[prev in list] [next in list] [prev in thread] [next in thread] 

List:       osdl-fastboot
Subject:    Re: [Fastboot] [RFC][PoC] Kexec based crash dumps
From:       ebiederm () xmission ! com (Eric W !  Biederman)
Date:       2004-07-29 17:34:51
Message-ID: m18yd2k98k.fsf () ebiederm ! dsl ! xmission ! com
[Download RAW message or body]

Hariprasad Nellitheertha <hari@in.ibm.com> writes:

> On Thu, Jul 29, 2004 at 10:59:16AM -0600, Eric W. Biederman wrote:
> > Hariprasad Nellitheertha <hari@in.ibm.com> writes:
> > 
> > > In the second kernel, this "old memory" can be accessed in two ways. The 
> > > first one is through a device interface. We can create a /dev/hmem or 
> > > whatever and write out the memory in raw format. The second interface is
> > > through /proc/vmcore. This exports the dump as an ELF format file which 
> > > can be written out using any file copy command (cp, scp, etc). Further, gdb
> > > can be used to perform some minimal debugging on the dump file.
> > 
> > There is a third way to access the old memory mmaping /dev/mem.  
> > Is there any reason not to use that?
> 
> When we have booted with only 16MB in the second kernel, isn't /dev/mem
> reflecting only that portion of the system's memory?

Only for reads.  mmap still let's you access everything.

The assumption is that the rest is I/O space.

/dev/mem is how X access the frame buffer for example.

Eric


_______________________________________________
fastboot mailing list
fastboot@lists.osdl.org
http://lists.osdl.org/mailman/listinfo/fastboot


[prev in list] [next in list] [prev in thread] [next in thread]