Translations:Handbook:MIPS/Installation/Kernel/2/zh-cn
可选：安装固件和微代码
固件
Suggested: Linux Firmware
On many systems, non-FOSS firmware is required for certain hardware to function. The sys-kernel/linux-firmware package contains firmware for many, but not all, devices.
Most wireless cards and GPUs require firmware to function.
root #emerge --ask sys-kernel/linux-firmware安装某些固件软件包时，经常需要接受固件关联的许可证。有需要的话，访问手册的许可证处理章节有助于你接受许可证。
Firmware Loading
Firmware files are typically loaded when the associated kernel module is loaded. This means the firmware must be built into the kernel using CONFIG_EXTRA_FIRMWARE if the kernel module is set to Y instead of M. In most cases, building-in a module which required firmware can complicate or break loading.
Architecture specific firmware
Placeholder for architecture-specific firmware information
{{#switch: | amd64 | x86 =
微码
除了独立显卡硬件和网络接口之外，CPU 可能也需要固件更新。通常这种固件被称为微码（microcode）。有时需要更新版本的微码来修补 CPU 硬件中的不稳定性、安全问题或其他复杂的错误。
AMD CPU 的微码更新在前面提到的 sys-kernel/linux-firmware 软件包内分发。Intel CPU 的微码可以在 sys-firmware/intel-microcode 包中找到，并且需要单独安装。更多有关如何更新微码的细节，请查看微码文章。
sys-kernel/installkernel
Installkernel may be used to automate the kernel installation, initramfs generation, unified kernel image generation and/or bootloader configuration among other things. sys-kernel/installkernel implements two paths of achieving this: the traditional installkernel originating from Debian and systemd's kernel-install. Which one to choose depends, among other things, on the system's bootloader. By default, systemd's kernel-install is used on systemd profiles, while the traditional installkernel is the default for other profiles.
Bootloader
Now is the time to think about which bootloader the user wants for the system, if unsure, follow the 'Traditional layout' subsection below.
GRUB
Users of GRUB can use either systemd's kernel-install or the traditional Debian installkernel. The systemd USE flag switches between these implementations. To automatically run grub-mkconfig when installing the kernel, enable the grub USE flag.
/etc/portage/package.use/installkernelsys-kernel/installkernel grub
root #emerge --ask sys-kernel/installkernelTraditional layout, other bootloaders (e.g. (e)lilo, syslinux, etc.)
The traditional /boot layout (for e.g. (e)LILO, syslinux, etc.) is used by default if the grub, systemd-boot, efistub and uki USE flags are not enabled. No further action is required.
Initramfs
An initial ram-based file system, or initramfs, may be required for a system to boot. A wide of variety of cases may necessitate one, but common cases include:
- Kernels where storage/filesystem drivers are modules.
- Layouts with /usr/ or /var/ on separate partitions.
- Encrypted root filesystems.
Distribution kernels are designed to be used with an initramfs, as many storage and filesystem drivers are built as modules.
In addition to mounting the root filesystem, an initramfs may also perform other tasks such as:
- Running file system consistency check fsck, a tool to check and repair consistency of a file system in such events of uncleanly shutdown a system.
- Providing a recovery environment in the event of late-boot failures.
Installkernel can automatically generate an initramfs when installing the kernel if the dracut or ugrd USE flag is enabled:
/etc/portage/package.use/installkernelsys-kernel/installkernel dracut
root #emerge --ask sys-kernel/installkernel内核配置和编译
It can be a wise move to use the dist-kernel on the first boot as it provides a very simple method to rule out system issues and kernel config issues. Always having a known working kernel to fallback on can speed up debugging and alleviate anxiety when updating that your system will no longer boot.
现在是时候来配置和编译内核源代码了。将介绍三种用内核管理安装的方法，但是安装后，任何时候都可以采用新的方法。
During the installation phase of Gentoo, only one kernel type should be installed i.e. either the sys-kernel/gentoo-kernel-bin or sys-kernel/gentoo-sources.
由操作最少到操作最多排序：
- 全自动方法：Distribution 内核
- Distribution 内核用来配置、自动构建安装 Linux 内核、相关模块和 initramfs 文件（可选，但是默认启用）。将来内核就像其他的系统软件包一样，通过使用包管理器全自动升级。如果需要定制内核，它可以提供自定义内核配置文件。这种过程操作最少，并且非常适合新 Gentoo 用户，因为它开箱即用，并且系统管理员最少参与。
- 混合方法：Genkernel
- 通过系统包管理器安装新内核源代码。系统管理员可以使用 Gentoo 的 genkernel 工具的配置，构建和安装 Linux 内核、相关模块和 initramfs 文件（可选，但默认不 启用）。如果要自定义内核，它可以提供自定义内核配置文件。将来每次更新内核配置、编译和安装都需要系统管理员运行 eselect kernel，genkernel和其他可能的命令。
- 全手动方法
- 通过系统包管理器安装新的内核源代码。使用 eselect kernel 和一大堆 make 命令手动配置、构建和安装内核。将来内核升级需要重复手动配置、构建和安装内核文件的过程。这是操作做多的过程，但是在内核更新过程提供最大程度控制。
Linux内核是所有发行版的核心。它位于用户程序和系统硬件之间。尽管手册提供给用户一些可选的内核源码，但是在内核概述页面有更全面的列表，上面有着更多的细节描述。
Kernel installation tasks such as copying the kernel image to /boot or the EFI System Partition, generating an initramfs and/or Unified Kernel Image, updating bootloader configuration, can be automated with installkernel. Users may wish to configure and install sys-kernel/installkernel before proceeding. See the Kernel installation section below for more more information.
安装内核源码
当为基于 的系统安装和编译内核时，Gentoo 推荐使用 sys-kernel/ 软件包。
选择一个合适的内核并使用 emerge 来安装它。
root #emerge --ask sys-kernel/这将在 /usr/src/ 中安装路径中特定版本的 Linux 内核源码。如果没有在所选内核源码包内启用 USE=symlink，它将不会自行创建符号链接。
我们习惯性的维护 /usr/src/linux 符号链接。这样，它指向与当前运行的内核相对应的源代码。然而，默认情况下不会创建这个符号链接。有一个简单创建符号链接的方法是利用 eselect 的内核模块。
更多有关符号链接的信息以及如何管理符号链接，请参考升级内核。
首先，列出所有已安装的内核：
root #eselect kernel listAvailable kernel symlink targets: [1] linux-
要创建一个名为 linux 的符号链接，使用：
root #eselect kernel set 1root #ls -l /usr/src/linuxlrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -> linux-
可选：手动配置
In case it was missed, this section requires the kernel sources to be installed. Be sure to obtain the relevant kernel sources, then return here for the rest of section.
Manually configuring a kernel is commonly seen as one of the most difficult procedures a system administrator has to perform. Nothing is less true - after configuring a few kernels no one remembers that it was difficult! There are two ways for a Gentoo user to manage a manual kernel system, both of which are listed below:
Modprobed-db process
A very easy way to manage the kernel is to first install sys-kernel/gentoo-kernel-bin and use the sys-kernel/modprobed-db to collect information about what the system requires. modprobed-db is a tool which monitors the system via crontab to add all modules of all devices over the system's life to make sure it everything a user needs is supported. For example, if an Xbox controller is added after installation, then modprobed-db will add the modules to be built next time the kernel is rebuilt. More on this topic can be found in the Modprobed-db article.
Manual process
This method allows a user to have full control of how their kernel is built with as minimal help from outside tools as they wish. Some could consider this as making it hard for the sake of it.
无论如何，有一件事是真实的：当手动配置内核时，了解（硬件）系统是至关重要的。大多数信息可以通过安装包含lspci命令的sys-apps/pciutils来收集：
root #emerge --ask sys-apps/pciutils在chroot中，可以安全的忽略任何lspci可能抛出的关于pcilib的警告（比如pcilib: cannot open /sys/bus/pci/devices）。
另一个系统信息来源是运行lsmod来查看安装CD使用什么内核模块，它可能对启用什么提供了一个好的暗示。
现在进入内核源码目录并执行make menuconfig。这将启动一个菜单驱动的配置屏幕。
root #cd /usr/src/linux
root #make menuconfig
The kernel has a method of autodetecting the modules currently being used on the installcd which will give a great starting point to allow a user to configure their own. This can be called by using:
root #make localmodconfigIt's now time to configure using nconfig:
root #make nconfigLinux 内核配置有很多很多的章节。我们先列出一些必须激活的选项（否则 Gentoo 将无法工作，或者离开附加的调整将无法正常工作）。我们同时在 Gentoo 维基上有一个 Gentoo 内核配置指南可能会在将来有帮助。
Enabling required options
当使用 sys-kernel/gentoo-sources 时，强烈推荐启用 Gentoo 特有的配置选项。这些确保了系统可以正常运行所需的最少内核特性：
Gentoo Linux --->
Generic Driver Options --->
[*] Gentoo Linux support
[*] Linux dynamic and persistent device naming (userspace devfs) support
[*] Select options required by Portage features
Support for init systems, system and service managers --->
[*] OpenRC, runit and other script based systems and managers
[*] systemd
当然，最后两行的选择取决于所选择的 init 系统 (OpenRC 对比 systemd)。但是两种 init 系统都启用也并没有害处。
当使用 sys-kernel/vanilla-sources时，不能使用额外的 init 系统。可以使用已启用的 init 系统，但这超出了手册的范围。
Enabling support for typical system components
确保引导系统的每一个至关重要的驱动（比如 SATA 控制器，NVMe 块设备支持，文件系统支持，等等）是编译进内核而不是作为一个模块，否则系统将无法完全引导。
接下来选择最正确的CPU类型。同时建议启用MCE功能（如果可用）能在硬件出现问题时通知用户。在一些架构（比如x86_64），这些错误不会打印到 dmesg，但是会到/dev/mcelog。这需要app-admin/mcelog包。
同时选择Maintain a devtmpfs file system to mount at /dev来让重要的设备文件在引导过程的早期就已就绪(CONFIG_DEVTMPFS and CONFIG_DEVTMPFS_MOUNT):
Device Drivers --->
Generic Driver Options --->
[*] Maintain a devtmpfs filesystem to mount at /dev
[*] Automount devtmpfs at /dev, after the kernel mounted the rootfs
验证 SCSI 磁盘支持是否已激活(CONFIG_BLK_DEV_SD):
Device Drivers --->
SCSI device support --->
<*> SCSI device support
<*> SCSI disk support
Device Drivers --->
<*> Serial ATA and Parallel ATA drivers (libata) --->
[*] ATA ACPI Support
[*] SATA Port Multiplier support
<*> AHCI SATA support (ahci)
[*] ATA BMDMA support
[*] ATA SFF support (for legacy IDE and PATA)
<*> Intel ESB, ICH, PIIX3, PIIX4 PATA/SATA support (ata_piix)
验证已经启用基础 NVMe 支持：
Device Drivers --->
<*> NVM Express block device
Device Drivers --->
NVME Support --->
<*> NVM Express block device
也可以启用下列额外的 NVMe 支持：
[*] NVMe multipath support
[*] NVMe hardware monitoring
<M> NVM Express over Fabrics FC host driver
<M> NVM Express over Fabrics TCP host driver
<M> NVMe Target support
[*] NVMe Target Passthrough support
<M> NVMe loopback device support
<M> NVMe over Fabrics FC target driver
< > NVMe over Fabrics FC Transport Loopback Test driver (NEW)
<M> NVMe over Fabrics TCP target support
现在进入File Systems并选择系统将使用的文件系统。不要作为模块来编译根文件系统所使用的文件系统，否则系统可能不挂载这个分区。同时选择Virtual memory和/proc file system根据系统的需要选择一个或多个以下选项：
File systems --->
<*> Second extended fs support
<*> The Extended 3 (ext3) filesystem
<*> The Extended 4 (ext4) filesystem
<*> Btrfs filesystem support
<*> XFS filesystem support
DOS/FAT/NT Filesystems --->
<*> MSDOS fs support
<*> VFAT (Windows-95) fs support
Pseudo Filesystems --->
[*] /proc file system support
[*] Tmpfs virtual memory file system support (former shm fs)
如果使用PPPoE连接到互联网，或者是拨号调制解调器，则启用下面的选项(CONFIG_PPP, CONFIG_PPP_ASYNC, and CONFIG_PPP_SYNC_TTY)：
Device Drivers --->
Network device support --->
<*> PPP (point-to-point protocol) support
<*> PPP support for async serial ports
<*> PPP support for sync tty ports
这两个压缩选项将是无害的，但是它们一定是不需要的，包括基于以太网的PPP选项也是一样，只有在配置内核模式PPPoE时才会需要。
不要忘记在内核中包括网（以太网或无线）卡。
大多数系统会有多核心处理，所以激活 Symmetric multi-processing support（对称多处理） 很重要 (CONFIG_SMP)：
Processor type and features --->
[*] Symmetric multi-processing support
在多核系统中，每个核心视为一个处理器。
如果使用USB输入设备（比如键盘和鼠标）或其他USB设备，不要忘记启用那些：
HID support --->
-*- HID bus support
<*> Generic HID driver
[*] Battery level reporting for HID devices
USB HID support --->
<*> USB HID transport layer
[*] USB support --->
<*> xHCI HCD (USB 3.0) support
<*> EHCI HCD (USB 2.0) support
<*> OHCI HCD (USB 1.1) support
Optional: Signed kernel modules
To automatically sign the kernel modules enable CONFIG_MODULE_SIG_ALL:
[*] Enable loadable module support
-*- Module signature verification
[*] Automatically sign all modules
Which hash algorithm should modules be signed with? (Sign modules with SHA-512) --->
Optionally change the hash algorithm if desired.
To enforce that all modules are signed with a valid signature, enable CONFIG_MODULE_SIG_FORCE as well:
[*] Enable loadable module support
-*- Module signature verification
[*] Require modules to be validly signed
[*] Automatically sign all modules
Which hash algorithm should modules be signed with? (Sign modules with SHA-512) --->
To use a custom key, specify the location of this key in CONFIG_MODULE_SIG_KEY. If unspecified, the kernel build system will generate a key. It is recommended to generate one manually instead. This can be done with:
root #openssl req -new -nodes -utf8 -sha256 -x509 -outform PEM -out kernel_key.pem -keyout kernel_key.pemOpenSSL will ask some questions about the user generating the key, it is recommended to fill in these questions as detailed as possible.
Store the key in a safe location, at the very least the key should be readable only by the root user. Verify this with:
root #ls -l kernel_key.pem-r-------- 1 root root 3164 Jan 4 10:38 kernel_key.pem
If this outputs anything other then the above, correct the permissions with:
root #chown root:root kernel_key.pem
root #chmod 400 kernel_key.pem
-*- Cryptographic API --->
Certificates for signature checking --->
(/path/to/kernel_key.pem) File name or PKCS#11 URI of module signing key
To also sign external kernel modules installed by other packages via linux-mod-r1.eclass, enable the modules-sign USE flag globally:
/etc/portage/make.confEnable module signingUSE="modules-sign"
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# Optionally, when using custom signing keys.
MODULES_SIGN_KEY="/path/to/kernel_key.pem"
MODULES_SIGN_CERT="/path/to/kernel_key.pem" # Only required if the MODULES_SIGN_KEY does not also contain the certificate
MODULES_SIGN_HASH="sha512" # Defaults to sha512
MODULES_SIGN_KEY and MODULES_SIGN_CERT may point to different files. For this example, the pem file generated by OpenSSL includes both the key and the accompanying certificate, and thus both variables are set to the same value.
Architecture specific kernel configurations
Placeholder for architecture-specific kernel build information
Compiling and installing
Placeholder for instructions for building and installing the kernel sources
Deprecated: Genkernel
Genkernel should only be considered by users with a required need that only Genkernel can meet. For others, it is recommended to use the Distribution kernel or manually compile their own as it will make maintaining a Gentoo system a lot more simple. An example of why genkernel is more difficult to manage is the lack of integration with sys-kernel/installkernel. This means a user will not get the same level of automation as provided by the other methods; for example, Unified Kernel Images will need to be created manually when using Genkernel.
Users still wishing to use Genkernel should see the Genkernel article for more information.
内核模块
列出可用的内核模块
硬件模块手动列出是可选的。在大多数情况下，udev 通常将加载所有被检测为已连接的硬件模块。然而，列出自动检测到的模块并没有什么不良影响的。有时，一些奇特硬件需要帮助来加载其驱动程序。
可以在 /etc/modules-load.d/*.conf 文件中添加需要在每次启动时加载的模块，格式为每行一个模块。如果模块需要附加选项，可以在 /etc/modprobe.d/*.conf 文件内设置。
对于特定的内核版本，如果要查看所有可用模块，使用下面的 find 命令。不要忘记在查找时替换 “<kernel version>” 为对应的内核版本：
root #find /lib/modules/<kernel version>/ -type f -iname '*.o' -or -iname '*.ko' | less强制加载特定内核模块
要强制加载内核 3c59x.ko 模块（3Com 网卡家族的特定驱动），编辑/etc/modules-load.d/network.conf 文件并在里面输入模块名字。
root #mkdir -p /etc/modules-load.d
root #nano -w /etc/modules-load.d/network.conf
注意，模块的 .ko 文件后缀对加载机制影响不大，所以配置文件中没有文件后缀：
/etc/modules-load.d/network.conf强制加载 3c59x 模块3c59x
继续到配置系统来安装。