For at least "gcc (Ubuntu 5.4.0-6ubuntu1~16.04.10) 5.4.0 20160609", the
typecast of buf triggers a Variable Length Array warning.
Alter the asm expression to avoid the typecast, which necessitates the
introduction of a memory clobber as the compiler can no longer identify
the total quantity of written memory.
Despite the memory clobber, there is no change to the generated.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Wei Liu <wei.l...@citrix.com>
CC: Paul Durrant <paul.durr...@citrix.com>
---
xen/arch/x86/hvm/emulate.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index a577685..eab66ea 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1859,7 +1859,7 @@ static int hvmemul_rep_stos(
switch ( p2mt )
{
unsigned long bytes;
- void *buf;
+ char *buf;
default:
/* Allocate temporary buffer. */
@@ -1882,10 +1882,10 @@ static int hvmemul_rep_stos(
#define CASE(bits, suffix) \
case (bits) / 8: \
asm ( "rep stos" #suffix \
- : "=m" (*(char (*)[bytes])buf), \
+ : "=m" (*buf), \
"=D" (dummy), "=c" (dummy) \
: "a" (*(const uint##bits##_t *)p_data), \
- "1" (buf), "2" (*reps) ); \
+ "1" (buf), "2" (*reps) : "memory" ); \
break
CASE(8, b);
CASE(16, w);
--
2.1.4
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