diff --git a/deps/v8/include/v8-version.h b/deps/v8/include/v8-version.h
index 66e1ab98071300..e0efde2b0b6dc2 100644
--- a/deps/v8/include/v8-version.h
+++ b/deps/v8/include/v8-version.h
@@ -11,7 +11,7 @@
 #define V8_MAJOR_VERSION 5
 #define V8_MINOR_VERSION 1
 #define V8_BUILD_NUMBER 281
-#define V8_PATCH_LEVEL 76
+#define V8_PATCH_LEVEL 77
 
 // Use 1 for candidates and 0 otherwise.
 // (Boolean macro values are not supported by all preprocessors.)
diff --git a/deps/v8/test/cctest/test-platform.cc b/deps/v8/test/cctest/test-platform.cc
index 6012fd4ae17d94..48eda3dbaa9f57 100644
--- a/deps/v8/test/cctest/test-platform.cc
+++ b/deps/v8/test/cctest/test-platform.cc
@@ -25,9 +25,9 @@ void GetStackPointer(const v8::FunctionCallbackInfo<v8::Value>& args) {
 #elif V8_HOST_ARCH_MIPS64
   __asm__ __volatile__("sd $sp, %0" : "=g"(sp_addr));
 #elif defined(__s390x__) || defined(_ARCH_S390X)
-  __asm__ __volatile__("stg 15, %0" : "=g"(sp_addr));
+  __asm__ __volatile__("stg 15, %0" : "=m"(sp_addr));
 #elif defined(__s390__) || defined(_ARCH_S390)
-  __asm__ __volatile__("st 15, %0" : "=g"(sp_addr));
+  __asm__ __volatile__("st 15, %0" : "=m"(sp_addr));
 #elif defined(__PPC64__) || defined(_ARCH_PPC64)
   __asm__ __volatile__("std 1, %0" : "=g"(sp_addr));
 #elif defined(__PPC__) || defined(_ARCH_PPC)