Messages in this thread | | | Date | Fri, 9 Jan 2009 14:48:04 -0800 | From | Suresh Siddha <> | Subject | Re: [patch] x86, pat: fix reserve_memtype() for legacy 1MB range |
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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.
thanks, suresh
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