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From:   Atish Patra <atishp@atishpatra.org>
Date:   Sun, 22 Mar 2020 20:03:17 -0700
Message-ID: <CAOnJCULYLBV0O+xrgnCkv6FgFC2wz0U54uYV7S5hkBfQf+7vRg@mail.gmail.com>
Subject: Re: [PATCH v11 00/11] Add support for SBI v0.2 and CPU hotplug
To:     Emil Renner Berthing <emil.renner.berthing@gmail.com>
Cc:     Atish Patra <atish.patra@wdc.com>,
        Albert Ou <aou@eecs.berkeley.edu>, Gary Guo <gary@garyguo.net>,
        Nick Hu <nickhu@andestech.com>,
        Anup Patel <anup@brainfault.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Vincent Chen <vincent.chen@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Zong Li <zong.li@sifive.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Greentime Hu <greentime.hu@sifive.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Bin Meng <bmeng.cn@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Mao Han <han_mao@c-sky.com>
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On Sun, Mar 22, 2020 at 10:49 AM Emil Renner Berthing
<emil.renner.berthing@gmail.com> wrote:
>
> Hi Atish,
>
> On Wed, 18 Mar 2020 at 02:12, Atish Patra <atish.patra@wdc.com> wrote:
> >
> > The Supervisor Binary Interface(SBI) specification[1] now defines a
> > base extension that provides extendability to add future extensions
> > while maintaining backward compatibility with previous versions.
> > The new version is defined as 0.2 and older version is marked as 0.1.
> >
> > This series adds following features to RISC-V Linux.
> > 1. Adds support for SBI v0.2
> > 2. A Unified calling convention implementation between 0.1 and 0.2.
> > 3. SBI Hart state management extension (HSM)
> > 4. Ordered booting of harts
> > 4. CPU hotplug
>
> If it's any help I tried this series with both OpenSBI v0.6 and master
> (9a74a64ae08),
> and in both cases Linux found all four cpus. I can test the hotplug
> stuff too if you send
> me instructions. In any case you can add my
>
> Tested-by: Emil Renner Berthing <kernel@esmil.dk>
>

Thanks for testing the patches. Here are the steps to online/offline a cpu.

To mark a cpu offline
$echo 0 > /sys/devices/system/cpu/cpuX/online

To mark a cpu online
$echo 1 > /sys/devices/system/cpu/cpuX/online

Here are the official kernel documentation.
https://www.kernel.org/doc/html/latest/core-api/cpu_hotplug.html

> /Emil
>


-- 
Regards,
Atish