[LTP] [PATCH 4/5] syscalls: Don't pass struct timespec to tst_syscall()

[Viresh Kumar <viresh.kumar@linaro.org>]

On 20-05-20, 11:35, Arnd Bergmann wrote:
> On Wed, May 20, 2020 at 11:05 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > On 20-05-20, 10:47, Arnd Bergmann wrote:
> > > On Wed, May 20, 2020 at 9:31 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> >
> > > int tst_clock_gettime(clockid_t clk_id, struct timespec *ts)
> > >  {
> > >        int ret;
> > >
> > > #ifdef(__NR_clock_gettime64)
> > >         struct __kernel_timespec newts;
> > >         ret = tst_syscall(__NR_clock_gettime64, clk_id, &newts);
> > >         *ts = (struct timespec) { .tv_sec = newts.tv_sec, .tv_nsec =
> > > newts.tv_nsec };
> > >         if (ret != -ENOSYS)
> > >               return ret;
> > > #endif
> > >
> > > #ifdef __NR_clock_gettime
> > >         struct __kernel_old_timespec oldts;
> > >         ret = tst_syscall(__NR_clock_gettime, clk_id, &oldts);
> > >         *ts = (struct timespec) { .tv_sec = oldts.tv_sec, .tv_nsec =
> > > oldts.tv_nsec };
> > >         if (ret != -ENOSYS)
> > >               return ret;
> > > #endif
> > >
> > >        /* fallback for prehistoric linux */
> > >         struct timeval tv;
> > >         ret = gettimeofday(&tv, NULL);
> > >         *ts = (struct timespec) { .tv_sec = newts.tv_sec, .tv_usec =
> > > newts.tv_nsec / 1000};
> > >
> > >         return ret;
> > > }
> >
> > This is used only for the internal working of the library and so we may not need
> > to support all these timespec types TBH and make it complex.
> 
> Well, the point here is that you need the function to reliably return the
> current time in the right format, and I don't think a simpler implementation
> would be correct. In fact, I just realized that your patch version cannot work
> on riscv32 since it only has __NR_clock_gettime64 but not __NR_clock_gettime.

I am wondering that there would be lots of such issues across LTP, all existing
ones btw, and should we try to fix them or not ? No one ever ran it on Risk I
believe, otherwise they would have seen it.

-- 
viresh