broken memory chip -> software fix?

From: David Madore (david.madore@ens.fr)
Date: Fri Aug 17 2001 - 09:15:05 EST

Hi all.

I have a broken bit in my memory - at address 0x04d5ae38 if you want
to know the details (bit 29 of the double word there sometimes reads
as 1 when it was written as 0, in particular if bit 15 is at 1). I
discovered this by observing a one-bit corruption of some files, and
diagnosed it by running memtest86.

Now that I know the address, is there a way I can prevent Linux from
using that region of memory in any way? The simplest and cleanest
way, would be, I guess, for a userland process I would write to ask of
the kernel to map permanently and unswappably the page at physical
location 0x04d5a000 to its virtual address space. (Besides, that
would let me play with that broken bit.)

So: is there a way for a userland process (running at euid 0) to
request of the kernel an explicit physical address to virtual address
translation? If so, how? I would prefer not to have to patch the
kernel, if at all possible.

Thanks, 

-- 
     David A. Madore
    (david.madore@ens.fr,
     http://www.eleves.ens.fr:8080/home/madore/ )
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This archive was generated by hypermail 2b29 : Thu Aug 23 2001 - 21:00:23 EST