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>
The common filesystem infrastructure in fs/common.mk uses a smart
combination of makedevs and fakeroot to create the device files in the
target filesystem images without being root. This technique is applied
to all filesystem formats that rely on this common infrastructure, and
JFFS2 is one of them.
Therefore, using the -D option of mkfs.jffs2, which allows to specify
a device table, is redundant with the usage of makedevs. And it is
worst than redundant: for some reason, -D does not create all device
files with the correct major and minor numbers, as reported in
bug #1771.
For coherence, we just remove the usage of mkfs.jffs2 -D option, and
rely on makedevs/fakeroot to create the device files.
This commit fixes bug #1771.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
When initramfs was ported to the new fs structure the init symlink
macro was defined, but forgot to add it to PRE_GEN_HOOKS
Signed-off-by: Will Wagner <will_wagner@carallon.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
The restructure for building root filesystems changed the target name
for the initramfs file, to build the file the trget is now
initramfs-root but the generated file is rootfs.initramfs
Signed-off-by: Will Wagner <will_wagner@carallon.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
With the ROOTFS_TARGET conversion, EXT2_OPTS gets evaluated very early
(before TARGET_DIR is populated with files), so the calculated
blocks/inodes numbers are wrong.
Fix it by moving the calculation to a shell script wrapper around
genext2fs, so it only gets executed just before genext2fs runs.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
BR2_TARGET_ROOTFS_EXT2_RESBLKS is an int, so test against 0 rather than
the empty string - Otherwise the test is always true and a -m option
without arguments is added to the argument list, causing genext2fs to
get confused.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Until now, the location of the device table was specified by a
variable in board Makefiles. Unfortunately, this variable is not
accessible from fs/common.mk, since the target/ code is included
*after* fs/common.mk.
Anyway, the general idea is to move away from these boards Makefile,
and provide configuration option for things like the device table
location.
Therefore, this patch adds a BR2_ROOTFS_DEVICE_TABLE option which
allows to specify which device table should be used.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
The dependency on gzip, bzip2 and lzma are properly handled
automatically. No need to tell the user about this.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
