This patch provides new __clock_getres64 explicit 64 bit function for
getting the resolution (precision) of specified clock ID. Moreover, a
32 bit version - __clock_getres has been refactored to internally use
__clock_getres64.
The __clock_getres is now supposed to be used on systems still supporting
32 bit time (__TIMESIZE != 64) - hence the necessary conversion from 64 bit
struct __timespec64 to struct timespec.
The new clock_getres_time64 syscall available from Linux 5.1+ has been used,
when applicable.
On systems which are not supporting clock_getres_time64 (as their
clock_getres supports 64 bit time ABI) the vDSO syscall is attempted.
On the contrary the non-vDSO syscall is used for clock_getres_time64 as
up till now the kernel is not providing such interface.
No additional checks (i.e. if tv_nsec value overflow) are performed on
values returned via clock_getres{_time64} syscall, as it is assumed that
the Linux kernel will either return 0 and provide correct value or error.
The check for tv_sec being out of range on systems still supporting 32 bit
time (__TIMESIZE != 64) without Y2038 time support is also omitted as it is
_very_ unlikely that we would have a timer with resolution which exceeds 32
bit time_t range.
Build tests:
- The code has been tested on x86_64/x86 (native compilation):
make PARALLELMFLAGS="-j8" && make xcheck PARALLELMFLAGS="-j8"
- The glibc has been build tested (make PARALLELMFLAGS="-j8") for
x86 (i386), x86_64-x32, and armv7
Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
https://github.com/lmajewski/meta-y2038 and run tests:
https://github.com/lmajewski/y2038-tests/commits/master
- Use of cross-test-ssh.sh for ARM (armv7):
make PARALLELMFLAGS="-j8" test-wrapper='./cross-test-ssh.sh root@192.168.7.2' xcheck
Linux kernel, headers and minimal kernel version for glibc build test
matrix:
- Linux v5.1 (with clock_getres_time64) and glibc build with v5.1 as
minimal kernel version (--enable-kernel="5.1.0")
The __ASSUME_TIME64_SYSCALLS flag defined.
- Linux v5.1 and default minimal kernel version
The __ASSUME_TIME64_SYSCALLS not defined, but kernel supports
clock_getres_time64 syscall.
- Linux v4.19 (no clock_getres_time64 support) with default minimal kernel
version for contemporary glibc
This kernel doesn't support clock_getres_time64 syscall, so the fallback
to clock_getres is tested.
The above tests were performed with Y2038 redirection applied as well as
without (so the __TIMESIZE != 64 execution path is checked as well).
No regressions were observed.
In glibc 2.17, the functions clock_getcpuclockid, clock_getres,
clock_gettime, clock_nanosleep, and clock_settime were moved from
librt.so to libc.so, leaving compatibility stubs behind. Now that the
dynamic linker no longer insists on finding versioned symbols in the
same library that originally defined them, we do not need the stubs
anymore, and this means we don't need GLIBC_PRIVATE __-prefix aliases
for most of the functions anymore either. (clock_gettime still needs
one.) For ports added before 2.17, libc.so needs to provide two
symbol versions for each, the default at GLIBC_2.17 plus a compat
version matching what librt had.
While I'm at it, move the clock_*.c files and their tests from rt/ to
time/.
Clock_gettime, settime and getres implementations are unncessarily
complex due to using defines and C file inclusion. Simplify the
code by replacing the redundant defines and removing the inclusion,
making it much easier to understand. No functional changes.
* sysdeps/posix/clock_getres.c (__clock_getres): Cleanup.
* sysdeps/unix/clock_gettime.c (__clock_gettime): Cleanup.
* sysdeps/unix/clock_settime.c (__clock_settime): Cleanup.
* sysdeps/unix/sysv/linux/clock_getres.c (__clock_getres): Cleanup.
* sysdeps/unix/sysv/linux/clock_gettime.c (__clock_gettime): Cleanup.
* sysdeps/unix/sysv/linux/clock_settime.c (__clock_settime): Cleanup.
This patch consolidate the Linux vDSO define and usage across all ports
that uses it. The common vDSO definitions and calling through
{INLINE/INTERNAL}_VSYSCALL macros are moved to a common header
sysdep-vdso.h and vDSO name declaration and prototype is defined
using a common macro.
Also PTR_{MANGLE,DEMANGLE} is added to ports that does not use them
for vDSO calls (aarch64, powerpc, s390, and tile) and thus it will
reflect in code changes. For ports that already implement pointer
mangling/demangling in vDSO system (i386, x32, x86_64) this patch
is mainly a code refactor.
Checked on x32, x86_64, x32, ppc64le, and aarch64.
Tom Gall <tom_gall@vnet.ibm.com>
* elf/rtld.c (dl_main): Initialize l_local_scope for sysinfo_map.
* sysdeps/powerpc/elf/libc-start.c: Move this...
* sysdeps/unix/sysv/linux/powerpc/libc-start.c: ...to here.
* sysdeps/powerpc/powerpc32/dl-start.S: Add _dl_main_dispatch label.
* sysdeps/powerpc/powerpc32/hp-timing.h: New file.
* sysdeps/unix/sysv/linux/powerpc/Versions: New file.
* sysdeps/unix/sysv/linux/clock_getres.c: If HAVE_CLOCK_GETRES_VSYSCALL
is not defined, redefine INTERNAL_VSYSCALL and INLINE_VSYSCALL to
INTERNAL_SYSCALL and INLINE_SYSCALL respectively. Otherwise include
<bits/libc-vdso.h>. Use INLINE_VSYSCALL and INTERNAL_SYSCALL instead
of the normal versions throughout the code.
* sysdeps/unix/sysv/linux/clock_gettime.c: Likewise if
HAVE_CLOCK_GETTIME_VSYSCALL is defined.
* sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h: New file.
* sysdeps/unix/sysv/linux/powerpc/dl-vdso.c: New file.
* sysdeps/unix/sysv/linux/powerpc/dl-vdso.h: New file.
* sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c: Use vDSO.
* sysdeps/unix/sysv/linux/powerpc/gettimeofday.c: New file.
* sysdeps/unix/sysv/linux/powerpc/Makefile: Add dl-vdso to routines.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h: Define
INLINE_VSYSCALL, INTERNAL_VSYSCALL, INTERNAL_SYSCALL_NCS,
INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK, HAVE_CLOCK_GETRES_VSYSCALL,
and HAVE_CLOCK_GETTIME_VSYSCALL.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h: Likewise.
* sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h: New file.
* sysdeps/unix/sysv/linux/clock_getcpuclockid.c: New file.
* sysdeps/unix/sysv/linux/ia64/clock_getcpuclockid.c
(HAS_CPUCLOCK): New macro.
(clock_getcpuclockid): Function removed.
#include the new linux file to define it instead.
* sysdeps/unix/clock_gettime.c [HP_TIMING_AVAIL] (hp_timing_gettime):
New function, broken out of ...
(clock_gettime) [HP_TIMING_AVAIL]: ... here. Call it.
(realtime_gettime): New function, broken out of ...
(clock_gettime) [! HANDLED_REALTIME]: ... here. Call it.
(clock_gettime) [SYSDEP_GETTIME_CPU]: Use new macro in default case.
* sysdeps/unix/sysv/linux/clock_gettime.c (SYSCALL_GETTIME): New macro.
(SYSDEP_GETTIME_CPUTIME): New macro.
(SYSDEP_GETTIME): Use both.
[! __ASSUME_POSIX_TIMERS] (maybe_syscall_gettime): New function, broken
out of ...
(SYSDEP_GETTIME): ... here. Use it.
[__NR_clock_gettime] (HANDLED_CPUTIME): Define it.
(SYSDEP_GETTIME_CPUTIME): New macro. Handle CPU timers by trying
kernel support and falling back to hp-timing code.
* sysdeps/posix/clock_getres.c
[HP_TIMING_AVAIL] (hp_timing_getres): New function, broken out of ...
(clock_getres) [HP_TIMING_AVAIL]: ... here. Call it.
(realtime_getres): New function, broken out of ...
(clock_getres) [! HANDLED_REALTIME]: ... here. Call it.
(clock_getres) [SYSDEP_GETRES_CPU]: Use new macro in default case.
* sysdeps/unix/sysv/linux/clock_getres.c (SYSCALL_GETRES): New macro.
(SYSDEP_GETRES_CPUTIME): New macro.
(SYSDEP_GETRES): Use both.
[! __ASSUME_POSIX_TIMERS] (maybe_syscall_getres): New function, broken
out of ...
(SYSDEP_GETRES): ... here. Use it.
[__NR_clock_getres] (HANDLED_CPUTIME): Define it.
(SYSDEP_GETRES_CPUTIME): New macro. Handle CPU timers by trying
kernel support and falling back to hp-timing code.
* sysdeps/unix/sysv/linux/clock_nanosleep.c: Handle
CLOCK_PROCESS_CPUTIME_ID and CLOCK_PROCESS_THREAD_ID specially,
translating to the kernel clockid_t for our own process/thread clock.
