--- 6.1 Set variables to tweak the build to the architecture
--- 6.2 Add prerequisites to archprepare:
--- 6.3 List directories to visit when descending
- --- 6.4 Architecture specific boot images
+ --- 6.4 Architecture-specific boot images
--- 6.5 Building non-kbuild targets
--- 6.6 Commands useful for building a boot image
--- 6.7 Custom kbuild commands
Example:
obj-y += foo.o
- This tell kbuild that there is one object in that directory, named
+ This tells kbuild that there is one object in that directory, named
foo.o. foo.o will be built from foo.c or foo.S.
If foo.o shall be built as a module, the variable obj-m is used.
Special rules are used when the kbuild infrastructure does
not provide the required support. A typical example is
header files generated during the build process.
- Another example are the architecture specific Makefiles which
+ Another example are the architecture-specific Makefiles which
need special rules to prepare boot images etc.
Special rules are written as normal Make rules.
#arch/i386/kernel/Makefile
vsyscall-flags += $(call ld-option, -Wl$(comma)--hash-style=sysv)
- In the above example vsyscall-flags will be assigned the option
+ In the above example, vsyscall-flags will be assigned the option
-Wl$(comma)--hash-style=sysv if it is supported by $(CC).
The second argument is optional, and if supplied will be used
if first argument is not supported.
#arch/i386/Makefile
cflags-y += $(call cc-option,-march=pentium-mmx,-march=i586)
- In the above example cflags-y will be assigned the option
+ In the above example, cflags-y will be assigned the option
-march=pentium-mmx if supported by $(CC), otherwise -march=i586.
The second argument to cc-option is optional, and if omitted,
cflags-y will be assigned no value if first option is not supported.
located at the root of the obj tree.
The very first objects linked are listed in head-y, assigned by
arch/$(ARCH)/Makefile.
-7) Finally, the architecture specific part does any required post processing
+7) Finally, the architecture-specific part does any required post processing
and builds the final bootimage.
- This includes building boot records
- - Preparing initrd images and thelike
+ - Preparing initrd images and the like
--- 6.1 Set variables to tweak the build to the architecture
$(head-y) lists objects to be linked first in vmlinux.
$(libs-y) lists directories where a lib.a archive can be located.
- The rest lists directories where a built-in.o object file can be
+ The rest list directories where a built-in.o object file can be
located.
$(init-y) objects will be located after $(head-y).
$(core-y), $(libs-y), $(drivers-y) and $(net-y).
The top level Makefile defines values for all generic directories,
- and arch/$(ARCH)/Makefile only adds architecture specific directories.
+ and arch/$(ARCH)/Makefile only adds architecture-specific directories.
Example:
#arch/sparc64/Makefile
drivers-$(CONFIG_OPROFILE) += arch/sparc64/oprofile/
---- 6.4 Architecture specific boot images
+--- 6.4 Architecture-specific boot images
An arch Makefile specifies goals that take the vmlinux file, compress
it, wrap it in bootstrapping code, and copy the resulting files
"$(Q)$(MAKE) $(build)=<dir>" is the recommended way to invoke
make in a subdirectory.
- There are no rules for naming architecture specific targets,
+ There are no rules for naming architecture-specific targets,
but executing "make help" will list all relevant targets.
To support this, $(archhelp) must be defined.
$(call if_changed,ld/objcopy/gzip)
When the rule is evaluated, it is checked to see if any files
- needs an update, or the command line has changed since the last
+ need an update, or the command line has changed since the last
invocation. The latter will force a rebuild if any options
to the executable have changed.
Any target that utilises if_changed must be listed in $(targets),
assignment.
The kbuild infrastructure for *lds file are used in several
- architecture specific files.
+ architecture-specific files.
=== 7 Kbuild Variables
This variable defines a place for the arch Makefiles to install
the resident kernel image and System.map file.
- Use this for architecture specific install targets.
+ Use this for architecture-specific install targets.
INSTALL_MOD_PATH, MODLIB