[S390] initrd vs. bootmem bitmap.

Move initrd if the bitmap of the bootmem allocator would overwrite it.
In addition this patch sets the default size and address of the initrd to 0.
Therefore all boot loaders must set the initrd size and address correctly.
This is especially relevant for ftp boot via HMC/SE, where this change
requires a special patch file entry in the .ins file which sets these two
values contained at address 0x10408 and 0x10410.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 48 insertions, 13 deletions

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