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| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 71c602d6168..f29dca374aa 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -187,34 +187,35 @@ more details, with real examples. Note: In this example $(CONFIG_ISDN_PPP_BSDCOMP) evaluates to 'm' If a kernel module is built from several source files, you specify - that you want to build a module in the same way as above. - - Kbuild needs to know which the parts that you want to build your - module from, so you have to tell it by setting an - $(<module_name>-objs) variable. + that you want to build a module in the same way as above; however, + kbuild needs to know which object files you want to build your + module from, so you have to tell it by setting a $(<module_name>-y) + variable. Example: #drivers/isdn/i4l/Makefile - obj-$(CONFIG_ISDN) += isdn.o - isdn-objs := isdn_net_lib.o isdn_v110.o isdn_common.o + obj-$(CONFIG_ISDN_I4L) += isdn.o + isdn-y := isdn_net_lib.o isdn_v110.o isdn_common.o In this example, the module name will be isdn.o. Kbuild will - compile the objects listed in $(isdn-objs) and then run + compile the objects listed in $(isdn-y) and then run "$(LD) -r" on the list of these files to generate isdn.o. - Kbuild recognises objects used for composite objects by the suffix - -objs, and the suffix -y. This allows the Makefiles to use - the value of a CONFIG_ symbol to determine if an object is part - of a composite object. + Due to kbuild recognizing $(<module_name>-y) for composite objects, + you can use the value of a CONFIG_ symbol to optionally include an + object file as part of a composite object. Example: #fs/ext2/Makefile - obj-$(CONFIG_EXT2_FS) += ext2.o - ext2-y := balloc.o bitmap.o - ext2-$(CONFIG_EXT2_FS_XATTR) += xattr.o - - In this example, xattr.o is only part of the composite object - ext2.o if $(CONFIG_EXT2_FS_XATTR) evaluates to 'y'. + obj-$(CONFIG_EXT2_FS) += ext2.o + ext2-y := balloc.o dir.o file.o ialloc.o inode.o ioctl.o \ + namei.o super.o symlink.o + ext2-$(CONFIG_EXT2_FS_XATTR) += xattr.o xattr_user.o \ + xattr_trusted.o + + In this example, xattr.o, xattr_user.o and xattr_trusted.o are only + part of the composite object ext2.o if $(CONFIG_EXT2_FS_XATTR) + evaluates to 'y'. Note: Of course, when you are building objects into the kernel, the syntax above will also work. So, if you have CONFIG_EXT2_FS=y, |