X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fx86_64%2Fmm%2Fmmap.c;fp=arch%2Fx86_64%2Fmm%2Fmmap.c;h=43e9b99bdf25d6419afce6e81bab3c361e5f174d;hb=64ba3f394c830ec48a1c31b53dcae312c56f1604;hp=432d2aa8d9ab7ed6ece828c65a085b593ab80ae5;hpb=be1e6109ac94a859551f8e1774eb9a8469fe055c;p=linux-2.6.git

diff --git a/arch/x86_64/mm/mmap.c b/arch/x86_64/mm/mmap.c
index 432d2aa8d..43e9b99bd 100644
--- 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;
 }
+