Kernel Building

NOTE: This page has been identified as having content that is significantly out-of-date, usually because it refers to OpenEmbedded-Classic - for new projects, you should use OpenEmbedded-Core. See OpenEmbedded Wiki Update Project for more details.

Default Build

For a default build, just run:

 bitbake virtual/kernel

After done, you can collect the built image from under the deploy folder, for example: build/tmp/deploy/glibc/images/vmware/bzImage-vmware.bin.

Kernel image type

What kind of kernel image to build is controlled by the variable KERNEL_IMAGETYPE, which is normally defined in the machine config file. For example, build image for u-boot

 KERNEL_IMAGETYPE = "uImage"

Select kernel version

FIXME.

Default configuration

The default .config file used is normally placed somewhere under recipes/linux named defconfig. You may want to search for it, say for vmware:

 find recipes/linux -name "vmware*"
 

And you find it in:

 recipes/linux/linux/vmware/defconfig

Apply custom patches

FIXME

Customize configuration

If you need to customize the kernel configuration, you may run the menuconfig task by:

 bitbake -c menuconfig virtual/kernel

Note: by default these command requires you to run in X Windows. If you want to work in text terminal only, here's a how to.

Compile

After that, you can compile the kernel by:

 bitbake -f -c compile virtual/kernel

Fine control

If you need more control over the configuration and compile process, add this somewhere into your local.conf:

 INHERIT += "devshell"

and then you can go to the shell by:

 bitbake -c devshell virtual/kernel

The build environment will be well setup for you; you can run regular make commands like make bzImage ...etc

Please note, that the INHERIT step depends on the distribution you're using, some of the distributions already include the INHERIT in their configuration, so it might work already. You can check that easily using listtask task.

Preserving the custom configuration

Changes are lost if you remove the tmpdir or do a "bitbake -c clean virtual/kernel", so you may consider replacing the defconfig with it.