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
|
// -*- mode:doc -*- ;
[[packages-custom]]
=== Customizing packages
It is sometimes useful to apply 'extra' patches to packages - over and
above those provided in Buildroot. This might be used to support custom
features in a project, for example, or when working on a new architecture.
The +BR2_GLOBAL_PATCH_DIR+ configuration option can be used to specify
a space separated list of one or more directories containing package
patches. By specifying multiple global patch directories, a user could
implement a layered approach to patches. This could be useful when a
user has multiple boards that share a common processor architecture.
It is often the case that a subset of patches for a package need to be
shared between the different boards a user has. However, each board
may require specific patches for the package that build on top of the
common subset of patches.
For a specific version +<packageversion>+ of a specific package
+<packagename>+, patches are applied from +BR2_GLOBAL_PATCH_DIR+ as
follows:
. For every directory - +<global-patch-dir>+ - that exists in
+BR2_GLOBAL_PATCH_DIR+, a +<package-patch-dir>+ will be determined as
follows:
+
* +<global-patch-dir>/<packagename>/<packageversion>/+ if the
directory exists.
+
* Otherwise, +<global-patch-dir>/<packagename>+ if the directory
exists.
. Patches will then be applied from a +<package-patch-dir>+ as
follows:
+
* If a +series+ file exists in the package directory, then patches are
applied according to the +series+ file;
+
* Otherwise, patch files matching +<packagename>-*.patch+
are applied in alphabetical order.
So, to ensure they are applied in the right order, it is highly
recommended to name the patch files like this:
+<packagename>-<number>-<description>.patch+, where +<number>+
refers to the 'apply order'.
For information about how patches are applied for a package, see
xref:patch-apply-order[]
The +BR2_GLOBAL_PATCH_DIR+ option is the preferred method for
specifying a custom patch directory for packages. It can be used to
specify a patch directory for any package in buildroot. It should also
be used in place of the custom patch directory options that are
available for packages such as U-Boot and Barebox. By doing this, it
will allow a user to manage their patches from one top-level
directory.
The exception to +BR2_GLOBAL_PATCH_DIR+ being the preferred method for
specifying custom patches is +BR2_LINUX_KERNEL_PATCH+.
+BR2_LINUX_KERNEL_PATCH+ should be used to specify kernel patches that
are available at an URL. *Note:* +BR2_LINUX_KERNEL_PATCH+ specifies kernel
patches that are applied after patches available in +BR2_GLOBAL_PATCH_DIR+,
as it is done from a post-patch hook of the Linux package.
An example directory structure for where a user has multiple
directories specified for +BR2_GLOBAL_PATCH_DIR+ may look like this:
-----
board/
+-- common-fooarch
| +-- patches
| +-- linux
| | +-- linux-patch1.patch
| | +-- linux-patch2.patch
| +-- uboot
| +-- foopkg
+-- fooarch-board
+-- patches
+-- linux
| +-- linux-patch3.patch
+-- uboot
+-- foopkg
-----
If the user has the +BR2_GLOBAL_PATCH_DIR+ configuration option set as
follows:
-----
BR2_GLOBAL_PATCH_DIR="board/common-fooarch/patches board/fooarch-board/patches"
-----
Then the patches would applied as follows for the Linux kernel:
. board/common-fooarch/patches/linux/linux-patch1.patch
. board/common-fooarch/patches/linux/linux-patch2.patch
. board/fooarch-board/patches/linux/linux-patch3.patch
|
