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.
This patch relies on the C version of the rwlocks posted earlier.
With C rwlocks it is very straight forward to do adaptive elision
using TSX. It is based on the infrastructure added earlier
for mutexes, but uses its own elision macros. The macros
are fairly general purpose and could be used for other
elision purposes too.
This version is much cleaner than the earlier assembler based
version, and in particular implements adaptation which makes
it safer.
I changed the behavior slightly to not require any changes
in the test suite and fully conform to all expected
behaviors (generally at the cost of not eliding in
various situations). In particular this means the timedlock
variants are not elided. Nested trylock aborts.
The implementation of __get_nprocs uses a stactic variable to cache
the value of the current number of processors. The caching breaks when
'time (NULL) == 0':
$ cat nproc.c
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
int main(int argc, char *argv[])
{
time_t t;
struct timeval tv = {0, 0};
printf("settimeofday({0, 0}, NULL) = %d\n", settimeofday(&tv, NULL));
t = time(NULL);
printf("Time: %d, CPUs: %d\n", (unsigned int)t, get_nprocs());
return 0;
}
$ gcc -O3 nproc.c
$ ./a.out
settimeofday({0, 0}, NULL) = -1
Time: 1401311578, CPUs: 4
$ sudo ./a.out
settimeofday({0, 0}, NULL) = 0
Time: 0, CPUs: 0
The problem is with the condition used to check whether a cached
value should be returned or not:
static int cached_result;
static time_t timestamp;
time_t now = time (NULL);
time_t prev = timestamp;
atomic_read_barrier ();
if (now == prev)
return cached_result;
This patch fixes the problem by ensuring that 'cached_result' has
been set at least once before returning it.
The hppa port has no need of a custom lowlevellock.c, it should
use the generic version which is updated and correct. This
similarly fixes bug 15119 for hppa.
In several cases we've had asm routines rely on syscalls not clobbering
call-clobbered registers, and that's now deemed ABI. So take advantage
of this in the INLINE_SYSCALL path as well.
Shrinks libc.so by about 1k.
This macro was removed by
2005-11-16 Daniel Jacobowitz <dan@codesourcery.com>
but not applied to the (still separate) eabi port so necro'd
when the eabi port superceded the old abi. It was thence
copied into the new AArch64 port.
This also highlights that we'd been loading 64-bits instead of
the proper 32-bits. Caught by the linker as a relocation error,
since the variable happened to be unaligned for 64-bits.
sysdeps/unix/sysv/linux/arm/unwind-resume.c and
sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c have static
variables that are written in C code but only read from toplevel asms.
Current GCC trunk now optimizes away such apparently write-only static
variables, so causing a build failure. This patch marks those
variables with __attribute_used__ to avoid that optimization.
Tested that this fixes the build for ARM.
* sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c
(libgcc_s_resume): Use __attribute_used__.
* sysdeps/unix/sysv/linux/arm/unwind-resume.c (libgcc_s_resume):
Likewise.
Using the default header instead. This matches the kernel, which also
uses the generic header. Fixes the sys/wait.h conform issue, where
si_band had the wrong type.
The current code for nocancel syscalls does not do a comparison of
the system call return value. This leads to code being generated
where the b.cs follows the svc instruction directly without setting
the flags on which the branch depends.
ChangeLog:
2014-05-20 Will Newton <will.newton@linaro.org>
* sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h (PSEUDO):
Test the return value of the system call in the nocancel case.
This patch fixes an issue observed by the Xen project, where including
signal.h exposes various PSR_MODE #defines. This is due to the usage
in sys/user.h and sys/procfs.h of the struct user_pt_regs and
user_fpsimd_state included via asm/ptrace.h. The namespace pollution
this inclusion introduce is already partially fixed with some #undef
of the PTRACE_* symbols, but other symbols like the PSR_MODE ones are
still present, and undefining them is not safe since a user can
include ptrace.h before user.h.
My proposition is to define the 2 structures we need in user.h and get
rid of the asm/ptrace.h inclusion.
Build and make check are clean on AArch64.
2014-05-20 Will Newton <will.newton@linaro.org>
Yvan Roux <yvan.roux@linaro.org>
* sysdeps/unix/sysv/linux/aarch64/sys/user.h: Remove unused
#include of asm/ptrace.h.
(PTRACE_GET_THREAD_AREA): Remove #undef.
(PTRACE_GETHBPREGS): Likewise.
(PTRACE_SETHBPREGS): Likewise.
(struct user_regs_struct): New structure.
(struct user_fpsimd_struct): New structure.
* sysdeps/unix/sysv/linux/aarch64/sys/procfs.h: Remove unused
#include of asm/ptrace.h and second #include of sys/user.h.
(PTRACE_GET_THREAD_AREA): Remove #undef.
(PTRACE_GETHBPREGS): Likewise.
(PTRACE_SETHBPREGS): Likewise.
(ELF_NGREG): Use new struct user_regs_struct.
(elf_fpregset_t): Use new struct user_fpsimd_struct.
This patch guard the BSD definition for terminal modes in PowerPC
specific header fixing the following conformance failures:
FAIL: conform/POSIX/termios.h/conform
FAIL: conform/POSIX2008/termios.h/conform
FAIL: conform/UNIX98/termios.h/conform
prlimit and prlimit64 have been added in the main <bits/resource.h>, but
not in the SPARC specific version. Fix that.
Note: this is Debian bug#703559, reported by Emilio Pozuelo Monfort
<pochu@debian.org>
If the fd refers to a terminal device, but not a pty master, the
TIOCGPTN ioctl returns with ENOTTY. This error is not caught, and the
possibly undefined buffer passed to ptsname_r is sent directly to the
stat64 syscall.
Fix this by using a fallback to the old method only if the TIOCGPTN
ioctl fails with EINVAL. This also fix the return value in that specific
case (it return ENOENT without this patch).
Also add tests to the ptsname_r function (and ptsname at the same time).
Note: this is Debian bug#741482, reported by Jakub Wilk <jwilk@debian.org>
This patch reduces duplication between different architectures'
kernel-features.h files by making the architecture-independent file
define various macros unconditionally (instead of only for a
particular list of architectures), with the architecture-specific
files then undefining the macros if necessary.
Specifically, __ASSUME_O_CLOEXEC (O_CLOEXEC flag to open) and
__ASSUME_SOCK_CLOEXEC (SOCK_NONBLOCK and SOCK_CLOEXEC flags to socket)
are supported on all architectures as of 2.6.32 or the minimum kernel
version for the architecture if later. For __ASSUME_IN_NONBLOCK,
__ASSUME_PIPE2, __ASSUME_EVENTFD2, __ASSUME_SIGNALFD4 and
__ASSUME_DUP3, the relevant syscalls were added for alpha in 2.6.33
but otherwise the features are available as of 2.6.32. For
__ASSUME_UTIMES, support is everywhere in 2.6.32 except for
asm-generic architectures and hppa.
Although those were the main cases of duplication among
kernel-features.h files, some other cases of unnecessary definitions
were also cleaned up: the hppa file defined various macros that were
either no longer used at all, or defined by the main file by default
anyway, the ia64 file had duplicative definitions of __ASSUME_PSELECT
and __ASSUME_PPOLL, while mips had such a definition of
__ASSUME_IPC64.
Really, rather than being defined in the main file then undefined for
asm-generic architectures, __ASSUME_UTIMES should become an
hppa-specific macro. Given that __ASSUME_ATFCTS and
__ASSUME_UTIMENSAT are now always true, the only live __ASSUME_UTIMES
conditional is in sysdeps/unix/sysv/linux/utimes.c, which is not used
for asm-generic architectures. I think the desired state would be an
hppa-specific file (that includes sysdeps/unix/sysv/linux/utimes.c if
__ASSUME_UTIMES, and otherwise has fallback code), with the fallback
code being removed from the main utimes.c. But I think that's most
reasonably a separate cleanup once __ASSUME_ATFCTS and
__ASSUME_UTIMESAT have both had conditional code cleaned up.
Given this patch, I think it's straightforward to move non-ex-ports
architectures to having their own kernel-features.h files, like
ex-ports architectures, rather than conditionals in the main file
(i.e., such a move won't require the architecture-specific file to
contain anything that isn't genuinely architecture-specific), and
would encourage architecture maintainers to do so.
Tested x86_64 that the installed shared libraries are unchanged by
this patch. Note that on some architectures this *will* cause
__ASSUME_* macros to be defined in cases where they weren't previously
but should have been (but this is just optimization, not a fix to a
user-visible bug, so doesn't need a bug report in Bugzilla).
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_UTIMES):
Define unconditionally.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h
(__ASSUME_DUP3): Do not define.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_UTIMES): Undefine.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_UTIMES): Do not define.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Undefine if [__LINUX_KERNEL_VERSION <
0x020621] instead of defining if [__LINUX_KERNEL_VERSION >=
0x020621].
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
[__LINUX_KERNEL_VERSION < 0x020621] (__ASSUME_DUP3): Undefine.
* sysdeps/unix/sysv/linux/arm/kernel-features.h (__ASSUME_UTIMES):
Do not define.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
(__ASSUME_32BITUIDS): Likewise.
(__ASSUME_TRUNCATE64_SYSCALL): Likewise.
(__ASSUME_IPC64): Likewise.
(__ASSUME_ST_INO_64_BIT): Likewise.
(__ASSUME_GETDENTS64_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION < 0x030e00] (__ASSUME_UTIMES): Undefine.
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
(__ASSUME_UTIMES): Do not define.
(__ASSUME_PSELECT): Likewise.
(__ASSUME_PPOLL): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_UTIMES): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_UTIMES): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/mips/kernel-features.h (__ASSUME_IPC64):
Likewise.
(__ASSUME_UTIMES): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
(__ASSUME_UTIMES): Undefine.
This patch cleans up some symbol versioning code in the ARM port that
exists only as relics of the old-ABI port, which was removed some time
ago.
The minimum symbol version in the ARM port is GLIBC_2.4 (the version
where the EABI port was introduced). Thus, any SHLIB_COMPAT
conditionals where the later version is 2.4 or later are obsolete and
can be removed. In addition, there is no need to set symbol versions
before 2.4 explicitly if the symbols would have a version of 2.4 by
default anyway. This includes most of the entries in
sysdeps/unix/sysv/linux/arm/Versions: those for GLIBC_2.0 are for
libgcc unwind functions that aren't actually in ARM EABI glibc at all,
while those for GLIBC_2.2 and GLIBC_2.3.3 are for functions which for
the old-ABI port may have had versions different from the
architecture-independent default, but where for EABI the default
suffices (both the default and the version in that file map to 2.4, so
the entries in that file do nothing). The GLIBC_2.1 entries are
needed (architecture-specific functions), but it seems less confusing
for those to say GLIBC_2.4, as the actual version those symbols in
fact have.
Various cases in the <fenv.h> functions where a function is defined as
__fe* with an fe* versioned alias are cleaned up just to define fe*
directly, as done e.g. on AArch64. If in future we actually need an
__fe* name for use from C90 functions in libm as discussed recently,
of course we can add one on all architectures and make the fe* name
into a weak alias for that particular function, but for now the __fe*
names aren't needed.
In the case of posix_fadvise64, the __posix_fadvise64_l64 name and
posix_fadvise64 alias are kept as __posix_fadvise64_l64 is used in
posix_fadvise. (For that to be a namespace-clean use, posix_fadvise64
needs to be a *weak* alias not a strong one as at present, but that's
an independent preexisting bug.)
(There remain references to GLIBC_2_2 in
sysdeps/unix/sysv/linux/arm/{msgctl.c,semctl.c,shmctl.c}. As those
files are used by alpha which has a genuine 2.2 version for those
functions, I think those references need to stay as-is.)
Tested that the disassembly of installed shared libraries is unchanged
by this patch (though function names shown in disassembly change to no
longer have @@GLIBC_2.4, now those functions get versioned only by the
version map and not redundantly at assembler time) and that the ABI
tests pass.
* sysdeps/arm/fclrexcpt.c (__feclearexcept): Rename to
feclearexcept. Remove symbol versioning code.
* sysdeps/arm/fegetenv.c (__fegetenv): Rename to fegetenv. Remove
symbol versioning code.
* sysdeps/arm/fesetenv.c (__fesetenv): Rename to fesetenv. Remove
symbol versioning code.
* sysdeps/arm/feupdateenv.c (__feupdateenv): Rename to
feupdateenv. Remove symbol versioning code.
* sysdeps/arm/fgetexcptflg.c (__fegetexceptflag): Rename to
fegetexceptflag. Remove symbol versioning code.
* sysdeps/arm/fsetexcptflg.c (__fesetexceptflag): Rename to
fesetexceptflag. Remove symbol versioning code.
* sysdeps/unix/sysv/linux/arm/Versions (libc): Remove GLIBC_2.0,
GLIBC_2.2 and GLIBC_2.3.3 entries. Change GLIBC_2.1 to GLIBC_2.4.
* sysdeps/unix/sysv/linux/arm/posix_fadvise64.c
(__posix_fadvise64_l32): Remove prototype.
[SHLIB_COMPAT(libc, GLIBC_2_2, GLIBC_2_3_3)]: Remove conditional
code.
This patch does some initial cleanup, following the move to 2.6.32
minimum kernel version, by removing __LINUX_KERNEL_VERSION
conditionals that are now always-true or always-false. In the case of
__ASSUME_ARG_MAX_STACK_BASED, where the conditional used a kernel
version that was itself in a macro, the associated sysconf.c code is
also cleaned up and __ASSUME_ARG_MAX_STACK_BASED removed completely.
Tested x86_64 that disassembly of installed shared libraries is
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h [__s390__]
(__ASSUME_UTIMES): Do not condition on kernel version.
(__ASSUME_PSELECT): Define unconditionally.
(__ASSUME_PPOLL): Likewise.
(__ASSUME_ATFCTS): Likewise.
(__ASSUME_SET_ROBUST_LIST): Do not condition on kernel version.
(__ASSUME_COMPLETE_READV_WRITEV): Define unconditionally.
(__ASSUME_FUTEX_LOCK_PI): Do not condition on kernel version.
(__ASSUME_UTIMENSAT): Define unconditionally.
(__ASSUME_PRIVATE_FUTEX): Likewise.
(__ASSUME_FALLOCATE): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__LINUX_ARG_MAX_STACK_BASED_MIN_KERNEL): Remove.
(__ASSUME_ARG_MAX_STACK_BASED): Likewise.
(__ASSUME_ADJ_OFFSET_SS_READ): Define unconditionally.
(__ASSUME_SOCK_CLOEXEC): Do not condition on kernel version.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
[__x86_64__ || __sparc__] (__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_FUTEX_CLOCK_REALTIME): Define unconditionally.
(__ASSUME_AT_RANDOM): Likewise.
(__ASSUME_PREADV): Likewise.
(__ASSUME_PWRITEV): Likewise.
(__ASSUME_REQUEUE_PI): Do not condition on kernel version.
(__ASSUME_F_GETOWN_EX): Define unconditionally.
(__ASSUME_XFS_RESTRICTED_CHOWN): Likewise.
* sysdeps/unix/sysv/linux/sysconf.c (__sysconf)
[!__ASSUME_ARG_MAX_STACK_BASED]: Remove conditional code.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_O_CLOEXEC): Define unconditionally.
(__ASSUME_PSELECT): Do not undefine conditionally.
(__ASSUME_PPOLL): Likewise.
(__ASSUME_ATFCTS): Likewise.
(__ASSUME_SET_ROBUST_LIST): Likewise.
(__ASSUME_UTIMENSAT): Likewise.
(__ASSUME_FDATASYNC): Define unconditionally.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
(__ASSUME_SIGFRAME_V2): Likewise.
)__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_PSELECT): Do not undefine conditionally.
(__ASSUME_PPOLL): Likewise.
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
(__ASSUME_PSELECT): Define unconditionally.
(__ASSUME_PPOLL): Likewise.
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_O_CLOEXEC): Likewise.
(__ASSUME_SOCK_CLOEXEC): Likewise.
(__ASSUME_IN_NONBLOCK): Likewise.
(__ASSUME_PIPE2): Likewise.
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_DUP3): Likewise.
* sysdeps/unix/sysv/linux/mips/kernel-features.h
(__ASSUME_EVENTFD2): Likewise.
(__ASSUME_SIGNALFD4): Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
Andi Kleen
Meador Inge
Roland McGrath
Chris Metcalf
Bernard Ogden
Ondřej Bílka
Richard Henderson
Eric Wong
Adhemerval Zanella
Richard Henderson
Joseph Myers
Will Newton
Yvan Roux
David S. Miller
Aurelien Jarno
Andreas Schwab