With the 2.6.32 minimum kernel on x86 and 3.2 on other architectures,
__NR_openat is always defined.
Changelog:
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64) [__NR_openat]:
Make code unconditional.
The x86-specific versions of both pthread_cond_wait and
pthread_cond_timedwait have (in their fall-back-to-futex-wait slow
paths) calls to __pthread_mutex_cond_lock_adjust followed by
__pthread_mutex_unlock_usercnt, which load the parameters before the
first call but then assume that the first parameter, in %eax, will
survive unaffected. This happens to have been true before now, but %eax
is a call-clobbered register, and this assumption is not safe: it could
change at any time, at GCC's whim, and indeed the stack-protector canary
checking code clobbers %eax while checking that the canary is
uncorrupted.
So reload %eax before calling __pthread_mutex_unlock_usercnt. (Do this
unconditionally, even when stack-protection is not in use, because it's
the right thing to do, it's a slow path, and anything else is dicing
with death.)
* sysdeps/unix/sysv/linux/i386/pthread_cond_timedwait.S: Reload
call-clobbered %eax on retry path.
* sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S: Likewise.
This patch removes the __ASSUME_GETDENTS64_SYSCALL macro, as its
definition is constant given the new kernel version requirements (and
was constant anyway before those requirements except for MIPS n32).
Note that the "#ifdef __NR_getdents64" conditional *is* still needed,
because MIPS n64 only has the getdents syscall (being a 64-bit ABI,
that syscall is 64-bit; the difference between the two on 64-bit
architectures is where d_type goes). If MIPS n64 were to gain the
getdents64 syscall and we wanted to use it conditionally on the kernel
version at runtime we'd have to revert this patch, but I think that's
unlikely (and in any case, we could follow the simpler approach of
undefining __NR_getdents64 if the syscall can't be assumed, just like
we do for accept4 / recvmmsg / sendmmsg syscalls on architectures
where socketcall support came first).
Most of the getdents.c changes are reindentation.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_GETDENTS64_SYSCALL): Remove macro.
* sysdeps/unix/sysv/linux/getdents.c
[!__ASSUME_GETDENTS64_SYSCALL]: Remove conditional code.
[!have_no_getdents64_defined]: Likewise.
(__GETDENTS): Remove __have_no_getdents64 conditional.
Current Linux kernel version requirements mean the signalfd4 syscall
can always be assumed to be available. This patch removes
__ASSUME_SIGNALFD4 and associated conditionals.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_SIGNALFD4):
Remove macro.
* sysdeps/unix/sysv/linux/signalfd.c: Do not include
<kernel-features.h>.
(signalfd) [__NR_signalfd4]: Make code unconditional.
(signalfd) [!__ASSUME_SIGNALFD4]: Remove conditional code.
This patch fixes the implicit check style add in 2a69f853c for the
general convention one.
Checked on x86_64.
* sysdeps/unix/sysv/linux/spawni.c (__spawnix): Fix implict checks
style.
When PLT may be used, JUMPTARGET should be used instead calling the
function directly.
* sysdeps/unix/sysv/linux/x86_64/cancellation.S
(__pthread_enable_asynccancel): Use JUMPTARGET to call
__pthread_unwind.
* sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S
(__condvar_cleanup2): Use JUMPTARGET to call _Unwind_Resume.
* sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
(__condvar_cleanup1): Likewise.
Current Linux posix_spawn spawn do not test if the pid argument is
valid before trying to update it for success case. This patch fixes
it.
Tested on x86_64 and i686.
* sysdeps/unix/sysv/linux/spawni.c (__spawnix): Fix invalid memory
access where posix_spawn success and pid argument is null.
* posix/tst-spawn.c (do_test): Add posix_spawn null pid argument for
success case.
Given current Linux kernel version requirements, we can assume the
presence of the eventfd2 syscall. This means that __ASSUME_EVENTFD2
can be removed, and a syscalls.list entry suffices for eventfd instead
of needing a .c file. This patch implements those changes.
Tested for x86_64 and x86 (not that that means much, given the lack of
testsuite coverage for eventfd).
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_EVENTFD2):
Remove macro.
* sysdeps/unix/sysv/linux/eventfd.c: Remove file.
* sysdeps/unix/sysv/linux/syscalls.list (eventfd): New syscall
entry.
Given current Linux kernel version requirements, we can always assume
the fallocate syscall to be available. This patch removes
__ASSUME_FALLOCATE and a test for whether __NR_fallocate is defined.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_FALLOCATE):
Remove macro.
* sysdeps/unix/sysv/linux/wordsize-64/posix_fallocate.c: Do not
include <kernel-features.h>.
[!__ASSUME_FALLOCATE]: Remove conditional code.
(posix_fallocate) [__NR_fallocate]: Make code unconditional.
With current kernel version requirements, the ppoll Linux syscall can
be assumed to be present on all architectures; this patch removes the
__ASSUME_PPOLL macro and conditionals on it and on whether __NR_ppoll
is defined. (Note that the same can't yet be done for pselect,
because MicroBlaze only wired that up in the syscall table in 3.15.)
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_PPOLL):
Remove macro.
* sysdeps/unix/sysv/linux/ppoll.c: Do not include
<kernel-features.h>.
[__NR_ppoll]: Make code unconditional.
[!__ASSUME_PPOLL]: Remove conditional code.
This patch adjusts the defaults for kernel-features.h macros relating
to availability of accept4, recvmmsg and sendmmsg. It is not intended
to affect which macros end up getting defined in any configuration.
At present, all architectures with syscalls for those functions need
to define __ASSUME_*_SYSCALL macros; in particular, any new
architecture needs its own kernel-features.h file for that purpose,
though it may not otherwise need such a header. Those macros are then
used together with __ASSUME_SOCKETCALL to define macros for whether
the functions in question are available.
This patch changes the defaults so that the syscalls are assumed to be
available by default with recent-enough kernels, and it is the
responsibility of architecture headers to undefine the macros if they
are unavailable in supported kernels at least as recent as the version
where the architecture-independent functionality was introduced. The
__ASSUME_<function> macros are defaulted similarly instead of being
defined based on other macros (defining based on other macros would no
longer work because the #undefs appear after the generic header is
included), so where the syscall being unavailable means the function
is unavailable this means the architecture header has to undefine the
__ASSUME_<function> macro; this only affects __ASSUME_ACCEPT4 for
ia64, as other cases where the syscalls were added late enough to be
relevant with current kernel version requirements are all on
socketcall architectures.
As a consequence, the AArch64 and Nios II kernel-features.h header
files are removed, and others simplified. When the minimum kernel
version becomes 4.3 or later on all architectures, the syscalls in
question can just be assumed unconditionally, permitting further
simplification.
Tested for x86_64, x86 and powerpc (that installed shared libraries
are unchanged by the patch, and testsuite for x86_64 and x86).
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Define unconditionally.
(__ASSUME_ACCEPT4): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Define.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG):
Likewise.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h: Remove file.
* sysdeps/unix/sysv/linux/nios2/kernel-features.h: Likewise.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Do not define.
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/i386/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Do not define.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x030300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x030300].
[__LINUX_KERNEL_VERSION < 0x030300] (__ASSUME_ACCEPT4): Undefine.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x030300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x030300].
* sysdeps/unix/sysv/linux/mips/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/powerpc/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/s390/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/sh/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/sparc/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/x86_64/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
This patch updates the glibc headers with the defines MADV_FREE,
IPV6_HDRINCL and EPOLLEXCLUSIVE that are added in Linux 4.5.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/mman-linux.h [__USE_MISC] (MADV_FREE): New macro.
* sysdeps/unix/sysv/linux/hppa/bits/mman.h [__USE_MISC]
(MADV_FREE): Likewise.
* sysdeps/unix/sysv/linux/bits/in.h (IPV6_HDRINCL): Likewise.
* sysdeps/unix/sysv/linux/sys/epoll.h (enum EPOLL_EVENTS): Add
EPOLLEXCLUSIVE.
index_* and bit_* macros are used to access cpuid and feature arrays o
struct cpu_features. It is very easy to use bits and indices of cpuid
array on feature array, especially in assembly codes. For example,
sysdeps/i386/i686/multiarch/bcopy.S has
HAS_CPU_FEATURE (Fast_Rep_String)
which should be
HAS_ARCH_FEATURE (Fast_Rep_String)
We change index_* and bit_* to index_cpu_*/index_arch_* and
bit_cpu_*/bit_arch_* so that we can catch such error at build time.
[BZ #19762]
* sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
(EXTRA_LD_ENVVARS): Add _arch_ to index_*/bit_*.
* sysdeps/x86/cpu-features.c (init_cpu_features): Likewise.
* sysdeps/x86/cpu-features.h (bit_*): Renamed to ...
(bit_arch_*): This for feature array.
(bit_*): Renamed to ...
(bit_cpu_*): This for cpu array.
(index_*): Renamed to ...
(index_arch_*): This for feature array.
(index_*): Renamed to ...
(index_cpu_*): This for cpu array.
[__ASSEMBLER__] (HAS_FEATURE): Add and use field.
[__ASSEMBLER__] (HAS_CPU_FEATURE)): Pass cpu to HAS_FEATURE.
[__ASSEMBLER__] (HAS_ARCH_FEATURE)): Pass arch to HAS_FEATURE.
[!__ASSEMBLER__] (HAS_CPU_FEATURE): Replace index_##name and
bit_##name with index_cpu_##name and bit_cpu_##name.
[!__ASSEMBLER__] (HAS_ARCH_FEATURE): Replace index_##name and
bit_##name with index_arch_##name and bit_arch_##name.
In makecontext the FDE needs to be terminated before the return
trampoline otherwise backtrace called within a context created by
makecontext yields infinite backtrace.
This bug has been present for a long time, stdlib/tst-makecontext did
not fail until recent commit e535ce25. Tested on mips-linux-gnu and
mips64el-linux-gnuabi64 and mips-linux-gnu, no regression.
This fixes stdlib/tst-makecontext on MIPS.
Changelog:
[BZ #19792]
* sysdeps/unix/sysv/linux/mips/makecontext.S (__makecontext):
Terminate FDE before return label.
This patch implements a new posix_spawn{p} implementation for Linux. The main
difference is it uses the clone syscall directly with CLONE_VM and CLONE_VFORK
flags and a direct allocated stack. The new stack and start function solves
most the vfork limitation (possible parent clobber due stack spilling). The
remaning issue are related to signal handling:
1. That no signal handlers must run in child context, to avoid corrupt
parent's state.
2. Child must synchronize with parent to enforce stack deallocation and
to possible return execv issues.
The first one is solved by blocking all signals in child, even NPTL-internal
ones (SIGCANCEL and SIGSETXID). The second issue is done by a stack allocation
in parent and a synchronization with using a pipe or waitpid (in case or error).
The pipe has the advantage of allowing the child signal an exec error (checked
with new tst-spawn2 test).
There is an inherent race condition in pipe2 usage for architectures that do not
support the syscall directly. In such cases the a pipe plus fctnl is used
instead and it may lead to file descriptor leak in parent (as decribed by fcntl
documentation).
The child process stack is allocate with a mmap with MAP_STACK flag using
default architecture stack size. Although it is slower than use a stack buffer
from parent, it allows some slack for the compatibility code to run scripts
with no shebang (which may use a buffer with size depending of argument list
count).
Performance should be similar to the vfork default posix implementation and
way faster than fork path (vfork on mostly linux ports are basically
clone with CLONE_VM plus CLONE_VFORK). The only difference is the syscalls
required for the stack allocation/deallocation.
It fixes BZ#10354, BZ#14750, and BZ#18433.
Tested on i386, x86_64, powerpc64le, and aarch64.
[BZ #14750]
[BZ #10354]
[BZ #18433]
* include/sched.h (__clone): Add hidden prototype.
(__clone2): Likewise.
* include/unistd.h (__dup): Likewise.
* posix/Makefile (tests): Add tst-spawn2.
* posix/tst-spawn2.c: New file.
* sysdeps/posix/dup.c (__dup): Add hidden definition.
* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/alpha/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/arm/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/hppa/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/i386/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/ia64/clone2.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/m68k/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/microblaze/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/mips/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/nios2/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S (__clone):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S (__clone):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sh/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/tile/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/x86_64/clone.S (__clone): Likewise.
* sysdeps/unix/sysv/linux/nptl-signals.h
(____nptl_is_internal_signal): New function.
* sysdeps/unix/sysv/linux/spawni.c: New file.
We should turn on bit_Prefer_MAP_32BIT_EXEC in EXTRA_LD_ENVVARS without
overriding other bits.
[BZ #19758]
* sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
(EXTRA_LD_ENVVARS): Or bit_Prefer_MAP_32BIT_EXEC.
Now we require Linux 3.2 or later kernel headers everywhere, the
configure test for <linux/fanotify.h> is obsolete; this patch removes
it.
Tested for x86_64.
* sysdeps/unix/sysv/linux/configure.ac (linux/fanotify.h): Do not
test for header.
* sysdeps/unix/sysv/linux/configure: Regenerated.
* config.h.in (HAVE_LINUX_FANOTIFY_H): Remove #undef.
* sysdeps/unix/sysv/linux/tst-fanotify.c [!HAVE_LINUX_FANOTIFY_H]:
Remove conditional code.
[HAVE_LINUX_FANOTIFY_H]: Make code unconditional.
In <https://sourceware.org/ml/libc-alpha/2016-01/msg00885.html> I
proposed a minimum Linux kernel version of 3.2 for glibc 2.24, since
Linux 2.6.32 has reached EOL.
In the discussion in February, some concerns were expressed about
compatibility with OpenVZ containers. It's not clear that these are
real issues, given OpenVZ backporting kernel features and faking the
kernel version for guest software, as discussed in
<https://sourceware.org/ml/libc-alpha/2016-02/msg00278.html>. It's
also not clear that supporting running GNU/Linux distributions from
late 2016 (at the earliest) on a kernel series from 2009 is a sensible
expectation. However, as an interim step, this patch increases the
requirement everywhere except x86 / x86_64 (since the controversy was
only about those architectures); the special caveats and settings can
easily be removed later when we're ready to increase the requirements
on x86 / x86_64 (and if someone would like to raise the issue on LWN
as suggested in the previous discussion, that would be welcome). 3.2
kernel headers are required everywhere by this patch.
(x32 already requires 3.4 or later, so is unaffected by this patch.)
As usual for such a change, this patch only changes the configure
scripts and associated documentation. The intent is to follow up with
removal of dead __LINUX_KERNEL_VERSION conditionals. Each __ASSUME_*
or other macro that becomes dead can then be removed independently.
Tested for x86_64 and x86.
* sysdeps/unix/sysv/linux/configure.ac (LIBC_LINUX_VERSION):
Define to 3.2.0.
(arch_minimum_kernel): Likewise.
* sysdeps/unix/sysv/linux/configure: Regenerated.
* sysdeps/unix/sysv/linux/i386/configure.ac (arch_minimum_kernel):
Define to 2.6.32.
* sysdeps/unix/sysv/linux/i386/configure: Regenerated.
* sysdeps/unix/sysv/linux/x86_64/64/configure.ac
(arch_minimum_kernel): Define to 2.6.32.
* sysdeps/unix/sysv/linux/x86_64/64/configure: Regenerated.
* README: Document Linux 3.2 requirement.
* manual/install.texi (Linux): Document Linux 3.2 headers
requirement.
* INSTALL: Regenerated.
The handling of negative offsets in MIPS mmap is inconsistent with
other architectures, as shown by failure of the test
posix/tst-mmap-offset for o32 and n32. The MIPS mmap syscall uses a
signed argument and does a signed arithmetic shift on it, whereas the
glibc semantics expected by that test are for the offset to be
considered as a large positive offset. This patch makes MIPS
consistent with other architectures as far as possible by using the
mmap2 syscall on o32 (#including the generic implementation), and
making mmap not an alias for mmap64 for n32, with a custom
implementation for n32 that zero-extends the offset argument to 64-bit
before calling the mmap syscall.
Tested for MIPS64 (o32, n32, n64).
[BZ #19550]
* sysdeps/unix/sysv/linux/mips/mips32/mmap.c: New file.
* sysdeps/unix/sysv/linux/mips/mips64/mmap64.c: Move to ....
* sysdeps/unix/sysv/linux/mips/mips64/n64/mmap64.c: ... here.
* sysdeps/unix/sysv/linux/mips/mips64/n32/mmap.c: New file.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (mmap64):
New syscall entry.
* sysdeps/unix/sysv/linux/mips/mips64/n64/syscalls.list (mmap):
New syscall entry.
* sysdeps/unix/sysv/linux/mips/mips64/syscalls.list (mmap): Remove
syscall entry.
Complement the addition of the required kernel support, present upstream
as from commit 2b5e869ecfcb3112f7e1267cb0328f3ff6d49b18 ("MIPS: ELF:
Interpret the NAN2008 file header flag") and released with Linux 4.5-rc1
on Jan 24th, 2016.
* sysdeps/unix/sysv/linux/mips/configure.ac: Set
`arch_minimum_kernel' to 4.5.0 if 2008 NaN encoding is used.
* sysdeps/unix/sysv/linux/mips/configure: Regenerate.
Testing for powerpc-nofpu showed that localplt.data was out of date.
Two new soft-fp functions showed up in the list: __gtsf2 and
__unordsf2; this patch adds these as optional. __signbit and
__signbitl no longer appear as local PLT entries; given the move to
__builtin_signbit* for all GCC versions supported for building glibc
(and given the use of the type-generic signbit macro within glibc),
those can safely be removed from the list, which this patch does.
Tested for powerpc-nofpu.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/localplt.data
(__gtsf2): Add as optional for libc.so.
(__unordsf2): Likewise.
(__signbit): Remove for libc.so.
(__signbitl): Likewise.
The previous barrier implementation did not fulfill the POSIX requirements
for when a barrier can be destroyed. Specifically, it was possible that
threads that haven't noticed yet that their round is complete still access
the barrier's memory, and that those accesses can happen after the barrier
has been legally destroyed.
The new algorithm does not have this issue, and it avoids using a lock
internally.
This patch adds some new header definitions from Linux 4.4:
* MCL_ONFAULT is added to bits/mman.h / bits/mman-linux.h (this was
already done for hppa).
* PTRACE_SECCOMP_GET_FILTER is added to sys/ptrace.h. Along with it,
the older PTRACE_GETSIGMASK and PTRACE_SETSIGMASK, added in Linux
3.11 but missed at the time, are also added.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/mman-linux.h [!MCL_CURRENT] (MCL_ONFAULT): New macro.
* sysdeps/unix/sysv/linux/alpha/bits/mman.h (MCL_ONFAULT):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/bits/mman.h (MCL_ONFAULT):
Likewise.
* sysdeps/unix/sysv/linux/sparc/bits/mman.h (MCL_ONFAULT):
Likewise.
* sysdeps/unix/sysv/linux/sys/ptrace.h (PTRACE_GETSIGMASK): New
enum constant and macro.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/aarch64/sys/ptrace.h
(PTRACE_GETSIGMASK): Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h (PTRACE_GETSIGMASK):
Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/powerpc/sys/ptrace.h
(PTRACE_GETSIGMASK): Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/s390/sys/ptrace.h (PTRACE_GETSIGMASK):
Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/sparc/sys/ptrace.h (PTRACE_GETSIGMASK):
Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
* sysdeps/unix/sysv/linux/tile/sys/ptrace.h (PTRACE_GETSIGMASK):
Likewise.
(PTRACE_SETSIGMASK): Likewise.
(PTRACE_SECCOMP_GET_FILTER): Likewise.
Work around a GCC behavior with hardware transactional memory built-ins.
GCC doesn't treat the PowerPC transactional built-ins as compiler
barriers, moving instructions past the transaction boundaries and
altering their atomicity.
We define __ASSUME_ST_INO_64_BIT by default for Linux targets, and then
undef it for alpha/sh targets. But the code that uses it looks at its
value (as 0/1) rather than whether it's defined (like all other assume
knobs). Change the code to see if it's defined to fix build Wundef build
errors for alpha/sh.
The attached patch adds some upstream defines like MAP_HUGETLB and MAP_STACK
in mman.h for the hppa architecture.
The existing MADV_xxK_PAGES defines were dropped upstream, because they were
originally added many years ago based on a proposed patch for the Linux kernel
which was never applied. So, this patch drops those unneeded defines.
The personality system call, starting with linux kernel commit
v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, always
successfully changes the personality if requested. The syscall
wrapper, however, still can return an error in the following cases:
- the value returned by the system call looks like an error
due to architecture limitations of 32-bit kernels;
- a personality greater than 0xffffffff is passed to the system call,
and the 64-bit kernel does not have commit
v2.6.35-rc1-372-g485d527686850d68a0e9006dd9904f19f122485e
that would truncate this value to unsigned int;
- on sparc64, the value returned by the system call looks like an error
due to sparc64 kernel sign extension bug.
The solution is three-fold:
- move generic syscalls.list personality entry to generic 64-bit
syscalls.list file;
- for each 32-bit architecture that use negated errno semantics,
add a NOERRNO personality entry to their syscalls.list file;
- for sparc64 and 32-bit architectures that use dedicated registers
to flag syscall errors, add a wrapper around personality syscall;
if the system call return value is flagged as an error, this wrapper
returns the negated "would be errno" value, otherwise it returns
the system call return value; on sparc64, it also truncates the
personality argument to unsigned int before passing it to the kernel.
[BZ #19408]
* sysdeps/unix/sysv/linux/personality.c: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
(sysdep_routines): Add personality.
(tests): Add tst-personality.
* sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
* sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
Likewise.
Since GLIBC requires a minimum 2.6.32 kernel, the sysctl (CTL_BUS,
CTL_BUS_ISA, ISA_*) is always available. We can therefore remove the
fallback code reading /etc/arm_systype or parsing /proc/cpuinfo.
Remove fscanf from localplt.data as it is no longer called from within
GLIBC.
* sysdeps/unix/sysv/linux/arm/ioperm.c: Do not include <string.h>.
(PATH_ARM_SYSTYPE): Remove.
(PATH_CPUINFO): Likewise.
(IO_BASE_FOOTBRIDGE): Likewise.
(IO_SHIFT_FOOTBRIDGE): Likewise.
(struct platform): Likewise.
(init_iosys): Remove compatibility code for 2.4 kernels.
* sysdeps/unix/sysv/linux/arm/localplt.data: Remove fscanf.
POSIX and C++11 require that a thread can destroy a mutex if no other
thread owns the mutex, is blocked on the mutex, or will try to acquire
it in the future. After destroying the mutex, it can reuse or unmap the
underlying memory. Thus, we must not access a mutex' memory after
releasing it. Currently, we can load the private flag after releasing
the mutex, which is fixed by this patch.
See https://sourceware.org/bugzilla/show_bug.cgi?id=13690 for more
background.
We need to call futex_wake on the lock after releasing it, however. This
is by design, and can lead to spurious wake-ups on unrelated futex words
(e.g., when the mutex memory is reused for another mutex). This behavior
is documented in the glibc-internal futex API and in recent drafts of the
Linux kernel's futex documentation (see the draft_futex branch of
git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git).
Since times returns 64-bit clock_t on x32, we need to provide x32 times
by redefining INTERNAL_SYSCALL_NCS and INTERNAL_SYSCALL_ERROR_P with
64-bit return type for syscall. All system calls returning 64-bit
integer, which are lseek, time and times, must be handled specially for
x32. lseek is handled by x32 lseek.S and time doesn't check syscall
return. times is the only missed one. Before this patch, there are
0000000 <__times>:
0: b8 64 00 00 40 mov $0x40000064,%eax
5: 0f 05 syscall
7: 48 63 d0 movslq %eax,%rdx
^^^^^^^^^^ Incorrect signed extension
a: 48 83 fa f2 cmp $0xfffffffffffffff2,%rdx
e: 75 07 jne 17 <__times+0x17>
10: 3d 00 f0 ff ff cmp $0xfffff000,%eax
^^^^^^^^^^^^^^^^^^^^^ 32-bit compare
15: 77 11 ja 28 <__times+0x28>
17: 48 83 fa ff cmp $0xffffffffffffffff,%rdx
1b: b8 00 00 00 00 mov $0x0,%eax
20: 48 0f 45 c2 cmovne %rdx,%rax
24: c3 retq
After this patch, there are
00000000 <__times>:
0: b8 64 00 00 40 mov $0x40000064,%eax
5: 0f 05 syscall
7: 48 83 f8 f2 cmp $0xfffffffffffffff2,%rax
b: 75 08 jne 15 <__times+0x15>
d: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax
13: 77 13 ja 28 <__times+0x28>
15: 48 83 f8 ff cmp $0xffffffffffffffff,%rax
19: ba 00 00 00 00 mov $0x0,%edx
1e: 48 0f 44 c2 cmove %rdx,%rax
22: c3 retq
The incorrect signed extension and 32-bit compare are gone.
[BZ #19363]
* sysdeps/unix/sysv/linux/x86_64/x32/times.c: New file.
X86-64 system calls use a different calling convention, which clobbers
CC, %r11 an %rcx registers. Define REGISTERS_CLOBBERED_BY_SYSCALL for
x86-64 inline asm statements.
* sysdeps/unix/sysv/linux/x86_64/sysdep.h
(REGISTERS_CLOBBERED_BY_SYSCALL): New.
(INTERNAL_SYSCALL_NCS): Use it.
(INTERNAL_SYSCALL_NCS_TYPES): Likewise.
According to Silvermont software optimization guide, for 64-bit
applications, branch prediction performance can be negatively impacted
when the target of a branch is more than 4GB away from the branch. Add
the Prefer_MAP_32BIT_EXEC bit so that mmap will try to map executable
pages with MAP_32BIT first. NB: MAP_32BIT will map to lower 2GB, not
lower 4GB, address. Prefer_MAP_32BIT_EXEC reduces bits available for
address space layout randomization (ASLR), which is always disabled for
SUID programs and can only be enabled by setting environment variable,
LD_PREFER_MAP_32BIT_EXEC.
On Fedora 23, this patch speeds up GCC 5 testsuite by 3% on Silvermont.
[BZ #19367]
* sysdeps/unix/sysv/linux/wordsize-64/mmap.c: New file.
* sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/mmap.c: Likewise.
* sysdeps/x86/cpu-features.h (bit_Prefer_MAP_32BIT_EXEC): New.
(index_Prefer_MAP_32BIT_EXEC): Likewise.
Various Linux kernel syscalls have become obsolete over time.
Specifically, the following are obsolete in all kernel versions
supported by glibc, are not present for architectures more recently
added to the kernel, and as such, the wrapper functions for them
should be compat symbols, not in static libc and not available for new
links with shared libc.
* bdflush: in Linux 2.6, does nothing if present.
* create_module get_kernel_syms query_module: Linux 2.4 module
interface, syscalls not present in Linux 2.6.
* uselib: part of the mechanism for loading a.out shared libraries,
irrelevant with ELF.
This patch adds support for syscalls.list to list syscall aliases of
the form NAME@VERSION:OBSOLETED, with SHLIB_COMPAT conditionals being
generated for such aliases. Those five syscalls are then made into
compat symbols (obsoleted in glibc 2.23, so future ports won't have
these symbols at all), with the header <sys/kdaemon.h> declaring
bdflush being removed. When we move to 3.2 as minimum kernel version,
the same can be done for nfsservctl (removed in Linux 3.1) as well.
Tested for x86_64 and x86 (testsuite, as well as checking that the
symbols in question indeed become compat symbols, that they are indeed
omitted from static libc, and that the generated SHLIB_COMPAT
conditionals look right).
[BZ #18472]
* sysdeps/unix/Makefile ($(objpfx)stub-syscalls.c): Handle entries
for the form NAME@VERSION:OBSOLETED and generate SHLIB_COMPAT
conditionals for them.
* sysdeps/unix/make-syscalls.sh (emit_weak_aliases): Likewise.
* sysdeps/unix/sysv/linux/sys/kdaemon.h: Remove file.
* sysdeps/unix/sysv/linux/Makefile (sysdep_headers): Remove
sys/kdaemon.h.
* sysdeps/unix/sysv/linux/syscalls.list (bdflush): Make into
compat-only syscall, obsoleted in glibc 2.23.
(create_module): Likewise.
(get_kernel_syms): Likewise.
(query_module): Likewise.
(uselib): Likewise.
* manual/sysinfo.texi (System Parameters): Do not mention bdflush.
Now that we have __ASSUME_* macros for direct socket syscalls to use
them instead of socketcall when they can be assumed to be available on
socketcall architectures, this patch defines those macros when
appropriate for i386, m68k, microblaze and sh (for 4.3, 4.3, all
supported kernels and 2.6.37, respectively; the only use of socketcall
support on microblaze is it allows accept4 and sendmmsg to be
supported on a wider range of kernel versions).
David, it seems that 32-bit SPARC is the only architecture supported
by glibc that still lacks these direct syscalls. It would be good to
get them added to the SPARC kernel so we can eventually eliminate
socketcall support in glibc (and thereby just use entries in
sysdeps/unix/syscalls.list for most of these functions) when we can
assume new-enough kernels.
Tested for i386 (testsuite, and that installed shared libraries are
unchanged by this patch - not using a new enough kernel, so this
doesn't actually test much, but the i386 and m68k code is essentially
the same as that already in use for s390).
* sysdeps/unix/sysv/linux/i386/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SOCKET_SYSCALL):
New macro.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SOCKETPAIR_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_BIND_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_CONNECT_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_LISTEN_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_ACCEPT4_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_ACCEPT4_FOR_ACCEPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETSOCKNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETPEERNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SENDTO_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SENDTO_FOR_SEND_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SENDMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_RECVFROM_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_RECVFROM_FOR_RECV_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_RECVMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SHUTDOWN_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SOCKET_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SOCKETPAIR_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_BIND_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_CONNECT_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_LISTEN_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_ACCEPT4_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_ACCEPT4_FOR_ACCEPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETSOCKNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_GETPEERNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SENDTO_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_SENDTO_FOR_SEND_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SENDMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_RECVFROM_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300]
(__ASSUME_RECVFROM_FOR_RECV_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_RECVMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SHUTDOWN_SYSCALL):
Likewise.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_SOCKET_SYSCALL): Likewise.
(__ASSUME_BIND_SYSCALL): Likewise.
(__ASSUME_CONNECT_SYSCALL): Likewise.
(__ASSUME_LISTEN_SYSCALL): Likewise.
(__ASSUME_ACCEPT_SYSCALL): Likewise.
(__ASSUME_GETSOCKNAME_SYSCALL): Likewise.
(__ASSUME_GETPEERNAME_SYSCALL): Likewise.
(__ASSUME_SOCKETPAIR_SYSCALL): Likewise.
(__ASSUME_SEND_SYSCALL): Likewise.
(__ASSUME_SENDTO_SYSCALL): Likewise.
(__ASSUME_RECV_SYSCALL): Likewise.
(__ASSUME_RECVFROM_SYSCALL): Likewise.
(__ASSUME_SHUTDOWN_SYSCALL): Likewise.
(__ASSUME_GETSOCKOPT_SYSCALL): Likewise.
(__ASSUME_SETSOCKOPT_SYSCALL): Likewise.
(__ASSUME_SENDMSG_SYSCALL): Likewise.
(__ASSUME_RECVMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/sh/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_SOCKET_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_BIND_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_CONNECT_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_LISTEN_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_ACCEPT_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625]
(__ASSUME_GETSOCKNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625]
(__ASSUME_GETPEERNAME_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625]
(__ASSUME_SOCKETPAIR_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_SEND_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_SENDTO_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_RECV_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_RECVFROM_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_SHUTDOWN_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625]
(__ASSUME_GETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625]
(__ASSUME_SETSOCKOPT_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_SENDMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x020625] (__ASSUME_RECVMSG_SYSCALL):
Likewise.
On MIPS when the toolchain is using the O32 FPXX ABI, the testsuite
fails to build for pre-R2 CPU.
It assumes that it is possible to use the -mfp64 option to build
tst-abi-fp64amod and tst-abi-fp64mod, while this requires a CPU which
supports the mfhc1 and mthc1 instructions, ie at least a R2 CPU:
error: '-mgp32' and '-mfp64' can only be combined if the target
supports the mfhc1 and mthc1 instructions
The same way it assumes that it is possible to use the -modd-spreg option
to build tst-abi-fpxxomod and tst-abi-fp64mod, while this requires at
least a R1 CPU:
warning: the 'mips2' architecture does not support odd
single-precision registers
This patches changes that by checking the usability of -mfp64 and
-modd-spreg options in configure, and disable those tests when they can
not be used.
If a platform does not define "long-double-fcts = yes" in its
Makefiles and it does define __NO_LONG_DOUBLE_MATH in its installed
headers, it will currently create exported symbols for __finitel,
__isinfl, and __isnanl that can't be reached from userspace by
correct use of the finite(), isinf(), or isnan() macros in <math.h>.
To avoid this situation, by default for such platforms we now no
longer export these symbols, thus causing appropriate link-time
errors. However, for platforms that previously exported these
symbols, we continue to do so as compat symbols; this is enabled
by adding LDBL_CLASSIFY_COMPAT to math_private.h for the platform.
For tile, remove the now-unnecessary exports of those functions from
libc and libm.
