[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>

1 files changed, 38 insertions, 3 deletions

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;