[RFC PATCH 18/18] powerpc/boot: add PPC64_BOOT_WRAPPER config option

[Cédric Le Goater]

The previous patch broke compatibility for 64bit big endian kernels.

This patch adds a config option to compile the boot wrapper in 64bit
only when CPU_LITTLE_ENDIAN is selected. It restores 32bit compilation
and linking for the big endian kernel.

Signed-off-by: Cédric Le Goater <clg at fr.ibm.com>
---
 arch/powerpc/boot/Makefile             |    2 +-
 arch/powerpc/boot/wrapper              |    2 +-
 arch/powerpc/boot/zImage.lds.S         |    8 ++++----
 arch/powerpc/platforms/Kconfig.cputype |    5 +++++
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index de71d2a0af3b..7870620033c5 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -23,7 +23,7 @@ BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
 		 -fno-strict-aliasing -Os -msoft-float -pipe \
 		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
 		 -isystem $(shell $(CROSS32CC) -print-file-name=include)
-ifdef CONFIG_PPC64
+ifdef CONFIG_PPC64_BOOT_WRAPPER
 BOOTCFLAGS	+= -m64
 endif
 ifdef CONFIG_CPU_BIG_ENDIAN
diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index a1654b510ff3..299f327fb510 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -140,7 +140,7 @@ fi
 elfformat="`${CROSS}objdump -p "$kernel" | grep 'file format' | awk '{print $4}'`"
 case "$elfformat" in
     elf64-powerpcle)	format=elf64lppc	;;
-    elf64-powerpc)	format=elf64ppc	;;
+    elf64-powerpc)	format=elf32ppc	;;
     elf32-powerpc)	format=elf32ppc	;;
 esac
 
diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S
index afecab0aff5c..861e72109df2 100644
--- a/arch/powerpc/boot/zImage.lds.S
+++ b/arch/powerpc/boot/zImage.lds.S
@@ -1,6 +1,6 @@
 #include <asm-generic/vmlinux.lds.h>
 
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
 OUTPUT_ARCH(powerpc:common64)
 #else
 OUTPUT_ARCH(powerpc:common)
@@ -22,7 +22,7 @@ SECTIONS
     *(.rodata*)
     *(.data*)
     *(.sdata*)
-#ifdef CONFIG_PPC32
+#ifndef CONFIG_PPC64_BOOT_WRAPPER
     *(.got2)
 #endif
   }
@@ -37,7 +37,7 @@ SECTIONS
   .interp : { *(.interp) }
   .rela.dyn :
   {
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
     __rela_dyn_start = .;
 #endif
     *(.rela*)
@@ -67,7 +67,7 @@ SECTIONS
     _initrd_end =  .;
   }
 
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
   .got :
   {
     __toc_start = .;
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index bca2465a9c34..9476aacf59f6 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -420,6 +420,7 @@ config CPU_BIG_ENDIAN
 
 config CPU_LITTLE_ENDIAN
 	bool "Build little endian kernel"
+	select PPC64_BOOT_WRAPPER
 	help
 	  Build a little endian kernel.
 
@@ -428,3 +429,7 @@ config CPU_LITTLE_ENDIAN
 	  little endian powerpc.
 
 endchoice
+
+config PPC64_BOOT_WRAPPER
+	def_bool n
+	depends on CPU_LITTLE_ENDIAN
-- 
1.7.10.4