powerpc/boot: Add support for 64bit little endian wrapper

The code is only slightly modified : entry points now use the
FIXUP_ENDIAN trampoline to switch endian order. The 32bit wrapper
is kept for big endian kernels and 64bit is enforced for little
endian kernels with a PPC64_BOOT_WRAPPER config option.

The linker script is generated using the kernel preprocessor flags
to make use of the CONFIG_* definitions and the wrapper script is
modified to take into account the new elf64ppc format.

Finally, the zImage file is compiled as a position independent
executable (-pie) which makes it loadable at any address by the
firmware.

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index d9e2b19b7c8d..43b65ad1970a 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -422,6 +422,7 @@ config CPU_BIG_ENDIAN
 
 config CPU_LITTLE_ENDIAN
         bool "Build little endian kernel"
+        select PPC64_BOOT_WRAPPER
         help
           Build a little endian kernel.
 
@@ -430,3 +431,7 @@ config CPU_LITTLE_ENDIAN
           little endian powerpc.
 
 endchoice
+
+config PPC64_BOOT_WRAPPER
+        def_bool n
+        depends on CPU_LITTLE_ENDIAN