# Boot loader

Source: [https://docs.qualcomm.com/doc/80-70014-4Y/topic/bootloader.html](https://docs.qualcomm.com/doc/80-70014-4Y/topic/bootloader.html)

Boot loader 是在系统通电时运行的软件。可用作加载操作系统和其他所需应用程序的接口。

作为启动过程的一部分，Qualcomm Linux 系统包括 boot loader 的几个不同阶段：
![](data:image/png;base64,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)

## Primary boot loader (PBL)

- 为应用程序建立安全的信任根 (RoT) 和安全启动过程。
    有关详细信息，请参阅[安全启动](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-11/secure-boot.html)。
- 识别主存储设备并加载称为 eXtensible boot loader (XBL) 的二级 boot loader。
    在加载 XBL 镜像期间，任何可恢复的错误都会导致 PBL 进入紧急下载 (EDL) 模式。有关如何检测 EDL 模式的详细信息，请参阅 [EDL 设备管理器枚举](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-4/edl-device-manager-enumeration.html)。
- 将 XBL 段加载到启动内部存储器中。
    有关 PBL 如何加载 XBL 段的详细信息，请参阅[冷启动架构](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-4/bootloader-architecture.html)。

## eXtensible Boot Loader (XBL)

- 初始化内存子系统，包括总线、低功耗双数据速率 (LPDDR)、时钟和配置数据表 (CDT)。
- 将 RAM dump设置为 SD 卡、USB 驱动程序、USB 充电、thermal 检查、电源管理集成电路 ([PMIC](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-4/pmic-developer-touchpoints.html)) 和双数据速率 (DDR) 功能。
- 加载并验证 Qualcomm^®^ 受信任执行环境 (Qualcomm TEE)、Qualcomm Hypervisor 和 UEFI 镜像。
- 提供 XBL 配置 (XBL\_CFG)，这是冷启动流程的一个组件，包括 PMIC 和其他驱动程序设置。
- 为 XBL 提供 Qualcomm 签名的 ELF 段，以保证外部保护单元 (xPU) 的安全。
    XBL\_CFG 是一个独立的二进制文件，包含平台特定的配置和设置。XBL 使用 XBL\_CFG 驱动程序来加载和配置所需的设置。

    驱动程序使用二进制文件提供对 XBL\_CFG 的每个配置的读取权限。
- 如果发生崩溃，则使用以下方式抓取RAM dump：
    - UFS (闪存)
    - USB (无闪存)

## 统一可扩展固件接口 (UEFI)

UEFI 定义了 Linux 操作系统 (OS) 和平台固件之间的软件接口。

该接口由包含平台相关信息的数据表以及可用于 Linux 和 boot loader 的启动和运行时服务调用组成。它们共同为启动 Linux 操作系统和运行预启动应用程序提供了标准环境。

目前有 Qualcomm Linux 专有软件完全访问权限的用户可以使用 UEFI 应用程序开发和 UEFI 菜单。有关详细信息，请参阅 [Boot loader in Qualcomm Linux Boot Guide - Addendum](https://docs.qualcomm.com/bundle/resource/topics/80-70014-4A/bootloader.html)。

## systemd-boot 操作系统管理器

systemd-boot 是运行配置的可扩展固件接口 (EFI) 镜像的操作系统管理器。旨在专门支持具有 UEFI 固件的系统，并执行以下操作：

- 从 EFI 系统分区 (ESP) 加载启动项信息，通常在 Linux 操作系统运行时挂载在 /efi/、/boot/ 或 /boot/efi/，如果存在，则从扩展的 Boot Loader 分区 (XBOOTLDR) 进行加载（挂载在 /boot/）。
    配置文件段、内核、初始 RAM 磁盘 (initrd) 和其他 EFI 镜像必须位于 ESP 或 XBOOTLDR 中。
- 读取简单且完全通用的 boot loader 配置文件；为每个 boot loader 条目选择一个文件。所有文件必须位于 ESP 中。

为确保 Linux 内核可作为 EFI 镜像直接执行，应使用 `CONFIG_EFI_STUB` 编译内核。

有关 EFI 的详细信息，请参阅以下内容：

- 有关 EFI 启动存根，请参见 [https://docs.kernel.org/admin-guide/efi-stub.html](https://docs.kernel.org/admin-guide/efi-stub.html)。
- 有关 EFI 分区的示例结构，请参阅 [Qualcomm Linux Yocto 指南的 Systemd-boot](https://docs.qualcomm.com/bundle/publicresource/topics/80-70014-27/platform_software_features.html#sub$systemd_boot)。

**Parent Topic:** [架构](https://docs.qualcomm.com/doc/80-70014-4Y/topic/architecture.html)

Last Published: Feb 03, 2026

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