menu "Kernel" config BR2_LINUX_KERNEL bool "Linux Kernel" select BR2_PACKAGE_HOST_KMOD # Unconditional, even if modules not enabled select BR2_PACKAGE_HOST_IMAGEMAGICK if BR2_LINUX_KERNEL_CUSTOM_LOGO_PATH != "" help Enable this option if you want to build a Linux kernel for your embedded device if BR2_LINUX_KERNEL # Packages that need to have a kernel with support for loadable modules, # but do not use the kernel-modules infrastructure, should select that # option. config BR2_LINUX_NEEDS_MODULES bool # # Version selection. We provide the choice between: # # 1. A single fairly recent stable kernel version # 2. A custom stable version # 3. A custom tarball # 4. A set of custom repository locations # choice prompt "Kernel version" config BR2_LINUX_KERNEL_LATEST_VERSION bool "Latest version (5.12)" config BR2_LINUX_KERNEL_LATEST_CIP_VERSION bool "Latest CIP SLTS version (4.19.182-cip45)" help CIP launched in the spring of 2016 to address the needs of organizations in industries such as power generation and distribution, water, oil and gas, transportation, building automation and more for reliable and secure Linux-based embedded systems that can be sustained over a period of 10 to as many as 60 years. The project's goal is to provide an open source base layer of industrial-grade software that permits the use and implementation of software building blocks that meet these requirements. The CIP community plans to maintain 4.19 for security and bug fixes for more than 10 years. https://www.cip-project.org config BR2_LINUX_KERNEL_LATEST_CIP_RT_VERSION bool "Latest CIP RT SLTS version (4.19.165-cip41-rt18)" help Same as the CIP version, but this is the PREEMPT_RT realtime variant. The CIP community plans to maintain 4.19 for security and bug fixes for more than 10 years. https://www.cip-project.org config BR2_LINUX_KERNEL_CUSTOM_VERSION bool "Custom version" help This option allows to use a specific official version from kernel.org, like 2.6.x, 2.6.x.y, 3.x.y, ... Note: you cannot use this option to select a _longterm_ 2.6 kernel, because these kernels are not located at the standard URL at kernel.org. Instead, select "Custom tarball" and specify the right URL directly. config BR2_LINUX_KERNEL_CUSTOM_TARBALL bool "Custom tarball" help This option allows to specify a URL pointing to a kernel source tarball. This URL can use any protocol recognized by Buildroot, like http://, ftp://, file:// or scp://. When pointing to a local tarball using file://, you may want to use a make variable like $(TOPDIR) to reference the root of the Buildroot tree. config BR2_LINUX_KERNEL_CUSTOM_GIT bool "Custom Git repository" help This option allows Buildroot to get the Linux kernel source code from a Git repository. config BR2_LINUX_KERNEL_CUSTOM_HG bool "Custom Mercurial repository" help This option allows Buildroot to get the Linux kernel source code from a Mercurial repository. config BR2_LINUX_KERNEL_CUSTOM_SVN bool "Custom Subversion repository" help This option allows Buildroot to get the Linux kernel source code from a Subversion repository. endchoice config BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE string "Kernel version" depends on BR2_LINUX_KERNEL_CUSTOM_VERSION config BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION string "URL of custom kernel tarball" depends on BR2_LINUX_KERNEL_CUSTOM_TARBALL if BR2_LINUX_KERNEL_CUSTOM_GIT || BR2_LINUX_KERNEL_CUSTOM_HG || BR2_LINUX_KERNEL_CUSTOM_SVN config BR2_LINUX_KERNEL_CUSTOM_REPO_URL string "URL of custom repository" config BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION string "Custom repository version" help Revision to use in the typical format used by Git/Mercurial/Subversion E.G. a sha id, a tag, branch, .. endif config BR2_LINUX_KERNEL_VERSION string default "5.12.4" if BR2_LINUX_KERNEL_LATEST_VERSION default "4.19.182-cip45" if BR2_LINUX_KERNEL_LATEST_CIP_VERSION default "4.19.165-cip41-rt18" if BR2_LINUX_KERNEL_LATEST_CIP_RT_VERSION default BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE \ if BR2_LINUX_KERNEL_CUSTOM_VERSION default "custom" if BR2_LINUX_KERNEL_CUSTOM_TARBALL default BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION \ if BR2_LINUX_KERNEL_CUSTOM_GIT || BR2_LINUX_KERNEL_CUSTOM_HG || BR2_LINUX_KERNEL_CUSTOM_SVN # # Patch selection # config BR2_LINUX_KERNEL_PATCH string "Custom kernel patches" help A space-separated list of patches to apply to the kernel. Each patch can be described as an URL, a local file path, or a directory. In the case of a directory, all files matching *.patch in the directory will be applied. # # Configuration selection # choice prompt "Kernel configuration" default BR2_LINUX_KERNEL_USE_DEFCONFIG config BR2_LINUX_KERNEL_USE_DEFCONFIG bool "Using an in-tree defconfig file" config BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG bool "Use the architecture default configuration" help This option will use the default configuration for the selected architecture. I.e, it is equivalent to running "make ARCH= defconfig". This is useful on architectures that have a single defconfig file, such as ARM64. config BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG bool "Using a custom (def)config file" endchoice config BR2_LINUX_KERNEL_DEFCONFIG string "Defconfig name" depends on BR2_LINUX_KERNEL_USE_DEFCONFIG help Name of the kernel defconfig file to use, without the trailing _defconfig. The defconfig is located in arch//configs in the kernel tree. config BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE string "Configuration file path" depends on BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG help Path to the kernel configuration file Note: this can be a defconfig file or a complete .config file, which can later be saved back with make linux-update-(def)config. config BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES string "Additional configuration fragment files" help A space-separated list of kernel configuration fragment files, that will be merged to the main kernel configuration file. config BR2_LINUX_KERNEL_CUSTOM_LOGO_PATH string "Custom boot logo file path" help Use a custom Linux framebuffer boot logo. Custom logo should be in PNG or JPEG format, it will be converted to the linux kernel format (224 colors only) and copied over the original logo file. # # Binary format # choice prompt "Kernel binary format" default BR2_LINUX_KERNEL_ZIMAGE if BR2_arm || BR2_armeb config BR2_LINUX_KERNEL_UIMAGE bool "uImage" depends on BR2_arc || BR2_arm || BR2_armeb || \ BR2_powerpc || BR2_powerpc64 || BR2_powerpc64le || \ BR2_sh || BR2_mips || BR2_mipsel || \ BR2_mips64 || BR2_mips64el || BR2_xtensa select BR2_PACKAGE_HOST_UBOOT_TOOLS config BR2_LINUX_KERNEL_APPENDED_UIMAGE bool "uImage with appended DT" depends on BR2_arm || BR2_armeb select BR2_LINUX_KERNEL_DTS_SUPPORT select BR2_LINUX_KERNEL_APPENDED_DTB select BR2_PACKAGE_HOST_UBOOT_TOOLS config BR2_LINUX_KERNEL_BZIMAGE bool "bzImage" depends on BR2_i386 || BR2_x86_64 || BR2_s390x config BR2_LINUX_KERNEL_ZIMAGE bool "zImage" depends on BR2_arm || BR2_armeb || BR2_powerpc || \ BR2_powerpc64 || BR2_powerpc64le || BR2_sparc || \ BR2_sh || BR2_xtensa config BR2_LINUX_KERNEL_ZIMAGE_EPAPR bool "zImage.epapr" depends on BR2_powerpc64 || BR2_powerpc64le config BR2_LINUX_KERNEL_APPENDED_ZIMAGE bool "zImage with appended DT" depends on BR2_arm || BR2_armeb select BR2_LINUX_KERNEL_DTS_SUPPORT select BR2_LINUX_KERNEL_APPENDED_DTB config BR2_LINUX_KERNEL_CUIMAGE bool "cuImage" depends on BR2_powerpc select BR2_PACKAGE_HOST_UBOOT_TOOLS select BR2_LINUX_KERNEL_DTS_SUPPORT select BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT config BR2_LINUX_KERNEL_SIMPLEIMAGE bool "simpleImage" depends on BR2_microblaze select BR2_PACKAGE_HOST_UBOOT_TOOLS select BR2_LINUX_KERNEL_DTS_SUPPORT select BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT config BR2_LINUX_KERNEL_IMAGE bool "Image" depends on BR2_aarch64 || BR2_riscv config BR2_LINUX_KERNEL_IMAGEGZ bool "Image.gz" depends on BR2_aarch64 || BR2_riscv config BR2_LINUX_KERNEL_LINUX_BIN bool "linux.bin" depends on BR2_microblaze select BR2_PACKAGE_HOST_UBOOT_TOOLS config BR2_LINUX_KERNEL_VMLINUX_BIN bool "vmlinux.bin" depends on BR2_mips || BR2_mipsel || BR2_sh config BR2_LINUX_KERNEL_VMLINUX bool "vmlinux" config BR2_LINUX_KERNEL_VMLINUZ bool "vmlinuz" depends on BR2_mips || BR2_mipsel config BR2_LINUX_KERNEL_VMLINUZ_BIN bool "vmlinuz.bin" depends on BR2_mips || BR2_mipsel config BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM bool "custom target" help For certain cases a board-specific target image must be used. For example, on powerPC where the OpenFirmware description is attached in a board-specific kernel image target like 'cuImage.mpc8379_rdb'. Select this option and specify the make target in "Kernel image target name". endchoice # # Kernel compression format # choice prompt "Kernel compression format" help This selection will just ensure that the correct host tools are built. The actual compression for the kernel should be selected in the kernel configuration menu. config BR2_LINUX_KERNEL_GZIP bool "gzip compression" config BR2_LINUX_KERNEL_LZ4 bool "lz4 compression" config BR2_LINUX_KERNEL_LZMA bool "lzma compression" config BR2_LINUX_KERNEL_LZO bool "lzo compression" config BR2_LINUX_KERNEL_XZ bool "xz compression" config BR2_LINUX_KERNEL_ZSTD bool "zstd compression" config BR2_LINUX_KERNEL_UNCOMPRESSED bool "uncompressed" depends on BR2_s390x endchoice config BR2_LINUX_KERNEL_IMAGE_TARGET_NAME string "Kernel image target name" depends on BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM help Specify the kernel make target to build the kernel that you need. config BR2_LINUX_KERNEL_IMAGE_NAME string "Kernel image name" depends on BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM help The filename of the kernel image, if it is different from the make target (above). Defaults to BR2_LINUX_KERNEL_IMAGE_TARGET_NAME. If specified, the filename is relative to arch/ARCH/boot/. If unsure, leave it empty. config BR2_LINUX_KERNEL_UIMAGE_LOADADDR string "load address (for 3.7+ multi-platform image)" depends on BR2_arm || BR2_armeb depends on BR2_LINUX_KERNEL_UIMAGE || BR2_LINUX_KERNEL_APPENDED_UIMAGE help If your ARM system's Linux kernel is configured with the new (3.7+) multi-architecture support (CONFIG_ARCH_MULTIPLATFORM=y in your kernel config), then it is necessary to specify a kernel load address when building the uImage. This should be a hexadecimal string beginning with 0x, for example: 0x00008000. If unsure, let this option empty. config BR2_LINUX_KERNEL_DTS_SUPPORT bool "Build a Device Tree Blob (DTB)" help Compile one or more device tree sources into device tree blobs. Select the dts files to compile in the options below. if BR2_LINUX_KERNEL_DTS_SUPPORT # We have mainly three cases when it comes to device tree support: # 1) We don't want any support at all. Then the ..DTS_SUPPORT # variable won't be set # 2) We want device tree support, so we need the user to enter the # device tree name or the path to the custom device he uses, but # the kernel abstracts this from us and only build an image that # looks like a regular kernel image. In this case, we only need # to derive the kernel image name from the given device tree # name, and all the rest is as usual # 3) We want device tree support, but the kernel requires us to # build the device tree blob separately. In this case, some # more logic will be needed. # The variable below address the second case, were you only want # limited actions from buildroot. config BR2_LINUX_KERNEL_DTB_IS_SELF_BUILT bool "DTB is built by kernel itself" help Normally, the device tree(s) to be built have to be passed explicitly to the kernel build system. For some binary formats, however, the kernel build system links in the device tree directly in the kernel binary. Select this option if you have such a kernel binary format. config BR2_LINUX_KERNEL_APPENDED_DTB bool config BR2_LINUX_KERNEL_INTREE_DTS_NAME string "In-tree Device Tree Source file names" help Name of in-tree device tree source file, without the trailing .dts. You can provide a list of dts files to build, separated by spaces. config BR2_LINUX_KERNEL_CUSTOM_DTS_PATH string "Out-of-tree Device Tree Source file paths" help Path to to out-of-tree device tree source files. You can provide a list of dts paths to copy and build, separated by spaces. config BR2_LINUX_KERNEL_DTB_KEEP_DIRNAME bool "Keep the directory name of the Device Tree" help If enabled, the device tree blobs keep their directory prefixes when they get copied to the output image directory or the target directory. config BR2_LINUX_KERNEL_DTB_OVERLAY_SUPPORT bool "Build Device Tree with overlay support" help If enabled, pass the "-@" option to dtc, such that symbols are generated in the compiled Device Tree. Choose this option to support Device Tree overlays on the target system. endif config BR2_LINUX_KERNEL_INSTALL_TARGET bool "Install kernel image to /boot in target" depends on !BR2_TARGET_ROOTFS_INITRAMFS help Select this option to have the kernel image installed to /boot in the target root filesystem, as is typically done on x86/x86_64 systems. Note that this option also installs the Device Tree Blobs to /boot if DTBs have been generated by the kernel build process. config BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL bool "Needs host OpenSSL" help Some Linux kernel configuration options (such as CONFIG_SYSTEM_TRUSTED_KEYRING) require building a host program called extract-cert, which itself needs OpenSSL. Enabling this option will ensure host-openssl gets built before the Linux kernel. Enable this option if you get a Linux kernel build failure such as "scripts/extract-cert.c:21:25: fatal error: openssl/bio.h: No such file or directory". config BR2_LINUX_KERNEL_NEEDS_HOST_LIBELF bool "Needs host libelf" help Some Linux kernel configuration options (such as CONFIG_UNWINDER_ORC) require building a host program that needs libelf. Enabling this option will ensure host-elfutils (which provides libelf) gets built before the Linux kernel. Enable this option if you get a Linux kernel build failure such as "Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel". # Linux extensions source "linux/Config.ext.in" # Linux tools source "package/linux-tools/Config.in" endif # BR2_LINUX_KERNEL endmenu