1.. _changes: 2 3Minimal requirements to compile the Kernel 4++++++++++++++++++++++++++++++++++++++++++ 5 6Intro 7===== 8 9This document is designed to provide a list of the minimum levels of 10software necessary to run the current kernel version. 11 12This document is originally based on my "Changes" file for 2.0.x kernels 13and therefore owes credit to the same people as that file (Jared Mauch, 14Axel Boldt, Alessandro Sigala, and countless other users all over the 15'net). 16 17Current Minimal Requirements 18**************************** 19 20Upgrade to at **least** these software revisions before thinking you've 21encountered a bug! If you're unsure what version you're currently 22running, the suggested command should tell you. 23 24Again, keep in mind that this list assumes you are already functionally 25running a Linux kernel. Also, not all tools are necessary on all 26systems; obviously, if you don't have any PC Card hardware, for example, 27you probably needn't concern yourself with pcmciautils. 28 29====================== =============== ======================================== 30 Program Minimal version Command to check the version 31====================== =============== ======================================== 32GNU C 5.1 gcc --version 33Clang/LLVM (optional) 11.0.0 clang --version 34Rust (optional) 1.68.2 rustc --version 35bindgen (optional) 0.56.0 bindgen --version 36GNU make 3.82 make --version 37bash 4.2 bash --version 38binutils 2.25 ld -v 39flex 2.5.35 flex --version 40bison 2.0 bison --version 41pahole 1.16 pahole --version 42util-linux 2.10o fdformat --version 43kmod 13 depmod -V 44e2fsprogs 1.41.4 e2fsck -V 45jfsutils 1.1.3 fsck.jfs -V 46reiserfsprogs 3.6.3 reiserfsck -V 47xfsprogs 2.6.0 xfs_db -V 48squashfs-tools 4.0 mksquashfs -version 49btrfs-progs 0.18 btrfsck 50pcmciautils 004 pccardctl -V 51quota-tools 3.09 quota -V 52PPP 2.4.0 pppd --version 53nfs-utils 1.0.5 showmount --version 54procps 3.2.0 ps --version 55udev 081 udevd --version 56grub 0.93 grub --version || grub-install --version 57mcelog 0.6 mcelog --version 58iptables 1.4.2 iptables -V 59openssl & libcrypto 1.0.0 openssl version 60bc 1.06.95 bc --version 61Sphinx\ [#f1]_ 1.7 sphinx-build --version 62cpio any cpio --version 63GNU tar 1.28 tar --version 64gtags (optional) 6.6.5 gtags --version 65====================== =============== ======================================== 66 67.. [#f1] Sphinx is needed only to build the Kernel documentation 68 69Kernel compilation 70****************** 71 72GCC 73--- 74 75The gcc version requirements may vary depending on the type of CPU in your 76computer. 77 78Clang/LLVM (optional) 79--------------------- 80 81The latest formal release of clang and LLVM utils (according to 82`releases.llvm.org <https://releases.llvm.org>`_) are supported for building 83kernels. Older releases aren't guaranteed to work, and we may drop workarounds 84from the kernel that were used to support older versions. Please see additional 85docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`. 86 87Rust (optional) 88--------------- 89 90A particular version of the Rust toolchain is required. Newer versions may or 91may not work because the kernel depends on some unstable Rust features, for 92the moment. 93 94Each Rust toolchain comes with several "components", some of which are required 95(like ``rustc``) and some that are optional. The ``rust-src`` component (which 96is optional) needs to be installed to build the kernel. Other components are 97useful for developing. 98 99Please see Documentation/rust/quick-start.rst for instructions on how to 100satisfy the build requirements of Rust support. In particular, the ``Makefile`` 101target ``rustavailable`` is useful to check why the Rust toolchain may not 102be detected. 103 104bindgen (optional) 105------------------ 106 107``bindgen`` is used to generate the Rust bindings to the C side of the kernel. 108It depends on ``libclang``. 109 110Make 111---- 112 113You will need GNU make 3.82 or later to build the kernel. 114 115Bash 116---- 117 118Some bash scripts are used for the kernel build. 119Bash 4.2 or newer is needed. 120 121Binutils 122-------- 123 124Binutils 2.25 or newer is needed to build the kernel. 125 126pkg-config 127---------- 128 129The build system, as of 4.18, requires pkg-config to check for installed 130kconfig tools and to determine flags settings for use in 131'make {g,x}config'. Previously pkg-config was being used but not 132verified or documented. 133 134Flex 135---- 136 137Since Linux 4.16, the build system generates lexical analyzers 138during build. This requires flex 2.5.35 or later. 139 140 141Bison 142----- 143 144Since Linux 4.16, the build system generates parsers 145during build. This requires bison 2.0 or later. 146 147pahole: 148------- 149 150Since Linux 5.2, if CONFIG_DEBUG_INFO_BTF is selected, the build system 151generates BTF (BPF Type Format) from DWARF in vmlinux, a bit later from kernel 152modules as well. This requires pahole v1.16 or later. 153 154It is found in the 'dwarves' or 'pahole' distro packages or from 155https://fedorapeople.org/~acme/dwarves/. 156 157Perl 158---- 159 160You will need perl 5 and the following modules: ``Getopt::Long``, 161``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel. 162 163BC 164-- 165 166You will need bc to build kernels 3.10 and higher 167 168 169OpenSSL 170------- 171 172Module signing and external certificate handling use the OpenSSL program and 173crypto library to do key creation and signature generation. 174 175You will need openssl to build kernels 3.7 and higher if module signing is 176enabled. You will also need openssl development packages to build kernels 4.3 177and higher. 178 179Tar 180--- 181 182GNU tar is needed if you want to enable access to the kernel headers via sysfs 183(CONFIG_IKHEADERS). 184 185gtags / GNU GLOBAL (optional) 186----------------------------- 187 188The kernel build requires GNU GLOBAL version 6.6.5 or later to generate 189tag files through ``make gtags``. This is due to its use of the gtags 190``-C (--directory)`` flag. 191 192System utilities 193**************** 194 195Architectural changes 196--------------------- 197 198DevFS has been obsoleted in favour of udev 199(https://www.kernel.org/pub/linux/utils/kernel/hotplug/) 200 20132-bit UID support is now in place. Have fun! 202 203Linux documentation for functions is transitioning to inline 204documentation via specially-formatted comments near their 205definitions in the source. These comments can be combined with ReST 206files the Documentation/ directory to make enriched documentation, which can 207then be converted to PostScript, HTML, LaTex, ePUB and PDF files. 208In order to convert from ReST format to a format of your choice, you'll need 209Sphinx. 210 211Util-linux 212---------- 213 214New versions of util-linux provide ``fdisk`` support for larger disks, 215support new options to mount, recognize more supported partition 216types, have a fdformat which works with 2.4 kernels, and similar goodies. 217You'll probably want to upgrade. 218 219Ksymoops 220-------- 221 222If the unthinkable happens and your kernel oopses, you may need the 223ksymoops tool to decode it, but in most cases you don't. 224It is generally preferred to build the kernel with ``CONFIG_KALLSYMS`` so 225that it produces readable dumps that can be used as-is (this also 226produces better output than ksymoops). If for some reason your kernel 227is not build with ``CONFIG_KALLSYMS`` and you have no way to rebuild and 228reproduce the Oops with that option, then you can still decode that Oops 229with ksymoops. 230 231Mkinitrd 232-------- 233 234These changes to the ``/lib/modules`` file tree layout also require that 235mkinitrd be upgraded. 236 237E2fsprogs 238--------- 239 240The latest version of ``e2fsprogs`` fixes several bugs in fsck and 241debugfs. Obviously, it's a good idea to upgrade. 242 243JFSutils 244-------- 245 246The ``jfsutils`` package contains the utilities for the file system. 247The following utilities are available: 248 249- ``fsck.jfs`` - initiate replay of the transaction log, and check 250 and repair a JFS formatted partition. 251 252- ``mkfs.jfs`` - create a JFS formatted partition. 253 254- other file system utilities are also available in this package. 255 256Reiserfsprogs 257------------- 258 259The reiserfsprogs package should be used for reiserfs-3.6.x 260(Linux kernels 2.4.x). It is a combined package and contains working 261versions of ``mkreiserfs``, ``resize_reiserfs``, ``debugreiserfs`` and 262``reiserfsck``. These utils work on both i386 and alpha platforms. 263 264Xfsprogs 265-------- 266 267The latest version of ``xfsprogs`` contains ``mkfs.xfs``, ``xfs_db``, and the 268``xfs_repair`` utilities, among others, for the XFS filesystem. It is 269architecture independent and any version from 2.0.0 onward should 270work correctly with this version of the XFS kernel code (2.6.0 or 271later is recommended, due to some significant improvements). 272 273PCMCIAutils 274----------- 275 276PCMCIAutils replaces ``pcmcia-cs``. It properly sets up 277PCMCIA sockets at system startup and loads the appropriate modules 278for 16-bit PCMCIA devices if the kernel is modularized and the hotplug 279subsystem is used. 280 281Quota-tools 282----------- 283 284Support for 32 bit uid's and gid's is required if you want to use 285the newer version 2 quota format. Quota-tools version 3.07 and 286newer has this support. Use the recommended version or newer 287from the table above. 288 289Intel IA32 microcode 290-------------------- 291 292A driver has been added to allow updating of Intel IA32 microcode, 293accessible as a normal (misc) character device. If you are not using 294udev you may need to:: 295 296 mkdir /dev/cpu 297 mknod /dev/cpu/microcode c 10 184 298 chmod 0644 /dev/cpu/microcode 299 300as root before you can use this. You'll probably also want to 301get the user-space microcode_ctl utility to use with this. 302 303udev 304---- 305 306``udev`` is a userspace application for populating ``/dev`` dynamically with 307only entries for devices actually present. ``udev`` replaces the basic 308functionality of devfs, while allowing persistent device naming for 309devices. 310 311FUSE 312---- 313 314Needs libfuse 2.4.0 or later. Absolute minimum is 2.3.0 but mount 315options ``direct_io`` and ``kernel_cache`` won't work. 316 317Networking 318********** 319 320General changes 321--------------- 322 323If you have advanced network configuration needs, you should probably 324consider using the network tools from ip-route2. 325 326Packet Filter / NAT 327------------------- 328The packet filtering and NAT code uses the same tools like the previous 2.4.x 329kernel series (iptables). It still includes backwards-compatibility modules 330for 2.2.x-style ipchains and 2.0.x-style ipfwadm. 331 332PPP 333--- 334 335The PPP driver has been restructured to support multilink and to 336enable it to operate over diverse media layers. If you use PPP, 337upgrade pppd to at least 2.4.0. 338 339If you are not using udev, you must have the device file /dev/ppp 340which can be made by:: 341 342 mknod /dev/ppp c 108 0 343 344as root. 345 346NFS-utils 347--------- 348 349In ancient (2.4 and earlier) kernels, the nfs server needed to know 350about any client that expected to be able to access files via NFS. This 351information would be given to the kernel by ``mountd`` when the client 352mounted the filesystem, or by ``exportfs`` at system startup. exportfs 353would take information about active clients from ``/var/lib/nfs/rmtab``. 354 355This approach is quite fragile as it depends on rmtab being correct 356which is not always easy, particularly when trying to implement 357fail-over. Even when the system is working well, ``rmtab`` suffers from 358getting lots of old entries that never get removed. 359 360With modern kernels we have the option of having the kernel tell mountd 361when it gets a request from an unknown host, and mountd can give 362appropriate export information to the kernel. This removes the 363dependency on ``rmtab`` and means that the kernel only needs to know about 364currently active clients. 365 366To enable this new functionality, you need to:: 367 368 mount -t nfsd nfsd /proc/fs/nfsd 369 370before running exportfs or mountd. It is recommended that all NFS 371services be protected from the internet-at-large by a firewall where 372that is possible. 373 374mcelog 375------ 376 377On x86 kernels the mcelog utility is needed to process and log machine check 378events when ``CONFIG_X86_MCE`` is enabled. Machine check events are errors 379reported by the CPU. Processing them is strongly encouraged. 380 381Kernel documentation 382******************** 383 384Sphinx 385------ 386 387Please see :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>` 388for details about Sphinx requirements. 389 390rustdoc 391------- 392 393``rustdoc`` is used to generate the documentation for Rust code. Please see 394Documentation/rust/general-information.rst for more information. 395 396Getting updated software 397======================== 398 399Kernel compilation 400****************** 401 402gcc 403--- 404 405- <ftp://ftp.gnu.org/gnu/gcc/> 406 407Clang/LLVM 408---------- 409 410- :ref:`Getting LLVM <getting_llvm>`. 411 412Rust 413---- 414 415- Documentation/rust/quick-start.rst. 416 417bindgen 418------- 419 420- Documentation/rust/quick-start.rst. 421 422Make 423---- 424 425- <ftp://ftp.gnu.org/gnu/make/> 426 427Bash 428---- 429 430- <ftp://ftp.gnu.org/gnu/bash/> 431 432Binutils 433-------- 434 435- <https://www.kernel.org/pub/linux/devel/binutils/> 436 437Flex 438---- 439 440- <https://github.com/westes/flex/releases> 441 442Bison 443----- 444 445- <ftp://ftp.gnu.org/gnu/bison/> 446 447OpenSSL 448------- 449 450- <https://www.openssl.org/> 451 452System utilities 453**************** 454 455Util-linux 456---------- 457 458- <https://www.kernel.org/pub/linux/utils/util-linux/> 459 460Kmod 461---- 462 463- <https://www.kernel.org/pub/linux/utils/kernel/kmod/> 464- <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git> 465 466Ksymoops 467-------- 468 469- <https://www.kernel.org/pub/linux/utils/kernel/ksymoops/v2.4/> 470 471Mkinitrd 472-------- 473 474- <https://code.launchpad.net/initrd-tools/main> 475 476E2fsprogs 477--------- 478 479- <https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/> 480- <https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/> 481 482JFSutils 483-------- 484 485- <http://jfs.sourceforge.net/> 486 487Reiserfsprogs 488------------- 489 490- <https://git.kernel.org/pub/scm/linux/kernel/git/jeffm/reiserfsprogs.git/> 491 492Xfsprogs 493-------- 494 495- <https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git> 496- <https://www.kernel.org/pub/linux/utils/fs/xfs/xfsprogs/> 497 498Pcmciautils 499----------- 500 501- <https://www.kernel.org/pub/linux/utils/kernel/pcmcia/> 502 503Quota-tools 504----------- 505 506- <http://sourceforge.net/projects/linuxquota/> 507 508 509Intel P6 microcode 510------------------ 511 512- <https://downloadcenter.intel.com/> 513 514udev 515---- 516 517- <https://www.freedesktop.org/software/systemd/man/udev.html> 518 519FUSE 520---- 521 522- <https://github.com/libfuse/libfuse/releases> 523 524mcelog 525------ 526 527- <http://www.mcelog.org/> 528 529cpio 530---- 531 532- <https://www.gnu.org/software/cpio/> 533 534Networking 535********** 536 537PPP 538--- 539 540- <https://download.samba.org/pub/ppp/> 541- <https://git.ozlabs.org/?p=ppp.git> 542- <https://github.com/paulusmack/ppp/> 543 544NFS-utils 545--------- 546 547- <http://sourceforge.net/project/showfiles.php?group_id=14> 548 549Iptables 550-------- 551 552- <https://netfilter.org/projects/iptables/index.html> 553 554Ip-route2 555--------- 556 557- <https://www.kernel.org/pub/linux/utils/net/iproute2/> 558 559OProfile 560-------- 561 562- <http://oprofile.sf.net/download/> 563 564NFS-Utils 565--------- 566 567- <http://nfs.sourceforge.net/> 568 569Kernel documentation 570******************** 571 572Sphinx 573------ 574 575- <https://www.sphinx-doc.org/> 576