Re: gate.S and recent toolchains

[Jack Steiner <steiner@sgi.com>]

On Wed, Mar 29, 2006 at 10:51:14AM -0600, Russ Anderson wrote:
> Jes Sorensen wrote:
> > 
> > Hi,
> > 
> > I've been chasing a very strange but since Monday and I am starting
> > to hit a brick wall.
> > 
> > Basically I am unable to build a kernel from Linus' git tree on one
> > system since Monday morning, whereas it boots fine if I build it on an
> > older system. I tried installing an older toolchain on this box but it
> > still didn't seem to make a difference. The system boots, calls init and
> > I most often get the message "INIT: 2.85 booting", then a hang. In some
> > instances I don't even get the INIT message.

Have you NMI'ed the system to see where it is hanging.

Also, give it a spin on the simulator. These kinds of bugs are
frequently easier to debug on the simulator. If you
want, send me a pointer to a kernel & I see what happens.


> 
> It builds and boots on all the machines I have tried,
> including the same build and boot machines Jes uses.
> Jes can't get it to work, I can't get it to fail.
> 
> > What sparked it was Russ Anderson's patch which added a few lines to
> > include/asm-ia64/asmmacros.h, git id
> > d2a28ad9fa7bf16761d070d8a3338375e1574b32
> > 
> > I've tracked it down to being the two lines doing a .section/.previous
> > in the below patch chunk causing it. However it doesn't seem to be the
> > specific .section name that does it, ie. any random .section/.previous
> > pair I add to arch/ia64/kernel/gate.S has the same effect.
> > 
> > Now I am not a wiz in linker/gas magic, so I was hoping someone else
> > had an idea what could be causing this? Anyone seen anything similar?
> > 
> > The specific toolchain I am using is gcc-4.1.0 based, but I tried
> > 3.3.4 (with binutils 2.15) and it failed as well. However 4.0.2 on
> > another system seems to do fine (admittedly it had binutils 2.14.90.x).
> > 
> > Any suggestions would be greatly appreciated.
> > 
> > Thanks,
> > Jes
> > 
> > 
> > 
> > diff --git a/include/asm-ia64/asmmacro.h b/include/asm-ia64/asmmacro.h
> > index 77af457..d4cec32 100644
> > --- a/include/asm-ia64/asmmacro.h
> > +++ b/include/asm-ia64/asmmacro.h
> > @@ -51,6 +51,17 @@ name:
> >    [99:]        x
> > 
> >  /*
> > + * Tag MCA recoverable instruction ranges.
> > + */
> > +
> > +       .section "__mca_table", "a"             // declare section &
> > section attributes
> > +       .previous
> > +
> > +# define MCA_RECOVER_RANGE(y)                  \
> > +       .xdata4 "__mca_table", y-., 99f-.;      \
> > +  [99:]
> > +
> > +/*
> >   * Mark instructions that need a load of a virtual address patched to be
> >   * a load of a physical address.  We use this either in critical
> > performance
> >   * path (ivt.S - TLB miss processing) or in places where it might not be
> > 
> 
> 
> -- 
> Russ Anderson, OS RAS/Partitioning Project Lead  
> SGI - Silicon Graphics Inc          rja@sgi.com
> -
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-- 
Thanks

Jack Steiner (steiner@sgi.com)          651-683-5302
Principal Engineer                      SGI - Silicon Graphics, Inc.