[PATCH 3.2 114/152] parisc: fix copy_from_user()

[Ben Hutchings]

3.2.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <v...@zeniv.linux.org.uk>

commit aace880feea38875fbc919761b77e5732a3659ef upstream.

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -10,6 +10,8 @@
 #include <asm/errno.h>
 #include <asm-generic/uaccess-unaligned.h>
 
+#include <linux/string.h>
+
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1
 
@@ -255,13 +257,14 @@ static inline unsigned long __must_check
                                           unsigned long n)
 {
         int sz = __compiletime_object_size(to);
-        int ret = -EFAULT;
+        unsigned long ret = n;
 
         if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
                 ret = __copy_from_user(to, from, n);
         else
                 copy_from_user_overflow();
-
+       if (unlikely(ret))
+               memset(to + (n - ret), 0, ret);
         return ret;
 }