x86: user_regset user-copy helpers

This defines two new inlines in linux/regset.h, for use in arch_ptrace
implementations and the like.  These provide simplified wrappers for using
the user_regset interfaces to copy thread regset data into the caller's
user-space memory.  The inlines are trivial, but make the common uses in
places such as ptrace implementation much more concise, easier to read, and
less prone to code-copying errors.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 46 insertions, 0 deletions

diff --git a/include/linux/regset.h b/include/linux/regset.h
index 761c931af975..8abee6556223 100644
--- a/include/linux/regset.h
+++ b/include/linux/regset.h
@@ -318,5 +318,51 @@ static inline int user_regset_copyin_ignore(unsigned int *pos,
         return 0;
 }
 
+/**
+ * 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 (!access_ok(VERIFY_WRITE, data, size))
+                return -EIO;
+
+        return regset->get(target, regset, offset, size, NULL, data);
+}
+
+/**
+ * copy_regset_from_user - store into thread's user_regset data from 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 from
+ */
+static inline int copy_regset_from_user(struct task_struct *target,
+                                        const struct user_regset_view *view,
+                                        unsigned int setno,
+                                        unsigned int offset, unsigned int size,
+                                        const void __user *data)
+{
+        const struct user_regset *regset = &view->regsets[setno];
+
+        if (!access_ok(VERIFY_READ, data, size))
+                return -EIO;
+
+        return regset->set(target, regset, offset, size, NULL, data);
+}
+
 
 #endif  /* <linux/regset.h> */