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initramfs: add support for in-kernel initramfs compressed with LZO

Add the necessary parts to be enable the use of LZO-compressed initramfs
build into the kernel.

Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 parent edcd1d8 commit 2a2a400f66e9e23eba960905c36dd37904bd9970 Albin Tonnerre committed with May 26, 2010
Showing with 34 additions and 1 deletion.
  1. +1 −0 scripts/gen_initramfs_list.sh
  2. +4 −1 usr/Makefile
  3. +29 −0 usr/initramfs_data.lzo.S
@@ -242,6 +242,7 @@ case "$arg" in
echo "$output_file" | grep -q "\.gz$" && compr="gzip -9 -f"
echo "$output_file" | grep -q "\.bz2$" && compr="bzip2 -9 -f"
echo "$output_file" | grep -q "\.lzma$" && compr="lzma -9 -f"
+ echo "$output_file" | grep -q "\.lzo$" && compr="lzop -9 -f"
echo "$output_file" | grep -q "\.cpio$" && compr="cat"
shift
;;
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@@ -15,6 +15,9 @@ suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) = .bz2
# Lzma
suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA) = .lzma
+# Lzo
+suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZO) = .lzo
+
# Generate builtin.o based on initramfs_data.o
obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data$(suffix_y).o
@@ -45,7 +48,7 @@ endif
quiet_cmd_initfs = GEN $@
cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)
-targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_data.cpio
+targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_data.cpio.lzo initramfs_data.cpio
# do not try to update files included in initramfs
$(deps_initramfs): ;
@@ -0,0 +1,29 @@
+/*
+ initramfs_data includes the compressed binary that is the
+ filesystem used for early user space.
+ Note: Older versions of "as" (prior to binutils 2.11.90.0.23
+ released on 2001-07-14) dit not support .incbin.
+ If you are forced to use older binutils than that then the
+ following trick can be applied to create the resulting binary:
+
+
+ ld -m elf_i386 --format binary --oformat elf32-i386 -r \
+ -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o
+ ld -m elf_i386 -r -o built-in.o initramfs_data.o
+
+ initramfs_data.scr looks like this:
+SECTIONS
+{
+ .init.ramfs : { *(.data) }
+}
+
+ The above example is for i386 - the parameters vary from architectures.
+ Eventually look up LDFLAGS_BLOB in an older version of the
+ arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced.
+
+ Using .incbin has the advantage over ld that the correct flags are set
+ in the ELF header, as required by certain architectures.
+*/
+
+.section .init.ramfs,"a"
+.incbin "usr/initramfs_data.cpio.lzo"

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