1 // SPDX-License-Identifier: GPL-2.0-or-later
2
3 #include "shared.h"
4
5
6 bool fail_prealloc;
7 unsigned long mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
8 unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
9 unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
10
11 const struct vm_operations_struct vma_dummy_vm_ops;
12 struct anon_vma dummy_anon_vma;
13 struct task_struct __current;
14
alloc_vma(struct mm_struct * mm,unsigned long start,unsigned long end,pgoff_t pgoff,vma_flags_t vma_flags)15 struct vm_area_struct *alloc_vma(struct mm_struct *mm,
16 unsigned long start, unsigned long end,
17 pgoff_t pgoff, vma_flags_t vma_flags)
18 {
19 struct vm_area_struct *vma = vm_area_alloc(mm);
20
21 if (vma == NULL)
22 return NULL;
23
24 vma->vm_start = start;
25 vma->vm_end = end;
26 vma_set_pgoff(vma, pgoff);
27 vma_set_anon_pgoff(vma, start >> PAGE_SHIFT);
28 vma->flags = vma_flags;
29 vma_assert_detached(vma);
30
31 return vma;
32 }
33
detach_free_vma(struct vm_area_struct * vma)34 void detach_free_vma(struct vm_area_struct *vma)
35 {
36 vma_mark_detached(vma);
37 vm_area_free(vma);
38 }
39
alloc_and_link_vma(struct mm_struct * mm,unsigned long start,unsigned long end,pgoff_t pgoff,vma_flags_t vma_flags)40 struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm,
41 unsigned long start, unsigned long end,
42 pgoff_t pgoff, vma_flags_t vma_flags)
43 {
44 struct vm_area_struct *vma = alloc_vma(mm, start, end, pgoff, vma_flags);
45
46 if (vma == NULL)
47 return NULL;
48
49 if (attach_vma(mm, vma)) {
50 detach_free_vma(vma);
51 return NULL;
52 }
53
54 /*
55 * Reset this counter which we use to track whether writes have
56 * begun. Linking to the tree will have caused this to be incremented,
57 * which means we will get a false positive otherwise.
58 */
59 vma->vm_lock_seq = UINT_MAX;
60
61 return vma;
62 }
63
reset_dummy_anon_vma(void)64 void reset_dummy_anon_vma(void)
65 {
66 dummy_anon_vma.was_cloned = false;
67 dummy_anon_vma.was_unlinked = false;
68 }
69
cleanup_mm(struct mm_struct * mm,struct vma_iterator * vmi)70 int cleanup_mm(struct mm_struct *mm, struct vma_iterator *vmi)
71 {
72 struct vm_area_struct *vma;
73 int count = 0;
74
75 fail_prealloc = false;
76 reset_dummy_anon_vma();
77
78 vma_iter_set(vmi, 0);
79 for_each_vma(*vmi, vma) {
80 detach_free_vma(vma);
81 count++;
82 }
83
84 mtree_destroy(&mm->mm_mt);
85 mm->map_count = 0;
86 return count;
87 }
88
vma_write_started(struct vm_area_struct * vma)89 bool vma_write_started(struct vm_area_struct *vma)
90 {
91 int seq = vma->vm_lock_seq;
92
93 /* We reset after each check. */
94 vma->vm_lock_seq = UINT_MAX;
95
96 /* The vma_start_write() stub simply increments this value. */
97 return seq > -1;
98 }
99
__vma_set_dummy_anon_vma(struct vm_area_struct * vma,struct anon_vma_chain * avc,struct anon_vma * anon_vma)100 void __vma_set_dummy_anon_vma(struct vm_area_struct *vma,
101 struct anon_vma_chain *avc, struct anon_vma *anon_vma)
102 {
103 vma->anon_vma = anon_vma;
104 INIT_LIST_HEAD(&vma->anon_vma_chain);
105 list_add(&avc->same_vma, &vma->anon_vma_chain);
106 avc->anon_vma = vma->anon_vma;
107 }
108
vma_set_dummy_anon_vma(struct vm_area_struct * vma,struct anon_vma_chain * avc)109 void vma_set_dummy_anon_vma(struct vm_area_struct *vma,
110 struct anon_vma_chain *avc)
111 {
112 __vma_set_dummy_anon_vma(vma, avc, &dummy_anon_vma);
113 }
114
get_current(void)115 struct task_struct *get_current(void)
116 {
117 return &__current;
118 }
119
rlimit(unsigned int limit)120 unsigned long rlimit(unsigned int limit)
121 {
122 return (unsigned long)-1;
123 }
124