[PATCH] powerpc/mm/book3s64/hash: Update 4k PAGE_SIZE kernel mapping

[Aneesh Kumar K.V]

On 10/16/19 11:35 AM, Christoph Hellwig wrote:
> On Wed, Oct 16, 2019 at 11:21:30AM +0530, Aneesh Kumar K.V wrote:
>> With commit: 0034d395f89d ("powerpc/mm/hash64: Map all the kernel
>> regions in the same 0xc range"), kernel now split the 64TB address range
>> into 4 contexts each of 16TB. That implies we can do only 16TB linear
>> mapping. This results in boot failure on some P9 systems.
>>
>> Fix this by redoing the hash 4k mapping as below.
>>
>>   vmalloc start     = 0xd000000000000000
>>   IO start          = 0xd000380000000000
>>   vmemmap start     = 0xf000000000000000
>>
>> Vmalloc area is now 56TB in size and IO remap 8TB.
> 
> Btw, is there any good reason to keep the vmalloc and ioremap ranges
> separate on powerpc?  Most architectures just use the low-level vmap
> code to implement both and share a range.
> 

The base page size we use to map these two can be different.


-aneesh