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 | |
14 | if (!regset->regset_get) |
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 | } |
23 | res = regset->regset_get(target, regset, |
24 | (struct membuf){.p = p, .left = size}); |
25 | if (res < 0) { |
26 | kfree(objp: to_free); |
27 | return res; |
28 | } |
29 | *data = p; |
30 | return size - res; |
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: &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); |
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(to: data, from: buf, n: ret) ? -EFAULT : 0; |
74 | kfree(objp: buf); |
75 | return ret; |
76 | } |
77 | |