Commit Graph

54 Commits

Author SHA1 Message Date
Thomas De Schampheleire
707d44d0a2 linux: install dtc (device tree compiler) as host tool if selected
Having dtc as a host tool can be useful for users that have a custom
boot scenario where the device tree is not embedded in the kernel.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-05-15 22:59:20 +02:00
Thomas Petazzoni
f18c51657f linux: improve the 'make linux-*' special commands
This patch improves two things:

 * It makes sure that the linux-menuconfig and al. commands can be
   executed even if the user hasn't executed 'make' before. Until now,
   the commands were depending on the .configured stamp, which is not
   sufficient since the linux package has been converted to the
   GENTARGETS infrastructure. Instead, depend on the linux-configure
   phony target.

 * It makes sure that those commands are not available when the Linux
   package is not selected, just like we do for Barebox.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-05-05 08:49:02 +02:00
Maxime Ripard
90759a6636 Enable cgroups in Linux if we use systemd
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-04-02 23:14:04 +02:00
Markus Kaindl
c9ccdf877a linux.mk: .ub-File copying after building initramfs
test should exit with Exit-Code 0 if no .ub-File present and copy the
file if Exit-Code 1, otherwise make fails

Signed-off-by: Markus Kaindl <markus.kaindl@stusta.mhn.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-03-21 11:44:22 +01:00
Stephan Hoffmann
aaed42d156 Microblaze: build kernel with device tree
This patch adds the options needed to build the SimpleImage containing
the device tree structure needed for the Microblaze architecture.

Handling Device Tree and SimpleImage will be handled in a general way
in the future.

I provide this patch to be able to build the system in the meantime.

Signed-off-by: Stephan Hoffmann <sho@relinux.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-03-18 22:55:18 +01:00
Alvaro G. M
0a4856ce27 DOWNLOAD: change $1=DIRECTORY_URL, $2=FILE_NAME to $1=FULL_FILE_URL, $2=FILE_NAME
This modifies the definition of DOWNLOAD to receive two arguments:
the first one is the full URL of the file to download, whereas the second
(and optional) is the name the file will have once downloaded.

Same thing with the SOURCE_CHECK_WGET and SCP functions.

All calls to these functions have been changed to the shortest form of
the new API, except for toolchains acquisition. Since there is quite a
number of different toolchains this call to DOWNLOAD is better set to the
generic one.

Signed-off-by: Alvaro G. M <alvaro.gamez@hazent.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Tested-by: Stephan Hoffmann <sho@relinux.de>
Downloading Microblaze LE toolchain works on a clean install
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-03-18 22:21:16 +01:00
Peter Korsgaard
7b911b583a linux: drop LZMA environment variable
Not used anymore.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-02-10 10:44:47 +01:00
Thomas Petazzoni
5ba5301cdc linux: use the depmod built in HOST_DIR
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2012-01-31 23:23:11 +01:00
Thomas De Schampheleire
0900c12556 linux: add linux-update-config and linux-update-defconfig targets
In analogy to build targets uclibc-update and busybox-update, add
extra targets to copy the current configuration to the custom
configuration file set in buildroot. These targets facilitate the
work of developers adding support for a specific board.

linux-update-config copies .config directly.
linux-update-defconfig first creates a defconfig and copies that.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-11-11 20:13:14 +01:00
Kelvin Cheung
c1485d51e8 Add vmlinuz support in Kernel binary format for MIPS.
Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Acked-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-10-28 10:52:31 +02:00
Gustavo Zacarias
80d7b68167 linux: bump default kernel to version 3.1
Bump default kernel vesion to 3.1 to match headers.
Also implement downloads for 3.x series kernels.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-10-24 17:49:13 +02:00
Thomas Petazzoni
0849e8193e package: remove useless arguments from GENTARGETS
Thanks to the pkgparentdir and pkgname functions, we can rewrite the
GENTARGETS macro in a way that avoids the need for each package to
repeat its name and the directory in which it is present.

[Peter: pkgdir->pkgparentdir]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-09-29 23:09:58 +02:00
Arnout Vandecappelle (Essensium/Mind)
13a3afc536 fs/initramfs: refactor with fs/cpio
An initramfs is in fact the same as a cpio archive, but embedded in
the kernel.  So instead of duplicating the cpio infrastructure,
we can simply build images/rootfs.cpio and link that into the
kernel.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-09-27 22:46:00 +02:00
Thomas De Schampheleire
3011d23518 linux: Add Linux Kernel extensions menu
Add a kernel sub-menu (called "Linux Kernel Extensions"), which makes
possible to patch it or tweak the kernel build step.

 * All linux/linux-ext-*.mk files will be read by the make process.
 * The menu can be customized in "linux/Config.ext.in".

[Peter: small fixes]
Signed-off-by: Benoit Mauduit <benoit.mauduit@openwide.fr>
Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-09-18 22:59:20 +02:00
Thomas Petazzoni
59a326b934 support: move patch-kernel.sh and rename it
The name "patch-kernel.sh" is a bit stupid, since this script is used
to patch everything in Buildroot, not only kernel trees.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-09-17 08:15:32 +02:00
Jean-Christophe PLAGNIOL-VILLARD
f5777ce8fb linux: add linux/linux26-savedefconfig support
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-08-22 22:15:35 +02:00
Peter Korsgaard
7a2fa1f8db uboot-tools: add fw_printenv, rename to uboot-tools
Move fw_printenv / fw_setenv options from the uboot bootloader build to
the uboot-mkimage package, and rename it to uboot-tools.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-18 15:27:52 +02:00
Peter Korsgaard
ea7f5ff976 linux: fix build with release candidates
Fixes *** Recursive variable `LINUX_SITE' references itself

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-14 16:38:07 +02:00
Thomas Petazzoni
f45f775b4f linux: add support for 3.x and -rc versions
The assumption that all kernels are in
http://www.kernel.org/pub/linux/kernel/v2.6/ is no longer true:
versions 3.x are in separate directories.

We now compute the directory name from the major and minor versions of
the version provided by the user. This assumes that the 3.1 version
will be in a /v3.1/ directory, which we don't know yet because the 3.1
cycle hasn't started yet.

At the same time, we add support for the official -rcX versions.

Patch tested by compiling 3.0-rc6, which Buildroot has successfully
downloaded and built.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-11 23:43:48 +02:00
Thomas Petazzoni
205fb19cdb linux: allow specification of a custom Git repository as a source
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-11 23:40:49 +02:00
Thomas Petazzoni
b0d446dee4 Improve TARGETS handling for bootloaders and kernel
As the kernel and bootloaders do not use the normal BR2_PACKAGE_*
Kconfig options, their target name was not automatically added to the
global TARGETS variable. Each bootloader .mk and the linux.mk had to
add their own target manually to TARGETS, and the package
infrastructure was making tests on non-existing Kconfig variables.

This commit improves the package infrastructure so that it looks at
BR2_PACKAGE_<pkg> for packages, BR2_TARGET_<pkg> for bootloaders and
at the special BR2_LINUX_KERNEL for the linux package.

This allows to simplify a little bit the bootloaders and linux .mk
files.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-11 23:40:23 +02:00
Thomas Petazzoni
9af0ee86b7 linux: convert to the GENTARGETS infrastructure
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-11 23:39:17 +02:00
Thomas Petazzoni
af52661d19 linux: rename LINUX26 to LINUX
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-11 23:38:58 +02:00
Peter Korsgaard
ce03b89881 linux: simplify modules check
No need to mix make and shell code.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-07 23:40:09 +02:00
Thomas Petazzoni
eff25f4cca linux: make it possible to install the kernel in /boot
[Peter: always copy to output/images as requested by Luca]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-07-07 23:16:05 +02:00
Yegor Yefremov
726b15f64a Create menu entry to select device creation method
Four methods for the creation of device files in /dev are now
proposed:

 - static method uses device table as before
 - devtmpfs method enables this feature in kernel
 - mdev method adds mdev starting script to the file system
    and selects mdev itself for installation
 - udev method selects udev for installation

All dynamic methods are based on devtmpfs, so one doesn't need to care
about /dev folder.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-05-09 14:20:03 +02:00
Martin Hicks
e2ed6c8e77 linux: Add support to specify special Kernel Image make target
This is useful for ARCHes like PowerPC that have a whole lot of
special targets for each different board.  The kernel image target
tells make which OpenFirmware machine description file is combined into
the kernel binary.

[Peter: fix long lines]
Signed-Off-By:  Martin Hicks <mort@bork.org>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-04-01 14:53:46 +02:00
Mike Frysinger
871db074b1 initial support for Blackfin processors
[Peter: don't allow MMU on bfin]
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-02-07 14:29:19 +01:00
Martin Hicks
d10e46fb76 Enable ccache for kernel compile
Just needed to pass in ccache as a prefix to the CROSS_TARGET variable.

Signed-off-by: Martin Hicks <mort@bork.org>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2011-02-01 20:51:15 +01:00
Peter Korsgaard
c1ce30f7f7 linux: fix linux- aliases
The generic linux-% alias conflicts with the linux-fusion package, so
add explicit aliases instead.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-27 22:50:18 +01:00
Thomas Petazzoni
e88704dfba linux: don't force IPv6 configuration in kernel
As per the discussion at
http://lists.busybox.net/pipermail/buildroot/2010-December/040030.html,
remove the bits that forced the IPv6 configuration in the kernel
depending on the toolchain ability to support (or not) IPv6. You may
have a toolchain with IPv6 support but still don't want to have IPv6
in your kernel.

The only parameters we adjust in the kernel configuration are:

 * ARM EABI, since we got a lot of bug reports regarding misconfigured
   kernel compared to the ABI used by userspace applications.

 * initramfs, since its contents are generated by Buildroot itself

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-22 22:19:30 +01:00
Bjørn Forsman
14c1a15fab linux: fix linux-% shortcut targets
linux-% shortcut targets (short for linux26-%) ignores the ouput dir
$(O) so that 'make O=output.arm linux-menuconfig' is actually run in the
default $(O) directory output/ and not in output.arm/. Fix by passing on
$(O) if set.

[Peter: Use EXTRAMAKEARGS]
Signed-off-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-19 21:16:37 +01:00
Bjørn Forsman
bf6fa18f4d linux: support 'make linux26-nconfig'
Signed-off-by: Bjørn Forsman <bjorn.forsman@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-19 21:10:00 +01:00
Thomas Petazzoni
84c4a10a75 linux: add KERNEL_ARCH_PATH to fix x86-specific issue
Both i386 and x86_64 architectures are supported by the arch/x86
directory in the kernel. So, when we copy the kernel configuration
file to arch/$(KERNEL_ARCH)/configs/, it does not work because
arch/i386 and arch/x86_64 do not exist.

So, we introduce KERNEL_ARCH_PATH, which is the path to the
architecture specific directory in the kernel source tree.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-17 17:00:18 +01:00
Thomas Petazzoni
71c05023d7 linux: add support for ELF vmlinux image
The ELF vmlinux image found at the root of the kernel source tree is
the format that Qemu needs when emulating mips(el) or ppc targets, so
add support for it.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-17 16:53:18 +01:00
Thomas Petazzoni
55b0a375ea linux: support a space-separated list of patches
The kernel being a component that often needs a fairly important set
of changes to be adapted to a particular hardware platform, having
maximum flexibility on the patching process is a nice
thing. Therefore, as per the discussions from the Buildroot Developer
Day, we add a mechanism to apply a list of patches (that could come
either from URLs, local files or local directories).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-16 22:30:18 +01:00
Thomas Petazzoni
fb358f7b38 linux: Import minimal defconfigs as defconfigs
Now that minimal kernel defconfigs are used in Buildroot, the problem
is that copying those minimal configuration files to .config in the
kernel source tree does not work, as kconfig will ask interactively
what should be the value for all unspecified options.

On suggestion on Sam Ravnborg, the easiest way to solve this is to
import the minimal defconfig file as a defconfig inside the kernel
tree (in arch/$(ARCH)/configs) and configure the kernel with it.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-16 22:25:32 +01:00
Mike Frysinger
b7a2358f0b linux: restore DEPMOD usage
The linux.mk rewrite lost the DEPMOD setting while installing modules
which means depending on host-module-init-tools has been useless.
Instead, the build system has been executing /sbin/depmod.

While we're here, drop the INSTALL_MOD_PATH since LINUX26_MAKE_FLAGS
already contains it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-11 22:57:07 +01:00
Mike Frysinger
176afdb3a1 linux: add shorter shortcuts
We only have one Linux kernel package, and "linux26-" is an anachronism
in today's world.  So add useful "linux-%" shortcuts to the "linux26-%".

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-11 02:01:10 +01:00
Mike Frysinger
56d387716a linux: set a few more initramfs opts for newer kernels
Building with linux-2.6.36 and initramfs support causes the build to
pause while it prompts for newer options (uid/gid/compression).  So
have the build system inject the newer options into the linux config
automatically.  Older versions should just ignore these.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-11 01:41:00 +01:00
Mike Frysinger
3bbf1c2ea6 linux: drop LDFLAGS override
The current linux code overrides LDFLAGS that the kernel itself might be
setting up. Looking at the history, there doesn't seem to be any reason
for this override. It was added in ea8b1fa6a6 without any logic.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-07 23:01:35 +01:00
Mike Frysinger
f80fdd2a33 linux: update paths to compiled cpio files
Linux has been using "usr/initramfs_data.cpio" for a few releases as the
generated cpio name, so the buildroot match of "...cpio.*" won't actually
clean out the previous result.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-11-17 17:22:51 +01:00
Peter Korsgaard
d0c3d1cf43 sed: get rid of host-sed variant
And all the infrastructure surrounding it. A broken sed implementation
is quite rare nowadays, as seen by the fact that the current host-sed
support has been broken for a while, so just get rid of it.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-09-30 23:09:39 +02:00
Thomas Petazzoni
96652637cc linux: fix uImage location on AVR32
On most architectures, the kernel image can be found in
arch/<ARCH>/boot, but on AVR32, it's in arch/<ARCH>/boot/images.

Issue initially reported by Joachim Pihl
<joachim.pihl@sensordevelopments.com>.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2010-09-29 00:14:21 +02:00
Thomas Petazzoni
b626dc0791 linux: restrict output image formats to the appropriate arches
Some Linux kernel output image formats are available on some archs,
some not. For example 'uImage' is not supported on MIPS, so let's
prevent the user from making this selection.

Issue initially reported by Choi, David <David.Choi@Micrel.Com>.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2010-09-29 00:14:21 +02:00
Peter Korsgaard
3e5e39a8a2 barebox/u-boot/linux: don't error out on missing config when make source
As it breaks 'make allyesconfig; make source', used for the source mirror.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-09-28 14:43:25 +02:00
Thomas Petazzoni
ee3f319249 linux: don't force no initramfs
When initramfs was not selected as a root filesystem, we forcefully
disabled the initramfs in the kernel configuration.

However, it prevents an user from manually managing its initramfs, as
we override the option he has set in his kernel configuration
file. There's no real reason to do so: when initramfs is not selected
as the root filesystem, just don't touch initramfs related options in
the kernel configuration.

Problem reported by Sergey Naumov <sknaumov@gmail.com>.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-09-15 21:17:35 +02:00
Thomas Petazzoni
af5dc83da4 linux: more mistake detection
Just as we do for U-Boot, error out in the Linux kernel makefile when
the defconfig name or the configuration file path are not
correct. What prompted me to implement this was a report on IRC from
an user using BR 2010.05 and not understand why the kernel build
process was failing. It was because he just forgot to set the path of
the configuration file.

Of course, it doesn't catch all mistakes (like pointing to a
non-existing defconfig or to a non-existing configuration file), but
it at least catches basic mistakes.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2010-07-29 22:18:57 +02:00
Peter Korsgaard
c9ff3273eb linux: linux26-{menu,x,g}config needs host-sed
Similar to how it's done for uclibc-menuconfig.

Reported-by: Paul Jones <paul@pauljones.id.au>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-07-20 08:45:45 +02:00
Thomas Petazzoni
f507921d39 linux: add support for initramfs
In Buildroot, the kernel is built and installed *before* the root
filesystems are built. This allows the root filesystem to correctly
contain the kernel modules that have been installed.

However, in the initramfs case, the root filesystem is part of the
kernel. Therefore, the kernel should be built *after* the root
filesystem (which, in the initramfs case simply builds a text file
listing all files/directories/devices/symlinks that should be part of
the initramfs). However, this isn't possible as the initramfs text
file would lack all kernel modules.

So, the solution choosen here is to keep the normal order: kernel is
built before the root filesystem is generated, and to add a little
quirk to retrigger a kernel compilation after the root filesystem
generation.

To do so, we add a ROOTFS_$(FSTYPE)_POST_TARGETS variable to the
fs/common.mk infrastructure. This allows individual filesystems to set
a target name that we should depend on *after* generating the root
filesystem itself (contrary to normal ROOTFS_$(FSTYPE)_DEPENDENCIES,
on which we depend *before* generating the root filesystem).

The initramfs code in fs/initramfs/initramfs.mk uses this to add a
dependency on 'linux26-rebuild-with-initramfs'.

In linux/linux.mk, we do various things :

 * If BR2_TARGET_ROOTFS_INITRAMFS is enabled (i.e if initramfs is
   enabled as a root filesystem type), then we create an empty
   rootfs.initramfs file (remember that at this point, the root
   filesystem hasn't been generated) and we adjust the kernel
   configuration to include an initramfs. Of course, in the initial
   kernel build, this initramfs will be empty.

 * In the linux26-rebuild-with-initramfs target, we retrigger a
   compilation of the kernel image, after removing the initramfs in
   the kernel sources to make sure it gets properly rebuilt (we've
   experienced cases were modifying the rootfs.initramfs file wouldn't
   retrigger the generation of the initramfs at the kernel level).

This is fairly quirky, but initramfs really is a special case, so in
one way or another, we need a little quirk to solve its specialness.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2010-06-22 21:20:28 +02:00