8.3. Linux-3.19

8.3.1. 安装内核

编译内核包括以下步骤——配置、编译和安装。阅读内核源码树中的 README 可以获得替代本手册配置的方法。

通过以下命令来编译：

make mrproper

这将保证内核树的绝对干净。内核小组建议在每次编译之前都执行此命令，无用的代码将会在解压后删除。

通过菜单界面配置内核。配置内核的一般信息请查看：http://www.linuxfromscratch.org/hints/downloads/files/kernel-configuration.txt。BLFS 包含有一些内核的特殊配置，可以查看：http://www.linuxfromscratch.org/blfs/view/systemd/longindex.html#kernel-config-index. 内核配置和编译的附加信息可查看：http://www.kroah.com/lkn/

make LANG=<host_LANG_value> LC_ALL= menuconfig

Alternatively, make oldconfig may be more appropriate in some situations. See the README file for more information.

If desired, skip kernel configuration by copying the kernel config file, .config, from the host system (assuming it is available) to the unpacked linux-3.19 directory. However, we do not recommend this option. It is often better to explore all the configuration menus and create the kernel configuration from scratch.

Compile the kernel image and modules:

make

If using kernel modules, module configuration in /etc/modprobe.d may be required. Information pertaining to modules and kernel configuration is located in Section 7.3, “Device and Module Handling on an LFS System” and in the kernel documentation in the linux-3.19/Documentation directory. Also, modprobe.d(5) may be of interest.

Install the modules, if the kernel configuration uses them:

make modules_install

After kernel compilation is complete, additional steps are required to complete the installation. Some files need to be copied to the /boot directory.

The path to the kernel image may vary depending on the platform being used. The filename below can be changed to suit your taste, but the stem of the filename should be vmlinuz to be compatible with the automatic setup of the boot process described in the next section. The following command assumes an x86 architecture:

cp -v arch/x86/boot/bzImage /boot/vmlinuz-3.19-lfs-7.7-systemd

System.map is a symbol file for the kernel. It maps the function entry points of every function in the kernel API, as well as the addresses of the kernel data structures for the running kernel. It is used as a resource when investigating kernel problems. Issue the following command to install the map file:

cp -v System.map /boot/System.map-3.19

The kernel configuration file .config produced by the make menuconfig step above contains all the configuration selections for the kernel that was just compiled. It is a good idea to keep this file for future reference:

cp -v .config /boot/config-3.19

Install the documentation for the Linux kernel:

install -d /usr/share/doc/linux-3.19
cp -r Documentation/* /usr/share/doc/linux-3.19

It is important to note that the files in the kernel source directory are not owned by root. Whenever a package is unpacked as user root (like we did inside chroot), the files have the user and group IDs of whatever they were on the packager's computer. This is usually not a problem for any other package to be installed because the source tree is removed after the installation. However, the Linux source tree is often retained for a long time. Because of this, there is a chance that whatever user ID the packager used will be assigned to somebody on the machine. That person would then have write access to the kernel source.

If the kernel source tree is going to be retained, run chown -R 0:0 on the linux-3.19 directory to ensure all files are owned by user root.

install -v -m755 -d /etc/modprobe.d
cat > /etc/modprobe.d/usb.conf << "EOF"
# Begin /etc/modprobe.d/usb.conf

install ohci_hcd /sbin/modprobe ehci_hcd ; /sbin/modprobe -i ohci_hcd ; true
install uhci_hcd /sbin/modprobe ehci_hcd ; /sbin/modprobe -i uhci_hcd ; true

# End /etc/modprobe.d/usb.conf
EOF