Messages in this thread | | | Date | Fri, 9 Jan 2009 15:13:16 -0800 | From | Suresh Siddha <> | Subject | Re: [patch] x86, pat: fix reserve_memtype() for legacy 1MB range |
| |
On Fri, Jan 09, 2009 at 02:55:55PM -0800, H. Peter Anvin wrote: > Suresh Siddha wrote: > > On Fri, Jan 09, 2009 at 02:39:31PM -0800, H. Peter Anvin wrote: > >> Suresh Siddha wrote: > >>> Here X is trying to map first 8KB of memory using /dev/mem. Existing > >>> code treats first 0-4KB of memory as non-RAM and 4KB-8KB as RAM. Recent > >>> code changes don't allow to map memory with different attributes > >>> at the same time. > >>> > >> Why was 0-4 KB marked as non-RAM? It is most definitely RAM, and should > >> be WB. > > > > While in reality it is RAM, we have CONFIG_STRICT_DEVMEM which doesn't allow > > apps to map RAM pages using /dev/mem. And to allow app's to map the > > legacy 0-4KB bios data page, we consider it as non-RAM. > > Permission to map and memory type should not be connected. Just to > clarify, when mapped, was it still WB?
yes it is. It's just treated and tracked differently.
| |