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