On Wed, 14 Dec 2011 22:24:37 -0000, "Ali Saidi" <[email protected]>
wrote:
On 2011-12-13 13:35:40, Geoffrey Blake wrote:
> Cleaned up the code in base_dyn_inst.hh to use templates. Cleaned
up the code in arch/arm/isa.cc to get the ITB/DTB pointers from the
CheckerCPU object.
>
> I have implemented a solution for functional accesses that go to
the IOBus by adding a "reflect_functional_access" parameter to
isa_fake.cc. This parameter allows accesses to pass through if they
are detected to be functional via checking if the Packet object can be
safely cast to a FunctionalPacket object to identify just functional
accesses. I then added this io_device with the reflect param set to
the IOBus as a default responder for the ARM setup in
configs/common/FSConfig.py. Not sure if this is what is ultimately
desired, but it fixes the problem with the Checker's functional
accesses without the hack in the bus.cc code. I looked at using the
default_range variable as Steve suggested, but saw in bus.cc line 359
that the code would panic if the access did not fit in the default
range. Also would like some suggestions as to how to warn on
detecting no default responder attached to the IOBus (any bus), should
it be in the Python or C++ code?
This solution doesn't work if you've got a PCI config space device
attached as the default responder for a certain range on the I/O bus.
In this case you'll hit the panic that Geoff described.
Every solution i've come up with seems to fail however, e.g.:
You could say if a cache is top_level then don't forward it on, but
this would prevent snooping into an lsq or something similar.
The best I can come up with is that you want to change findPort() to
say if this is a request based on a recvFunctional() then return a
NO_PORT if a destination isn't found rather than panicing and if
NO_PORT is returned then don't call port->sendFunctional() and just
do
the snoop.
thoughts?
bump.
Ali
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