it canonical.
When either an input or result is a NaN, this standard does not interpret the
sign of a NaN. However, operations on bit strings—copy, negate, abs,
copySign—specify the sign bit of a NaN result, sometimes based upon the sign
bit of a NaN operand. The logical predicates totalOrder and isSignMinus are
also affected by the sign bit of a NaN operand. For all other operations, this
standard does not specify the sign bit of a NaN result, even when there is only
one input NaN, or when the NaN is produced from an invalid operation.
converting NAN or -NAN with type float to double doesn't need to keep
the signbit. As a result, this test case isn't mandatory.
The problem is that according to RISC-V ISA manual in chapter 11.3 of
riscv-isa-20191213,
Except when otherwise stated, if the result of a floating-point operation is
NaN, it is the canonical NaN. The canonical NaN has a positive sign and all
significand bits clear except the MSB, a.k.a. the quiet bit. For
single-precision floating-point, this corresponds to the pattern 0x7fc00000.
which means that conversion -NAN from float to double won't keep the signbit.
Since glibc ought to be consistent here between types and architectures, this
patch adds copysign to fix this problem if the string is NAN. This patch
adds two different functions under sysdeps directory to work around the
issue.
This patch has been tested on x86_64 and riscv64.
Resolves: BZ #29501
v2: Change from macros to different inline functions.
v3: Add unlikely check to isnan.
v4: Fix wrong commit message header.
v5: Fix style: add space before parentheses.
v6: Add copyright.
Signed-off-by: Letu Ren <fantasquex@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The extension header is two 32bit words and in the last header both
should be 0. There is plenty space in the __reserved area, but it's
better not to write more than we mean to.
Use an empty wordcopy.c to avoid building the generic one.
It does not seem to be used anywhere.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This consolidates the destructor invocations from _dl_fini and
dlclose. Remove the micro-optimization that avoids
calling _dl_call_fini if they are no destructors (as dlclose is quite
expensive anyway). The debug log message is now printed
unconditionally.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This allows the rest of dynamic loader to check whether the TCB
has been set up (and THREAD_GETMEM and THREAD_SETMEM will work).
Reviewed-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
Since __memcpy_simd is the fastest memcpy on almost all cores, replace
the generic memcpy with it. If SVE is available, a SVE memcpy will be
used by default (including for Neoverse N2).
