# Copyright (c) 2019 ARM Limited
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# Copyright (c) 2015 Advanced Micro Devices, Inc.
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import m5
from m5.objects import *
from m5.util.convert import *

from functools import reduce
import operator, os, platform, getpass
from os import mkdir, makedirs, getpid, listdir, stat, access
from pwd import getpwuid
from os.path import join as joinpath
from os.path import isdir
from shutil import rmtree, copyfile

def hex_mask(terms):
    dec_mask = reduce(operator.or_, [2**i for i in terms], 0)
    return "%08x" % dec_mask

def file_append(path, contents):
    with open(joinpath(*path), 'a') as f:
        f.write(str(contents))

def replace_tree(path):
    if isdir(path):
        rmtree(path)
    mkdir(path)

def config_filesystem(system, options = None):
    """ This function parses the system object to create the pseudo file system
    @param system: The system to create the config for
    @param options: An optional argument which contains an Options.py options
           object. This is useful if when use se.py and will set the L2 cache
           size and the clock in /proc/cpuinfo if provided.

    First, this function walks the system object to find all CPUs.
    Then, this function creates the following files with the CPU information
      - /proc/cpuinfo which contains the clock  and the L2 size
        (assumes all L2s private and the same size)
      - /proc/stat simply lists all CPUs
      - /sys/devices/system/cpu/online and /sys/devices/system/cpu/possible
        These files list all of the CPUs in this system.
      - /tmp

    These files are created in the `fs` directory in the outdir path.
    """
    fsdir = joinpath(m5.options.outdir, 'fs')
    replace_tree(fsdir)

    # Set up /proc
    procdir = joinpath(fsdir, 'proc')
    mkdir(procdir)

    try:
        cpus = \
            [obj for obj in system.descendants() if isinstance(obj, BaseCPU)]
    except NameError:
        # BaseCPU is not defined for the NULL ISA
        cpus = []

    cpu_clock = 0
    if hasattr(options, 'cpu_clock'):
        cpu_clock = toFrequency(options.cpu_clock) / mega

    l2_size = 0
    if hasattr(options, 'l2_size'):
        l2_size = toMemorySize(options.l2_size) / kibi

    for i,cpu in enumerate(cpus):
        one_cpu = 'processor       : {proc}\n'                    + \
                  'vendor_id       : Generic\n'                   + \
                  'cpu family      : 0\n'                         + \
                  'model           : 0\n'                         + \
                  'model name      : Generic\n'                   + \
                  'stepping        : 0\n'                         + \
                  'cpu MHz         : {clock:0.3f}\n'              + \
                  'cache size:     : {l2_size}K\n'                + \
                  'physical id     : 0\n'                         + \
                  'siblings        : {num_cpus}\n'                + \
                  'core id         : {proc}\n'                    + \
                  'cpu cores       : {num_cpus}\n'                + \
                  'fpu             : yes\n'                       + \
                  'fpu exception   : yes\n'                       + \
                  'cpuid level     : 1\n'                         + \
                  'wp              : yes\n'                       + \
                  'flags           : fpu\n'                       + \
                  'cache alignment : {cacheline_size}\n'          + \
                  '\n'
        one_cpu = one_cpu.format(proc = i, num_cpus = len(cpus),
                       # Note: it would be nice to use cpu.clock, but it hasn't
                       # been finalized yet since m5.instantiate() isn't done.
                       clock = cpu_clock,
                       # Note: this assumes the L2 is private to each core
                       l2_size = l2_size,
                       cacheline_size=system.cache_line_size.getValue())
        file_append((procdir, 'cpuinfo'), one_cpu)

    file_append((procdir, 'stat'), 'cpu 0 0 0 0 0 0 0\n')
    for i in range(len(cpus)):
        file_append((procdir, 'stat'), 'cpu%d 0 0 0 0 0 0 0\n' % i)

    # Set up /sys
    sysdir = joinpath(fsdir, 'sys')
    mkdir(sysdir)

    # Set up /sys/devices/system/cpu
    cpudir = joinpath(sysdir, 'devices', 'system', 'cpu')
    makedirs(cpudir)

    file_append((cpudir, 'online'), '0-%d' % (len(cpus) - 1))
    file_append((cpudir, 'possible'), '0-%d' % (len(cpus) - 1))

    # Set up /tmp
    tmpdir = joinpath(fsdir, 'tmp')
    replace_tree(tmpdir)

    system.redirect_paths = _redirect_paths(options)

    # Setting the interpreter path. This is used to load the
    # guest dynamic linker itself from the elf file.
    interp = getattr(options, 'interp_dir', None)
    if interp:
        from m5.core import setInterpDir
        setInterpDir(interp)

        print("Setting the interpreter path to:", interp,
              "\nFor dynamically linked applications you might still "
              "need to setup the --redirects so that libraries are "
              "found\n")

def register_node(cpu_list, mem, node_number):
    nodebasedir = joinpath(m5.options.outdir, 'fs', 'sys', 'devices',
                           'system', 'node')

    nodedir = joinpath(nodebasedir,'node%d' % node_number)
    makedirs(nodedir)

    file_append((nodedir, 'cpumap'), hex_mask(cpu_list))
    file_append((nodedir, 'meminfo'),
                'Node %d MemTotal: %dkB' % (node_number,
                toMemorySize(str(mem))/kibi))

def register_cpu(physical_package_id, core_siblings,
                 core_id, thread_siblings):
    cpudir = joinpath(m5.options.outdir, 'fs',  'sys', 'devices', 'system',
                      'cpu', 'cpu%d' % core_id)

    if not isdir(joinpath(cpudir, 'topology')):
        makedirs(joinpath(cpudir, 'topology'))
    if not isdir(joinpath(cpudir, 'cache')):
        makedirs(joinpath(cpudir, 'cache'))

    file_append((cpudir, 'online'), '1')
    file_append((cpudir, 'topology', 'physical_package_id'),
                physical_package_id)
    file_append((cpudir, 'topology', 'core_siblings'),
                hex_mask(core_siblings))
    file_append((cpudir, 'topology', 'core_id'), core_id)
    file_append((cpudir, 'topology', 'thread_siblings'),
                hex_mask(thread_siblings))

def register_cache(level, idu_type, size, line_size, assoc, cpus):
    fsdir = joinpath(m5.options.outdir, 'fs')
    for i in cpus:
        cachedir = joinpath(fsdir, 'sys', 'devices', 'system', 'cpu',
                            'cpu%d' % i, 'cache')

        j = 0
        while isdir(joinpath(cachedir, 'index%d' % j)):
            j += 1
        indexdir = joinpath(cachedir, 'index%d' % j)
        makedirs(indexdir)

        file_append((indexdir, 'level'), level)
        file_append((indexdir, 'type'), idu_type)
        file_append((indexdir, 'size'), "%dK" % (toMemorySize(size)/kibi))
        file_append((indexdir, 'coherency_line_size'), line_size)

        # Since cache size = number of indices * associativity * block size
        num_sets = toMemorySize(size) / int(assoc) * int(line_size)

        file_append((indexdir, 'number_of_sets'), num_sets)
        file_append((indexdir, 'physical_line_partition'), '1')
        file_append((indexdir, 'shared_cpu_map'), hex_mask(cpus))
        file_append((indexdir, 'shared_cpu_list'),
                    ','.join(str(cpu) for cpu in cpus))

def _redirect_paths(options):
    # Redirect filesystem syscalls from src to the first matching dests
    redirect_paths = [RedirectPath(app_path = "/proc",
                          host_paths = ["%s/fs/proc" % m5.options.outdir]),
                      RedirectPath(app_path = "/sys",
                          host_paths = ["%s/fs/sys"  % m5.options.outdir]),
                      RedirectPath(app_path = "/tmp",
                          host_paths = ["%s/fs/tmp"  % m5.options.outdir])]

    # Setting the redirect paths so that the guest dynamic linker
    # can point to the proper /lib collection (e.g. to load libc)
    redirects = getattr(options, 'redirects', [])
    for redirect in redirects:
        app_path, host_path = redirect.split("=")
        redirect_paths.append(
            RedirectPath(app_path = app_path, host_paths = [ host_path ]))

    chroot = getattr(options, 'chroot', None)
    if chroot:
        redirect_paths.append(
            RedirectPath(
                app_path = "/",
                host_paths = ["%s" % os.path.expanduser(chroot)]))

    return redirect_paths