linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / arch / x86_64 / mm / mmap.c

diff --git a/arch/x86_64/mm/mmap.c b/arch/x86_64/mm/mmap.c
index 432d2aa..43e9b99 100644 (file)
--- a/arch/x86_64/mm/mmap.c
+++ b/arch/x86_64/mm/mmap.c
@@ -1,87 +1,30 @@
-/*
- *  linux/arch/x86-64/mm/mmap.c
- *
- *  flexible mmap layout support
- *
- * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
- * All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- *
- * Started by Ingo Molnar <mingo@elte.hu>
+/* Copyright 2005 Andi Kleen, SuSE Labs.
+ * Licensed under GPL, v.2
  */
-
-#include <linux/personality.h>
+#include <linux/config.h>
 #include <linux/mm.h>
+#include <linux/sched.h>
 #include <linux/random.h>
+#include <asm/ia32.h>
 
-/*
- * Top of mmap area (just below the process stack).
- *
- * Leave an at least ~128 MB hole.
- */
-#define MIN_GAP (128*1024*1024)
-#define MAX_GAP (TASK_SIZE/6*5)
-
-static inline unsigned long mmap_base(void)
-{
-       unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
-
-       if (gap < MIN_GAP)
-               gap = MIN_GAP;
-       else if (gap > MAX_GAP)
-               gap = MAX_GAP;
-
-       return TASK_SIZE - (gap & PAGE_MASK);
-}
+/* Notebook: move the mmap code from sys_x86_64.c over here. */
 
-static inline int mmap_is_legacy(void)
-{
-       /*
-        * Force standard allocation for 64 bit programs.
-        */
-       if (!test_thread_flag(TIF_IA32))
-               return 1;
-
-       if (current->personality & ADDR_COMPAT_LAYOUT)
-               return 1;
-
-       if (current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY)
-               return 1;
-
-       return sysctl_legacy_va_layout;
-}
-
-/*
- * This function, called very early during the creation of a new
- * process VM image, sets up which VM layout function to use:
- */
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
-       /*
-        * Fall back to the standard layout if the personality
-        * bit is set, or if the expected stack growth is unlimited:
-        */
-       if (mmap_is_legacy()) {
-               mm->mmap_base = TASK_UNMAPPED_BASE;
-               mm->get_unmapped_area = arch_get_unmapped_area;
-               mm->unmap_area = arch_unmap_area;
-       } else {
-               mm->mmap_base = mmap_base();
-               mm->get_unmapped_area = arch_get_unmapped_area_topdown;
-               mm->unmap_area = arch_unmap_area_topdown;
+#ifdef CONFIG_IA32_EMULATION
+       if (current_thread_info()->flags & _TIF_IA32)
+               return ia32_pick_mmap_layout(mm);
+#endif
+       mm->mmap_base = TASK_UNMAPPED_BASE;
+       if (current->flags & PF_RANDOMIZE) {
+               /* Add 28bit randomness which is about 40bits of address space
+                  because mmap base has to be page aligned.
+                  or ~1/128 of the total user VM
+                  (total user address space is 47bits) */
+               unsigned rnd = get_random_int() & 0xfffffff;
+               mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
        }
+       mm->get_unmapped_area = arch_get_unmapped_area;
+       mm->unmap_area = arch_unmap_area;
 }
+