[PATCH 14/22] gpu: host1x: Forbid relocation address shifting in the firewall

[Dmitry Osipenko]

On 01.06.2017 21:51, Mikko Perttunen wrote:
> On 06/01/2017 09:44 PM, Dmitry Osipenko wrote:
>> On 01.06.2017 21:37, Dmitry Osipenko wrote:
>>> On 01.06.2017 20:39, Mikko Perttunen wrote:
>>>> Reviewed-by: Mikko Perttunen <mperttunen at nvidia.com>
>>>>
>>>> On 05/23/2017 03:14 AM, Dmitry Osipenko wrote:
>>>>> Incorrectly shifted relocation address will cause a lower memory corruption
>>>>> and likely a hang on a write or a read of an arbitrary data in case of IOMMU
>>>>> absent. As of now there is no use for the address shifting (at least on
>>>>> Tegra20) and adding a proper shifting / sizes validation is much more work.
>>>>
>>>> Perhaps change to "As of now there is no use for the address shifting on
>>>> Tegra20" if you post another revision.
>>>>
>>> I'll post a new revision of the series after getting comments to the all
>>> patches, to not churn the ML. Thank you very much for the reviews!
>>>
>>
>> However, given your previous comments to this patch, I'll probably add a bypass
>> of the shit checking in case of IOMMU presence.
>>

The IOMMU presence checking probably wouldn't be enough. Better to check the
Host1x version instead, to not break the non-IOMMU case on modern Tegras.

> 
> I don't think that's needed - the firewall will deny pretty much all VIC
> submissions due to is_addr_reg not being implemented so it cannot reasonably be
> used on modern Tegras anyway.

Either firewall should be completely avoided on newer Tegras or it should
perform at least some checks and not break the newer Tegras.

-- 
Dmitry