ppc64 gdb register problem

[Reynolds, Terry (Contractor-SIMTECH)]

Hi,

 

I've had this problem show up in several 64 bit (ppc64) Linux versions 2.6.4 through 2.6.9.  When debugging a program compiled for 64 bits (gcc -m64)  The debugger is unable to display the contents of the fpscr register (info reg fpscr, or info reg all).  Gdb says :

 

fpscr        reading register fpscr (#70) Input/output error.

 

This would just be irritating, except a program I'm trying to debug, an infiniband verb layer app, fails to load in gdb with:

 

Error while reading shared library symbols:

reading register fpscr (#70); Input/output error.

 

The details of what I'm running are:

 

PowerMac G5

 

uname -a

Linux g5linux1 2.6.9.0-ydl.1.custom #1 SMP ppc64 ppc64 ppc64 GNU/Linux

 

gcc -v

gcc version 3.3.3

 

gdb -v

6.1.post-1.20040607.41rh

 

and the same results with:

6.2

 

This is repeatable with a simple hello world program.  Break in main, and do info reg fpscr.

 

I haven't been able to find any reference to this problem anywhere else.

 

Anyone have any ideas?

 

Thanks!

 

Terry Reynolds