x86, relocs: Move ELF relocation handling to C

Moves the relocation handling into C, after decompression. This requires
that the decompressed size is passed to the decompression routine as
well so that relocations can be found. Only kernels that need relocation
support will use the code (currently just x86_32), but this is laying
the ground work for 64-bit using it in support of KASLR.

Based on work by Neill Clift and Michael Davidson.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130708161517.GA4832@www.outflux.net
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 07639c656fcd..41250fb33985 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -16,6 +16,10 @@ endif
 # e.g.: obj-y += foo_$(BITS).o
 export BITS
 
+ifdef CONFIG_X86_NEED_RELOCS
+        LDFLAGS_vmlinux := --emit-relocs
+endif
+
 ifeq ($(CONFIG_X86_32),y)
         BITS := 32
         UTS_MACHINE := i386
@@ -25,10 +29,6 @@ ifeq ($(CONFIG_X86_32),y)
         KBUILD_AFLAGS += $(biarch)
         KBUILD_CFLAGS += $(biarch)
 
-        ifdef CONFIG_RELOCATABLE
-                LDFLAGS_vmlinux := --emit-relocs
-        endif
-
         KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
 
         # Never want PIC in a 32-bit kernel, prevent breakage with GCC built