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authorJean-Paul Saman <jean-paul.saman@nxp.com>2007-02-10 01:44:43 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-11 10:51:25 -0800
commitc33df4eaaf41fd3e34837a6ae9a5f9970c393d9f (patch)
treeb53498e6cd10a6da004b1835f285ed64493abdf2
parentdd65aa6690e30fdad84a62191c7ab37da89d9865 (diff)
downloadlinux-stericsson-c33df4eaaf41fd3e34837a6ae9a5f9970c393d9f.tar.gz
[PATCH] disable init/initramfs.c
The file init/initramfs.c is always compiled and linked in the kernel vmlinux even when BLK_DEV_RAM and BLK_DEV_INITRD are disabled and the system isn't using any form of an initramfs or initrd. In this situation the code is only used to unpack a (static) default initial rootfilesystem. The current init/initramfs.c code. usr/initramfs_data.o compiles to a size of ~15 kbytes. Disabling BLK_DEV_RAM and BLK_DEV_INTRD shrinks the kernel code size with ~60 Kbytes. This patch avoids compiling in the code and data for initramfs support if CONFIG_BLK_DEV_INITRD is not defined. Instead of the initramfs code and data it uses a small routine in init/noinitramfs.c to setup an initial static default environment for mounting a rootfilesystem later on in the kernel initialisation process. The new code is: 164 bytes of size. The patch is separated in two parts: 1) doesn't compile initramfs code when CONFIG_BLK_DEV_INITRD is not set 2) changing all plaforms vmlinux.lds.S files to not reserve an area of PAGE_SIZE when CONFIG_BLK_DEV_INITRD is not set. [deweerdt@free.fr: warning fix] Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/block/Kconfig4
-rw-r--r--init/Kconfig4
-rw-r--r--init/Makefile7
-rw-r--r--init/noinitramfs.c52
-rw-r--r--usr/Makefile2
5 files changed, 66 insertions, 3 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 58c1debf86f1..cacb1c816e35 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -417,8 +417,10 @@ config BLK_DEV_INITRD
etc. See <file:Documentation/initrd.txt> for details.
If RAM disk support (BLK_DEV_RAM) is also included, this
- also enables initial RAM disk (initrd) support.
+ also enables initial RAM disk (initrd) support and adds
+ 15 Kbytes (more on some other architectures) to the kernel size.
+ If unsure say Y.
config CDROM_PKTCDVD
tristate "Packet writing on CD/DVD media"
diff --git a/init/Kconfig b/init/Kconfig
index a3f83e2c8250..ab6942231045 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -280,8 +280,12 @@ config RELAY
If unsure, say N.
+if BLK_DEV_INITRD
+
source "usr/Kconfig"
+endif
+
config CC_OPTIMIZE_FOR_SIZE
bool "Optimize for size (Look out for broken compilers!)"
default y
diff --git a/init/Makefile b/init/Makefile
index 633a268d270d..0154aea1e52d 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -2,7 +2,12 @@
# Makefile for the linux kernel.
#
-obj-y := main.o version.o mounts.o initramfs.o
+obj-y := main.o version.o mounts.o
+ifneq ($(CONFIG_BLK_DEV_INITRD),y)
+obj-y += noinitramfs.o
+else
+obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
+endif
obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
mounts-y := do_mounts.o
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
new file mode 100644
index 000000000000..f4c1a3a1b8c5
--- /dev/null
+++ b/init/noinitramfs.c
@@ -0,0 +1,52 @@
+/*
+ * init/noinitramfs.c
+ *
+ * Copyright (C) 2006, NXP Semiconductors, All Rights Reserved
+ * Author: Jean-Paul Saman <jean-paul.saman@nxp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <linux/init.h>
+#include <linux/stat.h>
+#include <linux/kdev_t.h>
+#include <linux/syscalls.h>
+
+/*
+ * Create a simple rootfs that is similar to the default initramfs
+ */
+static int __init default_rootfs(void)
+{
+ int err;
+
+ err = sys_mkdir("/dev", 0755);
+ if (err < 0)
+ goto out;
+
+ err = sys_mknod((const char __user *) "/dev/console",
+ S_IFCHR | S_IRUSR | S_IWUSR,
+ new_encode_dev(MKDEV(5, 1)));
+ if (err < 0)
+ goto out;
+
+ err = sys_mkdir("/root", 0700);
+ if (err < 0)
+ goto out;
+
+ return 0;
+
+out:
+ printk(KERN_WARNING "Failed to create a rootfs\n");
+ return err;
+}
+rootfs_initcall(default_rootfs);
diff --git a/usr/Makefile b/usr/Makefile
index 382702ad663b..201f27f8cbaf 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -7,7 +7,7 @@ PHONY += klibcdirs
# Generate builtin.o based on initramfs_data.o
-obj-y := initramfs_data.o
+obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o
# initramfs_data.o contains the initramfs_data.cpio.gz image.
# The image is included using .incbin, a dependency which is not