tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1Output files
2
3modules.order
4--------------------------------------------------
5This file records the order in which modules appear in Makefiles. This
6is used by modprobe to deterministically resolve aliases that match
7multiple modules.
8
9modules.builtin
10--------------------------------------------------
11This file lists all modules that are built into the kernel. This is used
12by modprobe to not fail when trying to load something builtin.
13
14
15Environment variables
16
17KCPPFLAGS
18--------------------------------------------------
19Additional options to pass when preprocessing. The preprocessing options
20will be used in all cases where kbuild does preprocessing including
21building C files and assembler files.
22
23KAFLAGS
24--------------------------------------------------
25Additional options to the assembler (for built-in and modules).
26
27AFLAGS_MODULE
28--------------------------------------------------
29Additional module specific options to use for $(AS).
30
31AFLAGS_KERNEL
32--------------------------------------------------
33Additional options for $(AS) when used for assembler
34code for code that is compiled as built-in.
35
36KCFLAGS
37--------------------------------------------------
38Additional options to the C compiler (for built-in and modules).
39
40CFLAGS_KERNEL
41--------------------------------------------------
42Additional options for $(CC) when used to compile
43code that is compiled as built-in.
44
45CFLAGS_MODULE
46--------------------------------------------------
47Additional module specific options to use for $(CC).
48
49LDFLAGS_MODULE
50--------------------------------------------------
51Additional options used for $(LD) when linking modules.
52
53KBUILD_VERBOSE
54--------------------------------------------------
55Set the kbuild verbosity. Can be assigned same values as "V=...".
56See make help for the full list.
57Setting "V=..." takes precedence over KBUILD_VERBOSE.
58
59KBUILD_EXTMOD
60--------------------------------------------------
61Set the directory to look for the kernel source when building external
62modules.
63The directory can be specified in several ways:
641) Use "M=..." on the command line
652) Environment variable KBUILD_EXTMOD
663) Environment variable SUBDIRS
67The possibilities are listed in the order they take precedence.
68Using "M=..." will always override the others.
69
70KBUILD_OUTPUT
71--------------------------------------------------
72Specify the output directory when building the kernel.
73The output directory can also be specified using "O=...".
74Setting "O=..." takes precedence over KBUILD_OUTPUT.
75
76KBUILD_DEBARCH
77--------------------------------------------------
78For the deb-pkg target, allows overriding the normal heuristics deployed by
79deb-pkg. Normally deb-pkg attempts to guess the right architecture based on
80the UTS_MACHINE variable, and on some architectures also the kernel config.
81The value of KBUILD_DEBARCH is assumed (not checked) to be a valid Debian
82architecture.
83
84ARCH
85--------------------------------------------------
86Set ARCH to the architecture to be built.
87In most cases the name of the architecture is the same as the
88directory name found in the arch/ directory.
89But some architectures such as x86 and sparc have aliases.
90x86: i386 for 32 bit, x86_64 for 64 bit
91sparc: sparc for 32 bit, sparc64 for 64 bit
92
93CROSS_COMPILE
94--------------------------------------------------
95Specify an optional fixed part of the binutils filename.
96CROSS_COMPILE can be a part of the filename or the full path.
97
98CROSS_COMPILE is also used for ccache in some setups.
99
100CF
101--------------------------------------------------
102Additional options for sparse.
103CF is often used on the command-line like this:
104
105 make CF=-Wbitwise C=2
106
107INSTALL_PATH
108--------------------------------------------------
109INSTALL_PATH specifies where to place the updated kernel and system map
110images. Default is /boot, but you can set it to other values.
111
112INSTALLKERNEL
113--------------------------------------------------
114Install script called when using "make install".
115The default name is "installkernel".
116
117The script will be called with the following arguments:
118 $1 - kernel version
119 $2 - kernel image file
120 $3 - kernel map file
121 $4 - default install path (use root directory if blank)
122
123The implementation of "make install" is architecture specific
124and it may differ from the above.
125
126INSTALLKERNEL is provided to enable the possibility to
127specify a custom installer when cross compiling a kernel.
128
129MODLIB
130--------------------------------------------------
131Specify where to install modules.
132The default value is:
133
134 $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
135
136The value can be overridden in which case the default value is ignored.
137
138INSTALL_MOD_PATH
139--------------------------------------------------
140INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
141relocations required by build roots. This is not defined in the
142makefile but the argument can be passed to make if needed.
143
144INSTALL_MOD_STRIP
145--------------------------------------------------
146INSTALL_MOD_STRIP, if defined, will cause modules to be
147stripped after they are installed. If INSTALL_MOD_STRIP is '1', then
148the default option --strip-debug will be used. Otherwise,
149INSTALL_MOD_STRIP value will be used as the options to the strip command.
150
151INSTALL_FW_PATH
152--------------------------------------------------
153INSTALL_FW_PATH specifies where to install the firmware blobs.
154The default value is:
155
156 $(INSTALL_MOD_PATH)/lib/firmware
157
158The value can be overridden in which case the default value is ignored.
159
160INSTALL_HDR_PATH
161--------------------------------------------------
162INSTALL_HDR_PATH specifies where to install user space headers when
163executing "make headers_*".
164The default value is:
165
166 $(objtree)/usr
167
168$(objtree) is the directory where output files are saved.
169The output directory is often set using "O=..." on the commandline.
170
171The value can be overridden in which case the default value is ignored.
172
173KBUILD_SIGN_PIN
174--------------------------------------------------
175This variable allows a passphrase or PIN to be passed to the sign-file
176utility when signing kernel modules, if the private key requires such.
177
178KBUILD_MODPOST_WARN
179--------------------------------------------------
180KBUILD_MODPOST_WARN can be set to avoid errors in case of undefined
181symbols in the final module linking stage. It changes such errors
182into warnings.
183
184KBUILD_MODPOST_NOFINAL
185--------------------------------------------------
186KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
187This is solely useful to speed up test compiles.
188
189KBUILD_EXTRA_SYMBOLS
190--------------------------------------------------
191For modules that use symbols from other modules.
192See more details in modules.txt.
193
194ALLSOURCE_ARCHS
195--------------------------------------------------
196For tags/TAGS/cscope targets, you can specify more than one arch
197to be included in the databases, separated by blank space. E.g.:
198
199 $ make ALLSOURCE_ARCHS="x86 mips arm" tags
200
201To get all available archs you can also specify all. E.g.:
202
203 $ make ALLSOURCE_ARCHS=all tags
204
205KBUILD_ENABLE_EXTRA_GCC_CHECKS
206--------------------------------------------------
207If enabled over the make command line with "W=1", it turns on additional
208gcc -W... options for more extensive build-time checking.
209
210KBUILD_BUILD_TIMESTAMP
211--------------------------------------------------
212Setting this to a date string overrides the timestamp used in the
213UTS_VERSION definition (uname -v in the running kernel). The value has to
214be a string that can be passed to date -d. The default value
215is the output of the date command at one point during build.
216
217KBUILD_BUILD_USER, KBUILD_BUILD_HOST
218--------------------------------------------------
219These two variables allow to override the user@host string displayed during
220boot and in /proc/version. The default value is the output of the commands
221whoami and host, respectively.
222
223KBUILD_LDS
224--------------------------------------------------
225The linker script with full path. Assigned by the top-level Makefile.
226
227KBUILD_VMLINUX_INIT
228--------------------------------------------------
229All object files for the init (first) part of vmlinux.
230Files specified with KBUILD_VMLINUX_INIT are linked first.
231
232KBUILD_VMLINUX_MAIN
233--------------------------------------------------
234All object files for the main part of vmlinux.
235
236KBUILD_VMLINUX_LIBS
237--------------------------------------------------
238All .a "lib" files for vmlinux.
239KBUILD_VMLINUX_INIT, KBUILD_VMLINUX_MAIN, and KBUILD_VMLINUX_LIBS together
240specify all the object files used to link vmlinux.