On 07/07/2026 2:36 pm, Mike Rapoport wrote:

On Tue, Jul 07, 2026 at 02:17:29PM +0100, Robin Murphy wrote:

...

Given the precedent of memblock_mark_nomap(), as long as the reusable reserved-memory regions also get split into distinct memblocks, then it seems like in principle we ought to be able to give them a new MEMBLOCK_PTEMAP (or whatever) flag which could then be picked up in map_mem() without needing to override force_pte_mapping() globally?

Please don't. _nomap() caused enough pain.

Indeed I was there for pretty much the whole pfn_valid() saga :)

Bad example maybe - in this case the only actual similarity to nomap would be the fact that it would also be set by the of_reserved_mem code based on what it finds in DT; in all other aspects it should be functionally closer to something like MEMBLOCK_RSRV_NOINIT, i.e. just carrying information through the mm init phase, then ceasing to matter at all once the linear mapping is done.

Cheers, Robin.