Minimal requirements to compile the Kernel¶
Intro¶
This document is designed to provide a list of the minimum levels of software necessary to run the current kernel version.
This document is originally based on my “Changes” file for 2.0.x kernels and therefore owes credit to the same people as that file (Jared Mauch, Axel Boldt, Alessandro Sigala, and countless other users all over the ‘net).
Current Minimal Requirements¶
Upgrade to at least these software revisions before thinking you’ve encountered a bug! If you’re unsure what version you’re currently running, the suggested command should tell you.
Again, keep in mind that this list assumes you are already functionally running a Linux kernel. Also, not all tools are necessary on all systems; obviously, if you don’t have any PC Card hardware, for example, you probably needn’t concern yourself with pcmciautils.
Program |
Minimal version |
Command to check the version |
|---|---|---|
GNU C |
5.1 |
gcc --version |
Clang/LLVM (optional) |
13.0.1 |
clang --version |
Rust (optional) |
1.78.0 |
rustc --version |
bindgen (optional) |
0.65.1 |
bindgen --version |
GNU make |
3.82 |
make --version |
bash |
4.2 |
bash --version |
binutils |
2.25 |
ld -v |
flex |
2.5.35 |
flex --version |
bison |
2.0 |
bison --version |
pahole |
1.16 |
pahole --version |
util-linux |
2.10o |
mount --version |
kmod |
13 |
depmod -V |
e2fsprogs |
1.41.4 |
e2fsck -V |
jfsutils |
1.1.3 |
fsck.jfs -V |
reiserfsprogs |
3.6.3 |
reiserfsck -V |
xfsprogs |
2.6.0 |
xfs_db -V |
squashfs-tools |
4.0 |
mksquashfs -version |
btrfs-progs |
0.18 |
btrfsck |
pcmciautils |
004 |
pccardctl -V |
quota-tools |
3.09 |
quota -V |
PPP |
2.4.0 |
pppd --version |
nfs-utils |
1.0.5 |
showmount --version |
procps |
3.2.0 |
ps --version |
udev |
081 |
udevd --version |
grub |
0.93 |
grub --version || grub-install --version |
mcelog |
0.6 |
mcelog --version |
iptables |
1.4.2 |
iptables -V |
openssl & libcrypto |
1.0.0 |
openssl version |
bc |
1.06.95 |
bc --version |
Sphinx[1] |
2.4.4 |
sphinx-build --version |
cpio |
any |
cpio --version |
GNU tar |
1.28 |
tar --version |
gtags (optional) |
6.6.5 |
gtags --version |
mkimage (optional) |
2017.01 |
mkimage --version |
Python (optional) |
3.5.x |
python3 --version |
Kernel compilation¶
GCC¶
The gcc version requirements may vary depending on the type of CPU in your computer.
Clang/LLVM (optional)¶
The latest formal release of clang and LLVM utils (according to releases.llvm.org) are supported for building kernels. Older releases aren’t guaranteed to work, and we may drop workarounds from the kernel that were used to support older versions. Please see additional docs on Building Linux with Clang/LLVM.
Rust (optional)¶
A particular version of the Rust toolchain is required. Newer versions may or may not work because the kernel depends on some unstable Rust features, for the moment.
Each Rust toolchain comes with several “components”, some of which are required
(like rustc) and some that are optional. The rust-src component (which
is optional) needs to be installed to build the kernel. Other components are
useful for developing.
Please see Quick Start for instructions on how to
satisfy the build requirements of Rust support. In particular, the Makefile
target rustavailable is useful to check why the Rust toolchain may not
be detected.
bindgen (optional)¶
bindgen is used to generate the Rust bindings to the C side of the kernel.
It depends on libclang.
Make¶
You will need GNU make 3.82 or later to build the kernel.
Bash¶
Some bash scripts are used for the kernel build. Bash 4.2 or newer is needed.
Binutils¶
Binutils 2.25 or newer is needed to build the kernel.
pkg-config¶
The build system, as of 4.18, requires pkg-config to check for installed kconfig tools and to determine flags settings for use in ‘make {g,x}config’. Previously pkg-config was being used but not verified or documented.
Flex¶
Since Linux 4.16, the build system generates lexical analyzers during build. This requires flex 2.5.35 or later.
Bison¶
Since Linux 4.16, the build system generates parsers during build. This requires bison 2.0 or later.
pahole¶
Since Linux 5.2, if CONFIG_DEBUG_INFO_BTF is selected, the build system generates BTF (BPF Type Format) from DWARF in vmlinux, a bit later from kernel modules as well. This requires pahole v1.16 or later.
It is found in the ‘dwarves’ or ‘pahole’ distro packages or from https://fedorapeople.org/~acme/dwarves/.
Perl¶
You will need perl 5 and the following modules: Getopt::Long,
Getopt::Std, File::Basename, and File::Find to build the kernel.
BC¶
You will need bc to build kernels 3.10 and higher
OpenSSL¶
Module signing and external certificate handling use the OpenSSL program and crypto library to do key creation and signature generation.
You will need openssl to build kernels 3.7 and higher if module signing is enabled. You will also need openssl development packages to build kernels 4.3 and higher.
Tar¶
GNU tar is needed if you want to enable access to the kernel headers via sysfs (CONFIG_IKHEADERS).
mkimage¶
This tool is used when building a Flat Image Tree (FIT), commonly used on ARM
platforms. The tool is available via the u-boot-tools package or can be
built from the U-Boot source code. See the instructions at
https://docs.u-boot.org/en/latest/build/tools.html#building-tools-for-linux
System utilities¶
Architectural changes¶
DevFS has been obsoleted in favour of udev (https://www.kernel.org/pub/linux/utils/kernel/hotplug/)
32-bit UID support is now in place. Have fun!
Linux documentation for functions is transitioning to inline documentation via specially-formatted comments near their definitions in the source. These comments can be combined with ReST files the Documentation/ directory to make enriched documentation, which can then be converted to PostScript, HTML, LaTex, ePUB and PDF files. In order to convert from ReST format to a format of your choice, you’ll need Sphinx.
Util-linux¶
New versions of util-linux provide fdisk support for larger disks,
support new options to mount, recognize more supported partition
types, and similar goodies.
You’ll probably want to upgrade.
Ksymoops¶
If the unthinkable happens and your kernel oopses, you may need the
ksymoops tool to decode it, but in most cases you don’t.
It is generally preferred to build the kernel with CONFIG_KALLSYMS so
that it produces readable dumps that can be used as-is (this also
produces better output than ksymoops). If for some reason your kernel
is not build with CONFIG_KALLSYMS and you have no way to rebuild and
reproduce the Oops with that option, then you can still decode that Oops
with ksymoops.
Mkinitrd¶
These changes to the /lib/modules file tree layout also require that
mkinitrd be upgraded.
E2fsprogs¶
The latest version of e2fsprogs fixes several bugs in fsck and
debugfs. Obviously, it’s a good idea to upgrade.
JFSutils¶
The jfsutils package contains the utilities for the file system.
The following utilities are available:
fsck.jfs- initiate replay of the transaction log, and check and repair a JFS formatted partition.mkfs.jfs- create a JFS formatted partition.other file system utilities are also available in this package.
Reiserfsprogs¶
The reiserfsprogs package should be used for reiserfs-3.6.x
(Linux kernels 2.4.x). It is a combined package and contains working
versions of mkreiserfs, resize_reiserfs, debugreiserfs and
reiserfsck. These utils work on both i386 and alpha platforms.
Xfsprogs¶
The latest version of xfsprogs contains mkfs.xfs, xfs_db, and the
xfs_repair utilities, among others, for the XFS filesystem. It is
architecture independent and any version from 2.0.0 onward should
work correctly with this version of the XFS kernel code (2.6.0 or
later is recommended, due to some significant improvements).
PCMCIAutils¶
PCMCIAutils replaces pcmcia-cs. It properly sets up
PCMCIA sockets at system startup and loads the appropriate modules
for 16-bit PCMCIA devices if the kernel is modularized and the hotplug
subsystem is used.
Quota-tools¶
Support for 32 bit uid’s and gid’s is required if you want to use the newer version 2 quota format. Quota-tools version 3.07 and newer has this support. Use the recommended version or newer from the table above.
Intel IA32 microcode¶
A driver has been added to allow updating of Intel IA32 microcode, accessible as a normal (misc) character device. If you are not using udev you may need to:
mkdir /dev/cpu
mknod /dev/cpu/microcode c 10 184
chmod 0644 /dev/cpu/microcode
as root before you can use this. You’ll probably also want to get the user-space microcode_ctl utility to use with this.
udev¶
udev is a userspace application for populating /dev dynamically with
only entries for devices actually present. udev replaces the basic
functionality of devfs, while allowing persistent device naming for
devices.
FUSE¶
Needs libfuse 2.4.0 or later. Absolute minimum is 2.3.0 but mount
options direct_io and kernel_cache won’t work.
Networking¶
General changes¶
If you have advanced network configuration needs, you should probably consider using the network tools from ip-route2.
Packet Filter / NAT¶
The packet filtering and NAT code uses the same tools like the previous 2.4.x kernel series (iptables). It still includes backwards-compatibility modules for 2.2.x-style ipchains and 2.0.x-style ipfwadm.
PPP¶
The PPP driver has been restructured to support multilink and to enable it to operate over diverse media layers. If you use PPP, upgrade pppd to at least 2.4.0.
If you are not using udev, you must have the device file /dev/ppp which can be made by:
mknod /dev/ppp c 108 0
as root.
NFS-utils¶
In ancient (2.4 and earlier) kernels, the nfs server needed to know
about any client that expected to be able to access files via NFS. This
information would be given to the kernel by mountd when the client
mounted the filesystem, or by exportfs at system startup. exportfs
would take information about active clients from /var/lib/nfs/rmtab.
This approach is quite fragile as it depends on rmtab being correct
which is not always easy, particularly when trying to implement
fail-over. Even when the system is working well, rmtab suffers from
getting lots of old entries that never get removed.
With modern kernels we have the option of having the kernel tell mountd
when it gets a request from an unknown host, and mountd can give
appropriate export information to the kernel. This removes the
dependency on rmtab and means that the kernel only needs to know about
currently active clients.
To enable this new functionality, you need to:
mount -t nfsd nfsd /proc/fs/nfsd
before running exportfs or mountd. It is recommended that all NFS services be protected from the internet-at-large by a firewall where that is possible.
mcelog¶
On x86 kernels the mcelog utility is needed to process and log machine check
events when CONFIG_X86_MCE is enabled. Machine check events are errors
reported by the CPU. Processing them is strongly encouraged.
Kernel documentation¶
Sphinx¶
Please see Sphinx Install in Documentation/doc-guide/sphinx.rst for details about Sphinx requirements.
rustdoc¶
rustdoc is used to generate the documentation for Rust code. Please see
General Information for more information.