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b4e9c954 AV |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/export.h> | |
3 | #include <linux/slab.h> | |
4 | #include <linux/regset.h> | |
5 | ||
6 | static int __regset_get(struct task_struct *target, | |
7 | const struct user_regset *regset, | |
8 | unsigned int size, | |
9 | void **data) | |
10 | { | |
11 | void *p = *data, *to_free = NULL; | |
12 | int res; | |
13 | ||
1e6986c9 | 14 | if (!regset->regset_get) |
b4e9c954 AV |
15 | return -EOPNOTSUPP; |
16 | if (size > regset->n * regset->size) | |
17 | size = regset->n * regset->size; | |
18 | if (!p) { | |
19 | to_free = p = kzalloc(size, GFP_KERNEL); | |
20 | if (!p) | |
21 | return -ENOMEM; | |
22 | } | |
1e6986c9 AV |
23 | res = regset->regset_get(target, regset, |
24 | (struct membuf){.p = p, .left = size}); | |
25 | if (res < 0) { | |
b4e9c954 AV |
26 | kfree(to_free); |
27 | return res; | |
28 | } | |
29 | *data = p; | |
1e6986c9 | 30 | return size - res; |
b4e9c954 AV |
31 | } |
32 | ||
33 | int regset_get(struct task_struct *target, | |
34 | const struct user_regset *regset, | |
35 | unsigned int size, | |
36 | void *data) | |
37 | { | |
38 | return __regset_get(target, regset, size, &data); | |
39 | } | |
40 | EXPORT_SYMBOL(regset_get); | |
41 | ||
42 | int regset_get_alloc(struct task_struct *target, | |
43 | const struct user_regset *regset, | |
44 | unsigned int size, | |
45 | void **data) | |
46 | { | |
47 | *data = NULL; | |
48 | return __regset_get(target, regset, size, data); | |
49 | } | |
50 | EXPORT_SYMBOL(regset_get_alloc); | |
dc12d796 AV |
51 | |
52 | /** | |
53 | * copy_regset_to_user - fetch a thread's user_regset data into user memory | |
54 | * @target: thread to be examined | |
55 | * @view: &struct user_regset_view describing user thread machine state | |
56 | * @setno: index in @view->regsets | |
57 | * @offset: offset into the regset data, in bytes | |
58 | * @size: amount of data to copy, in bytes | |
59 | * @data: user-mode pointer to copy into | |
60 | */ | |
61 | int copy_regset_to_user(struct task_struct *target, | |
62 | const struct user_regset_view *view, | |
63 | unsigned int setno, | |
64 | unsigned int offset, unsigned int size, | |
65 | void __user *data) | |
66 | { | |
67 | const struct user_regset *regset = &view->regsets[setno]; | |
68 | void *buf; | |
69 | int ret; | |
70 | ||
71 | ret = regset_get_alloc(target, regset, size, &buf); | |
72 | if (ret > 0) | |
73 | ret = copy_to_user(data, buf, ret) ? -EFAULT : 0; | |
74 | kfree(buf); | |
75 | return ret; | |
76 | } |