s390/decompressor: fix initrd corruption caused by bss clear

[pandora-kernel.git] / arch / s390 / boot / compressed / misc.c

diff --git a/arch/s390/boot/compressed/misc.c b/arch/s390/boot/compressed/misc.c
index 465eca7..52ba6c0 100644 (file)
--- a/arch/s390/boot/compressed/misc.c
+++ b/arch/s390/boot/compressed/misc.c
@@ -135,31 +135,34 @@ 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, NULL, error);
        puts("Ok, booting the kernel.\n");