1 files changed, 19 insertions, 16 deletions

diff --git a/arch/s390/boot/compressed/misc.c b/arch/s390/boot/compressed/misc.c
index fa95041fa9f6..33ca29333e18 100644
--- a/arch/s390/boot/compressed/misc.c
+++ b/arch/s390/boot/compressed/misc.c
@@ -141,31 +141,34 @@ static void check_ipl_parmblock(void *start, unsigned long size)
 
 unsigned long decompress_kernel(void)
 {
-        unsigned long output_addr;
-        unsigned char *output;
+        void *output, *kernel_end;
 
-        output_addr = ((unsigned long) &_end + HEAP_SIZE + 4095UL) & -4096UL;
-        check_ipl_parmblock((void *) 0, output_addr + SZ__bss_start);
-        memset(&_bss, 0, &_ebss - &_bss);
-        free_mem_ptr = (unsigned long)&_end;
-        free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
-        output = (unsigned char *) output_addr;
+        output = (void *) ALIGN((unsigned long) &_end + HEAP_SIZE, PAGE_SIZE);
+        kernel_end = output + SZ__bss_start;
+        check_ipl_parmblock((void *) 0, (unsigned long) kernel_end);
 
 #ifdef CONFIG_BLK_DEV_INITRD
         /*
          * Move the initrd right behind the end of the decompressed
-         * kernel image.
+         * kernel image. This also prevents initrd corruption caused by
+         * bss clearing since kernel_end will always be located behind the
+         * current bss section..
          */
-        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;
+        if (INITRD_START && INITRD_SIZE && kernel_end > (void *) INITRD_START) {
+                check_ipl_parmblock(kernel_end, INITRD_SIZE);
+                memmove(kernel_end, (void *) INITRD_START, INITRD_SIZE);
+                INITRD_START = (unsigned long) kernel_end;
         }
 #endif
 
+        /*
+         * Clear bss section. free_mem_ptr and free_mem_end_ptr need to be
+         * initialized afterwards since they reside in bss.
+         */
+        memset(&_bss, 0, &_ebss - &_bss);
+        free_mem_ptr = (unsigned long) &_end;
+        free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
+
         puts("Uncompressing Linux... ");
         __decompress(input_data, input_len, NULL, NULL, output, 0, NULL, error);
         puts("Ok, booting the kernel.\n");