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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/s390/mm/mmap.c
3 *
4 * flexible mmap layout support
5 *
6 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
7 * All Rights Reserved.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 *
23 *
24 * Started by Ingo Molnar <mingo@elte.hu>
25 */
26
27#include <linux/personality.h>
28#include <linux/mm.h>
29#include <linux/module.h>
Martin Schwidefsky6252d702008-02-09 18:24:37 +010030#include <asm/pgalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32/*
33 * Top of mmap area (just below the process stack).
34 *
35 * Leave an at least ~128 MB hole.
36 */
37#define MIN_GAP (128*1024*1024)
38#define MAX_GAP (TASK_SIZE/6*5)
39
40static inline unsigned long mmap_base(void)
41{
42 unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
43
44 if (gap < MIN_GAP)
45 gap = MIN_GAP;
46 else if (gap > MAX_GAP)
47 gap = MAX_GAP;
48
49 return TASK_SIZE - (gap & PAGE_MASK);
50}
51
52static inline int mmap_is_legacy(void)
53{
Martin Schwidefsky347a8dc2006-01-06 00:19:28 -080054#ifdef CONFIG_64BIT
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 /*
56 * Force standard allocation for 64 bit programs.
57 */
58 if (!test_thread_flag(TIF_31BIT))
59 return 1;
60#endif
61 return sysctl_legacy_va_layout ||
62 (current->personality & ADDR_COMPAT_LAYOUT) ||
63 current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY;
64}
65
Martin Schwidefsky6252d702008-02-09 18:24:37 +010066#ifndef CONFIG_64BIT
67
Linus Torvalds1da177e2005-04-16 15:20:36 -070068/*
69 * This function, called very early during the creation of a new
70 * process VM image, sets up which VM layout function to use:
71 */
72void arch_pick_mmap_layout(struct mm_struct *mm)
73{
74 /*
75 * Fall back to the standard layout if the personality
76 * bit is set, or if the expected stack growth is unlimited:
77 */
78 if (mmap_is_legacy()) {
79 mm->mmap_base = TASK_UNMAPPED_BASE;
80 mm->get_unmapped_area = arch_get_unmapped_area;
81 mm->unmap_area = arch_unmap_area;
82 } else {
83 mm->mmap_base = mmap_base();
84 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
85 mm->unmap_area = arch_unmap_area_topdown;
86 }
87}
88EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
89
Martin Schwidefsky6252d702008-02-09 18:24:37 +010090#else
91
92static unsigned long
93s390_get_unmapped_area(struct file *filp, unsigned long addr,
94 unsigned long len, unsigned long pgoff, unsigned long flags)
95{
96 struct mm_struct *mm = current->mm;
97 int rc;
98
99 addr = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
100 if (addr & ~PAGE_MASK)
101 return addr;
102 if (unlikely(mm->context.asce_limit < addr + len)) {
103 rc = crst_table_upgrade(mm, addr + len);
104 if (rc)
105 return (unsigned long) rc;
106 }
107 return addr;
108}
109
110static unsigned long
111s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
112 const unsigned long len, const unsigned long pgoff,
113 const unsigned long flags)
114{
115 struct mm_struct *mm = current->mm;
116 unsigned long addr = addr0;
117 int rc;
118
119 addr = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
120 if (addr & ~PAGE_MASK)
121 return addr;
122 if (unlikely(mm->context.asce_limit < addr + len)) {
123 rc = crst_table_upgrade(mm, addr + len);
124 if (rc)
125 return (unsigned long) rc;
126 }
127 return addr;
128}
129/*
130 * This function, called very early during the creation of a new
131 * process VM image, sets up which VM layout function to use:
132 */
133void arch_pick_mmap_layout(struct mm_struct *mm)
134{
135 /*
136 * Fall back to the standard layout if the personality
137 * bit is set, or if the expected stack growth is unlimited:
138 */
139 if (mmap_is_legacy()) {
140 mm->mmap_base = TASK_UNMAPPED_BASE;
141 mm->get_unmapped_area = s390_get_unmapped_area;
142 mm->unmap_area = arch_unmap_area;
143 } else {
144 mm->mmap_base = mmap_base();
145 mm->get_unmapped_area = s390_get_unmapped_area_topdown;
146 mm->unmap_area = arch_unmap_area_topdown;
147 }
148}
149EXPORT_SYMBOL_GPL(arch_pick_mmap_layout);
150
151#endif