ARM: 6026/1: ARM: Add support for LZMA-compressed kernel images

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 (about 25% smaller with LZMA compared to GZIP)

Tested-by: Martin Michlmayr <tbm@cyrius.com>
Tested-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

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

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 \

arch/arm/boot/compressed/decompress.c

@@ -40,6 +40,10 @@ 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);

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: