ARM: Eliminate decompressor -Dstatic= PIC hack

We used to build decompressors with -Dstatic= to avoid any local data
being generated.  The problem is that local data generates GOTOFF
relocations, which means we can't relocate the data relative to the
text segment.

Global data, on the other hand, goes through the GOT, and can be
relocated anywhere.

Unfortunately, with the new decompressors, this presents a problem
since they declare static data within functions, and this leads to
stack overflow.

Fix this by separating out the decompressor code into a separate file,
and removing 'static' from BSS data in misc.c.

Also, discard the .data section - this means that should we end up
with read/write initialized data, the decompressor will fail to link
and the problem will be obvious.

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 1 insertions, 5 deletions

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 2d4d88ba73bf..97c89e7de7d3 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -5,7 +5,7 @@
 #
 
 HEAD    = head.o
-OBJS    = misc.o
+OBJS    = misc.o decompress.o
 FONTC   = $(srctree)/drivers/video/console/font_acorn_8x8.c
 
 #
@@ -106,10 +106,6 @@ lib1funcs = $(obj)/lib1funcs.o
 $(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
         $(call cmd,shipped)
 
-# Don't allow any static data in misc.o, which
-# would otherwise mess up our GOT table
-CFLAGS_misc.o := -Dstatic=
-
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
                 $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
         $(call if_changed,ld)