exec: create initial stack independent of PAGE_SIZE

Currently we create the initial stack based on the PAGE_SIZE.  This is
unnecessary.

This creates this initial stack independent of the PAGE_SIZE.

It also bumps up the number of 4k pages allocated from 20 to 32, to
align with 64K page systems.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Helge Deller <deller@gmx.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 6348d79401de..da2b31dc4e1c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -556,8 +556,6 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
         return 0;
 }
 
-#define EXTRA_STACK_VM_PAGES    20      /* random */
-
 /*
  * Finalizes the stack vm_area_struct. The flags and permissions are updated,
  * the stack is optionally relocated, and some extra space is added.
@@ -632,7 +630,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
                         goto out_unlock;
         }
 
-        stack_expand = EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+        stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
         stack_size = vma->vm_end - vma->vm_start;
         /*
          * Align this down to a page boundary as expand_stack