diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index adad8863ee2f..a6e9bdb53591 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -272,7 +272,7 @@ iplstart:
 # load parameter file from ipl device
 #
 .Lagain1:
- 	l     %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # ramdisk loc. is temp
+	l     %r2,.Linitrd		       # ramdisk loc. is temp
         bas   %r14,.Lloader                    # load parameter file
         ltr   %r2,%r2                          # got anything ?
         bz    .Lnopf
@@ -280,7 +280,7 @@ iplstart:
 	bnh   .Lnotrunc
 	la    %r2,895
 .Lnotrunc:
-	l     %r4,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
+	l     %r4,.Linitrd
 	clc   0(3,%r4),.L_hdr		       # if it is HDRx
 	bz    .Lagain1			       # skip dataset header
 	clc   0(3,%r4),.L_eof		       # if it is EOFx
@@ -323,14 +323,15 @@ iplstart:
 # load ramdisk from ipl device
 #	
 .Lagain2:
- 	l     %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # addr of ramdisk
+	l     %r2,.Linitrd		       # addr of ramdisk
+	st    %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
         bas   %r14,.Lloader                    # load ramdisk
  	st    %r2,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r12) # store size of ramdisk
         ltr   %r2,%r2
         bnz   .Lrdcont
         st    %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # no ramdisk found
 .Lrdcont:
-	l     %r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
+	l     %r2,.Linitrd
 
 	clc   0(3,%r2),.L_hdr		       # skip HDRx and EOFx 
 	bz    .Lagain2
@@ -379,6 +380,7 @@ iplstart:
         l     %r1,.Lstartup
         br    %r1
 
+.Linitrd:.long _end + 0x400000		       # default address of initrd
 .Lparm:	.long  PARMAREA
 .Lstartup: .long startup
 .Lcvtab:.long  _ebcasc                         # ebcdic to ascii table
diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index a4dc61f3285e..0e46077d7140 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -26,8 +26,8 @@ startup:basr	%r13,0			# get base
 #
 	.org	PARMAREA
 	.long	0,0			# IPL_DEVICE
-	.long	0,RAMDISK_ORIGIN	# INITRD_START
-	.long	0,RAMDISK_SIZE		# INITRD_SIZE
+	.long	0,0			# INITRD_START
+	.long	0,0			# INITRD_SIZE
 
 	.org	COMMAND_LINE
 	.byte	"root=/dev/ram0 ro"
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 9d80c5b1ef95..3e0341acd04e 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -26,8 +26,8 @@ startup:basr  %r13,0			 # get base
 #
 	.org   PARMAREA
 	.quad  0			# IPL_DEVICE
-	.quad  RAMDISK_ORIGIN		# INITRD_START
-	.quad  RAMDISK_SIZE		# INITRD_SIZE
+	.quad  0			# INITRD_START
+	.quad  0			# INITRD_SIZE
 
 	.org   COMMAND_LINE
 	.byte  "root=/dev/ram0 ro"
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index c902f059c7aa..89051e8a5d8d 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -37,6 +37,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/device.h>
 #include <linux/notifier.h>
+#include <linux/pfn.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -501,13 +502,47 @@ setup_memory(void)
 	 * partially used pages are not usable - thus
 	 * we are rounding upwards:
 	 */
-	start_pfn = (__pa(&_end) + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	end_pfn = max_pfn = memory_end >> PAGE_SHIFT;
+	start_pfn = PFN_UP(__pa(&_end));
+	end_pfn = max_pfn = PFN_DOWN(memory_end);
 
 	/* Initialize storage key for kernel pages */
 	for (init_pfn = 0 ; init_pfn < start_pfn; init_pfn++)
 		page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
 
+#ifdef CONFIG_BLK_DEV_INITRD
+	/*
+	 * Move the initrd in case the bitmap of the bootmem allocater
+	 * would overwrite it.
+	 */
+
+	if (INITRD_START && INITRD_SIZE) {
+		unsigned long bmap_size;
+		unsigned long start;
+
+		bmap_size = bootmem_bootmap_pages(end_pfn - start_pfn + 1);
+		bmap_size = PFN_PHYS(bmap_size);
+
+		if (PFN_PHYS(start_pfn) + bmap_size > INITRD_START) {
+			start = PFN_PHYS(start_pfn) + bmap_size + PAGE_SIZE;
+
+			if (start + INITRD_SIZE > memory_end) {
+				printk("initrd extends beyond end of memory "
+				       "(0x%08lx > 0x%08lx)\n"
+				       "disabling initrd\n",
+				       start + INITRD_SIZE, memory_end);
+				INITRD_START = INITRD_SIZE = 0;
+			} else {
+				printk("Moving initrd (0x%08lx -> 0x%08lx, "
+				       "size: %ld)\n",
+				       INITRD_START, start, INITRD_SIZE);
+				memmove((void *) start, (void *) INITRD_START,
+					INITRD_SIZE);
+				INITRD_START = start;
+			}
+		}
+	}
+#endif
+
 	/*
 	 * Initialize the boot-time allocator (with low memory only):
 	 */
@@ -559,7 +594,7 @@ setup_memory(void)
 	reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size);
 
 #ifdef CONFIG_BLK_DEV_INITRD
-	if (INITRD_START) {
+	if (INITRD_START && INITRD_SIZE) {
 		if (INITRD_START + INITRD_SIZE <= memory_end) {
 			reserve_bootmem(INITRD_START, INITRD_SIZE);
 			initrd_start = INITRD_START;
diff --git a/include/asm-s390/setup.h b/include/asm-s390/setup.h
index 19e31979309a..02c96d57f0cf 100644
--- a/include/asm-s390/setup.h
+++ b/include/asm-s390/setup.h
@@ -14,8 +14,6 @@
 
 #define PARMAREA		0x10400
 #define COMMAND_LINE_SIZE 	896
-#define RAMDISK_ORIGIN		0x800000
-#define RAMDISK_SIZE		0x800000
 #define MEMORY_CHUNKS		16	/* max 0x7fff */
 #define IPL_PARMBLOCK_ORIGIN	0x2000