Documentation/process/changes.rst

   1 .. _changes:
   2
   3 Minimal requirements to compile the Kernel
   4 ++++++++++++++++++++++++++++++++++++++++++
   5
   6 Intro
   7 =====
   8
   9 This document is designed to provide a list of the minimum levels of
  10 software necessary to run the current kernel version.
  11
  12 This document is originally based on my "Changes" file for 2.0.x kernels
  13 and therefore owes credit to the same people as that file (Jared Mauch,
  14 Axel Boldt, Alessandro Sigala, and countless other users all over the
  15 'net).
  16
  17 Current Minimal Requirements
  18 ****************************
  19
  20 Upgrade to at **least** these software revisions before thinking you've
  21 encountered a bug!  If you're unsure what version you're currently
  22 running, the suggested command should tell you.
  23
  24 Again, keep in mind that this list assumes you are already functionally
  25 running a Linux kernel.  Also, not all tools are necessary on all
  26 systems; obviously, if you don't have any PC Card hardware, for example,
  27 you probably needn't concern yourself with pcmciautils.
  28
  29 ====================== ===============  ========================================
  30         Program        Minimal version       Command to check the version
  31 ====================== ===============  ========================================
  32 GNU C                  5.1              gcc --version
  33 Clang/LLVM (optional)  13.0.1           clang --version
  34 Rust (optional)        1.78.0           rustc --version
  35 bindgen (optional)     0.65.1           bindgen --version
  36 GNU make               4.0              make --version
  37 bash                   4.2              bash --version
  38 binutils               2.25             ld -v
  39 flex                   2.5.35           flex --version
  40 bison                  2.0              bison --version
  41 pahole                 1.16             pahole --version
  42 util-linux             2.10o            mount --version
  43 kmod                   13               depmod -V
  44 e2fsprogs              1.41.4           e2fsck -V
  45 jfsutils               1.1.3            fsck.jfs -V
  46 reiserfsprogs          3.6.3            reiserfsck -V
  47 xfsprogs               2.6.0            xfs_db -V
  48 squashfs-tools         4.0              mksquashfs -version
  49 btrfs-progs            0.18             btrfsck
  50 pcmciautils            004              pccardctl -V
  51 quota-tools            3.09             quota -V
  52 PPP                    2.4.0            pppd --version
  53 nfs-utils              1.0.5            showmount --version
  54 procps                 3.2.0            ps --version
  55 udev                   081              udevd --version
  56 grub                   0.93             grub --version || grub-install --version
  57 mcelog                 0.6              mcelog --version
  58 iptables               1.4.2            iptables -V
  59 openssl & libcrypto    1.0.0            openssl version
  60 bc                     1.06.95          bc --version
  61 Sphinx\ [#f1]_         2.4.4            sphinx-build --version
  62 cpio                   any              cpio --version
  63 GNU tar                1.28             tar --version
  64 gtags (optional)       6.6.5            gtags --version
  65 mkimage (optional)     2017.01          mkimage --version
  66 Python (optional)      3.5.x            python3 --version
  67 ====================== ===============  ========================================
  68
  69 .. [#f1] Sphinx is needed only to build the Kernel documentation
  70
  71 Kernel compilation
  72 ******************
  73
  74 GCC
  75 ---
  76
  77 The gcc version requirements may vary depending on the type of CPU in your
  78 computer.
  79
  80 Clang/LLVM (optional)
  81 ---------------------
  82
  83 The latest formal release of clang and LLVM utils (according to
  84 `releases.llvm.org <https://releases.llvm.org>`_) are supported for building
  85 kernels. Older releases aren't guaranteed to work, and we may drop workarounds
  86 from the kernel that were used to support older versions. Please see additional
  87 docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.
  88
  89 Rust (optional)
  90 ---------------
  91
  92 A recent version of the Rust compiler is required.
  93
  94 Please see Documentation/rust/quick-start.rst for instructions on how to
  95 satisfy the build requirements of Rust support. In particular, the ``Makefile``
  96 target ``rustavailable`` is useful to check why the Rust toolchain may not
  97 be detected.
  98
  99 bindgen (optional)
 100 ------------------
 101
 102 ``bindgen`` is used to generate the Rust bindings to the C side of the kernel.
 103 It depends on ``libclang``.
 104
 105 Make
 106 ----
 107
 108 You will need GNU make 4.0 or later to build the kernel.
 109
 110 Bash
 111 ----
 112
 113 Some bash scripts are used for the kernel build.
 114 Bash 4.2 or newer is needed.
 115
 116 Binutils
 117 --------
 118
 119 Binutils 2.25 or newer is needed to build the kernel.
 120
 121 pkg-config
 122 ----------
 123
 124 The build system, as of 4.18, requires pkg-config to check for installed
 125 kconfig tools and to determine flags settings for use in
 126 'make {g,x}config'.  Previously pkg-config was being used but not
 127 verified or documented.
 128
 129 Flex
 130 ----
 131
 132 Since Linux 4.16, the build system generates lexical analyzers
 133 during build.  This requires flex 2.5.35 or later.
 134
 135
 136 Bison
 137 -----
 138
 139 Since Linux 4.16, the build system generates parsers
 140 during build.  This requires bison 2.0 or later.
 141
 142 pahole
 143 ------
 144
 145 Since Linux 5.2, if CONFIG_DEBUG_INFO_BTF is selected, the build system
 146 generates BTF (BPF Type Format) from DWARF in vmlinux, a bit later from kernel
 147 modules as well.  This requires pahole v1.16 or later.
 148
 149 It is found in the 'dwarves' or 'pahole' distro packages or from
 150 https://fedorapeople.org/~acme/dwarves/.
 151
 152 Perl
 153 ----
 154
 155 You will need perl 5 and the following modules: ``Getopt::Long``,
 156 ``Getopt::Std``, ``File::Basename``, and ``File::Find`` to build the kernel.
 157
 158 BC
 159 --
 160
 161 You will need bc to build kernels 3.10 and higher
 162
 163
 164 OpenSSL
 165 -------
 166
 167 Module signing and external certificate handling use the OpenSSL program and
 168 crypto library to do key creation and signature generation.
 169
 170 You will need openssl to build kernels 3.7 and higher if module signing is
 171 enabled.  You will also need openssl development packages to build kernels 4.3
 172 and higher.
 173
 174 Tar
 175 ---
 176
 177 GNU tar is needed if you want to enable access to the kernel headers via sysfs
 178 (CONFIG_IKHEADERS).
 179
 180 gtags / GNU GLOBAL (optional)
 181 -----------------------------
 182
 183 The kernel build requires GNU GLOBAL version 6.6.5 or later to generate
 184 tag files through ``make gtags``.  This is due to its use of the gtags
 185 ``-C (--directory)`` flag.
 186
 187 mkimage
 188 -------
 189
 190 This tool is used when building a Flat Image Tree (FIT), commonly used on ARM
 191 platforms. The tool is available via the ``u-boot-tools`` package or can be
 192 built from the U-Boot source code. See the instructions at
 193 https://docs.u-boot.org/en/latest/build/tools.html#building-tools-for-linux
 194
 195 System utilities
 196 ****************
 197
 198 Architectural changes
 199 ---------------------
 200
 201 DevFS has been obsoleted in favour of udev
 202 (https://www.kernel.org/pub/linux/utils/kernel/hotplug/)
 203
 204 32-bit UID support is now in place.  Have fun!
 205
 206 Linux documentation for functions is transitioning to inline
 207 documentation via specially-formatted comments near their
 208 definitions in the source.  These comments can be combined with ReST
 209 files the Documentation/ directory to make enriched documentation, which can
 210 then be converted to PostScript, HTML, LaTex, ePUB and PDF files.
 211 In order to convert from ReST format to a format of your choice, you'll need
 212 Sphinx.
 213
 214 Util-linux
 215 ----------
 216
 217 New versions of util-linux provide ``fdisk`` support for larger disks,
 218 support new options to mount, recognize more supported partition
 219 types, and similar goodies.
 220 You'll probably want to upgrade.
 221
 222 Ksymoops
 223 --------
 224
 225 If the unthinkable happens and your kernel oopses, you may need the
 226 ksymoops tool to decode it, but in most cases you don't.
 227 It is generally preferred to build the kernel with ``CONFIG_KALLSYMS`` so
 228 that it produces readable dumps that can be used as-is (this also
 229 produces better output than ksymoops).  If for some reason your kernel
 230 is not build with ``CONFIG_KALLSYMS`` and you have no way to rebuild and
 231 reproduce the Oops with that option, then you can still decode that Oops
 232 with ksymoops.
 233
 234 Mkinitrd
 235 --------
 236
 237 These changes to the ``/lib/modules`` file tree layout also require that
 238 mkinitrd be upgraded.
 239
 240 E2fsprogs
 241 ---------
 242
 243 The latest version of ``e2fsprogs`` fixes several bugs in fsck and
 244 debugfs.  Obviously, it's a good idea to upgrade.
 245
 246 JFSutils
 247 --------
 248
 249 The ``jfsutils`` package contains the utilities for the file system.
 250 The following utilities are available:
 251
 252 - ``fsck.jfs`` - initiate replay of the transaction log, and check
 253   and repair a JFS formatted partition.
 254
 255 - ``mkfs.jfs`` - create a JFS formatted partition.
 256
 257 - other file system utilities are also available in this package.
 258
 259 Reiserfsprogs
 260 -------------
 261
 262 The reiserfsprogs package should be used for reiserfs-3.6.x
 263 (Linux kernels 2.4.x). It is a combined package and contains working
 264 versions of ``mkreiserfs``, ``resize_reiserfs``, ``debugreiserfs`` and
 265 ``reiserfsck``. These utils work on both i386 and alpha platforms.
 266
 267 Xfsprogs
 268 --------
 269
 270 The latest version of ``xfsprogs`` contains ``mkfs.xfs``, ``xfs_db``, and the
 271 ``xfs_repair`` utilities, among others, for the XFS filesystem.  It is
 272 architecture independent and any version from 2.0.0 onward should
 273 work correctly with this version of the XFS kernel code (2.6.0 or
 274 later is recommended, due to some significant improvements).
 275
 276 PCMCIAutils
 277 -----------
 278
 279 PCMCIAutils replaces ``pcmcia-cs``. It properly sets up
 280 PCMCIA sockets at system startup and loads the appropriate modules
 281 for 16-bit PCMCIA devices if the kernel is modularized and the hotplug
 282 subsystem is used.
 283
 284 Quota-tools
 285 -----------
 286
 287 Support for 32 bit uid's and gid's is required if you want to use
 288 the newer version 2 quota format.  Quota-tools version 3.07 and
 289 newer has this support.  Use the recommended version or newer
 290 from the table above.
 291
 292 Intel IA32 microcode
 293 --------------------
 294
 295 A driver has been added to allow updating of Intel IA32 microcode,
 296 accessible as a normal (misc) character device.  If you are not using
 297 udev you may need to::
 298
 299   mkdir /dev/cpu
 300   mknod /dev/cpu/microcode c 10 184
 301   chmod 0644 /dev/cpu/microcode
 302
 303 as root before you can use this.  You'll probably also want to
 304 get the user-space microcode_ctl utility to use with this.
 305
 306 udev
 307 ----
 308
 309 ``udev`` is a userspace application for populating ``/dev`` dynamically with
 310 only entries for devices actually present. ``udev`` replaces the basic
 311 functionality of devfs, while allowing persistent device naming for
 312 devices.
 313
 314 FUSE
 315 ----
 316
 317 Needs libfuse 2.4.0 or later.  Absolute minimum is 2.3.0 but mount
 318 options ``direct_io`` and ``kernel_cache`` won't work.
 319
 320 Networking
 321 **********
 322
 323 General changes
 324 ---------------
 325
 326 If you have advanced network configuration needs, you should probably
 327 consider using the network tools from ip-route2.
 328
 329 Packet Filter / NAT
 330 -------------------
 331 The packet filtering and NAT code uses the same tools like the previous 2.4.x
 332 kernel series (iptables).  It still includes backwards-compatibility modules
 333 for 2.2.x-style ipchains and 2.0.x-style ipfwadm.
 334
 335 PPP
 336 ---
 337
 338 The PPP driver has been restructured to support multilink and to
 339 enable it to operate over diverse media layers.  If you use PPP,
 340 upgrade pppd to at least 2.4.0.
 341
 342 If you are not using udev, you must have the device file /dev/ppp
 343 which can be made by::
 344
 345   mknod /dev/ppp c 108 0
 346
 347 as root.
 348
 349 NFS-utils
 350 ---------
 351
 352 In ancient (2.4 and earlier) kernels, the nfs server needed to know
 353 about any client that expected to be able to access files via NFS.  This
 354 information would be given to the kernel by ``mountd`` when the client
 355 mounted the filesystem, or by ``exportfs`` at system startup.  exportfs
 356 would take information about active clients from ``/var/lib/nfs/rmtab``.
 357
 358 This approach is quite fragile as it depends on rmtab being correct
 359 which is not always easy, particularly when trying to implement
 360 fail-over.  Even when the system is working well, ``rmtab`` suffers from
 361 getting lots of old entries that never get removed.
 362
 363 With modern kernels we have the option of having the kernel tell mountd
 364 when it gets a request from an unknown host, and mountd can give
 365 appropriate export information to the kernel.  This removes the
 366 dependency on ``rmtab`` and means that the kernel only needs to know about
 367 currently active clients.
 368
 369 To enable this new functionality, you need to::
 370
 371   mount -t nfsd nfsd /proc/fs/nfsd
 372
 373 before running exportfs or mountd.  It is recommended that all NFS
 374 services be protected from the internet-at-large by a firewall where
 375 that is possible.
 376
 377 mcelog
 378 ------
 379
 380 On x86 kernels the mcelog utility is needed to process and log machine check
 381 events when ``CONFIG_X86_MCE`` is enabled. Machine check events are errors
 382 reported by the CPU. Processing them is strongly encouraged.
 383
 384 Kernel documentation
 385 ********************
 386
 387 Sphinx
 388 ------
 389
 390 Please see :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>`
 391 for details about Sphinx requirements.
 392
 393 rustdoc
 394 -------
 395
 396 ``rustdoc`` is used to generate the documentation for Rust code. Please see
 397 Documentation/rust/general-information.rst for more information.
 398
 399 Getting updated software
 400 ========================
 401
 402 Kernel compilation
 403 ******************
 404
 405 gcc
 406 ---
 407
 408 - <ftp://ftp.gnu.org/gnu/gcc/>
 409
 410 Clang/LLVM
 411 ----------
 412
 413 - :ref:`Getting LLVM <getting_llvm>`.
 414
 415 Rust
 416 ----
 417
 418 - Documentation/rust/quick-start.rst.
 419
 420 bindgen
 421 -------
 422
 423 - Documentation/rust/quick-start.rst.
 424
 425 Make
 426 ----
 427
 428 - <ftp://ftp.gnu.org/gnu/make/>
 429
 430 Bash
 431 ----
 432
 433 - <ftp://ftp.gnu.org/gnu/bash/>
 434
 435 Binutils
 436 --------
 437
 438 - <https://www.kernel.org/pub/linux/devel/binutils/>
 439
 440 Flex
 441 ----
 442
 443 - <https://github.com/westes/flex/releases>
 444
 445 Bison
 446 -----
 447
 448 - <ftp://ftp.gnu.org/gnu/bison/>
 449
 450 OpenSSL
 451 -------
 452
 453 - <https://www.openssl.org/>
 454
 455 System utilities
 456 ****************
 457
 458 Util-linux
 459 ----------
 460
 461 - <https://www.kernel.org/pub/linux/utils/util-linux/>
 462
 463 Kmod
 464 ----
 465
 466 - <https://www.kernel.org/pub/linux/utils/kernel/kmod/>
 467 - <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git>
 468
 469 Ksymoops
 470 --------
 471
 472 - <https://www.kernel.org/pub/linux/utils/kernel/ksymoops/v2.4/>
 473
 474 Mkinitrd
 475 --------
 476
 477 - <https://code.launchpad.net/initrd-tools/main>
 478
 479 E2fsprogs
 480 ---------
 481
 482 - <https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/>
 483 - <https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/>
 484
 485 JFSutils
 486 --------
 487
 488 - <https://jfs.sourceforge.net/>
 489
 490 Reiserfsprogs
 491 -------------
 492
 493 - <https://git.kernel.org/pub/scm/linux/kernel/git/jeffm/reiserfsprogs.git/>
 494
 495 Xfsprogs
 496 --------
 497
 498 - <https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git>
 499 - <https://www.kernel.org/pub/linux/utils/fs/xfs/xfsprogs/>
 500
 501 Pcmciautils
 502 -----------
 503
 504 - <https://www.kernel.org/pub/linux/utils/kernel/pcmcia/>
 505
 506 Quota-tools
 507 -----------
 508
 509 - <https://sourceforge.net/projects/linuxquota/>
 510
 511
 512 Intel P6 microcode
 513 ------------------
 514
 515 - <https://downloadcenter.intel.com/>
 516
 517 udev
 518 ----
 519
 520 - <https://www.freedesktop.org/software/systemd/man/udev.html>
 521
 522 FUSE
 523 ----
 524
 525 - <https://github.com/libfuse/libfuse/releases>
 526
 527 mcelog
 528 ------
 529
 530 - <https://www.mcelog.org/>
 531
 532 cpio
 533 ----
 534
 535 - <https://www.gnu.org/software/cpio/>
 536
 537 Networking
 538 **********
 539
 540 PPP
 541 ---
 542
 543 - <https://download.samba.org/pub/ppp/>
 544 - <https://git.ozlabs.org/?p=ppp.git>
 545 - <https://github.com/paulusmack/ppp/>
 546
 547 NFS-utils
 548 ---------
 549
 550 - <https://sourceforge.net/project/showfiles.php?group_id=14>
 551 - <https://nfs.sourceforge.net/>
 552
 553 Iptables
 554 --------
 555
 556 - <https://netfilter.org/projects/iptables/index.html>
 557
 558 Ip-route2
 559 ---------
 560
 561 - <https://www.kernel.org/pub/linux/utils/net/iproute2/>
 562
 563 OProfile
 564 --------
 565
 566 - <https://oprofile.sf.net/download/>
 567
 568 Kernel documentation
 569 ********************
 570
 571 Sphinx
 572 ------
 573
 574 - <https://www.sphinx-doc.org/>