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, 45 insertions, 0 deletions

diff --git a/arch/arm/boot/compressed/decompress.c b/arch/arm/boot/compressed/decompress.c
new file mode 100644
index 000000000000..0da382f33157
--- /dev/null
+++ b/arch/arm/boot/compressed/decompress.c
@@ -0,0 +1,45 @@
+#define _LINUX_STRING_H_
+
+#include <linux/compiler.h>     /* for inline */
+#include <linux/types.h>        /* for size_t */
+#include <linux/stddef.h>       /* for NULL */
+#include <linux/linkage.h>
+#include <asm/string.h>
+
+extern unsigned long free_mem_ptr;
+extern unsigned long free_mem_end_ptr;
+extern void error(char *);
+
+#define STATIC static
+
+#define ARCH_HAS_DECOMP_WDOG
+
+/* Diagnostic functions */
+#ifdef DEBUG
+#  define Assert(cond,msg) {if(!(cond)) error(msg);}
+#  define Trace(x) fprintf x
+#  define Tracev(x) {if (verbose) fprintf x ;}
+#  define Tracevv(x) {if (verbose>1) fprintf x ;}
+#  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
+#  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
+#else
+#  define Assert(cond,msg)
+#  define Trace(x)
+#  define Tracev(x)
+#  define Tracevv(x)
+#  define Tracec(c,x)
+#  define Tracecv(c,x)
+#endif
+
+#ifdef CONFIG_KERNEL_GZIP
+#include "../../../../lib/decompress_inflate.c"
+#endif
+
+#ifdef CONFIG_KERNEL_LZO
+#include "../../../../lib/decompress_unlzo.c"
+#endif
+
+void do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
+{
+        decompress(input, len, NULL, NULL, output, NULL, error);
+}