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Commit | Line | Data |
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ba180fd4 JD |
1 | /* |
2 | * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) | |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
d67b569f | 6 | #include "linux/mm.h" |
ba180fd4 | 7 | #include "linux/sched.h" |
5a0e3ad6 | 8 | #include "linux/slab.h" |
d67b569f JD |
9 | #include "asm/pgalloc.h" |
10 | #include "asm/pgtable.h" | |
54ae36f2 | 11 | #include "as-layout.h" |
1da177e4 LT |
12 | #include "os.h" |
13 | #include "skas.h" | |
14 | ||
d67b569f JD |
15 | extern int __syscall_stub_start; |
16 | ||
17 | static int init_stub_pte(struct mm_struct *mm, unsigned long proc, | |
18 | unsigned long kernel) | |
19 | { | |
20 | pgd_t *pgd; | |
21 | pud_t *pud; | |
22 | pmd_t *pmd; | |
23 | pte_t *pte; | |
24 | ||
d67b569f JD |
25 | pgd = pgd_offset(mm, proc); |
26 | pud = pud_alloc(mm, pgd, proc); | |
27 | if (!pud) | |
28 | goto out; | |
29 | ||
30 | pmd = pmd_alloc(mm, pud, proc); | |
31 | if (!pmd) | |
32 | goto out_pmd; | |
33 | ||
34 | pte = pte_alloc_map(mm, pmd, proc); | |
35 | if (!pte) | |
36 | goto out_pte; | |
37 | ||
d67b569f | 38 | *pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT)); |
21c935e5 | 39 | *pte = pte_mkread(*pte); |
ba180fd4 | 40 | return 0; |
d67b569f | 41 | |
d67b569f | 42 | out_pte: |
5e541973 | 43 | pmd_free(mm, pmd); |
4d04c707 RK |
44 | out_pmd: |
45 | pud_free(mm, pud); | |
d67b569f | 46 | out: |
ba180fd4 | 47 | return -ENOMEM; |
d67b569f JD |
48 | } |
49 | ||
77bf4400 | 50 | int init_new_context(struct task_struct *task, struct mm_struct *mm) |
1da177e4 | 51 | { |
6c738ffa JD |
52 | struct mm_context *from_mm = NULL; |
53 | struct mm_context *to_mm = &mm->context; | |
8b51304e | 54 | unsigned long stack = 0; |
12919aa6 | 55 | int ret = -ENOMEM; |
1da177e4 | 56 | |
ba180fd4 | 57 | if (skas_needs_stub) { |
8b51304e | 58 | stack = get_zeroed_page(GFP_KERNEL); |
ba180fd4 | 59 | if (stack == 0) |
8b51304e | 60 | goto out; |
8b51304e | 61 | } |
858259cf BS |
62 | |
63 | to_mm->id.stack = stack; | |
ba180fd4 | 64 | if (current->mm != NULL && current->mm != &init_mm) |
6c738ffa | 65 | from_mm = ¤t->mm->context; |
9786a8f3 | 66 | |
ba180fd4 | 67 | if (proc_mm) { |
12919aa6 | 68 | ret = new_mm(stack); |
ba180fd4 JD |
69 | if (ret < 0) { |
70 | printk(KERN_ERR "init_new_context_skas - " | |
71 | "new_mm failed, errno = %d\n", ret); | |
8b51304e BS |
72 | goto out_free; |
73 | } | |
858259cf | 74 | to_mm->id.u.mm_fd = ret; |
8b51304e BS |
75 | } |
76 | else { | |
ba180fd4 | 77 | if (from_mm) |
858259cf BS |
78 | to_mm->id.u.pid = copy_context_skas0(stack, |
79 | from_mm->id.u.pid); | |
80 | else to_mm->id.u.pid = start_userspace(stack); | |
3e6f2ac4 JD |
81 | |
82 | if (to_mm->id.u.pid < 0) { | |
83 | ret = to_mm->id.u.pid; | |
84 | goto out_free; | |
85 | } | |
858259cf BS |
86 | } |
87 | ||
88 | ret = init_new_ldt(to_mm, from_mm); | |
ba180fd4 JD |
89 | if (ret < 0) { |
90 | printk(KERN_ERR "init_new_context_skas - init_ldt" | |
858259cf BS |
91 | " failed, errno = %d\n", ret); |
92 | goto out_free; | |
d67b569f JD |
93 | } |
94 | ||
ac2a6599 JD |
95 | to_mm->stub_pages = NULL; |
96 | ||
d67b569f JD |
97 | return 0; |
98 | ||
99 | out_free: | |
ba180fd4 | 100 | if (to_mm->id.stack != 0) |
858259cf | 101 | free_page(to_mm->id.stack); |
d67b569f JD |
102 | out: |
103 | return ret; | |
1da177e4 LT |
104 | } |
105 | ||
3963333f JD |
106 | void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) |
107 | { | |
108 | struct page **pages; | |
109 | int err, ret; | |
110 | ||
111 | if (!skas_needs_stub) | |
112 | return; | |
113 | ||
114 | ret = init_stub_pte(mm, STUB_CODE, | |
115 | (unsigned long) &__syscall_stub_start); | |
116 | if (ret) | |
117 | goto out; | |
118 | ||
119 | ret = init_stub_pte(mm, STUB_DATA, mm->context.id.stack); | |
120 | if (ret) | |
121 | goto out; | |
122 | ||
123 | pages = kmalloc(2 * sizeof(struct page *), GFP_KERNEL); | |
124 | if (pages == NULL) { | |
125 | printk(KERN_ERR "arch_dup_mmap failed to allocate 2 page " | |
126 | "pointers\n"); | |
127 | goto out; | |
128 | } | |
129 | ||
130 | pages[0] = virt_to_page(&__syscall_stub_start); | |
131 | pages[1] = virt_to_page(mm->context.id.stack); | |
ac2a6599 | 132 | mm->context.stub_pages = pages; |
3963333f JD |
133 | |
134 | /* dup_mmap already holds mmap_sem */ | |
135 | err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START, | |
136 | VM_READ | VM_MAYREAD | VM_EXEC | | |
137 | VM_MAYEXEC | VM_DONTCOPY, pages); | |
138 | if (err) { | |
139 | printk(KERN_ERR "install_special_mapping returned %d\n", err); | |
140 | goto out_free; | |
141 | } | |
142 | return; | |
143 | ||
144 | out_free: | |
145 | kfree(pages); | |
146 | out: | |
147 | force_sigsegv(SIGSEGV, current); | |
148 | } | |
149 | ||
150 | void arch_exit_mmap(struct mm_struct *mm) | |
151 | { | |
152 | pte_t *pte; | |
153 | ||
ac2a6599 JD |
154 | if (mm->context.stub_pages != NULL) |
155 | kfree(mm->context.stub_pages); | |
3963333f JD |
156 | pte = virt_to_pte(mm, STUB_CODE); |
157 | if (pte != NULL) | |
158 | pte_clear(mm, STUB_CODE, pte); | |
159 | ||
160 | pte = virt_to_pte(mm, STUB_DATA); | |
161 | if (pte == NULL) | |
162 | return; | |
163 | ||
164 | pte_clear(mm, STUB_DATA, pte); | |
165 | } | |
166 | ||
77bf4400 | 167 | void destroy_context(struct mm_struct *mm) |
1da177e4 | 168 | { |
6c738ffa | 169 | struct mm_context *mmu = &mm->context; |
1da177e4 | 170 | |
ba180fd4 | 171 | if (proc_mm) |
d67b569f | 172 | os_close_file(mmu->id.u.mm_fd); |
00a905e6 JD |
173 | else { |
174 | /* | |
175 | * If init_new_context wasn't called, this will be | |
176 | * zero, resulting in a kill(0), which will result in the | |
177 | * whole UML suddenly dying. Also, cover negative and | |
178 | * 1 cases, since they shouldn't happen either. | |
179 | */ | |
180 | if (mmu->id.u.pid < 2) { | |
181 | printk(KERN_ERR "corrupt mm_context - pid = %d\n", | |
182 | mmu->id.u.pid); | |
183 | return; | |
184 | } | |
d67b569f | 185 | os_kill_ptraced_process(mmu->id.u.pid, 1); |
00a905e6 | 186 | } |
8b51304e | 187 | |
3963333f | 188 | if (skas_needs_stub) |
d67b569f | 189 | free_page(mmu->id.stack); |
28078e8f JD |
190 | |
191 | free_ldt(mmu); | |
d67b569f | 192 | } |