UEFI 2.8规格文档:统一可扩展固件接口的最新标准与创新

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UEFI(统一可扩展固件接口)规格是当前操作系统(OS)与平台固件之间的重要交互标准,它继EFI 1.10之后发展而来,但保留了一些EFI的命名传统。UEFI规范以数据表的形式提供平台相关的信息,包括启动和服务调用,这些都对OS加载器和操作系统开放,共同构建一个标准的启动环境。其目标是定义一种只在支持操作系统启动过程时才进行通信的方式,通过一个形式化的、完整的抽象软件接口来呈现平台和固件给OS。 UEFI 2.8 Errata A 版本于2020年2月发布,旨在为从移动系统到服务器的各种硬件平台提供核心服务和一系列协议接口。随着技术的发展,这些接口可以选择性地优化以适应不同的市场细分,同时保持最大程度的可扩展性和定制能力,以便OEM厂商进行差异化。UEFI的主要目的是引导传统的个人计算机(PC-AT)风格的启动世界向无遗留API环境演进,允许随着时间的推移逐步替换过时的设备和固件代码,新的设备类型和相关代码可以通过统一的抽象接口提供功能,而无需修改OS启动支持代码。 该规范作为纯粹的接口规范,不仅定义了平台固件必须实现的接口和结构,还规定了操作系统在启动过程中可以使用的接口和结构。开发者可以根据自身需求决定如何实现这些元素,而不会对其他系统的兼容性造成影响。使用UEFI,OEM厂商能够在保持系统通用性的同时,引入新功能和提升平台性能,这有助于推动整个行业的创新和发展。因此,理解和掌握UEFI规格对于现代硬件和软件开发至关重要。
2020-03-11 上传
This Unified Extensible Firmware Interface (hereafter known as UEFI) Specification describes an interface between the operating system (OS) and the platform firmware. UEFI was preceded by the Extensible Firmware Interface Specification 1.10 (EFI). As a result, some code and certain protocol names retain the EFI designation. Unless otherwise noted, EFI designations in this specification may be assumed to be part of UEFI. The interface is in the form of data tables that contain platform-related information, and boot and runtime service calls that are available to the OS loader and the OS. Together, these provide a standard environment for booting an OS. This specification is designed as a pure interface specification. As such, the specification defines the set of interfaces and structures that platform firmware must implement. Similarly, the specification defines the set of interfaces and structures that the OS may use in booting. How either the firmware developer chooses to implement the required elements or the OS developer chooses to make use of those interfaces and structures is an implementation decision left for the developer. The intent of this specification is to define a way for the OS and platform firmware to communicate only information necessary to support the OS boot process. This is accomplished through a formal and complete abstract specification of the software-visible interface presented to the OS by the platform and firmware. Using this formal definition, a shrink-wrap OS intended to run on platforms compatible with supported processor specifications will be able to boot on a variety of system designs without further platform or OS customization. The definition will also allow for platform innovation to introduce new features and functionality that enhance platform capability without requiring new code to be written in the OS boot sequence. Furthermore, an abstract specification opens a route to replace legacy devices and firmware code over time. New device types and associated code can provide equivalent functionality through the same defined abstract interface, again without impact on the OS boot support code. The specification is applicable to a full range of hardware platforms from mobile systems to servers. The specification provides a core set of services along with a selection of protocol interfaces. The selection of protocol interfaces can evolve over time to be optimized for various platform market segments. At the same time, the specification allows maximum extensibility and customization abilities for OEMs to allow differentiation. In this, the purpose of UEFI is to define an evolutionary path from the traditional “PC-AT”- style boot world into a legacy-API free environment.