[S390] add support for compressed kernels

Add the "bzImage" compile target and the necessary code  to generate
compressed kernel images. The old style uncompressed "image" target
is preserved, a simple make will build them both.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/compressed/misc.c

@@ -0,0 +1,158 @@
+/*
+ * Definitions and wrapper functions for kernel decompressor
+ *
+ * Copyright IBM Corp. 2010
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <asm/uaccess.h>
+#include <asm/page.h>
+#include <asm/ipl.h>
+#include "sizes.h"
+
+/*
+ * gzip declarations
+ */
+#define STATIC static
+
+#undef memset
+#undef memcpy
+#undef memmove
+#define memzero(s, n) memset((s), 0, (n))
+
+/* Symbols defined by linker scripts */
+extern char input_data[];
+extern int input_len;
+extern int _text;
+extern int _end;
+
+static void error(char *m);
+
+static unsigned long free_mem_ptr;
+static unsigned long free_mem_end_ptr;
+
+#ifdef CONFIG_HAVE_KERNEL_BZIP2
+#define HEAP_SIZE	0x400000
+#else
+#define HEAP_SIZE	0x10000
+#endif
+
+#ifdef CONFIG_KERNEL_GZIP
+#include "../../../../lib/decompress_inflate.c"
+#endif
+
+#ifdef CONFIG_KERNEL_BZIP2
+#include "../../../../lib/decompress_bunzip2.c"
+#endif
+
+#ifdef CONFIG_KERNEL_LZMA
+#include "../../../../lib/decompress_unlzma.c"
+#endif
+
+extern _sclp_print_early(const char *);
+
+int puts(const char *s)
+{
+	_sclp_print_early(s);
+	return 0;
+}
+
+void *memset(void *s, int c, size_t n)
+{
+	char *xs;
+
+	if (c == 0)
+		return __builtin_memset(s, 0, n);
+
+	xs = (char *) s;
+	if (n > 0)
+		do {
+			*xs++ = c;
+		} while (--n > 0);
+	return s;
+}
+
+void *memcpy(void *__dest, __const void *__src, size_t __n)
+{
+	return __builtin_memcpy(__dest, __src, __n);
+}
+
+void *memmove(void *__dest, __const void *__src, size_t __n)
+{
+	char *d;
+	const char *s;
+
+	if (__dest <= __src)
+		return __builtin_memcpy(__dest, __src, __n);
+	d = __dest + __n;
+	s = __src + __n;
+	while (__n--)
+		*--d = *--s;
+	return __dest;
+}
+
+static void error(char *x)
+{
+	unsigned long long psw = 0x000a0000deadbeefULL;
+
+	puts("\n\n");
+	puts(x);
+	puts("\n\n -- System halted");
+
+	asm volatile("lpsw %0" : : "Q" (psw));
+}
+
+/*
+ * Safe guard the ipl parameter block against a memory area that will be
+ * overwritten. The validity check for the ipl parameter block is complex
+ * (see cio_get_iplinfo and ipl_save_parameters) but if the pointer to
+ * the ipl parameter block intersects with the passed memory area we can
+ * safely assume that we can read from that memory. In that case just copy
+ * the memory to IPL_PARMBLOCK_ORIGIN even if there is no ipl parameter
+ * block.
+ */
+static void check_ipl_parmblock(void *start, unsigned long size)
+{
+	void *src, *dst;
+
+	src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
+	if (src + PAGE_SIZE <= start || src >= start + size)
+		return;
+	dst = (void *) IPL_PARMBLOCK_ORIGIN;
+	memmove(dst, src, PAGE_SIZE);
+	S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
+}
+
+unsigned long decompress_kernel(void)
+{
+	unsigned long output_addr;
+	unsigned char *output;
+
+	free_mem_ptr = (unsigned long)&_end;
+	free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
+	output = (unsigned char *) ((free_mem_end_ptr + 4095UL) & -4096UL);
+
+	check_ipl_parmblock((void *) 0, (unsigned long) output + SZ__bss_start);
+
+#ifdef CONFIG_BLK_DEV_INITRD
+	/*
+	 * Move the initrd right behind the end of the decompressed
+	 * kernel image.
+	 */
+	if (INITRD_START && INITRD_SIZE &&
+	    INITRD_START < (unsigned long) output + SZ__bss_start) {
+		check_ipl_parmblock(output + SZ__bss_start,
+				    INITRD_START + INITRD_SIZE);
+		memmove(output + SZ__bss_start,
+			(void *) INITRD_START, INITRD_SIZE);
+		INITRD_START = (unsigned long) output + SZ__bss_start;
+	}
+#endif
+
+	puts("Uncompressing Linux... ");
+	decompress(input_data, input_len, NULL, NULL, output, NULL, error);
+	puts("Ok, booting the kernel.\n");
+	return (unsigned long) output;
+}
+