buildroot-novena/fs/initramfs, branch master

linux: Do not force GZIP initramfs compression

2013-07-08T12:50:31Z

Initramfs compression does not make much sense for the architectures that support compressed kernel images because in this case the data would be compressed twice. This will eventually result in a bigger kernel image and time overhead when uncompressing it. The only reason to use compressed initramfs is to reduce memory usage when the kernel prepares rootfs, and both the unpacked filesystem and initramfs.cpio are present in the memory. Buildroot attempts to force GZIP compression for initramfs, however it doesn't always work because initramfs compression mode depends on RAM disk compression supported by the kernel. Thus, CONFIG_INITRAMFS_COMPRESSION_GZIP depends on CONFIG_RD_GZIP. If CONFIG_RD_GZIP is not set, setting GZIP initramfs compression will have no effect. Besides, the kernel also supports other compression methods, like BZIP2, LZMA, XZ and LZO. Forcing the good old GZIP does not really make much sense any more. This removes initramfs compression settings from Buildroot, so that the default value preset in the kernel config is used, which is CONFIG_INITRAMFS_COMPRESSION_NONE. If initramfs compression is still needed, it can be set in the kernel config (using make linux-menuconfig) Signed-off-by: Valentine Barshak Acked-by: Arnout Vandecappelle (Essensium/Mind) Signed-off-by: Peter Korsgaard

Normalize separator size to 80

2013-06-07T08:54:54Z

Signed-off-by: Jerzy Grzegorek Signed-off-by: Peter Korsgaard

cpio/initramfs: clarify their use in the help text

2012-11-07T10:48:13Z

Recent mails on the list show that it is not very clear how to create an initial RAM fs with buildroot. So make this more explicit in the cpio and initramfs help texts. Hopefully this will reduce the /init debugging we have to do. Signed-off-by: Arnout Vandecappelle (Essensium/Mind) Signed-off-by: Peter Korsgaard

fs/initramfs: refactor with fs/cpio

2011-09-27T20:46:00Z

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) Signed-off-by: Peter Korsgaard

initramfs/init: make sure that 0, 1, 2 fds are available

2011-08-04T19:52:21Z

As the kernel doesn't automatically mount devtmpfs when an initramfs is used, commit 424888e47431db738f5f9b3c6392435bfce7a842 has introduced a small wrapper script that mounts devtmpfs before starting the real init. Unfortunately, the problem is that in this case, the init process runs without any 0, 1 and 2 file descriptors, so none of the messages/errors printed by the various initialization scripts can be seen. This is due to the fact the init process relies on 0, 1 and 2 being opened by the kernel before init is started. However, as /dev/console isn't present on the filesystem at the time the kernel tries to open the console to create the 0, 1 and 2 file descriptors, the kernel fails on this and prints the famous "Warning: unable to open an initial console". The proposed workaround is to actually open 0, 1 and 2 to /dev/console in the wrapper script, right after mounting the devtmpfs filesystem, and before starting the real init. The "Warning" from the kernel is still shown, but at least the messages from the init scripts are visible. Signed-off-by: Thomas Petazzoni Signed-off-by: Peter Korsgaard

initramfs: fix boot with dynamic /dev

2011-07-20T14:30:14Z

Devtmpfs (which is used by devtmpfs/mdev/udev options) doesn't get automounted by the kernel when an initramfs is used, causing boot failures when a dynamic /dev is used. Fix it by adding a pre-init script to mount devtmpfs before running init. Reported-by: Arnout Vandecappelle Signed-off-by: Peter Korsgaard

initramfs: fix init symlink creation

2010-11-17T20:20:45Z

The -e test will dereference the symlink, so if there is no /bin/init, we will constantly try to create the symlink. So rather than error on subsequent runs when the link exists, use the force flag to ln. Signed-off-by: Mike Frysinger Acked-by: Thomas Petazzoni Signed-off-by: Peter Korsgaard

Remove INITRAMFS_TARGET variable

2010-11-04T18:26:27Z

This used to be needed when the filesystem code was rewritten, but not the Linux compilation code. Now that the Linux compilation code has been rewritten, the mechanism to ensure that initramfs gets built *before* the kernel so that it can be integrated is different, and this INITRAMFS_TARGET variable is no longer used. See f507921d391bb2578261a9e45c003e72302dc67a for details. Signed-off-by: Thomas Petazzoni Signed-off-by: Peter Korsgaard

initramfs: Don't overwrite $(TARGET_DIR)/init if it exists

2010-08-29T21:34:03Z

Closes #2443 Allow use of custom init scripts. Signed-off-by: Simon Pasch Signed-off-by: Peter Korsgaard

initramfs: update help text

2010-06-26T05:44:16Z

Signed-off-by: Thomas Petazzoni Signed-off-by: Peter Korsgaard