Kernel 4.7: PAGE_GUARDED and _PAGE_NO_CACHE

[Julian Margetson]

On 6/5/2016 10:00 PM, Michael Ellerman wrote:
> On Sun, 2016-06-05 at 21:23 -0400, Julian Margetson wrote:
>>>> drivers/gpu/drm/drm_vm.c: In function ‘drm_dma_prot’:
>>>> drivers/gpu/drm/drm_vm.c:83:6: error: invalid operands to binary |
>>>> (have ‘pgprot_t {aka struct <anonymous>}’ and ‘int’)
>>>>      tmp |= _PAGE_NO_CACHE;
>>>>          ^
>>>>
>>> That is because that usage is wrong based on type. _PAGE_NO_CACHE is not
>>> of type pgprot_t. What you really need there is
>>>
>>> tmp = __pgprot(pgprot_val(tmp) | _PAGE_NO_CACHE);
>>>
>>> or a better option would be
>>>
>>> tmp = pgprot_noncached_wc(tmp);
>>>
>>> -aneesh
>> tmp = pgprot_noncached_wc(tmp);
>>
>> compiles but  I then run in to the following
>>
>>    CC      drivers/gpu/drm/drm_scatter.o
>> drivers/gpu/drm/drm_scatter.c: In function ‘drm_vmalloc_dma’:
>> drivers/gpu/drm/drm_scatter.c:44:49: error: invalid operands to binary |
>> (have ‘pgprot_t {aka struct <anonymous>}’ and ‘int’)
>>     return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL | _PAGE_NO_CACHE);
>>                                                    ^
>> drivers/gpu/drm/drm_scatter.c:48:1: warning: control reaches end of
>> non-void function [-Wreturn-type]
>>    }
>>    ^
> Aneesh showed you how to fix that in his reply above.
>
>      return __vmalloc(size, GFP_KERNEL, pgprot_noncached_wc(PAGE_KERNEL));
>
> cheers
>
>
>
Thanks .

With the two adjustment

tmp = pgprot_noncached_wc(tmp);

and

return __vmalloc(size, GFP_KERNEL, pgprot_noncached_wc(PAGE_KERNEL));

The rc2 builds and boots  on Sam460ex

Regards

Julian