1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) |
4 | * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
5 | */ |
6 | |
7 | #include <linux/mm.h> |
8 | #include <linux/sched/signal.h> |
9 | #include <linux/slab.h> |
10 | |
11 | #include <asm/pgalloc.h> |
12 | #include <asm/sections.h> |
13 | #include <as-layout.h> |
14 | #include <os.h> |
15 | #include <skas.h> |
16 | |
17 | int init_new_context(struct task_struct *task, struct mm_struct *mm) |
18 | { |
19 | struct mm_context *from_mm = NULL; |
20 | struct mm_context *to_mm = &mm->context; |
21 | unsigned long stack = 0; |
22 | int ret = -ENOMEM; |
23 | |
24 | stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES)); |
25 | if (stack == 0) |
26 | goto out; |
27 | |
28 | to_mm->id.stack = stack; |
29 | if (current->mm != NULL && current->mm != &init_mm) |
30 | from_mm = ¤t->mm->context; |
31 | |
32 | block_signals_trace(); |
33 | if (from_mm) |
34 | to_mm->id.u.pid = copy_context_skas0(stack, |
35 | from_mm->id.u.pid); |
36 | else to_mm->id.u.pid = start_userspace(stack); |
37 | unblock_signals_trace(); |
38 | |
39 | if (to_mm->id.u.pid < 0) { |
40 | ret = to_mm->id.u.pid; |
41 | goto out_free; |
42 | } |
43 | |
44 | ret = init_new_ldt(to_mm, from_mm); |
45 | if (ret < 0) { |
46 | printk(KERN_ERR "init_new_context_skas - init_ldt" |
47 | " failed, errno = %d\n" , ret); |
48 | goto out_free; |
49 | } |
50 | |
51 | return 0; |
52 | |
53 | out_free: |
54 | if (to_mm->id.stack != 0) |
55 | free_pages(to_mm->id.stack, ilog2(STUB_DATA_PAGES)); |
56 | out: |
57 | return ret; |
58 | } |
59 | |
60 | void destroy_context(struct mm_struct *mm) |
61 | { |
62 | struct mm_context *mmu = &mm->context; |
63 | |
64 | /* |
65 | * If init_new_context wasn't called, this will be |
66 | * zero, resulting in a kill(0), which will result in the |
67 | * whole UML suddenly dying. Also, cover negative and |
68 | * 1 cases, since they shouldn't happen either. |
69 | */ |
70 | if (mmu->id.u.pid < 2) { |
71 | printk(KERN_ERR "corrupt mm_context - pid = %d\n" , |
72 | mmu->id.u.pid); |
73 | return; |
74 | } |
75 | os_kill_ptraced_process(mmu->id.u.pid, 1); |
76 | |
77 | free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES)); |
78 | free_ldt(mmu); |
79 | } |
80 | |