linux-kernel - Re: [PATCH v2 1/2] optee: fix tee out of memory failure seen during kexec reboot

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Date:   Tue, 2 Mar 2021 11:21:33 +0530
From:   Allen Pais <apais@...ux.microsoft.com>
To:     Jens Wiklander <jens.wiklander@...aro.org>,
        Allen Pais <allen.lkml@...il.com>
Cc:     zajec5@...il.com, bcm-kernel-feedback-list@...adcom.com,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        op-tee@...ts.trustedfirmware.org
Subject: Re: [PATCH v2 1/2] optee: fix tee out of memory failure seen during
 kexec reboot

>>
>> From: Allen Pais <apais@...ux.microsoft.com>
>>
>> The following out of memory errors are seen on kexec reboot
>> from the optee core.
>>
>> [    0.368428] tee_bnxt_fw optee-clnt0: tee_shm_alloc failed
>> [    0.368461] tee_bnxt_fw: probe of optee-clnt0 failed with error -22
>>
>> tee_shm_release() is not invoked on dma shm buffer.
>>
>> Implement .shutdown() method to handle the release of the buffers
>> correctly.
>>
>> More info:
>> https://github.com/OP-TEE/optee_os/issues/3637
>>
>> Signed-off-by: Allen Pais <apais@...ux.microsoft.com>
>> ---
>>   drivers/tee/optee/core.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
> 
> This looks good to me. Do you have a practical way of testing this on
> QEMU for instance?

   I have not tried this on QEMU. I will give it a go today.

Thanks.

> 
> Thanks,
> Jens
> 
>>
>> diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
>> index cf4718c6d35d..80e2774b5e2a 100644
>> --- a/drivers/tee/optee/core.c
>> +++ b/drivers/tee/optee/core.c
>> @@ -582,6 +582,13 @@ static optee_invoke_fn *get_invoke_func(struct device *dev)
>>          return ERR_PTR(-EINVAL);
>>   }
>>
>> +/* optee_remove - Device Removal Routine
>> + * @pdev: platform device information struct
>> + *
>> + * optee_remove is called by platform subsystem to alter the driver
>> + * that it should release the device
>> + */
>> +
>>   static int optee_remove(struct platform_device *pdev)
>>   {
>>          struct optee *optee = platform_get_drvdata(pdev);
>> @@ -612,6 +619,18 @@ static int optee_remove(struct platform_device *pdev)
>>          return 0;
>>   }
>>
>> +/* optee_shutdown - Device Removal Routine
>> + * @pdev: platform device information struct
>> + *
>> + * platform_shutdown is called by the platform subsystem to alter
>> + * the driver that a shutdown/reboot(or kexec) is happening and
>> + * device must be disabled.
>> + */
>> +static void optee_shutdown(struct platform_device *pdev)
>> +{
>> +       optee_disable_shm_cache(platform_get_drvdata(pdev));
>> +}
>> +
>>   static int optee_probe(struct platform_device *pdev)
>>   {
>>          optee_invoke_fn *invoke_fn;
>> @@ -738,6 +757,7 @@ MODULE_DEVICE_TABLE(of, optee_dt_match);
>>   static struct platform_driver optee_driver = {
>>          .probe  = optee_probe,
>>          .remove = optee_remove,
>> +       .shutdown = optee_shutdown,
>>          .driver = {
>>                  .name = "optee",
>>                  .of_match_table = optee_dt_match,
>> --
>> 2.25.1
>>