This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [rfc, s390] [gdb part] Support extended register sets
- From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- To: tromey at redhat dot com (Tom Tromey)
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 6 Dec 2011 16:41:29 +0100 (CET)
- Subject: Re: [rfc, s390] [gdb part] Support extended register sets
Tom Tromey wrote:
> >>>>> "Ulrich" == Ulrich Weigand <uweigand@de.ibm.com> writes:
>
> Ulrich> Since I'm already at it, the patch also adds another register,
> Ulrich> which is unrelated to system call restarting, but also has been
> Ulrich> added to the kernel a while ago and is not yet supported in GDB:
>
> Ulrich> last_break: presented as a new register set NT_S390_LAST_BREAK,
> Ulrich> always size 8 bytes; holds the address of the last branch
> Ulrich> instruction
>
> Nice. Jan had an idea for a way this would be useful to gdb:
>
> http://sourceware.org/bugzilla/show_bug.cgi?id=11705
Yes, the Intel BTS is something similar (except that on S/390 the feature
is always on, on systems where it is supported, and it stores just a
single branch, not multiple of them).
I guess if GDB core ever makes use of this information, we need to define
a platform interface to make it available. For now, my patch simply shows
the data as a register value on S/390 ...
I've checked the patch set in now.
Bye,
Ulrich
--
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE
Ulrich.Weigand@de.ibm.com