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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/regset.h>
static int __regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
void *p = *data, *to_free = NULL;
int res;
if (!regset->get && !regset->regset_get)
return -EOPNOTSUPP;
if (size > regset->n * regset->size)
size = regset->n * regset->size;
if (!p) {
to_free = p = kzalloc(size, GFP_KERNEL);
if (!p)
return -ENOMEM;
}
if (regset->regset_get) {
res = regset->regset_get(target, regset,
(struct membuf){.p = p, .left = size});
if (res < 0) {
kfree(to_free);
return res;
}
*data = p;
return size - res;
}
res = regset->get(target, regset, 0, size, p, NULL);
if (unlikely(res < 0)) {
kfree(to_free);
return res;
}
*data = p;
if (regset->get_size) { // arm64-only kludge, will go away
unsigned max_size = regset->get_size(target, regset);
if (size > max_size)
size = max_size;
}
return size;
}
int regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void *data)
{
return __regset_get(target, regset, size, &data);
}
EXPORT_SYMBOL(regset_get);
int regset_get_alloc(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
*data = NULL;
return __regset_get(target, regset, size, data);
}
EXPORT_SYMBOL(regset_get_alloc);
/**
* copy_regset_to_user - fetch a thread's user_regset data into user memory
* @target: thread to be examined
* @view: &struct user_regset_view describing user thread machine state
* @setno: index in @view->regsets
* @offset: offset into the regset data, in bytes
* @size: amount of data to copy, in bytes
* @data: user-mode pointer to copy into
*/
int copy_regset_to_user(struct task_struct *target,
const struct user_regset_view *view,
unsigned int setno,
unsigned int offset, unsigned int size,
void __user *data)
{
const struct user_regset *regset = &view->regsets[setno];
void *buf;
int ret;
ret = regset_get_alloc(target, regset, size, &buf);
if (ret > 0)
ret = copy_to_user(data, buf, ret) ? -EFAULT : 0;
kfree(buf);
return ret;
}
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