[PATCH] uml: fix binary layout assumption

This patch calculates section boundaries differently so as to not get
tripped up by holes in the binary such as are introduced by exec-shield.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/kernel/tt/process_kern.c

@@ -423,7 +423,7 @@ static void mprotect_kernel_mem(int w)
 	protect_memory(start, end - start, 1, w, 1, 1);
 
 	start = (unsigned long) UML_ROUND_DOWN(&__bss_start);
-	end = (unsigned long) UML_ROUND_UP(&_end);
+	end = (unsigned long) UML_ROUND_UP(brk_start);
 	protect_memory(start, end - start, 1, w, 1, 1);
 
 	mprotect_kernel_vm(w);

arch/um/kernel/um_arch.c

@@ -306,7 +306,7 @@ unsigned long end_iomem;
 
 int linux_main(int argc, char **argv)
 {
-	unsigned long avail;
+	unsigned long avail, diff;
 	unsigned long virtmem_size, max_physmem;
 	unsigned int i, add;
 
@@ -324,6 +324,16 @@ int linux_main(int argc, char **argv)
 
 	brk_start = (unsigned long) sbrk(0);
 	CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
+	/* Increase physical memory size for exec-shield users
+	so they actually get what they asked for. This should
+	add zero for non-exec shield users */
+
+	diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
+	if(diff > 1024 * 1024){
+		printf("Adding %ld bytes to physical memory to account for "
+		       "exec-shield gap\n", diff);
+		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
+	}
 
 	uml_physmem = uml_start;