[PATCH v2] ARM: Add support for LZMA-compressed kernel images

[Albin Tonnerre]

This patch allows using a kernel image compressed with LZMA on ARM.
Extracting the image is fairly slow, but it might be useful on machines
with a very limited amount of storage, as the size benefit is quite
significant:
Gzip: Data Size:    1586352 Bytes = 1549.17 kB = 1.51 MB
LZMA: Data Size:    2135916 Bytes = 2085.86 kB = 2.04 MB

Signed-off-by: Albin Tonnerre <albin.tonnerre at free-electrons.com>
Tested-by: Martin Michlmayr <tbm at cyrius.com>
---
v2: Updated to apply on top of 2.6.34-rc1

 arch/arm/Kconfig                      |    1 +
 arch/arm/boot/compressed/Makefile     |    1 +
 arch/arm/boot/compressed/decompress.c |    4 ++++
 arch/arm/boot/compressed/piggy.lzma.S |    6 ++++++
 4 files changed, 12 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/boot/compressed/piggy.lzma.S

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3b18128..3ebc7c3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -21,6 +21,7 @@ config ARM
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZO
+	select HAVE_KERNEL_LZMA
 	select HAVE_PERF_EVENTS
 	select PERF_USE_VMALLOC
 	help
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 97c89e7..53faa90 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -65,6 +65,7 @@ SEDFLAGS	= s/TEXT_START/$(ZTEXTADDR)/;s/BSS_START/$(ZBSSADDR)/
 
 suffix_$(CONFIG_KERNEL_GZIP) = gzip
 suffix_$(CONFIG_KERNEL_LZO)  = lzo
+suffix_$(CONFIG_KERNEL_LZMA) = lzma
 
 targets       := vmlinux vmlinux.lds \
 		 piggy.$(suffix_y) piggy.$(suffix_y).o \
diff --git a/arch/arm/boot/compressed/decompress.c b/arch/arm/boot/compressed/decompress.c
index 0da382f..d554df6 100644
--- a/arch/arm/boot/compressed/decompress.c
+++ b/arch/arm/boot/compressed/decompress.c
@@ -39,6 +39,10 @@ extern void error(char *);
 #include "../../../../lib/decompress_unlzo.c"
 #endif
 
+#ifdef CONFIG_KERNEL_LZMA
+#include "../../../../lib/decompress_unlzma.c"
+#endif
+
 void do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
 {
 	decompress(input, len, NULL, NULL, output, NULL, error);
diff --git a/arch/arm/boot/compressed/piggy.lzma.S b/arch/arm/boot/compressed/piggy.lzma.S
new file mode 100644
index 0000000..d7e69cf
--- /dev/null
+++ b/arch/arm/boot/compressed/piggy.lzma.S
@@ -0,0 +1,6 @@
+	.section .piggydata,#alloc
+	.globl	input_data
+input_data:
+	.incbin	"arch/arm/boot/compressed/piggy.lzma"
+	.globl	input_data_end
+input_data_end:
-- 
1.7.0