Re: [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitraryphysical addresses

From: Dave Anderson
Date: Tue Jun 21 2011 - 09:03:25 EST

----- Original Message -----
> ä 2011å06æ20æ 21:24, Dave Anderson åé:
> >> On Mon, Jun 20, 2011 at 10:42:47, Amerigo Wang<amwang@xxxxxxxxxx>
> >
> > I don't know what you mean by I "didn't consider it", because
> > the crash utility does support using /proc/kcore as an alternative
> > live memory source.
> Sorry, I recall that in our last discussion you didn't
> mention this. But it is good to know that crash supports this!
> >
> > The problem is that /proc/kcore can only access highmem if it
> > is mapped as kernel virtual address. So it cannot read 32-bit
> > highmem PTE's, user-space memory, etc.
> >
> Hmm, looking at the code, you are right, it only has
> low memory in kernel space.
> But what's the problem of adding highmem into kcore? :-/
> Thanks.

/proc/kcore was presumably designed for use by gdb with a vmlinux
namelist, and like user-space core dumps, the PT_LOAD segments
reference virtual address regions with p_vaddr/p_paddr pairs.

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