[PATCH] x86-64: fix page align in e820 allocator

Currently some code pieces assume that address returned by find_e820_area()
are page aligned.  But looks like find_e820_area() had no such intention
and hence one might end up stomping over some of the data.  One such case
is bootmem allocator initialization code stomped over bss.

This patch modified find_e820_area() to return page aligned address.  This
might be little wasteful of memory but at the same time probably it is
easier to handle page aligned memory.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>

arch/x86_64/kernel/e820.c

@@ -54,13 +54,13 @@ static inline int bad_addr(unsigned long *addrp, unsigned long size)
 
 	/* various gunk below that needed for SMP startup */
 	if (addr < 0x8000) { 
-		*addrp = 0x8000;
+		*addrp = PAGE_ALIGN(0x8000);
 		return 1; 
 	}
 
 	/* direct mapping tables of the kernel */
 	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
-		*addrp = table_end << PAGE_SHIFT; 
+		*addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
 		return 1;
 	} 
 
@@ -68,18 +68,18 @@ static inline int bad_addr(unsigned long *addrp, unsigned long size)
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
 	    addr < INITRD_START+INITRD_SIZE) { 
-		*addrp = INITRD_START + INITRD_SIZE; 
+		*addrp = PAGE_ALIGN(INITRD_START + INITRD_SIZE);
 		return 1;
 	} 
 #endif
 	/* kernel code */
-	if (last >= __pa_symbol(&_text) && last < __pa_symbol(&_end)) {
-		*addrp = __pa_symbol(&_end);
+	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
+		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
 		return 1;
 	}
 
 	if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
-		*addrp = ebda_addr + ebda_size;
+		*addrp = PAGE_ALIGN(ebda_addr + ebda_size);
 		return 1;
 	}
 
@@ -152,7 +152,7 @@ unsigned long __init find_e820_area(unsigned long start, unsigned long end, unsi
 			continue; 
 		while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
 			;
-		last = addr + size;
+		last = PAGE_ALIGN(addr) + size;
 		if (last > ei->addr + ei->size)
 			continue;
 		if (last > end)