Re: [PATCH] tee: fix tee_ioctl_object_invoke_arg padding

From: Harshal Dev <harshal.dev@oss.qualcomm.com>
To: Jens Wiklander <jens.wiklander@linaro.org>,
	Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
Cc: Sumit Garg <sumit.garg@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Arnd Bergmann <arnd@kernel.org>, Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Sumit Garg <sumit.garg@oss.qualcomm.com>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Etienne Carriere <etienne.carriere@foss.st.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH] tee: fix tee_ioctl_object_invoke_arg padding
Date: Tue, 16 Dec 2025 16:25:53 +0530	[thread overview]
Message-ID: <ba8554b7-499b-4fb8-b792-471d83cf3893@oss.qualcomm.com> (raw)
In-Reply-To: <CAHUa44GO-D1YcQ_36pe-vQ83fB9rcOkny+M7a=CThAxWb6TLTQ@mail.gmail.com>

Hi Jens,

On 12/16/2025 1:18 PM, Jens Wiklander wrote:
> Hi,
> 
> On Tue, Dec 9, 2025 at 4:54 AM Amirreza Zarrabi
> <amirreza.zarrabi@oss.qualcomm.com> wrote:
>>
>> Hi,
>>
>> On 12/8/2025 11:54 PM, Harshal Dev wrote:
>>>
>>>
>>> On 12/8/2025 5:50 PM, Sumit Garg via OP-TEE wrote:
>>>> On Mon, Dec 08, 2025 at 04:24:17PM +1100, Amirreza Zarrabi wrote:
>>>>> Hi,
>>>>>
>>>>> On 12/5/2025 12:27 AM, Jens Wiklander wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On Thu, Dec 4, 2025 at 11:17 AM Arnd Bergmann <arnd@kernel.org> wrote:
>>>>>>>
>>>>>>> From: Arnd Bergmann <arnd@arndb.de>
>>>>>>>
>>>>>>> The tee_ioctl_object_invoke_arg structure has padding on some
>>>>>>> architectures but not on x86-32 and a few others:
>>>>>>>
>>>>>>> include/linux/tee.h:474:32: error: padding struct to align 'params' [-Werror=padded]
>>>>>>>
>>>>>>> I expect that all current users of this are on architectures that do
>>>>>>> have implicit padding here (arm64, arm, x86, riscv), so make the padding
>>>>>>> explicit in order to avoid surprises if this later gets used elsewhere.
>>>>>>>
>>>>>>> Fixes: d5b8b0fa1775 ("tee: add TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF")
>>>>>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>>>>>>> ---
>>>>>>> The new interface showed up in 6.18, but I only came across this after
>>>>>>> that was released. Changing it now is technically an ABI change on
>>>>>>> architectures with unusual padding rules, so please consider carefully
>>>>>>> whether we want to do it this way or not.
>>>>>>>
>>>>>>> Working around the ABI differences without an ABI change is possible,
>>>>>>> but adds a lot of complexity for compat handling.
>>>>>>
>>>>>> This is currently only used by the recently introduced qcomtee backend
>>>>>> driver. So it's only used on a few arm64 Qualcomm platforms right now.
>>>>>>
>>>>>> I think we should take this patch, but let's hear what others think.
>>>>
>>>> Yeah since it's not an ABI issue on arm64 platforms where QTEE runs, so:
>>>>
>>>> Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> Jens
>>>>>>
>>>>>
>>>>> I agree. We should take this patch. As noted, there are not many
>>>>> clients relying on it yet, so updating the userspace should
>>>>> be straightforward.
>>>>
>>>> You should rather test without any userspace library update to test it's
>>>> not an ABI issue. Just for correctness sake, you can update the library
>>>> too.
>>>>
>>>
>>> I'll take the time to test it at some point this week both with and without updating
>>> the library ABI.
>>>
>>
>> Summit, that was the plan from the beginning, that's why I did not add "Reviewed-by:"
>> in the first place. Thanks Harshal for volunteering.
> 
> Are we good with this patch now?
>

Yes, this is good from our side.

Tested-by: Harshal Dev <harshal.dev@oss.qualcomm.com>

> Cheers,
> Jens

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