Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
df1ca53c | 30 | #include <linux/random.h> |
6252d702 | 31 | #include <asm/pgalloc.h> |
7757591a | 32 | #include <asm/compat.h> |
1da177e4 | 33 | |
9046e401 HC |
34 | static unsigned long stack_maxrandom_size(void) |
35 | { | |
36 | if (!(current->flags & PF_RANDOMIZE)) | |
37 | return 0; | |
38 | if (current->personality & ADDR_NO_RANDOMIZE) | |
39 | return 0; | |
40 | return STACK_RND_MASK << PAGE_SHIFT; | |
41 | } | |
42 | ||
1da177e4 LT |
43 | /* |
44 | * Top of mmap area (just below the process stack). | |
45 | * | |
9e78a13b | 46 | * Leave at least a ~32 MB hole. |
1da177e4 | 47 | */ |
9e78a13b | 48 | #define MIN_GAP (32*1024*1024) |
f481bfaf | 49 | #define MAX_GAP (STACK_TOP/6*5) |
1da177e4 | 50 | |
1060f62e HC |
51 | static inline int mmap_is_legacy(void) |
52 | { | |
53 | if (current->personality & ADDR_COMPAT_LAYOUT) | |
54 | return 1; | |
55 | if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) | |
56 | return 1; | |
57 | return sysctl_legacy_va_layout; | |
58 | } | |
59 | ||
df1ca53c HC |
60 | static unsigned long mmap_rnd(void) |
61 | { | |
62 | if (!(current->flags & PF_RANDOMIZE)) | |
63 | return 0; | |
64 | /* 8MB randomization for mmap_base */ | |
65 | return (get_random_int() & 0x7ffUL) << PAGE_SHIFT; | |
66 | } | |
67 | ||
1da177e4 LT |
68 | static inline unsigned long mmap_base(void) |
69 | { | |
a58c26bb | 70 | unsigned long gap = rlimit(RLIMIT_STACK); |
1da177e4 LT |
71 | |
72 | if (gap < MIN_GAP) | |
73 | gap = MIN_GAP; | |
74 | else if (gap > MAX_GAP) | |
75 | gap = MAX_GAP; | |
df1ca53c HC |
76 | gap &= PAGE_MASK; |
77 | return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap; | |
1da177e4 LT |
78 | } |
79 | ||
6252d702 MS |
80 | #ifndef CONFIG_64BIT |
81 | ||
1da177e4 LT |
82 | /* |
83 | * This function, called very early during the creation of a new | |
84 | * process VM image, sets up which VM layout function to use: | |
85 | */ | |
86 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
87 | { | |
88 | /* | |
89 | * Fall back to the standard layout if the personality | |
90 | * bit is set, or if the expected stack growth is unlimited: | |
91 | */ | |
92 | if (mmap_is_legacy()) { | |
93 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
94 | mm->get_unmapped_area = arch_get_unmapped_area; | |
95 | mm->unmap_area = arch_unmap_area; | |
96 | } else { | |
97 | mm->mmap_base = mmap_base(); | |
98 | mm->get_unmapped_area = arch_get_unmapped_area_topdown; | |
99 | mm->unmap_area = arch_unmap_area_topdown; | |
100 | } | |
101 | } | |
102 | EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); | |
103 | ||
6252d702 MS |
104 | #else |
105 | ||
0fb1d9bc MS |
106 | int s390_mmap_check(unsigned long addr, unsigned long len) |
107 | { | |
7757591a | 108 | if (!is_compat_task() && |
0fb1d9bc MS |
109 | len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) |
110 | return crst_table_upgrade(current->mm, 1UL << 53); | |
111 | return 0; | |
112 | } | |
113 | ||
6252d702 MS |
114 | static unsigned long |
115 | s390_get_unmapped_area(struct file *filp, unsigned long addr, | |
116 | unsigned long len, unsigned long pgoff, unsigned long flags) | |
117 | { | |
118 | struct mm_struct *mm = current->mm; | |
0fb1d9bc | 119 | unsigned long area; |
6252d702 MS |
120 | int rc; |
121 | ||
0fb1d9bc MS |
122 | area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); |
123 | if (!(area & ~PAGE_MASK)) | |
124 | return area; | |
7757591a | 125 | if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) { |
0fb1d9bc MS |
126 | /* Upgrade the page table to 4 levels and retry. */ |
127 | rc = crst_table_upgrade(mm, 1UL << 53); | |
6252d702 MS |
128 | if (rc) |
129 | return (unsigned long) rc; | |
0fb1d9bc | 130 | area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); |
6252d702 | 131 | } |
0fb1d9bc | 132 | return area; |
6252d702 MS |
133 | } |
134 | ||
135 | static unsigned long | |
0fb1d9bc | 136 | s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, |
6252d702 MS |
137 | const unsigned long len, const unsigned long pgoff, |
138 | const unsigned long flags) | |
139 | { | |
140 | struct mm_struct *mm = current->mm; | |
0fb1d9bc | 141 | unsigned long area; |
6252d702 MS |
142 | int rc; |
143 | ||
0fb1d9bc MS |
144 | area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); |
145 | if (!(area & ~PAGE_MASK)) | |
146 | return area; | |
7757591a | 147 | if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) { |
0fb1d9bc MS |
148 | /* Upgrade the page table to 4 levels and retry. */ |
149 | rc = crst_table_upgrade(mm, 1UL << 53); | |
6252d702 MS |
150 | if (rc) |
151 | return (unsigned long) rc; | |
0fb1d9bc MS |
152 | area = arch_get_unmapped_area_topdown(filp, addr, len, |
153 | pgoff, flags); | |
6252d702 | 154 | } |
0fb1d9bc | 155 | return area; |
6252d702 MS |
156 | } |
157 | /* | |
158 | * This function, called very early during the creation of a new | |
159 | * process VM image, sets up which VM layout function to use: | |
160 | */ | |
161 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
162 | { | |
163 | /* | |
164 | * Fall back to the standard layout if the personality | |
165 | * bit is set, or if the expected stack growth is unlimited: | |
166 | */ | |
167 | if (mmap_is_legacy()) { | |
168 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
169 | mm->get_unmapped_area = s390_get_unmapped_area; | |
170 | mm->unmap_area = arch_unmap_area; | |
171 | } else { | |
172 | mm->mmap_base = mmap_base(); | |
173 | mm->get_unmapped_area = s390_get_unmapped_area_topdown; | |
174 | mm->unmap_area = arch_unmap_area_topdown; | |
175 | } | |
176 | } | |
177 | EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); | |
178 | ||
179 | #endif |