[PATCH v3 1/3] MIPS: zboot: Fix the build with XZ compression on older GCC versions

From: Alban Bedel
Date: Tue Jan 26 2016 - 03:38:53 EST

Some older GCC version (at least 4.6) emits calls to __bswapsi2() when
building the XZ decompressor. The link of the compressed image then
fails with the following error:

arch/mips/boot/compressed/decompress.o: In function '__fswab32':
include/uapi/linux/swab.h:60: undefined reference to '__bswapsi2'

Add bswapsi.o to the link to fix the build with these versions.

Signed-off-by: Alban Bedel <albeu@xxxxxxx>
v2: * Added CC to stable as the patch hasn't been merged in 4.4
v3: * Updated to 4.5-rc1
* Removed CC to stable as this version of the patch doesn't
apply to 4.4.
arch/mips/boot/compressed/Makefile | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index 4eff1ef..acfc3ce 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -39,10 +39,10 @@ vmlinuzobjs-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART_PROM) += $(obj)/uart-prom.o
vmlinuzobjs-$(CONFIG_MIPS_ALCHEMY) += $(obj)/uart-alchemy.o

-vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o
+vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o

-$(obj)/ashldi3.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
-$(obj)/ashldi3.c: $(srctree)/arch/mips/lib/ashldi3.c
+$(obj)/ashldi3.o $(obj)/bswapsi.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
+$(obj)/ashldi3.c $(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
$(call cmd,shipped)

targets := $(notdir $(vmlinuzobjs-y))