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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> | |
6252d702 | 30 | #include <asm/pgalloc.h> |
1da177e4 LT |
31 | |
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) | |
f481bfaf | 38 | #define MAX_GAP (STACK_TOP/6*5) |
1da177e4 LT |
39 | |
40 | static 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 | ||
f481bfaf | 49 | return STACK_TOP - (gap & PAGE_MASK); |
1da177e4 LT |
50 | } |
51 | ||
52 | static inline int mmap_is_legacy(void) | |
53 | { | |
347a8dc3 | 54 | #ifdef CONFIG_64BIT |
1da177e4 LT |
55 | /* |
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 | ||
6252d702 MS |
66 | #ifndef CONFIG_64BIT |
67 | ||
1da177e4 LT |
68 | /* |
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 | */ | |
72 | void 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 | } | |
88 | EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); | |
89 | ||
6252d702 MS |
90 | #else |
91 | ||
92 | static unsigned long | |
93 | s390_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 | ||
110 | static unsigned long | |
111 | s390_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 | */ | |
133 | void 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 | } | |
149 | EXPORT_SYMBOL_GPL(arch_pick_mmap_layout); | |
150 | ||
151 | #endif |