diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Platform.h b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Platform.h
index 85ed8a7..9c419da 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Platform.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/Platform.h
@@ -189,6 +189,18 @@
 #define WTF_CPU_SPARC 1
 #endif
 
+/* CPU(S390X) - S390 64-bit */
+#if defined(__s390x__)
+#define WTF_CPU_S390X 1
+#define WTF_CPU_BIG_ENDIAN 1
+#endif
+
+/* CPU(S390) - S390 32-bit */
+#if defined(__s390__) && !defined(__s390x__)
+#define WTF_CPU_S390 1
+#define WTF_CPU_BIG_ENDIAN 1
+#endif
+
 /* CPU(X86) - i386 / x86 32-bit */
 #if   defined(__i386__) \
     || defined(i386)     \
@@ -913,7 +925,7 @@
 #if !defined(WTF_USE_JSVALUE64) && !defined(WTF_USE_JSVALUE32) && !defined(WTF_USE_JSVALUE32_64)
 #if (CPU(X86_64) && !CPU(X32) && (OS(UNIX) || OS(WINDOWS) || OS(SOLARIS) || OS(HPUX))) || (CPU(IA64) && !CPU(IA64_32)) || CPU(ALPHA) || CPU(AIX64) || CPU(SPARC64) || CPU(MIPS64) || CPU(AARCH64)
 #define WTF_USE_JSVALUE64 1
-#elif CPU(ARM) || CPU(PPC64)
+#elif CPU(ARM) || CPU(PPC64) || CPU(S390X)
 #define WTF_USE_JSVALUE32 1
 #elif OS(WINDOWS) && COMPILER(MINGW)
 /* Using JSVALUE32_64 causes padding/alignement issues for JITStubArg