summaryrefslogtreecommitdiffstats
path: root/Documentation/process/changes.rst
blob: cf908d79666e423b27e352e68a093b44395bd019 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
.. _changes:

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 4.x kernels.

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)  10.0.1           clang --version
GNU make               3.81             make --version
binutils               2.23             ld -v
flex                   2.5.35           flex --version
bison                  2.0              bison --version
pahole                 1.16             pahole --version
util-linux             2.10o            fdformat --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\ [#f1]_         1.7              sphinx-build --version
====================== ===============  ========================================

.. [#f1] Sphinx is needed only to build the Kernel documentation

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 <https://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 :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.

Make
----

You will need GNU make 3.81 or later to build the kernel.

Binutils
--------

Binutils 2.23 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.


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, have a fdformat which works with 2.4 kernels, 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 :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>`
for details about Sphinx requirements.

Getting updated software
========================

Kernel compilation
******************

gcc
---

- <ftp://ftp.gnu.org/gnu/gcc/>

Clang/LLVM
----------

- :ref:`Getting LLVM <getting_llvm>`.

Make
----

- <ftp://ftp.gnu.org/gnu/make/>

Binutils
--------

- <https://www.kernel.org/pub/linux/devel/binutils/>

Flex
----

- <https://github.com/westes/flex/releases>

Bison
-----

- <ftp://ftp.gnu.org/gnu/bison/>

OpenSSL
-------

- <https://www.openssl.org/>

System utilities
****************

Util-linux
----------

- <https://www.kernel.org/pub/linux/utils/util-linux/>

Kmod
----

- <https://www.kernel.org/pub/linux/utils/kernel/kmod/>
- <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git>

Ksymoops
--------

- <https://www.kernel.org/pub/linux/utils/kernel/ksymoops/v2.4/>

Mkinitrd
--------

- <https://code.launchpad.net/initrd-tools/main>

E2fsprogs
---------

- <https://www.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/>
- <https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/>

JFSutils
--------

- <http://jfs.sourceforge.net/>

Reiserfsprogs
-------------

- <https://git.kernel.org/pub/scm/linux/kernel/git/jeffm/reiserfsprogs.git/>

Xfsprogs
--------

- <https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git>
- <https://www.kernel.org/pub/linux/utils/fs/xfs/xfsprogs/>

Pcmciautils
-----------

- <https://www.kernel.org/pub/linux/utils/kernel/pcmcia/>

Quota-tools
-----------

- <http://sourceforge.net/projects/linuxquota/>


Intel P6 microcode
------------------

- <https://downloadcenter.intel.com/>

udev
----

- <https://www.freedesktop.org/software/systemd/man/udev.html>

FUSE
----

- <https://github.com/libfuse/libfuse/releases>

mcelog
------

- <http://www.mcelog.org/>

Networking
**********

PPP
---

- <https://download.samba.org/pub/ppp/>
- <https://git.ozlabs.org/?p=ppp.git>
- <https://github.com/paulusmack/ppp/>

NFS-utils
---------

- <http://sourceforge.net/project/showfiles.php?group_id=14>

Iptables
--------

- <https://netfilter.org/projects/iptables/index.html>

Ip-route2
---------

- <https://www.kernel.org/pub/linux/utils/net/iproute2/>

OProfile
--------

- <http://oprofile.sf.net/download/>

NFS-Utils
---------

- <http://nfs.sourceforge.net/>

Kernel documentation
********************

Sphinx
------

- <https://www.sphinx-doc.org/>