Besides the option being gcc specific, this approach is still fragile
and not future proof since we do not know if this will be the only
optimization option gcc will add that transforms loops to memset
(or any libcall).
This patch adds a new header, dl-symbol-redir-ifunc.h, that can b
used to redirect the compiler generated libcalls to port the generic
memset implementation if required.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
A start.o compiled from start.S with -DPIC and no -DSHARED is used by
both crt1.o and rcrt1.o. So the LoongArch static PIE patch
unintentionally introduced PC-relative addressing for main and
__libc_start_main into crt1.o.
While the latest Binutils (trunk, which will be released as 2.40)
supports the PC-relative relocs against an external function by creating
a PLT entry, the 2.39 release branch doesn't (and won't) support this.
An error is raised:
"PLT stub does not represent and symbol not defined."
So, we need the following changes:
1. Check if ld supports the PC-relative relocs against an external
function. If it's not supported, we deem static PIE unsupported.
2. Change start.S. If static PIE is supported, use PC-relative
addressing for main and __libc_start_main and rely on the linker to
create PLT entries. Otherwise, restore the old behavior (using GOT
to address these functions).
An alternative would be adding a new "static-pie-start.S", and some
custom logic into Makefile to build rcrt1.o with it. And, restore
start.S to the state before static PIE change so crt1.o won't contain
PC-relative relocs against external symbols. But I can't see any
benefit of this alternative, so I'd just keep it simple.
Tested by building glibc with the following configurations:
1. Binutils trunk + GCC trunk. Static PIE enabled. All tests
passed.
2. Binutils 2.39 branch + GCC trunk. Static PIE disabled. Tests
related to ifunc failed (it's a known issue). All other tests
passed.
3. Binutils 2.39 branch + GCC 12 branch, cross compilation with
build-many-glibcs.py from x86_64-linux-gnu. Static PIE disabled.
Build succeeded.
As per other architectures. I have checked on a armv8 hardware with
the following configurations:
arm-linux-gnueabihf (gcc built with --with-float=hard --with-cpu=arm926ej-s)
armv5-linux-gnueabihf (-march=armv5te -mfpu=vfpv3)
armv7-linux-gnueabihf (-march=armv7-a -mfpu=vfpv3)
armv7-thumb-linux-gnueabihf (-march=armv7-a -mfpu=vfpv3 -mthumb)
armv7-neon-linux-gnueabihf (-march=armv7-a -mfpu=neon)
armv7-neonhard-linux-gnueabihf (-march=armv7-a -mfpu=neon -mfloat-abi=hard)
Without any regression.
I haven't dig into the code, but since Linux atomic-machine.h handle
pre-ARMv6 and ARMv6 I expect the compiler might have some small room
to optimize.
The code size also improves is most of the configurations:
* master
text data bss dec hex filename
1727801 9720 37928 1775449 1b1759 arm-linux-gnueabihf/libc.so
1691729 9720 37928 1739377 1a8a71 arm-linux-gnueabihf-armv7-disable-multi-arch/libc.so
1725509 9720 37928 1773157 1b0e65 armv5-linux-gnueabihf/libc.so
1700757 9720 37928 1748405 1aadb5 armv6-linux-gnueabihf/libc.so
1698973 9720 37928 1746621 1aa6bd armv6t2-linux-gnueabihf/libc.so
1695481 9752 37928 1743161 1a9939 armv7-linux-gnueabihf/libc.so
1692917 9744 37928 1740589 1a8f2d armv7-neonhard-linux-gnueabihf/libc.so
1692917 9744 37928 1740589 1a8f2d armv7-neon-linux-gnueabihf/libc.so
1225353 9752 37928 1273033 136cc9 armv7-thumb-linux-gnueabihf/libc.so
* patched
text data bss dec hex filename
1726805 9720 37928 1774453 1b1375 arm-linux-gnueabihf/libc.so
1689321 9720 37928 1736969 1a8109 arm-linux-gnueabihf-armv7-disable-multi-arch/libc.so
1724433 9720 37928 1772081 1b0a31 armv5-linux-gnueabihf/libc.so
1698301 9720 37928 1745949 1aa41d armv6-linux-gnueabihf/libc.so
1696525 9720 37928 1744173 1a9d2d armv6t2-linux-gnueabihf/libc.so
1693009 9752 37928 1740689 1a8f91 armv7-linux-gnueabihf/libc.so
1690493 9744 37928 1738165 1a85b5 armv7-neonhard-linux-gnueabihf/libc.so
1690493 9744 37928 1738165 1a85b5 armv7-neon-linux-gnueabihf/libc.so
1223837 9752 37928 1271517 1366dd armv7-thumb-linux-gnueabihf/libc.so
The idea is eventually move all architectures to use compiler builtins.
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Removal of legacy hwcaps support from the dynamic loader left
no users of _dl_string_hwcap.
Signed-off-by: Javier Pello <devel@otheo.eu>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Last commit made it so that the value passed for that parameter was
always 0 at its only call site.
Signed-off-by: Javier Pello <devel@otheo.eu>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
This was to test loading of shared libraries from platform
subdirectories, but this functionality is going away in the
following commits.
Signed-off-by: Javier Pello <devel@otheo.eu>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch updates the kernel version in the tests tst-mman-consts.py,
tst-mount-consts.py and tst-pidfd-consts.py to 6.0. (There are no new
constants covered by these tests in 6.0 that need any other header
changes.)
Tested with build-many-glibcs.py.
The compiler might transform __stpcpy calls (which are routed to
__builtin_stpcpy as an optimization) to strcpy and x86_64 strcpy
multiarch implementation does not build any working symbol due
ISA_SHOULD_BUILD not being evaluated for IS_IN(rtld).
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
This addition to the list of source headers in
sysdeps/mach/hurd/bits/errno.h appears in the source tree after
build-many-glibcs.py runs, I'm guessing resulting from gnumach commit
c566ad85a2d6728ebc8ec0f461a3b35df300e96e.
Linux 6.0 has no new syscalls. Update the version number in
syscall-names.list to reflect that it is still current for 6.0.
Tested with build-many-glibcs.py.
The AVX2 strrchr and wcsrchr implementation uses the 'blsmsk'
instruction which belongs to the BMI1 CPU feature and the 'shrx'
instruction, which belongs to the BMI2 CPU feature.
Fixes: df7e295d18 ("x86: Optimize {str|wcs}rchr-avx2")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 memrchr implementation uses the 'shlxl' instruction, which
belongs to the BMI2 CPU feature and uses the 'lzcnt' instruction, which
belongs to the LZCNT CPU feature.
Fixes: af5306a735 ("x86: Optimize memrchr-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 memchr, rawmemchr and wmemchr implementations use the 'bzhi'
and 'sarx' instructions, which belongs to the BMI2 CPU feature.
Fixes: acfd088a19 ("x86: Optimize memchr-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 wcs(n)cmp implementations use the 'bzhi' instruction, which
belongs to the BMI2 CPU feature.
NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
as BSF if the CPU doesn't support TZCNT, and produces the same result
for non-zero input.
Partially fixes: b77b06e0e2 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 strncmp implementations uses the 'bzhi' instruction, which
belongs to the BMI2 CPU feature.
NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
as BSF if the CPU doesn't support TZCNT, and produces the same result
for non-zero input.
Partially fixes: b77b06e0e2 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 strcmp implementation uses the 'bzhi' instruction, which
belongs to the BMI2 CPU feature.
NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
as BSF if the CPU doesn't support TZCNT, and produces the same result
for non-zero input.
Partially fixes: b77b06e0e2 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 str(n)casecmp implementations use the 'bzhi' instruction, which
belongs to the BMI2 CPU feature.
NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
as BSF if the CPU doesn't support TZCNT, and produces the same result
for non-zero input.
Partially fixes: b77b06e0e2 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The "System V Application Binary Interface AMD64 Architecture Processor
Supplement" mandates the BMI1 and BMI2 CPU features for the x86-64-v3
level.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Save a jmp on the lock path coming from an initial failure in
pthread_spin_lock.S. This costs 4-bytes of code but since the
function still fits in the same number of 16-byte blocks (default
function alignment) it does not have affect on the total binary size
of libc.so (unchanged after this commit).
pthread_spin_trylock was using a CAS when a simple xchg works which
is often more expensive.
Full check passes on x86-64.
After upgrading glibc to Debian 2.35-1, gdb faulted on
startup and dropped core in a function call in the main
application. This was caused by not initializing the
global dp register for the main application early enough.
Restore the code to initialize dp in _dl_start_user.
It was removed when code was added to initialize dp in
elf_machine_runtime_setup.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Use INTERNAL_SYSCALL_CALL instead of INLINE_SYSCALL_CALL. This
requires emulate the semantic for hurd call (so __arc4random_buf
uses the fallback).
Checked on x86_64-linux-gnu.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Using an unsigned type prevents the fallback to be used if kernel
does not support getrandom syscall.
Checked on x86_64-linux-gnu.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
If the compiler is new enough, enable static PIE support. In the static
PIE version of _start (in rcrt1.o), use la.pcrel instead of la.got
because in a static PIE we cannot use GOT entries until the dynamic
relocations for GOT are resolved.
Previous implementation was adjusting length (rsi) to match
bytes (eax), but since there is no bound to length this can cause
overflow.
Fix is to just convert the byte-count (eax) to length by dividing by
sizeof (wchar_t) before the comparison.
Full check passes on x86-64 and build succeeds w/ and w/o multiarch.
GCC 13 adds support for _FloatN and _FloatNx types in C++, so breaking
the installed glibc headers that assume such support is not present.
GCC mostly works around this with fixincludes, but that doesn't help
for building glibc and its tests (glibc doesn't itself contain C++
code, but there's C++ code built for tests). Update glibc's
bits/floatn-common.h and bits/floatn.h headers to handle the GCC 13
support directly.
In general the changes match those made by fixincludes, though I think
the ones in sysdeps/powerpc/bits/floatn.h, where the header tests
__LDBL_MANT_DIG__ == 113 or uses #elif, wouldn't match the existing
fixincludes patterns.
Some places involving special C++ handling in relation to _FloatN
support are not changed. There's no need to change the
__HAVE_FLOATN_NOT_TYPEDEF definition (also in a form that wouldn't be
matched by the fixincludes fixes) because it's only used in relation
to macro definitions using features not supported for C++
(__builtin_types_compatible_p and _Generic). And there's no need to
change the inline function overloads for issignaling, iszero and
iscanonical in C++ because cases where types have the same format but
are no longer compatible types are handled automatically by the C++
overload resolution rules.
This patch also does not change the overload handling for iseqsig, and
there I think changes *are* needed, beyond those in this patch or made
by fixincludes. The way that overload is defined, via a template
parameter to a structure type, requires overloads whenever the types
are incompatible, even if they have the same format. So I think we
need to add overloads with GCC 13 for every supported _FloatN and
_FloatNx type, rather than just having one for _Float128 when it has a
different ABI to long double as at present (but for older GCC, such
overloads must not be defined for types that end up defined as
typedefs for another type).
Tested with build-many-glibcs.py: compilers build for
aarch64-linux-gnu ia64-linux-gnu mips64-linux-gnu powerpc-linux-gnu
powerpc64le-linux-gnu x86_64-linux-gnu; glibcs build for
aarch64-linux-gnu ia64-linux-gnu i686-linux-gnu mips-linux-gnu
mips64-linux-gnu-n32 powerpc-linux-gnu powerpc64le-linux-gnu
x86_64-linux-gnu.
Fix the subscript on air->family, which was accidentally set to COUNT
when it should have remained as I.
Resolves: BZ #29605
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Rename atomic_exchange_rel/acq to use atomic_exchange_release/acquire
since these map to the standard C11 atomic builtins.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Replace atomic_decrement_and_test with atomic_fetch_add_relaxed.
These are simple counters which do not protect any shared data from
concurrent accesses. Also remove the unused file cond-perf.c.
Passes regress on AArch64.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Replace atomic_increment and atomic_increment_val with atomic_fetch_add_relaxed.
One case in sem_post.c uses release semantics (see comment above it).
The others are simple counters and do not protect any shared data from
concurrent accesses.
Passes regress on AArch64.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
We don't need RV32 specific floating point functions, instead make them
generic for RISC-V.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Both RV32 and RV64 should have the same libm-test-ulps, so consolidate
them into a single file.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
QEMU does not support support set_robust_list. Thus, we need
to enable detection of set_robust_list system call.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
It avoid a possible compiler warning where right size of operator
is converted from a negative value to unsigned.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
A new internal definition, __LIBC_LOCK_ALIGNMENT, is used to force
the 4-byte alignment only for m68k, other architecture keep the
natural alignment of the type used internally (and hppa does not
require 16-byte alignment for kernel-assisted CAS).
Reviewed-by: Florian Weimer <fweimer@redhat.com>
POSIX does not say this value is special. For example, old XFS file
systems may still use inode number zero.
Also update the comment regarding ENOENT. Linux may return ENOENT
for some file systems.
Non-at functions can be implemented by just calling the corresponding at
function with AT_FDCWD and zero at_flags.
In the linkat case, the at behavior is different (O_NOLINK), so this introduces
__linkat_common to pass O_NOLINK as appropriate.
lstat functions can also be implemented with fstatat by adding
__fstatat64_common which takes a flags parameter in addition to the at_flags
parameter,
In the end this factorizes chmod, chown, link, lstat64, mkdir, readlink,
rename, stat64, symlink, unlink, utimes.
This also makes __lstat, __lxstat64, __stat and __xstat64 directly use
__fstatat64_common instead of __lstat64 or __stat64.
__syscall_error may end up farther than 1MiB away from a caller,
especially when linking statically large binaries. tail allows for
4GiB jumps and is reduced to j when a linked symbol is within range.
Fixes: 36960f0c76 ("RISC-V: Linux Syscall Interface")
Fixes: 7f33b09c65 ("RISC-V: Linux ABI")
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
9e5c991106 ("hurd: Fix readlink() hanging on fifo") separated opening
the file for the stat call from opening the file for the read call. That
however opened a small window for the file to change. Better make this
atomic by reopening the file with O_READ.
readlink() opens the target with O_READ to be able to read the symlink
content. When the target is actually a fifo, that would hang waiting for a
writer (caught in the coreutils testsuite). We thus have to first lookup the
target without O_READ to perform io_stat and lookout for fifos, and only
after checking the symlink type, we can re-lookup with O_READ.
Replace the 3 uses of atomic_bit_set and atomic_bit_test_set with
atomic_fetch_or_relaxed. Using relaxed MO is correct since the
atomics are used to ensure memory is released only once.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
