Re: [PATCH] tee: fix tee_ioctl_object_invoke_arg padding

[Sumit Garg via OP-TEE <op-tee@lists.trustedfirmware.org>]

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.

-Sumit

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