[ARM] Improve non-executable support

Add support for detecting non-executable stack binaries, and adjust
permissions to prevent execution from data and stack areas.  Also,
ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that
is true, and for any executable-stack binary.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 1d296fc..4305345 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -10,7 +10,7 @@
 
 # Object file lists.
 
-obj-y		:= compat.o entry-armv.o entry-common.o irq.o \
+obj-y		:= compat.o elf.o entry-armv.o entry-common.o irq.o \
 		   process.o ptrace.o setup.o signal.o \
 		   sys_arm.o stacktrace.o time.o traps.o