RE: ppc64 altivec registers?

RE: ppc64 altivec registers?

[Reynolds, Terry (Contractor-SIMTECH)]

Hi,
 
Does anyone here know how to fix the configuration of the kernel so that
gdb can find the altivec registers?   The last time I heard from Andrew
Cagney he said :
 
"At the time the code was written it was for a special altivec kernel /
build / config. Hence it was only enabled when built powerpc-*-*altivec.
Time has passed and that restriction no longer applies. I'll see about
removing it."
 
 
 
TIA!
 

Terry Reynolds

Simulation Technologies, INC.

 

If you had to identify, in one word, the reason why the
human race has not achieved, and never will achieve,
its full potential, that word would be "meetings."
                                         Dave Barry

Re: ppc64 altivec registers?

[Daniel Jacobowitz]

On Wed, Sep 07, 2005 at 08:26:57AM -0500, Reynolds, Terry (Contractor-SIMTECH) wrote:
> Hi,
>  
> Does anyone here know how to fix the configuration of the kernel so that
> gdb can find the altivec registers?   The last time I heard from Andrew
> Cagney he said :
>  
> "At the time the code was written it was for a special altivec kernel /
> build / config. Hence it was only enabled when built powerpc-*-*altivec.
> Time has passed and that restriction no longer applies. I'll see about
> removing it."

Probably, the clean way to do this is through the "optional register
set" interface we defined a couple of months ago.  But I haven't had
time to implement that yet.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: ppc64 altivec registers?

[Paul Gilliam]

On Wednesday 07 September 2005 06:30, Daniel Jacobowitz wrote:
> On Wed, Sep 07, 2005 at 08:26:57AM -0500, Reynolds, Terry (Contractor-SIMTECH) wrote:
> > Hi,
> >  
> > Does anyone here know how to fix the configuration of the kernel so that
> > gdb can find the altivec registers?   The last time I heard from Andrew
> > Cagney he said :
> >  
> > "At the time the code was written it was for a special altivec kernel /
> > build / config. Hence it was only enabled when built powerpc-*-*altivec.
> > Time has passed and that restriction no longer applies. I'll see about
> > removing it."
> 
> Probably, the clean way to do this is through the "optional register
> set" interface we defined a couple of months ago.  But I haven't had
> time to implement that yet.
> 

(One of) The  problem(s) with Altivec is with the kernel and not with GDB.  The kernel (not sure which version, but I think all) just left out the GETVRREGS
and PUTVRREGS parts of the ptrace system call.  Even with a patched kernel, there seems to be some problems with Altivec.  I am working on them.  I 
hope to turn all the 'FAILS' to 'PASSES' in the the Altivec part of the testsuite (gdb.arch/altivec-abi.exp and gdb.arch/altivec-regs.exp)

Here is a link to a experimental patch to the 64-bit kernel that seems to fix the ptrace part of the problem(s):

http://ozlabs.org/pipermail/linuxppc64-dev/2005-August/005269.html