generic ...copy_..._user primitives

provide raw_copy_..._user() and select ARCH_HAS_RAW_COPY_USER to use those.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/usercopy.c b/lib/usercopy.c
new file mode 100644
index 000000000000..1b6010a3beb8
--- /dev/null
+++ b/lib/usercopy.c
@@ -0,0 +1,26 @@
+#include <linux/uaccess.h>
+
+/* out-of-line parts */
+
+#ifndef INLINE_COPY_FROM_USER
+unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+        unsigned long res = n;
+        if (likely(access_ok(VERIFY_READ, from, n)))
+                res = raw_copy_from_user(to, from, n);
+        if (unlikely(res))
+                memset(to + (n - res), 0, res);
+        return res;
+}
+EXPORT_SYMBOL(_copy_from_user);
+#endif
+
+#ifndef INLINE_COPY_TO_USER
+unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
+{
+        if (likely(access_ok(VERIFY_WRITE, to, n)))
+                n = raw_copy_to_user(to, from, n);
+        return n;
+}
+EXPORT_SYMBOL(_copy_to_user);
+#endif