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Re: gdbstub initial code, v16
- From: Roland McGrath <roland at redhat dot com>
- To: Oleg Nesterov <oleg at redhat dot com>
- Cc: archer at sourceware dot org, utrace-devel at redhat dot com
- Date: Tue, 16 Nov 2010 12:02:26 -0800 (PST)
- Subject: Re: gdbstub initial code, v16
- References: <20101115190537.GA15725@redhat.com>
> Well. I can't say this change is good. Because ugdb uses (unexported)
> arch_ptrace() to set debugregs in a very much x86-specific way. However,
> I do not see what else can I do.
That kludge is unworkable in several ways. It is just not worth pursuing.
Just use hw_breakpoint on kernels that have it, and don't try to support
the feature on kernels that don't.
> Say, should I implement vRun? From the very beginnig, I hate the idea
> to exec the target from kernel space, but otoh I'm afraid this is
> important for gdb users.
We've also vaguely discussed doing some hybrid solution where gdb does
something different for "run". If you can do a kludge to implement vRun
fairly quickly and it works OK--including that it remains possible for
ugdb to be a module--then go ahead. If that is too ungainly, or is just
plain infeasible (which I think it might be), then don't bend over
backwards for it. We may have reached the end of what it's possible to
get done at all sensibly without more active involvement from the GDB team.