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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/tools/testing/selftests/rcutorture/doc/initrd.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+This document describes one way to create the initrd directory hierarchy
+in order to allow an initrd to be built into your kernel. The trick
+here is to steal the initrd file used on your Linux laptop, Ubuntu in
+this case. There are probably much better ways of doing this.
+
+That said, here are the commands:
+
+------------------------------------------------------------------------
+cd tools/testing/selftests/rcutorture
+zcat /initrd.img > /tmp/initrd.img.zcat
+mkdir initrd
+cd initrd
+cpio -id < /tmp/initrd.img.zcat
+------------------------------------------------------------------------
+
+Interestingly enough, if you are running rcutorture, you don't really
+need userspace in many cases. Running without userspace has the
+advantage of allowing you to test your kernel independently of the
+distro in place, the root-filesystem layout, and so on. To make this
+happen, put the following script in the initrd's tree's "/init" file,
+with 0755 mode.
+
+------------------------------------------------------------------------
+#!/bin/sh
+
+[ -d /dev ] || mkdir -m 0755 /dev
+[ -d /root ] || mkdir -m 0700 /root
+[ -d /sys ] || mkdir /sys
+[ -d /proc ] || mkdir /proc
+[ -d /tmp ] || mkdir /tmp
+mkdir -p /var/lock
+mount -t sysfs -o nodev,noexec,nosuid sysfs /sys
+mount -t proc -o nodev,noexec,nosuid proc /proc
+# Some things don't work properly without /etc/mtab.
+ln -sf /proc/mounts /etc/mtab
+
+# Note that this only becomes /dev on the real filesystem if udev's scripts
+# are used; which they will be, but it's worth pointing out
+if ! mount -t devtmpfs -o mode=0755 udev /dev; then
+ echo "W: devtmpfs not available, falling back to tmpfs for /dev"
+ mount -t tmpfs -o mode=0755 udev /dev
+ [ -e /dev/console ] || mknod --mode=600 /dev/console c 5 1
+ [ -e /dev/kmsg ] || mknod --mode=644 /dev/kmsg c 1 11
+ [ -e /dev/null ] || mknod --mode=666 /dev/null c 1 3
+fi
+
+mkdir /dev/pts
+mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts || true
+mount -t tmpfs -o "nosuid,size=20%,mode=0755" tmpfs /run
+mkdir /run/initramfs
+# compatibility symlink for the pre-oneiric locations
+ln -s /run/initramfs /dev/.initramfs
+
+# Export relevant variables
+export ROOT=
+export ROOTDELAY=
+export ROOTFLAGS=
+export ROOTFSTYPE=
+export IP=
+export BOOT=
+export BOOTIF=
+export UBIMTD=
+export break=
+export init=/sbin/init
+export quiet=n
+export readonly=y
+export rootmnt=/root
+export debug=
+export panic=
+export blacklist=
+export resume=
+export resume_offset=
+export recovery=
+
+for i in /sys/devices/system/cpu/cpu*/online
+do
+ case $i in
+ '/sys/devices/system/cpu/cpu0/online')
+ ;;
+ '/sys/devices/system/cpu/cpu*/online')
+ ;;
+ *)
+ echo 1 > $i
+ ;;
+ esac
+done
+
+while :
+do
+ sleep 10
+done