[PATCH v4] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable

[Adhemerval Zanella]

On 05/11/2019 20:40, Alistair Francis wrote:
> The nanosleep syscall is not supported on newer 32-bit platforms (such
> as RV32). To fix this issue let's use clock_nanosleep_time64 if it is
> avaliable.
> 
> Let's use CLOCK_REALTIME when calling clock_nanosleep_time64 as the
> Linux specification says:
>   "POSIX.1 specifies that nanosleep() should measure time against the
>    CLOCK_REALTIME clock. However, Linux measures the time using the
>    CLOCK_MONOTONIC clock. This probably does not matter, since the POSIX.1
>    specification for clock_settime(2) says that discontinuous changes in
>    CLOCK_REALTIME should not affect nanosleep()"
> 
> Let's also expose __clock_nanosleep internally to avoid code
> duplication.
> ---
> This was patch was runtime tested with RV32 and RV64
> It was build tested using the ./scripts/build-many-glibcs.py script.
> 
> I am currently running:
> $ make ; make install ; make check
> tests on native ARM (32-bit) with the following three confiugrations:
>  - 4.19 Kernel and 4.19 Headers
>  - 5.2 Kernel and 4.19 Headers
>  - 5.2 Kernel and 5.2 Headers
> I should have the results tomorrow.
> 
> v4:
>  - Rebase on master
>  - Use __clock_nanosleep to avoid duplicate implementations
>  - Fix the error handling when a syscall fails

I sent a nanosleep/thrd_sleep refactor that should simplify this code
with advantage it consolidates more symbols on libc.so (instead of
exporting more through GLIBC_PRIVATE).