[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["缺少我需要的資訊","missingTheInformationINeed","thumb-down"],["過於複雜/步驟過多","tooComplicatedTooManySteps","thumb-down"],["過時","outOfDate","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["示例/程式碼問題","samplesCodeIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-07-27 (世界標準時間)。"],[],[],null,["# Kernel overview\n\nThe Android kernel is based on an upstream\n[Linux Long Term Supported (LTS) kernel](https://www.kernel.org/category/lts). At Google, LTS kernels are combined\nwith Android-specific patches to form *Android Common Kernels (ACKs)*.\n\nACKs are built from the [kernel/common](https://android.googlesource.com/kernel/common) repository. This repository is a\nsuperset of the upstream Linux kernel, with additional Android-specific patches.\n\nACKs that are 5.10 and higher are also known as \\*generic kernel images (GKI)\nkernels. GKI kernels support the separation of the hardware-agnostic *generic\ncore kernel* code and [GKI modules](/docs/core/architecture/kernel/modules#gki-modules) from hardware-specific\n[vendor modules](/docs/core/architecture/kernel/modules#vendor-modules).\n\nThe interaction between the GKI kernel and vendor modules is enabled by the\n*Kernel Module Interface (KMI)* consisting of symbol lists identifying the\nfunctions and global data required by vendor modules. Figure 1 shows the GKI\nkernel and vendor module architecture:\n\n**Figure 1.** GKI kernel and vendor module architecture.\n| **Note:** The GKI kernel, GKI module, and vendor module architecture is the result of a multi-year effort known as the Generic Kernel Image (GKI) project. For information about this project and its phases, refer to [The Generic Kernel Image (GKI) project](/docs/core/architecture/kernel/generic-kernel-image).\n| **Note:** Kernels are referred to by their platform version followed by a kernel version. For example, `android15-6.6` is kernel for Android 15 with a version of `6.6`.\n\nKernel glossary\n---------------\n\nFollowing are terms used throughout the kernel documentation.\n\n### Kernel types\n\n*Android Common Kernel (ACK)*\n: A kernel that is downstream of a LTS kernel and includes patches that are\n important to the Android community. These patches haven't been merged into\n Linux mainline or Long Term GKI kernels.\n\nKernel with versions of 5.10 and higher are also referred to as\n[Generic Kernel Image (GKI)](#gkik) kernels.\n\n*Android Open Source Project (AOSP) kernel*\n: See [Android Common Kernel](#ack).\n\nAndroid 12 features can't be backported to 4.19 kernels; the feature set would\nbe similar to a device that launched with 4.19 on Android 11 and upgraded to\nAndroid 12.\n\n*Generic Kernel Image (GKI) kernel*\n\n: Any 5.10 and higher [ACK kernel](#ack)(aarch64 only). The GKI kernel has these\n two parts:\n\n - *Generic kernel* - The portion of the GKI kernel that is common across\n all devices.\n\n - *GKI modules* - Kernel modules built by Google that can be dynamically\n loaded on devices where applicable. These modules are built as artifacts\n of the GKI kernel and are delivered alongside GKI as the\n `system_dlkm_staging_archive.tar.gz` archive. GKI modules are signed by\n Google using the kernel build time key pair and are compatible only with the\n GKI kernel that they're built with.\n\n*Kernel Module Interface (KMI) kernel*\n\n: See [GKI kernel](#gkik).\n\n*Long Term Supported (LTS) kernel*\n\n: A Linux kernel that's supported for 2 to 6 years. [LTS kernels](https://www.kernel.org/category/lts) are\n released once per year and are the basis for each of Google's\n [Android Common Kernels](#ack).\n\n### Branch types\n\n*ACK KMI kernel branch*\n: The branch for which [GKI kernels](#gkik) are built. Branch names correspond\n to kernel versions, such as `android15-6.6`.\n\n*Android-mainline*\n: The primary development branch for Android features. When a new\n [LTS kernel](#lts) is declared upstream, the corresponding new\n [GKI kernel](#gkik)GKI kernel is branched from android-mainline.\n\n*Linux mainline*\n:The primary development branch for the upstream Linux kernels, including LTS\nkernels.\n\n### Other terms\n\n*Certified boot image*\n: The kernel delivered in binary form (`boot.img`) and flashed onto the device.\n This image is considered certified because contains embedded certificates so\n Google can verify that the device ships with a kernel certified by Google.\n\n*Dynamically loadable kernel module (DLKM)*\n: A module that can be dynamically loaded during device boot depending on the\n needs of the device. GKI and vendor modules are both types of DLKMs. DLKMs are\n released in `.ko` form and can be drivers or can deliver other kernel\n functionality.\n\n*GKI project*\n: A Google project addressing kernel fragmentation by separating common core\n kernel functionality from vendor-specific SoC and board support into loadable\n modules.\n\n*Generic Kernel Image (GKI)*\n:A boot image certified by Google that contains a [GKI kernel](#gkik) built from\nan [ACK](#ack) source tree and is suitable to be flashed to the boot partition\nof an Android-powered device.\n\n*Kernel Module Interface (KMI)*\n: An interface between the [GKI kernel](#gkik) and vendor modules allowing\n vendor modules to be updated independently of the GKI kernel. This interface\n consists of kernel functions and global data that have been identified as\n vendor/OEM dependencies using per-partner symbol lists.\n\n*Vendor module*\n: A hardware-specific module developed by a partner and that contains SoC and\n device-specific functionality. A vendor module is a type of dynamically loadable\n kernel module.\n\nWhat's next\n-----------\n\nIf you're new to Android kernel development, start by reading the\nfollowing:\n\n- [Long Term Stable Kernels](/docs/core/architecture/kernel/releases) - Background on upstream LTS kernels which feed into ACKs.\n- [Android Common Kernels](/docs/core/architecture/kernel/android-common) - Background on ACKs.\n\nIf you're new to GKI kernel development, start by reading\n[GKI development](/docs/core/architecture/kernel/gki-dev)."]]
