Re: /dev/mem and highmem

From: Nicolas George (nicolas.george@ens.fr)
Date: Thu Mar 06 2003 - 11:22:08 EST


Le tridi 13 ventôse, an CCXI, Nicolas George a écrit :
> Is there any hope to have access to the highmem through /dev/mem, or a
> similar device? Or did I miss an already existing method?

Since nobody answered, I suppose that at least I did not miss something
obvious. Si I tried to write it.

What I understoud is that the way to access the byte at physical address
a is to kmap(mem_map[o >> PAGE_SHIFT]), and access at offet
o % PAGE_SHIFT (and then kunmap it). Perharps it is very ix86-centered.
Since it did not crash my PC, and it gave the same data as /dev/mem, I
think I was not totally wrong.

The code is available at <URL:
http://www.eleves.ens.fr/home/george/info/prg/highmem.c >. The write
part is not yet done, but since it is very similar to read, it should be
really straightforward. Nevertheless I will wait a bit before trying it.

Regards,

-- 
  Nicolas George


- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Fri Mar 07 2003 - 22:00:32 EST