Initial revision

diff --git a/arch/ppc64/mm/mmap.c b/arch/ppc64/mm/mmap.c
new file mode 100644 (file)
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+++ b/arch/ppc64/mm/mmap.c
@@ -0,0 +1,87 @@
+/*
+ *  linux/arch/ppc64/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>
+ */
+
+#include <linux/personality.h>
+#include <linux/mm.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->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);
+}
+
+static inline int mmap_is_legacy(void)
+{
+       /*
+        * Force standard allocation for 64 bit programs.
+        */
+       if (!test_thread_flag(TIF_32BIT))
+               return 1;
+               
+       if (current->personality & ADDR_COMPAT_LAYOUT) 
+               return 1;
+       
+       if (current->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->get_unmapped_exec_area = arch_get_unmapped_exec_area;
+               mm->unmap_area = arch_unmap_area_topdown;
+       }
+}