document special kernel cmdline parameters

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

2 files changed, 55 insertions, 0 deletions

diff --git a/install/fsck b/install/fsck
index e8b5ea3..dde219a 100644
--- a/install/fsck
+++ b/install/fsck
@@ -41,6 +41,10 @@ operation on the root device prior to mounting. If the autodetect hook is used,
 only the fsck helper specific to your filesystem will be added to the image. It
 is highly recommended that if you include this hook that you also include any
 necessary modules to ensure your keyboard will work in early userspace.
+
+To control the behavior of fsck on bootup, fsck.mode=force can be passed on
+the kernel command line to insist on running a full filesystem check. Similarly
+fsck.mode=skip can be passed to cause fsck not to run at all.
 HELPEOF
 }
 
diff --git a/mkinitcpio.8.txt b/mkinitcpio.8.txt
index f947514..070cfeb 100644
--- a/mkinitcpio.8.txt
+++ b/mkinitcpio.8.txt
@@ -98,6 +98,57 @@ you generate a new initial ramdisk, you define a preset and use the -p switch
 to generate an initial ramdisk according to your preset. Presets are located in
 /etc/mkinitcpio.d
 
+Early Init Environment
+----------------------
+mkinitcpio gives special treatment to certain environment variables passed on
+the kernel command line:
+
+*break*['=<premount|postmount>']::
+	If specified, mkinitcpio will start a shell during early init. The optional
+	parameter controls when this occurs: when 'premount' or no parameter are
+	specified, the shell will be launched prior to mounting root. If 'postmount'
+	is specified, the shell will be launched after mounting root.
+
+*disablehooks=*'hooklist'::
+	This is a comma separated list of hooks which will be skipped during early
+	init.
+
+*earlymodules=*'modulelist'::
+	This is a comma separated list of modules which will be loaded prior to any
+	others. This is generally not needed, and usually points to a configuration
+	or kernel problem.
+
+*quiet*::
+	Causes mkinitcpio to output fewer messages during boot. Errors will not be
+	suppressed.
+
+*ro*::
+	Specifies that root should be mounted with readonly permissions. This is the
+	default behavior.
+
+*rw*::
+	Specifies that root should be mounted with readwrite permissions. This is
+	generally only useful if your initramfs uses the 'fsck' hook.
+
+*root=*'rootdevice'::
+	This variable describes the root partition which early init will mount
+	before passing control to the real init. mkinitcpio understands a variety of
+	formats, the most basic of which is the path to the block device, either
+	directly, such as '/dev/sda2', or using a udev symlink such as
+	'/dev/disk/by-label/CorsairF80-root'.  Support for identification by LABEL or
+	UUID tags are also supported, such as, 'LABEL=CorsairF80-root'. As of
+	util-linux 2.22, PARTUUID is also supported.  Identification via hex encoded
+	major/minor device ID is supported for legacy reasons, but should not be used.
+
+*rootdelay=*'seconds'::
+	Sets the delay, in seconds, that mkinitcpio is willing to wait for the root
+	device to show up, if it is not available immediately. This defaults to 5
+	seconds. If an invalid integer is passed, this variable will have no effect.
+
+These are only the variables that the core of mkinitcpio honor. Additional
+hooks may look for other environment variables and should be documented by the
+help output for the hook.
+
 Files
 -----
 '/etc/mkinitcpio.conf'::