[Xen-changelog] [xen-unstable] x86/gnttab: fix asm() operand in gnttab_clear_flag()

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1332488379 -3600
# Node ID a66fb91cb8d3b1a01538ed8e5cda7847d93aaf06
# Parent  0ecb8ffe61b2ffff4331fcf49487c956ccb297a0
x86/gnttab: fix asm() operand in gnttab_clear_flag()

The operand needs to use the 'w' modifier in case the compiler happens
to pick a register (which apparently it does for no-one but the
reporter of this problem).

Reported-by: Lin Ming <mlin@xxxxxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 0ecb8ffe61b2 -r a66fb91cb8d3 xen/include/asm-x86/grant_table.h
--- a/xen/include/asm-x86/grant_table.h Thu Mar 22 17:15:22 2012 +0000
+++ b/xen/include/asm-x86/grant_table.h Fri Mar 23 08:39:39 2012 +0100
@@ -54,7 +54,7 @@
      * Note that this cannot be clear_bit(), as the access must be
      * confined to the specified 2 bytes.
      */
-    asm volatile ("lock btrw %1,%0" : "=m" (*st) : "Ir" (nr), "m" (*st));
+    asm volatile ("lock btrw %w1,%0" : "=m" (*st) : "Ir" (nr), "m" (*st));
 }
 
 /* Foreign mappings of HHVM-guest pages do not modify the type count. */

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