sparc: Make remote debugging with gdb work

Information
Submitter:	Palle Lyckegaard
Repository:	gem5
Branch:
Bugs:
Depends On:
Reviewers
Groups:	Default
People:

Description

sparc: Make remote debugging with gdb work
Remove sparc V8 TBR register from list of registers since it is not part of sparc V9. This brings the number of registers in sync with what gdb expects

Testing Done

Without this patch gdb complains about receoved packet too long.

with this patch gdb is able to work properly with gem5 for remote debugging.

Note: gdb is version 7.8
Note: gdb is configured with --target=sparc64-sun-solaris2.8

Ship It!

Boris Shingarov Nov. 9, 2015, 3:54 p.m. (Nov. 9, 2015, 3:54 p.m.)

Wait, wait... in line with the recent discussions of Chesterton's fence, I would very much like to understand how that TBR got there in the first place.  We have a conditinal over the PSTATE.AM flag; the 64-bit branch only makes sense in V9.  How did it ever work?

A more general problem that I see with the remote gdb code is that too much is shared statically between the 64-bit and the 32-bit cases.  For example, the gdb_regs.size is initialized in the constructor to the largest safe value, because at that point in time it's too early to know the value of PSTATE.AM.  I also think that we should have separate RegisterConstants32 and RegisterConstants64.

A similar problem is seen in ARM: GDB_REG_BYTES is taken to avoid overfilling the buffer, but then all the extra empty space is transmitted on the wire causing gdb to complain.

I will provide a patch addressing this within the next day or so.

The technical aspects of this patch look fine. Could you change the commit message to comply with gem5's commit message policy? See http://www.m5sim.org/Submitting_Contributions.

Change Summary:

Updated description to follow the commit message policy

Description:

~		sparc: Make remote debugging with gdb work - remove sparc V8 TBR register from list of registers since it is not part of sparc V9. This brings the number of registers in sync with what gdb expects
	~	sparc: Make remote debugging with gdb work
	+	Remove sparc V8 TBR register from list of registers since it is not part of sparc V9. This brings the number of registers in sync with what gdb expects

Ship It!

You have a pending review.

Review Board 2.0.15

This change has been marked as submitted.

Screenshots

Files

Change Summary:

Description:

Status: Closed (submitted)