Re: ksymoops changes for mips (was Kernel crash on boot with current cvs)

[Ralf Baechle <ralf@oss.sgi.com>]

On Wed, Jun 13, 2001 at 10:19:14PM +1000, Keith Owens wrote:

> >That can be done automatically.  For 32-bit ELF files mips*-linux binutils
> >dump some of the addresses as 32-bit addresses, some as sign-extended (!)
> >64-bit addresses.  So ksymops should just sign extend any 32-bit addresses
> >to 64-bit and then work on full lenght addresses.
> 
> Some utilities extend with leading 0, some with leading 1, some with
> special values (alpha).  It is safer to truncate everything to the
> specified width instead of guessing what the extension value is.

That's a processor specific thing.  In case of MIPS only signed extension
is correct.  Some older binutils did unsigned extension and that's plain
wrong.

> >Is ksymoops able to handle 64-bit addresses when running on a 32-bit host?
> >That is a common case for many people when decoding their MIPS oopses.
> 
> Yes and no.  The framework is there to handle 32/64 splits, sparc
> already uses it.  mips does not currently use the framework because the
> oops report does not identify the machine type 32/64, MSB/LSB.  We
> discussed this in January and I asked for a small change to mips64 oops
> output (below), was that ever done?

Nothing - ``Guilty as charged.  Filed in my "to do when I have time" folder,
which overflowed about 3 years ago :(.''

  Ralf