From: Jan Beulich <jbeulich@suse.com>
Date: Mon, 19 Dec 2016 16:52:42 +0000 (+0100)
Subject: x86: fix asm() constraint in clear_user()
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~3107
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=157db407533fb55c0ce0c133991e3cb951b76484;p=xen.git

x86: fix asm() constraint in clear_user()

Commit 2fdf5b2554 ("x86: streamline copying to/from user memory")
wrongly used "g" here, when it obviously needs to be a register.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/arch/x86/usercopy.c b/xen/arch/x86/usercopy.c
index d1303a9874..1d1ef075c9 100644
--- a/xen/arch/x86/usercopy.c
+++ b/xen/arch/x86/usercopy.c
@@ -141,7 +141,7 @@ unsigned clear_user(void __user *to, unsigned n)
             _ASM_EXTABLE(0b,3b)
             _ASM_EXTABLE(1b,2b)
             : [cnt] "=&c" (n), [to] "+D" (to)
-            : [bytes] "g" (n & (BYTES_PER_LONG - 1)),
+            : [bytes] "r" (n & (BYTES_PER_LONG - 1)),
               [longs] "0" (n / BYTES_PER_LONG), "a" (0) );
         clac();
     }