On 15/07/17 04:47 AM, Felix Kuehling wrote:
> On 17-07-13 11:26 PM, Michel Dänzer wrote:
>> On 14/07/17 06:08 AM, Felix Kuehling wrote:
>>> Allows gdb to access contents of user mode mapped BOs. VRAM access
>>> requires the driver to implement a new callback in ttm_bo_driver.
>> Thanks for doing this. Looks mostly good, but I still have some comments.
>>
>> The shortlog prefix should be "drm/ttm:".
>>
>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> index 9f53df9..0ef2eb9 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> @@ -294,10 +294,74 @@ static void ttm_bo_vm_close(struct vm_area_struct *vma)
>>> vma->vm_private_data = NULL;
>>> }
>>>
>>> +static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
>>> + unsigned long offset,
>>> + void *buf, int len, int write)
>>> +{
>>> + unsigned long first_page = offset >> PAGE_SHIFT;
>>> + unsigned long last_page = (offset + len - 1) >> PAGE_SHIFT;
>>> + unsigned long num_pages = last_page - first_page + 1;
>>> + struct ttm_bo_kmap_obj map;
>>> + void *ptr;
>>> + bool is_iomem;
>>> + int ret;
>>> +
>>> + ret = ttm_bo_kmap(bo, first_page, num_pages, &map);
>>> + if (ret)
>>> + return ret;
>> Could there be cases (e.g. on 32-bit) where mapping all pages at once
>> fails, but mapping one page at a time would work?
>
> Maybe. I'm not really familiar with ttm_bo_kmap limitations on 32-bit. I
> guess the the access would have to be really big. I think in practice
> GDB doesn't do very big accesses. So I'm not sure it's worth the trouble.
Okay, I guess it can always be changed later if necessary.
>>> + int (*access_vram)(struct ttm_buffer_object *bo, unsigned long offset,
>>> + void *buf, int len, int write);
>>> };
>> I suggest making the write parameter a bool.
>
> I made this as similar as possible to the vm_ops->access API, where
> write is also an integer.
I see, makes sense.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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