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

[Dmitry Osipenko]

On 23.05.2017 13:14, Mikko Perttunen wrote:
> Reloc shifts are implemented (see assignment of u32 reloc_addr in do_relocs),
> and they are required for VIC job submissions.
> 

The *validation* is unimplemented. Since VIC uses the shifts, we may add a
validation for it in a way it is done for the registers / class checks, i.e.
compare the per address register shift value. I suppose those registers are
documented somewhere(TRM), could you please point me to them (TRM page, reg name)?

> On 23.05.2017 03:14, 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.
>> Let's forbid it in the firewall till a proper validation is implemented.
>>
>> Signed-off-by: Dmitry Osipenko <digetx at gmail.com>
>> ---
>>  drivers/gpu/host1x/job.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
>> index 190353944d23..1a1568e64ba8 100644
>> --- a/drivers/gpu/host1x/job.c
>> +++ b/drivers/gpu/host1x/job.c
>> @@ -332,6 +332,10 @@ static bool check_reloc(struct host1x_reloc *reloc,
>> struct host1x_bo *cmdbuf,
>>      if (reloc->cmdbuf.bo != cmdbuf || reloc->cmdbuf.offset != offset)
>>          return false;
>>
>> +    /* relocation shift value validation isn't implemented yet */
>> +    if (reloc->shift)
>> +        return false;
>> +
>>      return true;
>>  }
>>
>>


-- 
Dmitry