Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220413030307.133807-1-heiko@sntech.de> <20220413030307.133807-12-heiko@sntech.de>
In-Reply-To: <20220413030307.133807-12-heiko@sntech.de>
From:   Philipp Tomsich <philipp.tomsich@vrull.eu>
Date:   Wed, 13 Apr 2022 11:16:22 +0200
Message-ID: <CAAeLtUDytpsYOcV1B1co6ufM_y7JdwrAZcN1HS9=ATyUiCmyZQ@mail.gmail.com>
Subject: Re: [PATCH v9 11/12] riscv: don't use global static vars to store
 alternative data
To:     Heiko Stuebner <heiko@sntech.de>
Cc:     palmer@dabbelt.com, paul.walmsley@sifive.com,
        aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org, wefu@redhat.com,
        liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org,
        anup@brainfault.org, drew@beagleboard.org, hch@lst.de,
        arnd@arndb.de, wens@csie.org, maxime@cerno.tech,
        gfavor@ventanamicro.com, andrea.mondelli@huawei.com,
        behrensj@mit.edu, xinhaoqu@huawei.com, mick@ics.forth.gr,
        allen.baum@esperantotech.com, jscheid@ventanamicro.com,
        rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, 13 Apr 2022 at 05:05, Heiko Stuebner <heiko@sntech.de> wrote:
>
> Right now the code uses a global struct to store vendor-ids
> and another global variable to store the vendor-patch-function.
>
> There exist specific cases where we'll need to patch the kernel
> at an even earlier stage, where trying to write to a static
> variable might actually result in hangs.
>
> Also collecting the vendor-information consists of 3 sbi-ecalls
> (or csr-reads) which is pretty negligible in the context of
> booting a kernel.
>
> So rework the code to not rely on static variables and instead
> collect the vendor-information when a round of alternatives is
> to be applied.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>