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SubjectRe: [patch] x86, pat: fix reserve_memtype() for legacy 1MB range
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?

-hpa


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