Re: [PATCH 5/5] kbuild: external module build doc

[Jari Ruusu <jariruusu@users.sourceforge.net>]

Sam Ravnborg wrote:
> --- /dev/null   Wed Dec 31 16:00:00 196900
> +++ b/Documentation/kbuild/extmodules.txt       2004-06-14 22:25:21 +02:00
[snip]
> +A more advanced example
> +- - - - - - - - - - - -
> +This example shows a setup where a distribution has wisely decided
> +to separate kernel source and output files:
> +
> +Kernel src:
> +/usr/src/linux-<kernel-version>/
> +
> +Output from a kernel compile, including .config:
> +/lib/modules/linux-<kernel-version>/build/
                                       ^^^^^
Wrong! The 'build' symlink has always pointed to kernel source dir in
separate source and object directory case. Maybe you meant:

Output from a kernel compile, including .config:
/lib/modules/linux-<kernel-version>/object/
                                    ^^^^^^
> +External module to be compiled:
> +/home/user/module/src/
> +
> +To compile the module located in the directory above use the
> +following command:
> +
> +       cd /home/user/module/src
> +       make -C /usr/src/linux-<kernel-version> \
> +       O=/lib/modules/linux-<kernel-version>/build \
                                                ^^^^^
O=/lib/modules/linux-<kernel-version>/object
                                      ^^^^^^
> +       M=`pwd`
> +
> +Then to install the module use the following command:
> +
> +       make -C /usr/src/linux-<kernel-version> \
> +               O=/lib/modules/linux-<kernel-version>/build \
                                                        ^^^^^
O=/lib/modules/linux-<kernel-version>/object
                                      ^^^^^^
> +               M='pwd` modules_install
[snip]
> +Prepare the kernel for building external modules
> +------------------------------------------------
> +When building external modules the kernel is expected to be prepared.
> +This includes the precense of certain binaries, the kernel configuration
> +and the symlink to include/asm.
> +To do this a convinient target is made:
> +
> +       make modules_prepare
> +
> +For a typical distribution this would look like the follwoing:
> +
> +       make modules_prepare O=/lib/modules/linux-<kernel version>/build
                                                                     ^^^^^
make modules_prepare O=/lib/modules/linux-<kernel version>/object
                                                           ^^^^^^
Sam, You don't seem to have any idea how much breakage you introduce if you
insist on redirecting the 'build' symlink from source tree to object tree.

-- 
Jari Ruusu  1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9  DB 1D EB E3 24 0E A9 DD