x86: Implement a remote GDB stub.

Information
Submitter:	Gabe Black
Repository:	gem5
Branch:	default
Bugs:
Depends On:
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Description

Changeset 10600:2f874ecfc989
---------------------------
x86: Implement a remote GDB stub.

This stub should allow remote debugging of 32 bit and 64 bit targets. Single
stepping seems to work, as do breakpoints. If both breakpoints and single
stepping affect an instruction, gdb will stop at the instruction twice before
continuing. That's a little surprising, but is generally harmless.

Testing Done

Issue Summary

Description	From	Last Updated	Status
this equation could use a comment	Steve Reinhardt	Dec. 5, 2014, 2:40 a.m.	Resolved
same here	Steve Reinhardt	Dec. 5, 2014, 2:40 a.m.	Resolved
Given that these two lines to grab the right comInstEventQueue appear twice here and once in patch 2540, it would ...	Steve Reinhardt	Dec. 5, 2014, 2:41 a.m.	Resolved

src/arch/x86/remote_gdb.hh (Diff revision 1)

this equation could use a comment

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src/arch/x86/remote_gdb.hh (Diff revision 1)

same here

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src/arch/x86/remote_gdb.cc (Diff revision 1)

Given that these two lines to grab the right comInstEventQueue appear twice here and once in patch 2540, it would be nice to wrap them up in a little helper method on the RemoteGDB object.

In fact, adding something like:

EventQueue *
RemoteGDB::commitQueue()
{
    return context->getCpuPtr()->comInstEventQueue[context->threadId()];
}

void
RemoteGDB::scheduleCommitEvent(Event *ev, int delta)
{
    EventQueue *eq = commitQueue();
    eq->schedule(ev, eq->getCurTick() + delta);
}

and then doing everything else in terms of these two functions would IMO make the rest of the code much more readable.

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Description:

~		Changeset 10570:bd9d8c7d2529
	~	Changeset 10600:c97799857f32

		x86: Implement a remote GDB stub.

		This stub should allow remote debugging of 32 bit and 64 bit targets. Single
		stepping seems to work, as do breakpoints, except it seemed that I got control
		back a little before I expected to in some cases. That should be looked into.

		I tried this stub on a 64 bit kernel. I haven't verified that it works on a 32
		bit kernel, nor have I verified that it works in SE mode.

Diff:

Revision 2 (+263 -27)

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	src/arch/x86/remote_gdb.hh
	src/arch/x86/remote_gdb.cc

Description:

~		Changeset 10600:c97799857f32
	~	Changeset 10600:2f874ecfc989

		x86: Implement a remote GDB stub.

		This stub should allow remote debugging of 32 bit and 64 bit targets. Single
~		stepping seems to work, as do breakpoints, except it seemed that I got control
~		back a little before I expected to in some cases. That should be looked into.
~
	~	stepping seems to work, as do breakpoints. If both breakpoints and single
	~	stepping affect an instruction, gdb will stop at the instruction twice before
	~	continuing. That's a little surprising, but is generally harmless.
-		I tried this stub on a 64 bit kernel. I haven't verified that it works on a 32
-		bit kernel, nor have I verified that it works in SE mode.

Diff:

Revision 3 (+263 -27)

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	src/arch/x86/remote_gdb.hh
	src/arch/x86/remote_gdb.cc

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Issue Summary

Description:

Changeset 10570:bd9d8c7d2529

Changeset 10600:c97799857f32

Diff:

Description:

Changeset 10600:c97799857f32

Changeset 10600:2f874ecfc989

Diff:

Status: Closed (submitted)