This patch splits i386 out of the main Linux kernel-features.h.
Tested x86 that there are no changes to disassembly of installed
shared libraries.
* sysdeps/unix/sysv/linux/i386/kernel-features.h: New file.
* sysdeps/unix/sysv/linux/kernel-features.h [__i386__]
(__ASSUME_SOCKETCALL): Do not define.
[__LINUX_KERNEL_VERSION >= 0x020621 && __i386__]
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
[__i386__] (__ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000 && __i386__]
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
[__i386__] (__ASSUME_SENDMMSG_SYSCALL_WITH_SOCKETCALL): Likewise.
Continuing the process of making non-ex-ports architectures follow the
preferred sysdeps practices followed by ex-ports architectures - that
is, putting things in architecture-specific sysdeps files rather than
having architecture-specific cases in architecture-independent files -
this patch moves architecture cases out of
sysdeps/unix/sysv/linux/configure.ac into (new or existing) configure
fragments for each architecture. (In the case of the
arch_minimum_kernel setting for x32,
sysdeps/unix/sysv/linux/x86_64/x32/configure already has such a
setting so the setting in sysdeps/unix/sysv/linux/configure.ac was a
duplicate that could just be removed - though I haven't tested for
x32.)
Tested for x86_64 and x86 that the patch causes no changes to the
installed shared libraries or ldd (or any part of the installation
except for the parts that always change because the files contain
timestamps - nscd and static libraries).
* sysdeps/unix/sysv/linux/configure.ac: Remove cases for
individual architectures.
* sysdeps/unix/sysv/linux/configure: Regenerated.
* sysdeps/unix/sysv/linux/i386/configure.ac: New file.
* sysdeps/unix/sysv/linux/i386/configure: New generated file.
* sysdeps/unix/sysv/linux/powerpc/configure.ac
(ldd_rewrite_script): Define variable.
* sysdeps/unix/sysv/linux/powerpc/configure: Regenerated.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure.ac: New
file.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure: New
generated file.
* sysdeps/unix/sysv/linux/s390/configure.ac: New file.
* sysdeps/unix/sysv/linux/s390/configure: New generated file.
* sysdeps/unix/sysv/linux/sh/configure.ac: New file.
* sysdeps/unix/sysv/linux/sh/configure: New generated file.
* sysdeps/unix/sysv/linux/sparc/configure.ac: New file.
* sysdeps/unix/sysv/linux/sparc/configure: New generated file.
* sysdeps/unix/sysv/linux/x86_64/configure.ac: New file.
* sysdeps/unix/sysv/linux/x86_64/configure: New generated file.
This patch cleans up for __ASSUME_ATFCTS now always being true for the
supported Linux kernel versions by removing conditional code in
sysdeps/unix/sysv/linux. Several fchownat.c files that were only
present because of differences in the fallback syscalls used
(depending on the architecture-specific names of chown-related
syscalls for 32-bit uids) are removed. Files that looks like they
could be replaced by syscalls.list entries have the standard "Consider
moving to syscalls.list." comment (see bug 14138) added. Conditionals
on the relevant __NR_* syscall numbers being defined are also removed,
since my analysis indicated that the relevant syscalls are always
defined for all relevant kernel versions using any affected file.
Much of the removed fallback code had unbounded stack allocations, so
this reduces the number of cases to consider for anyone reviewing uses
of alloca and VLAs in glibc.
There remain tests of __ASSUME_ATFCTS in io/openat.c (to determine
whether to define __have_atfcts) and sysdeps/posix/getcwd.c (which
also uses __have_atfcts); thus, the definition of __ASSUME_ATFCTS
remains in kernel-features.h. The logical condition relevant there is
whether openat64_not_cancel_3 is known to work. Hurd doesn't use this
version of getcwd at all, so the conditionals in getcwd.c are always
true in glibc. However, this code is also used in gnulib. So the
best way to deal with the conditionals there may be for gnulib people
to deal with merging all relevant changes in both directions between
the glibc and gnulib versions of this file, at the end of which the
openat conditionals should be in whatever form is best for gnulib, and
hardcoded in the _LIBC case to having openat supported.
Tested by comparing before-and-after disassembly of installed
(stripped) shared libraries, on x86_64 and x86. On x86 the patch made
no change to the disassembly; on x86_64, the only changes were in
readlinkat, where formerly the return value from the readlinkat
syscall was stored in an int variable before being converted to
ssize_t for the return, and now the return value is returned directly
without truncation to int. I think it's clearly correct not to
truncate the return value (although I also think the truncation would
not have been a user-visible bug because the kernel would never have
returned a value it could have affected).
* include/fcntl.h (__atfct_seterrno): Remove prototype.
(__atfct_seterrno_2): Likewise.
* sysdeps/unix/sysv/linux/alpha/dl-fxstatat64.c: Do not include
<kernel-features.h>.
(__ASSUME_ATFCTS): Do not undefine and redefine.
* sysdeps/unix/sysv/linux/alpha/fxstatat.c [__ASSUME_ATFCTS]
(__have_atfcts): Remove conditional definition.
(__fxstatat([__NR_fstatat64]: Make code unconditional.
(__fxstatat) [!__ASSUME_ATFCTS]: Remove conditional code and code
unreachable if [__ASSUME_ATFCTS].
* sysdeps/unix/sysv/linux/dl-fxstatat64.c (__ASSUME_ATFCTS): Do
not undefine and redefine.
* sysdeps/unix/sysv/linux/faccessat.c: Do not include
<kernel-features.h>.
(faccessat) [__NR_faccessat]: Make code unconditional.
(faccessat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/fchmodat.c: Do not include
<kernel-features.h>.
(fchmodat) [__NR_fchmodat]: Make code unconditional.
(fchmodat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/fchownat.c: Do not include
<kernel-features.h>.
(fchownat) [__NR_fchownat]: Make code unconditional.
(fchownat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/futimesat.c: Do not include
<kernel-features.h>.
(futimesat) [__NR_futimesat]: Make code unconditional.
(futimesat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/fxstatat.c: Do not include
<kernel-features.h>.
(__fxstatat) [__NR_newfstatat]: Make code unconditional.
(__fxstatat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/fxstatat64.c: Do not include
<kernel-features.h>.
(__fxstatat64) [__NR_fstatat64]: Make code unconditional.
(__fxstatat64) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/i386/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/i386/fxstatat.c: Do not include
<kernel-features.h>.
(__fxstatat) [__NR_fstatat64]: Make code unconditional.
(__fxstatat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/linkat.c: Do not include
<kernel-features.h>.
(linkat) [__NR_linkat]: Make code unconditional.
(linkat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/m68k/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/mips/mips64/fxstatat64.c: Do not include
<kernel-features.h>.
(__fxstatat64) [__NR_newfstatat]: Make code unconditional.
(__fxstatat64) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/mkdirat.c: Do not include
<kernel-features.h>.
(mkdirat) [__NR_mkdirat]: Make code unconditional.
(mkdirat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/openat.c: Do not include
<kernel-features.h>.
[!__ASSUME_ATFCTS] (__atfct_seterrno): Remove function.
[!__ASSUME_ATFCTS] (__have_atfcts): Remove variable.
(OPENAT_NOT_CANCEL) [__NR_openat]: Make code unconditional.
(OPENAT_NOT_CANCEL) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/powerpc/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/readlinkat.c: Do not include
<kernel-features.h>.
(readlinkat) [__NR_readlinkat]: Make code unconditional.
(readlinkat) [!__ASSUME_ATFCTS]: Remove conditional code. Return
result of INLINE_SYSCALL directly, not via int variable.
* sysdeps/unix/sysv/linux/renameat.c: Do not include
<kernel-features.h>.
[!__ASSUME_ATFCTS] (__atfct_seterrno_2): Remove function.
(renameat) [__NR_renameat]: Make code unconditional.
(renameat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/s390/s390-32/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/sh/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/sparc/sparc32/fchownat.c: Remove file.
* sysdeps/unix/sysv/linux/sparc/sparc64/dl-fxstatat64.c
(__ASSUME_ATFCTS): Do not undefine and redefine.
* sysdeps/unix/sysv/linux/symlinkat.c: Do not include
<kernel-features.h>.
(symlinkat) [__NR_symlinkat]: Make code unconditional.
(symlinkat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/unlinkat.c: Do not include
<kernel-features.h>.
(unlinkat) [__NR_unlinkat]: Make code unconditional.
(unlinkat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/wordsize-64/dl-fxstatat64.c
(__ASSUME_ATFCTS): Do not undefine and redefine.
* sysdeps/unix/sysv/linux/wordsize-64/fxstatat.c: Do not include
<kernel-features.h>.
(__fxstatat) [__NR_newfstatat]: Make code unconditional.
(__fxstatat) [!__ASSUME_ATFCTS]: Remove conditional code.
* sysdeps/unix/sysv/linux/xmknodat.c: Do not include
<kernel-features.h>.
(__xmknodat) [__NR_mknodat]: Make code unconditional.
(__xmknodat) [!__ASSUME_ATFCTS]: Remove conditional code.
With the recent tuning the C version of rwlocks is basically the same
performance as the x86 assembler version for uncontended locks (with a
a few cycles near the run-to-run variability). For others it should not
matter anyways.
So remove the assembler code and use the C version like other
architectures.
In <https://sourceware.org/ml/libc-alpha/2013-12/msg00008.html>,
Aurelien noted issues with the definition of __ASSUME_ACCEPT4, which I
discussed in more detail in
<https://sourceware.org/ml/libc-alpha/2013-12/msg00014.html>; these
are now bug 16609.
As previously noted, __ASSUME_ACCEPT4 is used in two ways:
* In OS-independent code, to mean "accept4 can be assumed to work
rather than fail with ENOSYS". It doesn't matter whether it's
implemented with socketcall or a separate syscall.
* In Linux-specific code, to mean "the socketcall multiplex syscall
can be assumed to handle the accept4 operation. When used in
Linux-specific code, it *never* refers to anything relating to the
accept4 syscall, only to the socketcall multiplexer.
This patch splits the macro into separate __ASSUME_ACCEPT4_SOCKETCALL,
__ASSUME_ACCEPT4_SYSCALL and __ASSUME_ACCEPT4 to clarify the different
cases involved. A macro __ASSUME_SOCKETCALL is added for convenience
in writing logic relating to all socketcall architectures. In
addition, to address the issue of architectures where socketcall
support for accept4 was added before a separate syscall was added (and
so the separate syscall should not be used unless known to be present
or fallback to socketcall is available), a fourth macro
__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL is added to indicate that the
syscall became available at the same time as socketcall support. This
is then used in the relevant places in a conditional determining
whether to undefine __NR_accept4 (the simple approach to avoiding the
syscall's presence causing problems; I didn't try to implement runtime
fallback from the syscall to socketcall).
Architecture-specific note: alpha defined __ASSUME_ACCEPT4 for 2.6.33
and later, but actually the syscall was added for alpha in 3.2, so
this patch uses the correct condition for __ASSUME_ACCEPT4_SYSCALL
there.
Tested x86_64, including that disassembly of the installed shared
libraries is unchanged by this patch.
[BZ #16609]
* sysdeps/unix/sysv/linux/kernel-features.h [__i386__ ||
__powerpc__ || __s390__ || __sh__ || __sparc__]
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION && __ASSUME_SOCKETCALL]
(__ASSUME_ACCEPT4_SOCKETCALL): Likewise.
[(__LINUX_KERNEL_VERSION >= 0x02061c && (__x86_64__ || __sparc__))
|| (__LINUX_KERNEL_VERSION >= 0x020625 && (__powerpc__ ||
__sh__))] (__ASSUME_ACCEPT4_SYSCALL): Likewise.
[__sparc__] (__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL): Likewise.
[__ASSUME_ACCEPT4_SOCKETCALL || __ASSUME_ACCEPT4_SYSCALL]
(__ASSUME_ACCEPT4): Define instead of using previous
[__LINUX_KERNEL_VERSION >= 0x02061c && (__i386__ || __x86_64__ ||
__powerpc__ || __sparc__ || __s390__)] condition.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/accept4.c [__ASSUME_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[!__ASSUME_ACCEPT4]: Change condition to
[!__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. Correct
condition to [__LINUX_KERNEL_VERSION >= 0x030200].
* sysdeps/unix/sysv/linux/arm/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020624] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/i386/accept4.S [__ASSUME_ACCEPT4]:
Change conditions to [__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x030300] (__ASSUME_ACCEPT4): Change to
__ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/internal_accept4.S [__ASSUME_SOCKETCALL
&& !__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL &&
!__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine.
[__ASSUME_ACCEPT4]: Change condition to
[__ASSUME_ACCEPT4_SOCKETCALL].
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
[__LINUX_KERNEL_VERSION >= 0x02061c] (__ASSUME_ACCEPT4): Remove.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_SOCKETCALL): Define.
(__ASSUME_ACCEPT4): Remove.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_ACCEPT4_SYSCALL):
Define.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x02061f] (__ASSUME_ACCEPT4_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020622] (__ASSUME_ACCEPT4_SYSCALL):
Define.
This patch introduces two new convenience functions to set the default
thread attributes used for creating threads. This allows a programmer
to set the default thread attributes just once in a process and then
run pthread_create without additional attributes.
This feature is specifically for the C++ compiler to offload calling
thread_local object destructors on thread program exit, to glibc.
This is to overcome the possible complication of destructors of
thread_local objects getting called after the DSO in which they're
defined is unloaded by the dynamic linker. The DSO is marked as
'unloadable' if it has a constructed thread_local object and marked as
'unloadable' again when all the constructed thread_local objects
defined in it are destroyed.
