Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
Date:   Thu, 21 Sep 2023 20:11:23 +0200
From:   Stephan Gerhold <stephan@gerhold.net>
To:     Bjorn Andersson <quic_bjorande@quicinc.com>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Caleb Connolly <caleb.connolly@linaro.org>
Subject: Re: [PATCH v3 3/3] soc: qcom: rtmfs: Handle reserved-memory
 allocation issues
Message-ID: <ZQyHS__ZPlnvMIFo@gerhold.net>
References: <20230920-rmtfs-mem-guard-pages-v3-0-305b37219b78@quicinc.com>
 <20230920-rmtfs-mem-guard-pages-v3-3-305b37219b78@quicinc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230920-rmtfs-mem-guard-pages-v3-3-305b37219b78@quicinc.com>
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Wed, Sep 20, 2023 at 07:37:32PM -0700, Bjorn Andersson wrote:
> In the even that Linux failed to allocate the reserved memory range
> specified in the DeviceTree, the size of the reserved_mem will be 0,
> which results in a oops when memory remapping is attempted.
> 
> Detect this and report that the memory region was not found instead.
> 
> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>

I dropped these checks in my remoteproc patches because Caleb suggested
maybe putting this check directly in of_reserved_mem_lookup() (or
similar) given that almost none of the users verify this [1].

Do you have any opinion on that? I asked back then too but you did not
reply yet [2]. :-)

[1]: https://lore.kernel.org/linux-arm-msm/c3f59fb4-4dd8-f27a-d3f5-b1870006a75c@linaro.org/
[2]: https://lore.kernel.org/linux-arm-msm/ZIsld-MAdkKvdzTx@gerhold.net/

> ---
>  drivers/soc/qcom/rmtfs_mem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
> index 83bba9321e72..13823abd85c2 100644
> --- a/drivers/soc/qcom/rmtfs_mem.c
> +++ b/drivers/soc/qcom/rmtfs_mem.c
> @@ -180,7 +180,7 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
>  	int ret, i;
>  
>  	rmem = of_reserved_mem_lookup(node);
> -	if (!rmem) {
> +	if (!rmem || !rmem->size) {
>  		dev_err(&pdev->dev, "failed to acquire memory region\n");
>  		return -EINVAL;
>  	}
> 
> -- 
> 2.25.1
>