PPC debug setcontext syscall implementation

[Matt Porter]

On Thu, Dec 02, 2004 at 03:23:50PM -0700, Tom Rini wrote:
> On Thu, Dec 02, 2004 at 02:41:32PM -0600, Corey Minyard wrote:
> 
> > Hello all,
> > 
> > I have attached a patch with the implementation of the debug_setcontext 
> > system call.  The syscall has been reserved for a while and I've posted 
> > this before.  So I've ported to the newest kernel and here it is again.
> > 
> > This syscall allows signal handlers to perform debug functions.  It 
> > allows the signal handler to turn on single-stepping, for instance, and 
> > the thread will get a trap after executing the next instruction.  It can 
> > also (on supported PPC processors) turn on branch tracing and get a trap 
> > after the next branch instruction is executed.  This is useful for 
> > in-application debugging.
> 
> I asked Corey off-list, and this is vs 2.6.10-rc2-mm3.
> I propose (and will update the patch tracker
> (http://ozlabs.org/ppc32-patches/, I don't recall if/how well it was
> advertised)) that so long as KGDB still works (I'll even go test it on
> classic) as well as GDB testsuite (this is a 'touchy' area, so I'd like
> to well-test changes) is still 'OK', pushing this into 2.6.11.

I don't see a problem so long as both the 40x||booke and classic paths
are tested with gdb and kgdb. I don't want to fix the former path again.

-Matt