From 7d292228c194abde79d7f50ffc7bdd4a47e826bd Mon Sep 17 00:00:00 2001 From: Jiakai Zhang Date: Thu, 18 Jan 2024 17:27:42 +0000 Subject: Determine GC type based on BUILT_KERNEL_VERSION_FILE. How it works: 1. build/make/core/Makefile generates a txt file with the kernel version, which is taken from an explicit BOARD_KERNEL_VERSION value, or extracted from the kernel image on the source tree, or extracted from the kernel image extracted from the prebuilt boot.img. The file is saved at $ANDROID_PRODUCT_OUT/obj/PACKAGING/check_vintf_all_intermediates/kernel_version.txt. 2. If PRODUCT_ENABLE_UFFD_GC is "default", meaning the GC type needs to be determined by the kernel version, build/make/core/Makefile copies kernel_version.txt to out/soong/dexpreopt/kernel_version_for_uffd_gc.txt. 3. build/soong/dexpreopt/config.go writes the the UFFD GC flag to out/soong/dexpreopt/uffd_gc_flag.txt. The flag is determined by an explicit PRODUCT_ENABLE_UFFD_GC value or by contruct_uffd_gc_flag.py, which reads kernel_version_for_uffd_gc.txt and determines the flag accordingly. 4. dex2oat takes the UFFD GC flag from uffd_gc_flag.txt. 5. post_process_props.py mangles ro.dalvik.vm.enable_uffd_gc based on the same logic. Bug: 321751629 Bug: 319554951 Bug: 318763448 Bug: 319648491 Test: m --no-skip-soong-tests nothing Test: atest uffd_gc_utils_test Test: Build with `OVERRIDE_ENABLE_UFFD_GC=default m` for device with no UFFD support - 1. Check the existence of `-Xgc:CMC` in out/soong/dexpreopt_arm64/dex_bootjars/android/system/framework/arm64/boot.invocation (dex2oat invocation for a boot image) 2. Check the existence of `-Xgc:CMC` in out/soong/.intermediates/packages/apps/Settings/Settings/android_common/dexpreopt/Settings/oat/arm64/package.invocation (dex2oat invocation for an app defined in .bp) 3. Check the existence of `-Xgc:CMC` in $ANDROID_PRODUCT_OUT/obj/APPS/Dialer_intermediates/oat/arm64/package.invocation (dex2oat invocation for an app defined in .mk) 4. Check the value of ro.dalvik.vm.enable_uffd_gc in $ANDROID_PRODUCT_OUT/product/etc/build.prop Test: Build with `OVERRIDE_ENABLE_UFFD_GC=default m` for device with UFFD support, and do the steps above. Test: Build with `OVERRIDE_ENABLE_UFFD_GC=true m`, and do the steps above. Test: Build with `OVERRIDE_ENABLE_UFFD_GC=false m`, and do the steps above. Change-Id: I035ad32233e49e2a30ce11f6c7c318a648511ef8 --- scripts/uffd_gc_utils.py | 68 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 scripts/uffd_gc_utils.py (limited to 'scripts/uffd_gc_utils.py') diff --git a/scripts/uffd_gc_utils.py b/scripts/uffd_gc_utils.py new file mode 100644 index 000000000..2d35494dc --- /dev/null +++ b/scripts/uffd_gc_utils.py @@ -0,0 +1,68 @@ +#!/usr/bin/env python +# +# Copyright (C) 2024 The Android Open Source Project +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# +"""Utils to determine whether to enable UFFD GC.""" + +import re +import sys + + +def should_enable_uffd_gc(kernel_version_file): + with open(kernel_version_file, 'r') as f: + kernel_version = f.read().strip() + return should_enable_uffd_gc_impl(kernel_version) + +def should_enable_uffd_gc_impl(kernel_version): + # See https://source.android.com/docs/core/architecture/kernel/gki-versioning#determine-release + p = r"^(?P\d+)[.](?P\d+)[.](?P\d+)(-android(?P\d+)-(?P\d+).*$)?" + m = re.match(p, kernel_version) + if m is not None: + if m.group('z') is not None: + android_release = int(m.group('z')) + # No need to check w, x, y because all Android 12 kernels have backports. + return android_release >= 12 + else: + # Old kernel or non-GKI kernel. + version = int(m.group('w')) + patch_level = int(m.group('x')) + if version < 5: + # Old kernel. + return False + elif (version == 5 and patch_level >= 7) or version >= 6: + # New non-GKI kernel. 5.7 supports MREMAP_DONTUNMAP without the need for + # backports. + return True + else: + # Non-GKI kernel between 5 and 5.6. It may have backports. + raise exit_with_error(kernel_version) + elif kernel_version == '': + # The kernel information isn't available to the build system, probably + # because PRODUCT_OTA_ENFORCE_VINTF_KERNEL_REQUIREMENTS is set to false. We + # assume that the kernel supports UFFD GC because it is the case for most of + # the products today and it is the future. + return True + else: + # Unrecognizable non-GKI kernel. + raise exit_with_error(kernel_version) + +def exit_with_error(kernel_version): + sys.exit(f""" +Unable to determine UFFD GC flag for kernel version "{kernel_version}". +You can fix this by explicitly setting PRODUCT_ENABLE_UFFD_GC to "true" or +"false" based on the kernel version. +1. Set PRODUCT_ENABLE_UFFD_GC to "true" if the kernel supports userfaultfd(2) + and MREMAP_DONTUNMAP. +2. Set PRODUCT_ENABLE_UFFD_GC to "false" otherwise.""") -- cgit v1.2.3-59-g8ed1b