rol64() is roubust against too large shift values and fixes UBSan
warnings.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
 contrib/elf2dmp/main.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/contrib/elf2dmp/main.c b/contrib/elf2dmp/main.c
index 51e1abe26a17..e404612bec00 100644
--- a/contrib/elf2dmp/main.c
+++ b/contrib/elf2dmp/main.c
@@ -6,6 +6,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/bitops.h"
 
 #include "err.h"
 #include "addrspace.h"
@@ -47,11 +48,6 @@ static const uint64_t SharedUserData = 0xfffff78000000000;
     s ? printf(#s" = 0x%016"PRIx64"\n", s) :\
     eprintf("Failed to resolve "#s"\n"), s)
 
-static uint64_t rol(uint64_t x, uint64_t y)
-{
-    return (x << y) | (x >> (64 - y));
-}
-
 /*
  * Decoding algorithm can be found in Volatility project
  */
@@ -64,7 +60,7 @@ static void kdbg_decode(uint64_t *dst, uint64_t *src, size_t size,
         uint64_t block;
 
         block = src[i];
-        block = rol(block ^ kwn, (uint8_t)kwn);
+        block = rol64(block ^ kwn, kwn);
         block = __builtin_bswap64(block ^ kdbe) ^ kwa;
         dst[i] = block;
     }

-- 
2.44.0