uml: remove page_size()

userspace code used to have to call the kernelspace function page_size() in
order to determine the value of the kernel's PAGE_SIZE.  Since this is now
available directly from kern_constants.h as UM_KERN_PAGE_SIZE, page_size() can
be deleted and calls changed to use the constant.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index f35220c..2184ddb 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -15,6 +15,7 @@
 #include "kern_util.h"
 #include "os.h"
 #include "um_malloc.h"
+#include "kern_constants.h"
 
 struct helper_data {
 	void (*pre_exec)(void*);
@@ -69,7 +70,7 @@
 		goto out_close;
 	}
 
-	sp = stack + page_size() - sizeof(void *);
+	sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
 	data.pre_exec = pre_exec;
 	data.pre_data = pre_data;
 	data.argv = argv;
@@ -123,7 +124,7 @@
 	if (stack == 0)
 		return -ENOMEM;
 
-	sp = stack + (page_size() << stack_order) - sizeof(void *);
+	sp = stack + (UM_KERN_PAGE_SIZE << stack_order) - sizeof(void *);
 	pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
 	if (pid < 0) {
 		err = -errno;