linux_dsm_epyc7002/kernel/regset.c
Al Viro dc12d7968f copy_regset_to_user(): do all copyout at once.
Turn copy_regset_to_user() into regset_get_alloc() + copy_to_user().
Now all ->get() calls have a kernel buffer as destination.

Note that we'd already eliminated the callers of copy_regset_to_user()
with non-zero offset; now that argument is simply unused.

Uninlined, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:07 -04:00

81 lines
2.0 KiB
C

// 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)
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;
}
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;
}