[Crash-utility] ARM support for CONFIG_SPARSEMEM: (was Re: DD image)

Dave Anderson anderson at redhat.com
Tue May 24 13:58:48 UTC 2011



----- Original Message -----
> ----- Original Message -----
> > Hi
> >
> > I had the same problem with CONFIG_SPARSEMEM and if I do not
> > remember
> > wrong I added:
> > machdep->max_physmem_bits = _MAX_PHYSMEM_BITS;
> > machdep->section_size_bits = _SECTION_SIZE_BITS;
> > to arm.c
> >
> > and:
> > #define _SECTION_SIZE_BITS 22
> > #define _MAX_PHYSMEM_BITS 32
> > to defs.h in a section for ARM.
> >
> > I am not certain what these figures stand for but they seems to work
> > for me.
> >
> > Jan Karlsson
> >
> 
> There seems to be some discussion about future support for SPARSEMEM
> on ARM, although like I mentioned before, it doesn't appear to be
> in the latest upstream kernel as of yet.
> 
> In any case, for it to apply to the crash utility, it should be a
> matter of supplying the _MAX_PHYSMEM_BITS and _SECTION_SIZE_BITS
> #define's that match the kernel's MAX_PHYSMEM_BITS and SECTION_SIZE_BITS.
> And then in arm_init(), they should be initialized as you've shown
> above.
> 
> Dave

BTW, I await any patches from the ARM folks to set these bits
appropriately.  Currently there is this for ARM in defs.h:

  #ifdef ARM
  ... [ cut ] ...

  #define _SECTION_SIZE_BITS      28
  #define _MAX_PHYSMEM_BITS       32

  #endif  /* ARM */

Yet you state above that you're using 22 for _SECTION_SIZE_BITS.

So let me know what you guys want.

Thanks,
  Dave






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