# Copyright (c) 2021 The Regents of the University of California
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"""
This script will run a simple boot exit test.
"""

import m5
from m5.objects import Root

from gem5.runtime import (
    get_runtime_coherence_protocol,
    get_runtime_isa,
)
from gem5.isas import ISA
from gem5.utils.requires import requires
from gem5.resources.resource import Resource
from gem5.coherence_protocol import CoherenceProtocol
from gem5.components.boards.x86_board import X86Board
from gem5.components.processors.cpu_types import CPUTypes
from gem5.components.processors.simple_processor import SimpleProcessor

import argparse
import importlib

parser = argparse.ArgumentParser(
    description="A script to run the gem5 boot test. This test boots the "
    "linux kernel."
)
parser.add_argument(
    "-m",
    "--mem-system",
    type=str,
    choices=("classic", "mi_example", "mesi_two_level"),
    required=True,
    help="The memory system.",
)
parser.add_argument(
    "-n",
    "--num-cpus",
    type=int,
    choices=(1, 2, 4, 8),
    required=True,
    help="The number of CPUs.",
)
parser.add_argument(
    "-c",
    "--cpu",
    type=str,
    choices=("kvm", "atomic", "timing", "o3"),
    required=True,
    help="The CPU type.",
)
parser.add_argument(
    "-d",
    "--dram-class",
    type=str,
    required=True,
    help="The python class for the memory interface to use"
)
parser.add_argument(
    "-b",
    "--boot-type",
    type=str,
    choices=("systemd", "init"),
    required=True,
    help="The boot type.",
)

parser.add_argument(
    "-t",
    "--tick-exit",
    type=int,
    required=False,
    help="The tick to exit the simulation. Note: using this may make the "
    "selected boot-type selection pointless.",
)

parser.add_argument(
    "-r",
    "--resource-directory",
    type=str,
    required=False,
    help="The directory in which resources will be downloaded or exist.",
)

args = parser.parse_args()

coherence_protocol_required = None
if args.mem_system == "mi_example":
    coherence_protocol_required = CoherenceProtocol.MI_EXAMPLE
elif args.mem_system == "mesi_two_level":
    coherence_protocol_required = CoherenceProtocol.MESI_TWO_LEVEL

requires(isa_required=ISA.X86,
         coherence_protocol_required=coherence_protocol_required,
         kvm_required=(args.cpu == "kvm"))

cache_hierarchy = None
if args.mem_system == "mi_example":
    from gem5.components.cachehierarchies.ruby.\
        mi_example_cache_hierarchy import (
        MIExampleCacheHierarchy,
    )

    cache_hierarchy = MIExampleCacheHierarchy(size="32kB", assoc=8)
elif args.mem_system == "mesi_two_level":
    from gem5.components.cachehierarchies.ruby.\
        mesi_two_level_cache_hierarchy import (
        MESITwoLevelCacheHierarchy,
    )

    cache_hierarchy = MESITwoLevelCacheHierarchy(
        l1d_size="16kB",
        l1d_assoc=8,
        l1i_size="16kB",
        l1i_assoc=8,
        l2_size="256kB",
        l2_assoc=16,
        num_l2_banks=1,
    )
elif args.mem_system == "classic":
    from gem5.components.cachehierarchies.classic.\
        private_l1_cache_hierarchy import (
        PrivateL1CacheHierarchy,
    )

    cache_hierarchy = PrivateL1CacheHierarchy(l1d_size="16kB", l1i_size="16kB")
else:
    raise NotImplementedError(
        "Memory system '{}' is not supported in the boot tests.".format(
            args.mem_system
        )
    )

assert cache_hierarchy != None

# Setup the system memory.
# Warning: This must be kept at 3GB for now. X86Motherboard does not support
# anything else right now!
python_module = "gem5.components.memory"
memory_class = getattr(
    importlib.import_module(python_module), args.dram_class
)
memory = memory_class(size="3GiB")

# Setup a Processor.

cpu_type = None
if args.cpu == "kvm":
    cpu_type = CPUTypes.KVM
elif args.cpu == "atomic":
    cpu_type = CPUTypes.ATOMIC
elif args.cpu == "timing":
    cpu_type = CPUTypes.TIMING
elif args.cpu == "o3":
    cpu_type = CPUTypes.O3
else:
    raise NotImplementedError(
        "CPU type '{}' is not supported in the boot tests.".format(args.cpu)
    )

assert cpu_type != None

processor = SimpleProcessor(cpu_type=cpu_type, num_cores=args.num_cpus)

# Setup the motherboard.
motherboard = X86Board(
    clk_freq="3GHz",
    processor=processor,
    memory=memory,
    cache_hierarchy=cache_hierarchy,
)

kernal_args = motherboard.get_default_kernel_args()
if args.boot_type == "init":
    kernal_args.append("init=/root/exit.sh")

# Set the Full System workload.
motherboard.set_kernel_disk_workload(
    kernel=Resource(
        "x86-linux-kernel-5.4.49",
        resource_directory=args.resource_directory,
    ),
    disk_image=Resource(
        "x86-ubuntu-img",
        resource_directory=args.resource_directory,
    ),
    kernel_args=kernal_args,
)


# Begin running of the simulation. This will exit once the Linux system boot
# is complete.
print("Running with ISA: " + get_runtime_isa().name)
print("Running with protocol: " + get_runtime_coherence_protocol().name)
print()

root = Root(full_system=True, system=motherboard)

if args.cpu == "kvm":
    # TODO: This of annoying. Is there a way to fix this to happen
    # automatically when running KVM?
    root.sim_quantum = int(1e9)

m5.instantiate()

print("Beginning simulation!")
if args.tick_exit != None:
    exit_event = m5.simulate(args.tick_exit)
else:
    exit_event = m5.simulate()
print(
    "Exiting @ tick {} because {}.".format(m5.curTick(), exit_event.getCause())
)