ppc64 altivec registers?

Paul Gilliam pgilliam@us.ibm.com
Wed Sep 7 19:06:00 GMT 2005


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



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