[PATCH v5 1/6] perf bench futex: Add support for 32-bit systems with 64-bit time_t

[Arnd Bergmann]

On Fri, Dec 10, 2021 at 2:44 PM Arnaldo Carvalho de Melo
<acme at kernel.org> wrote:
> Em Fri, Dec 10, 2021 at 10:36:30AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Dec 10, 2021 at 09:58:52AM +1000, Alistair Francis escreveu:
> > > From: Alistair Francis <alistair.francis at wdc.com>
> > >
> > > Some 32-bit architectures (such are 32-bit RISC-V) only have a 64-bit
> > > time_t and as such don't have the SYS_futex syscall. This patch will
> > > allow us to use the SYS_futex_time64 syscall on those platforms.
> > >
> > > This also converts the futex calls to be y2038 safe (when built for a
> > > 5.1+ kernel).
> > >
> > > This is a revert of commit ba4026b09d83acf56c040b6933eac7916c27e728
> > > "Revert "perf bench futex: Add support for 32-bit systems with 64-bit time_t"".
> > >
> > > The original commit was reverted as including linux/time_types.h would
> > > fail to compile on older kernels. This commit doesn't include
> > > linux/time_types.h to avoid this issue.
> >
> >   10     9.99 alpine:3.12                   : FAIL gcc version 9.3.0 (Alpine 9.3.0)
> >     In file included from bench/futex-hash.c:29:
> >     bench/futex.h:37:2: error: unknown type name '__kernel_old_time_t'
> >        37 |  __kernel_old_time_t tv_sec;  /* seconds */
> >           |  ^~~~~~~~~~~~~~~~~~~
> >     In file included from bench/futex-wake.c:25:

It looks like we need to add include/uapi/linux/time_types.h to
tools/include/linux/ and update tools/include/linux/types.h
in order to address this.

         Arnd