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27#include <linux/personality.h>
28#include <linux/mm.h>
29#include <linux/mman.h>
30#include <linux/module.h>
31#include <linux/random.h>
32#include <linux/compat.h>
33#include <asm/pgalloc.h>
34
35static unsigned long stack_maxrandom_size(void)
36{
37 if (!(current->flags & PF_RANDOMIZE))
38 return 0;
39 if (current->personality & ADDR_NO_RANDOMIZE)
40 return 0;
41 return STACK_RND_MASK << PAGE_SHIFT;
42}
43
44
45
46
47
48
49#define MIN_GAP (32*1024*1024)
50#define MAX_GAP (STACK_TOP/6*5)
51
52static inline int mmap_is_legacy(void)
53{
54 if (current->personality & ADDR_COMPAT_LAYOUT)
55 return 1;
56 if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
57 return 1;
58 return sysctl_legacy_va_layout;
59}
60
61static unsigned long mmap_rnd(void)
62{
63 if (!(current->flags & PF_RANDOMIZE))
64 return 0;
65
66 return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
67}
68
69static inline unsigned long mmap_base(void)
70{
71 unsigned long gap = rlimit(RLIMIT_STACK);
72
73 if (gap < MIN_GAP)
74 gap = MIN_GAP;
75 else if (gap > MAX_GAP)
76 gap = MAX_GAP;
77 gap &= PAGE_MASK;
78 return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;
79}
80
81#ifndef CONFIG_64BIT
82
83
84
85
86
87void arch_pick_mmap_layout(struct mm_struct *mm)
88{
89
90
91
92
93 if (mmap_is_legacy()) {
94 mm->mmap_base = TASK_UNMAPPED_BASE;
95 mm->get_unmapped_area = arch_get_unmapped_area;
96 mm->unmap_area = arch_unmap_area;
97 } else {
98 mm->mmap_base = mmap_base();
99 mm->get_unmapped_area = arch_get_unmapped_area_topdown;
100 mm->unmap_area = arch_unmap_area_topdown;
101 }
102}
103
104#else
105
106int s390_mmap_check(unsigned long addr, unsigned long len)
107{
108 if (!is_compat_task() &&
109 len >= TASK_SIZE && TASK_SIZE < (1UL << 53))
110 return crst_table_upgrade(current->mm, 1UL << 53);
111 return 0;
112}
113
114static unsigned long
115s390_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;
119 unsigned long area;
120 int rc;
121
122 area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
123 if (!(area & ~PAGE_MASK))
124 return area;
125 if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
126
127 rc = crst_table_upgrade(mm, 1UL << 53);
128 if (rc)
129 return (unsigned long) rc;
130 area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
131 }
132 return area;
133}
134
135static unsigned long
136s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
137 const unsigned long len, const unsigned long pgoff,
138 const unsigned long flags)
139{
140 struct mm_struct *mm = current->mm;
141 unsigned long area;
142 int rc;
143
144 area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
145 if (!(area & ~PAGE_MASK))
146 return area;
147 if (area == -ENOMEM && !is_compat_task() && TASK_SIZE < (1UL << 53)) {
148
149 rc = crst_table_upgrade(mm, 1UL << 53);
150 if (rc)
151 return (unsigned long) rc;
152 area = arch_get_unmapped_area_topdown(filp, addr, len,
153 pgoff, flags);
154 }
155 return area;
156}
157
158
159
160
161void arch_pick_mmap_layout(struct mm_struct *mm)
162{
163
164
165
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
178#endif
179