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>
---
 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

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
>

On Thu, Sep 21, 2023 at 08:11:23PM +0200, Stephan Gerhold wrote:
> 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]. :-)
> 

I'm struggling to come up with a use case where one would like to get
hold of the rmem when it wasn't properly initialized. So, let's make an
attempt at returning NULL from of_reserved_mem_lookup() instead.

Thanks,
Bjorn

> [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
> >

On 9/21/23 04:37, 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>
> ---
typo in subject: rtmfs

Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad