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References: <20211209235857.423773-1-alistair.francis@opensource.wdc.com>
 <YbNX3mRT0A9/N2il@kernel.org> <YbNZw1/cUXJ8up5b@kernel.org>
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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Fri, 10 Dec 2021 15:23:42 +0100
Message-ID: <CAK8P3a05D=fb9stZEL6rUMs7c=S6gJxN5gR7HG_i8RiXAbaB5Q@mail.gmail.com>
Subject: Re: [PATCH v5 1/6] perf bench futex: Add support for 32-bit systems
 with 64-bit time_t
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Alistair Francis <alistair.francis@opensource.wdc.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Darren Hart <dvhart@infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Alistair Francis <alistair23@gmail.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Jiri Olsa <jolsa@redhat.com>, linux-perf-users@vger.kernel.org,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alistair Francis <alistair.francis@wdc.com>,
        Atish Patra <atish.patra@wdc.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>
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On Fri, Dec 10, 2021 at 2:44 PM Arnaldo Carvalho de Melo
<acme@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@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