diff --git a/Source/JavaScriptCore/CMakeLists.txt b/Source/JavaScriptCore/CMakeLists.txt
index afd76ca1a..3fca6e049 100644
--- a/Source/JavaScriptCore/CMakeLists.txt
+++ b/Source/JavaScriptCore/CMakeLists.txt
@@ -1289,6 +1289,7 @@ elseif (WTF_CPU_MIPS)
 elseif (WTF_CPU_SH4)
 elseif (WTF_CPU_X86)
 elseif (WTF_CPU_X86_64)
+elseif (WTF_CPU_RISCV64)
     if (MSVC AND ENABLE_JIT)
         add_custom_command(
             OUTPUT ${DERIVED_SOURCES_DIR}/JITStubsMSVC64.obj
diff --git a/Source/ThirdParty/brotli/dec/port.h b/Source/ThirdParty/brotli/dec/port.h
index 6b3d7352b..54f51b010 100644
--- a/Source/ThirdParty/brotli/dec/port.h
+++ b/Source/ThirdParty/brotli/dec/port.h
@@ -56,6 +56,10 @@
 #define BROTLI_TARGET_POWERPC64
 #endif
 
+#if defined(__riscv) && defined(__riscv_xlen) && __riscv_xlen == 64
+#define BROTLI_TARGET_RISCV64
+#endif
+
 #ifdef BROTLI_BUILD_PORTABLE
 #define BROTLI_ALIGNED_READ (!!1)
 #elif defined(BROTLI_TARGET_X86) || defined(BROTLI_TARGET_X64) || \
@@ -96,7 +100,7 @@ static BROTLI_INLINE void BrotliDump(const char* f, int l, const char* fn) {
 #elif defined(BROTLI_BUILD_32_BIT)
 #define BROTLI_64_BITS 0
 #elif defined(BROTLI_TARGET_X64) || defined(BROTLI_TARGET_ARMV8) || \
-    defined(BROTLI_TARGET_POWERPC64)
+    defined(BROTLI_TARGET_POWERPC64) || defined(BROTLI_TARGET_RISCV64)
 #define BROTLI_64_BITS 1
 #else
 #define BROTLI_64_BITS 0
diff --git a/Tools/Scripts/webkitdirs.pm b/Tools/Scripts/webkitdirs.pm
index 45b6649a9..1b32756fc 100755
--- a/Tools/Scripts/webkitdirs.pm
+++ b/Tools/Scripts/webkitdirs.pm
@@ -1264,6 +1264,11 @@ sub isARM()
     return ($Config{archname} =~ /^arm[v\-]/) || ($Config{archname} =~ /^aarch64[v\-]/);
 }
 
+sub isRISCV()
+{
+    return ($Config{archname} =~ /^riscv(|32|64)\-/);
+}
+
 sub isX86_64()
 {
     return (architecture() eq "x86_64") || 0;