Message-ID: <615d907e-fd7c-f235-405b-d112f1373280@linaro.org>
Date:   Wed, 8 Mar 2023 12:53:42 +0000
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Subject: Re: [PATCH v3 1/4] firmware: qcom_scm: Export SCM call functions
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To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Bjorn Andersson <andersson@kernel.org>
Cc:     Andy Gross <agross@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Johan Hovold <johan@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        Sumit Garg <sumit.garg@linaro.org>,
        Steev Klimaszewski <steev@kali.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230305022119.1331495-1-luzmaximilian@gmail.com>
 <20230305022119.1331495-2-luzmaximilian@gmail.com>
 <a2c97f09-3360-b2b1-184a-8e3b869a70ef@linaro.org>
From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
In-Reply-To: <a2c97f09-3360-b2b1-184a-8e3b869a70ef@linaro.org>
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On 07/03/2023 15:23, Dmitry Baryshkov wrote:
> 
>> Make qcom_scm_call, qcom_scm_call_atomic and associated types accessible
>> to other modules.
> 
> Generally all the qcom_scm calls are a part of qcom_scm.c. I think it is 
> better to make qseecom_scm_call a part qcom_scm.c (as we were previously 
> doing) rather than exporting the core function.
>

Other big issue I see in exporting qcom_scm_call() is that there is 
danger of misuse of this api as this could lead to a path where new apis 
and its payloads can come directly from userspace via a rogue/hacking 
modules. This will bypass scm layer completely within kernel.

--srini

> If you wish to limit the kernel bloat, you can split the qcom_scm into 
> per-driver backend and add Kconfig symbols to limit the impact. However 
> I think that these functions are pretty small to justify the effort.
> 


>>
>> Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>