Al Viro | b4e9c95 | 2020-06-01 19:42:40 -0400 | [diff] [blame] | 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->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->get(target, regset, 0, size, p, NULL); |
| 24 | if (unlikely(res < 0)) { |
| 25 | kfree(to_free); |
| 26 | return res; |
| 27 | } |
| 28 | *data = p; |
| 29 | if (regset->get_size) { // arm64-only kludge, will go away |
| 30 | unsigned max_size = regset->get_size(target, regset); |
| 31 | if (size > max_size) |
| 32 | size = max_size; |
| 33 | } |
| 34 | return size; |
| 35 | } |
| 36 | |
| 37 | int regset_get(struct task_struct *target, |
| 38 | const struct user_regset *regset, |
| 39 | unsigned int size, |
| 40 | void *data) |
| 41 | { |
| 42 | return __regset_get(target, regset, size, &data); |
| 43 | } |
| 44 | EXPORT_SYMBOL(regset_get); |
| 45 | |
| 46 | int regset_get_alloc(struct task_struct *target, |
| 47 | const struct user_regset *regset, |
| 48 | unsigned int size, |
| 49 | void **data) |
| 50 | { |
| 51 | *data = NULL; |
| 52 | return __regset_get(target, regset, size, data); |
| 53 | } |
| 54 | EXPORT_SYMBOL(regset_get_alloc); |
Al Viro | dc12d79 | 2020-02-17 12:25:14 -0500 | [diff] [blame^] | 55 | |
| 56 | /** |
| 57 | * copy_regset_to_user - fetch a thread's user_regset data into user memory |
| 58 | * @target: thread to be examined |
| 59 | * @view: &struct user_regset_view describing user thread machine state |
| 60 | * @setno: index in @view->regsets |
| 61 | * @offset: offset into the regset data, in bytes |
| 62 | * @size: amount of data to copy, in bytes |
| 63 | * @data: user-mode pointer to copy into |
| 64 | */ |
| 65 | int copy_regset_to_user(struct task_struct *target, |
| 66 | const struct user_regset_view *view, |
| 67 | unsigned int setno, |
| 68 | unsigned int offset, unsigned int size, |
| 69 | void __user *data) |
| 70 | { |
| 71 | const struct user_regset *regset = &view->regsets[setno]; |
| 72 | void *buf; |
| 73 | int ret; |
| 74 | |
| 75 | ret = regset_get_alloc(target, regset, size, &buf); |
| 76 | if (ret > 0) |
| 77 | ret = copy_to_user(data, buf, ret) ? -EFAULT : 0; |
| 78 | kfree(buf); |
| 79 | return ret; |
| 80 | } |