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

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Message-ID: <9f4b44c1-cf86-a061-a9c6-726c4e23f99b@linux.microsoft.com>
Date:   Wed, 24 Feb 2021 22:23:34 +0530
From:   Allen Pais <apais@...ux.microsoft.com>
To:     Jens Wiklander <jens.wiklander@...aro.org>
Cc:     Dhananjay Phadke <dphadke@...ux.microsoft.com>,
        allen.lkml@...il.com, zajec5@...il.com,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        op-tee@...ts.trustedfirmware.org,
        linux-arm-kernel@...ts.infradead.org,
        bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH 1/2] optee: fix tee out of memory failure seen during
 kexec reboot


>>>>>> -	/*
>>>>>> -	 * Ask OP-TEE to free all cached shared memory objects to decrease
>>>>>> -	 * reference counters and also avoid wild pointers in secure world
>>>>>> -	 * into the old shared memory range.
>>>>>> -	 */
>>>>>> -	optee_disable_shm_cache(optee);
>>>>>> +	if (shutdown) {
>>>>>> +		optee_disable_shm_cache(optee);
>>>>>> +	} else {
>>>>>> +		/*
>>>>>> +		 * Ask OP-TEE to free all cached shared memory
>>>>>> +		 * objects to decrease reference counters and
>>>>>> +		 * also avoid wild pointers in secure world
>>>>>> +		 * into the old shared memory range.
>>>>>> +		 */
>>>>>> +		optee_disable_shm_cache(optee);
>>>>> Calling optee_disable_shm_cache() in both if and else. It could be
>>>>> put in front of if().
>>>>>
>>>>
>>>>     Ideally, I could just use optee_remove for shutdown() too.
>>>> But it would not look good. Hence this approach.
>>>
>>> What is the problem with using optee_remove() for shutdown()?
>>>
>>
>>   There is no problem, I just thought it would be more cleaner/readable
>> with this approach. If you'd like to keep it simple by just calling
>> optee_remove() for shutdown() too, I could quickly send out V2.
> 
> In the patch you posted it looks like you'd like to call
> only optee_disable_shm_cache() in the case of shutdown. Like:
> 
> static void optee_shutdown(struct platform_device *pdev)
> {
>          optee_disable_shm_cache(platform_get_drvdata(pdev));
> }
> 
> and optee_remove() kept as it was before this patch.
> 

  Sure, Will have it fixed and send out V2.

Thanks.