69 lines
2.6 KiB
Python
69 lines
2.6 KiB
Python
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#!/usr/bin/env python
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#
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# Copyright (C) 2024 The Android Open Source Project
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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"""Utils to determine whether to enable UFFD GC."""
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import re
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import sys
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def should_enable_uffd_gc(kernel_version_file):
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with open(kernel_version_file, 'r') as f:
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kernel_version = f.read().strip()
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return should_enable_uffd_gc_impl(kernel_version)
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def should_enable_uffd_gc_impl(kernel_version):
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# See https://source.android.com/docs/core/architecture/kernel/gki-versioning#determine-release
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p = r"^(?P<w>\d+)[.](?P<x>\d+)[.](?P<y>\d+)(-android(?P<z>\d+)-(?P<k>\d+).*$)?"
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m = re.match(p, kernel_version)
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if m is not None:
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if m.group('z') is not None:
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android_release = int(m.group('z'))
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# No need to check w, x, y because all Android 12 kernels have backports.
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return android_release >= 12
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else:
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# Old kernel or non-GKI kernel.
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version = int(m.group('w'))
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patch_level = int(m.group('x'))
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if version < 5:
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# Old kernel.
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return False
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elif (version == 5 and patch_level >= 7) or version >= 6:
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# New non-GKI kernel. 5.7 supports MREMAP_DONTUNMAP without the need for
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# backports.
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return True
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else:
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# Non-GKI kernel between 5 and 5.6. It may have backports.
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raise exit_with_error(kernel_version)
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elif kernel_version == '<unknown-kernel>':
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# The kernel information isn't available to the build system, probably
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# because PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS is set to false. We
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# assume that the kernel supports UFFD GC because it is the case for most of
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# the products today and it is the future.
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return True
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else:
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# Unrecognizable non-GKI kernel.
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raise exit_with_error(kernel_version)
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def exit_with_error(kernel_version):
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sys.exit(f"""
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Unable to determine UFFD GC flag for kernel version "{kernel_version}".
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You can fix this by explicitly setting PRODUCT_ENABLE_UFFD_GC to "true" or
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"false" based on the kernel version.
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1. Set PRODUCT_ENABLE_UFFD_GC to "true" if the kernel supports userfaultfd(2)
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and MREMAP_DONTUNMAP.
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2. Set PRODUCT_ENABLE_UFFD_GC to "false" otherwise.""")
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