arch, base, cpu, dev, mem, sim: Remove #if 0-ed out code.

This code will be preserved through version control, but otherwise
creates clutter and will rot in place since it's never compiled.

Change-Id: Id265f6deac445116843956ea5cf1210d8127274e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18608
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch, cpu, dev, gpu, mem, sim, python: start using getPort.

Replace the getMasterPort, getSlavePort, and getEthPort functions
with getPort, and remove extraneous mechanisms that are no longer
necessary.

Change-Id: Iab7e3c02d2f3a0cf33e7e824e18c28646b5bc318
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17040
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

dev: Explicitly specify the endianness for packet accessors.

Generally speaking, the endianness of the data devices provide or
accept is dependent on the device and not the ISA the system
executes. This change makes the devices in dev pick an endianness
rather than using the guest's.

For the ISA bus and the UART, accesses are byte sized and so endianness
doesn't matter. The ISA and PCI busses and the devices which use them
are defined to be little endian.

Change-Id: Ib0aa70f192e1d6f3b886d9f3ad41ae03bddb583f
Reviewed-on: https://gem5-review.googlesource.com/c/13462
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

dev: Replace EventWrapper use with EventFunctionWrapper

Change-Id: I6b03cc6f67e76dffb79940431711ae6171901c6a
Signed-off-by: Sean Wilson <spwilson2@wisc.edu>
Reviewed-on: https://gem5-review.googlesource.com/3748
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

dev: Fix buffer length when unserializing an eth pkt

Changeset 11701 only serialized the useful portion of of an ethernet packets'
payload. However, the device models expect each ethernet packet to contain
a 16KB buffer, even if there is no data in it. This patch adds a 'bufLength'
field to EthPacketData so the original size of the packet buffer can always
be unserialized.

Reported-by: Gabor Dozsa <Gabor.Dozsa@arm.com>

dev: Add 'simLength' parameter in EthPacketData
Currently, all the network devices create a 16K buffer for the 'data' field
in EthPacketData, and use 'length' to keep track of the size of the packet
in the buffer. This patch introduces the 'simLength' parameter to
EthPacketData, which is used to hold the effective length of the packet used
for all timing calulations in the simulator. Serialization is performed using
only the useful data in the packet ('length') and not necessarily the entire
original buffer.

sim: don't ignore SIG_TRAP

By ignoring SIG_TRAP, using --debug-break <N> when not connected to
a debugger becomes a no-op. Apparently this was intended to be a
feature, though the rationale is not clear.

If we don't ignore SIG_TRAP, then using --debug-break <N> when not
connected to a debugger causes the simulation process to terminate
at tick N. This is occasionally useful, e.g., if you just want to
collect a trace for a specific window of execution then you can combine
this with --debug-start to do exactly that.

In addition to not ignoring the signal, this patch also updates
the --debug-break help message and deletes a handful of unprotected
calls to Debug::breakpoint() that relied on the prior behavior.

dev: Move network devices to src/dev/net/