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# Copyright (c) Meta Platforms, Inc. and affiliates.
# SPDX-License-Identifier: LGPL-2.1-or-later
from ctypes import c_int, c_int64, c_size_t, c_void_p
import mmap
import unittest
from _drgn_util.platform import NORMALIZED_MACHINE_NAME
from drgn.helpers.linux.boot import pgtable_l5_enabled
from tests.linux_kernel import LinuxKernelTestCase, _c, iter_maps
def first_available_slot(size, min_addr):
for map in iter_maps():
if map.start >= min_addr + size:
break
elif map.end >= min_addr:
min_addr = map.end
return min_addr
def can_mmap_high_address():
mmap_func = _c.mmap
mmap_func.argtypes = [c_void_p, c_size_t, c_int, c_int, c_int, c_int64]
mmap_func.restype = c_void_p
munmap_func = _c.munmap
munmap_func.argtypes = [c_void_p, c_size_t]
hint_addr = first_available_slot(mmap.PAGESIZE, 1 << 48)
ret = mmap_func(
hint_addr,
mmap.PAGESIZE,
mmap.PROT_READ | mmap.PROT_WRITE,
# Ideally we would use MAP_FIXED, but its value is not exposed by the
# mmap module, and it varies by architecture. Having identified a free
# slot in our memory mappings (and hopefully not changing them since
# then), we can be reasonably confident that we should get the address
# we hinted anyway.
mmap.MAP_PRIVATE | mmap.MAP_ANONYMOUS,
-1,
0,
)
if ret != c_void_p(-1).value:
munmap_func(ret, mmap.PAGESIZE)
return ret == hint_addr
class TestBoot(LinuxKernelTestCase):
@unittest.skipUnless(NORMALIZED_MACHINE_NAME == "x86_64", "machine is not x86_64")
def test_pgtable_l5_enabled(self):
self.assertEqual(pgtable_l5_enabled(self.prog), can_mmap_high_address())
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