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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>
This commit is contained in:
Al Viro 2020-02-17 12:25:14 -05:00
parent 1e56f6d289
commit dc12d7968f
2 changed files with 30 additions and 25 deletions
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29
include/linux/regset.h
View File

@ -362,31 +362,10 @@ extern int regset_get_alloc(struct task_struct *target,
unsigned int size,
void **data);
/**
* 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
*/
static inline 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];
if (!regset->get)
return -EOPNOTSUPP;
if (!access_ok(data, size))
return -EFAULT;
return regset->get(target, regset, offset, size, NULL, data);
}
extern 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);
/**
* copy_regset_from_user - store into thread's user_regset data from user memory

26
kernel/regset.c
View File

@ -52,3 +52,29 @@ int regset_get_alloc(struct task_struct *target,
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;
}