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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * flexible mmap layout support
3 *
4 * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
5 * All Rights Reserved.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 *
22 * Started by Ingo Molnar <mingo@elte.hu>
23 */
24
25#include <linux/personality.h>
26#include <linux/mm.h>
Martin Schwidefsky638ad342011-10-30 15:17:13 +010027#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/module.h>
Heiko Carstensdf1ca532011-01-12 09:55:27 +010029#include <linux/random.h>
Heiko Carstens048cd4e2012-02-27 10:01:52 +010030#include <linux/compat.h>
Martin Schwidefsky6252d702008-02-09 18:24:37 +010031#include <asm/pgalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Heiko Carstens9046e402011-01-12 09:55:22 +010033static unsigned long stack_maxrandom_size(void)
34{
35 if (!(current->flags & PF_RANDOMIZE))
36 return 0;
37 if (current->personality & ADDR_NO_RANDOMIZE)
38 return 0;
39 return STACK_RND_MASK << PAGE_SHIFT;
40}
41
Linus Torvalds1da177e2005-04-16 15:20:36 -070042/*
43 * Top of mmap area (just below the process stack).
44 *
Heiko Carstens9e78a132011-01-12 09:55:23 +010045 * Leave at least a ~32 MB hole.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 */
Heiko Carstens9e78a132011-01-12 09:55:23 +010047#define MIN_GAP (32*1024*1024)
Martin Schwidefskyf481bfa2009-03-18 13:27:36 +010048#define MAX_GAP (STACK_TOP/6*5)
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
Heiko Carstens1060f622011-01-12 09:55:26 +010050static inline int mmap_is_legacy(void)
51{
52 if (current->personality & ADDR_COMPAT_LAYOUT)
53 return 1;
54 if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
55 return 1;
56 return sysctl_legacy_va_layout;
57}
58
Heiko Carstensdf1ca532011-01-12 09:55:27 +010059static unsigned long mmap_rnd(void)
60{
61 if (!(current->flags & PF_RANDOMIZE))
62 return 0;
63 /* 8MB randomization for mmap_base */
64 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
65}
66
Linus Torvalds1da177e2005-04-16 15:20:36 -070067static inline unsigned long mmap_base(void)
68{
Jiri Slabya58c26b2010-01-13 20:44:33 +010069 unsigned long gap = rlimit(RLIMIT_STACK);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
71 if (gap < MIN_GAP)
72 gap = MIN_GAP;
73 else if (gap > MAX_GAP)
74 gap = MAX_GAP;
Heiko Carstensdf1ca532011-01-12 09:55:27 +010075 gap &= PAGE_MASK;
76 return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077}
78
Martin Schwidefsky6252d702008-02-09 18:24:37 +010079#ifndef CONFIG_64BIT
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081/*
82 * This function, called very early during the creation of a new
83 * process VM image, sets up which VM layout function to use:
84 */
85void arch_pick_mmap_layout(struct mm_struct *mm)
86{
87 /*
88 * Fall back to the standard layout if the personality
89 * bit is set, or if the expected stack growth is unlimited:
90 */
91 if (mmap_is_legacy()) {
92 mm->mmap_base = TASK_UNMAPPED_BASE;
93 mm->get_unmapped_area = arch_get_unmapped_area;
94 mm->unmap_area = arch_unmap_area;
95 } else {
96 mm->mmap_base = mmap_base();
97 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
98 mm->unmap_area = arch_unmap_area_topdown;
99 }
100}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100102#else
103
Hendrik Brueckner486c0a02013-02-11 14:29:49 +0100104int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100105{
Martin Schwidefsky0f6f2812012-07-26 08:53:06 +0200106 int rc;
107
Hendrik Brueckner486c0a02013-02-11 14:29:49 +0100108 if (is_compat_task() || (TASK_SIZE >= (1UL << 53)))
109 return 0;
110 if (!(flags & MAP_FIXED))
111 addr = 0;
112 if ((addr + len) >= TASK_SIZE) {
Martin Schwidefsky0f6f2812012-07-26 08:53:06 +0200113 rc = crst_table_upgrade(current->mm, 1UL << 53);
114 if (rc)
115 return rc;
116 update_mm(current->mm, current);
117 }
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100118 return 0;
119}
120
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100121static unsigned long
122s390_get_unmapped_area(struct file *filp, unsigned long addr,
123 unsigned long len, unsigned long pgoff, unsigned long flags)
124{
125 struct mm_struct *mm = current->mm;
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100126 unsigned long area;
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100127 int rc;
128
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100129 area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
130 if (!(area & ~PAGE_MASK))
131 return area;
Heiko Carstens77575912009-06-12 10:26:25 +0200132 if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100133 /* Upgrade the page table to 4 levels and retry. */
134 rc = crst_table_upgrade(mm, 1UL << 53);
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100135 if (rc)
136 return (unsigned long) rc;
Martin Schwidefsky0f6f2812012-07-26 08:53:06 +0200137 update_mm(mm, current);
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100138 area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100139 }
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100140 return area;
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100141}
142
143static unsigned long
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100144s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100145 const unsigned long len, const unsigned long pgoff,
146 const unsigned long flags)
147{
148 struct mm_struct *mm = current->mm;
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100149 unsigned long area;
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100150 int rc;
151
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100152 area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
153 if (!(area & ~PAGE_MASK))
154 return area;
Heiko Carstens77575912009-06-12 10:26:25 +0200155 if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100156 /* Upgrade the page table to 4 levels and retry. */
157 rc = crst_table_upgrade(mm, 1UL << 53);
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100158 if (rc)
159 return (unsigned long) rc;
Martin Schwidefsky0f6f2812012-07-26 08:53:06 +0200160 update_mm(mm, current);
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100161 area = arch_get_unmapped_area_topdown(filp, addr, len,
162 pgoff, flags);
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100163 }
Martin Schwidefsky0fb1d9b2009-03-18 13:27:37 +0100164 return area;
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100165}
166/*
167 * This function, called very early during the creation of a new
168 * process VM image, sets up which VM layout function to use:
169 */
170void arch_pick_mmap_layout(struct mm_struct *mm)
171{
172 /*
173 * Fall back to the standard layout if the personality
174 * bit is set, or if the expected stack growth is unlimited:
175 */
176 if (mmap_is_legacy()) {
177 mm->mmap_base = TASK_UNMAPPED_BASE;
178 mm->get_unmapped_area = s390_get_unmapped_area;
179 mm->unmap_area = arch_unmap_area;
180 } else {
181 mm->mmap_base = mmap_base();
182 mm->get_unmapped_area = s390_get_unmapped_area_topdown;
183 mm->unmap_area = arch_unmap_area_topdown;
184 }
185}
Martin Schwidefsky6252d702008-02-09 18:24:37 +0100186
187#endif