Nicholas Piggin <npig...@gmail.com> writes: > Aneesh Kumar K.V's on February 19, 2019 4:00 pm: >> On 2/19/19 11:28 AM, Nicholas Piggin wrote: >>> Aneesh Kumar K.V's on February 17, 2019 3:16 pm: >>>> This patch maps vmap, IO and vmemap regions in the 0xc address range >>>> instead of the current 0xd and 0xf range. This brings the mapping closer >>>> to radix translation mode. >>> >>> What was the reason for that address layout in the first place? >>> >> >> To bring in closer to radix translation mode and it should also help >> with KASAN implementation. > > No I mean the old implementation. Your change seems fine, it would just > be good to know what the downside (if any) is from changing. Maybe it > was just to make debugging slightly simpler?
I don't know what the reason was for using 0xd to begin with. The original ppc64 port already had it. Takes a few seconds to load: https://github.com/mpe/linux-fullhistory/commit/c3aa9878533e724f639852c3d951e6a169e04081#diff-0adfdefb64f0f0ef306be06ce7f953ebR173 #define PAGE_OFFSET 0xC000000000000000 #define KERNELBASE PAGE_OFFSET #define VMALLOCBASE 0xD000000000000000 #define IOREGIONBASE 0xE000000000000000 cheers