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References: <20211126060024.3290177-1-alistair.francis@opensource.wdc.com>
In-Reply-To: <20211126060024.3290177-1-alistair.francis@opensource.wdc.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Fri, 26 Nov 2021 08:19:53 +0100
Message-ID: <CAK8P3a1WPgrkw5N9acSZ1bRPjBUS0bXSjSBRSW2pYA-m-mc=Qw@mail.gmail.com>
Subject: Re: [PATCH v3 1/6] perf bench futex: Add support for 32-bit systems
 with 64-bit time_t
To:     Alistair Francis <alistair.francis@opensource.wdc.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Alistair Francis <alistair23@gmail.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Ingo Molnar <mingo@redhat.com>,
        Darren Hart <dvhart@infradead.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        linux-perf-users@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        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, Nov 26, 2021 at 7:00 AM Alistair Francis
<alistair.francis@opensource.wdc.com> wrote:
> 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.
>
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>


Reviewed-by: Arnd Bergmann <arnd@arndb.de>