diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1dbd16e64251..c322ba80e24f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,6 +69,8 @@ if (LOWERCASE_CMAKE_SYSTEM_PROCESSOR MATCHES "^arm")
     set(WTF_CPU_ARM 1)
 elseif (LOWERCASE_CMAKE_SYSTEM_PROCESSOR MATCHES "^aarch64")
     set(WTF_CPU_ARM64 1)
+elseif (LOWERCASE_CMAKE_SYSTEM_PROCESSOR MATCHES "alpha*")
+    set(WTF_CPU_ALPHA 1)
 elseif (LOWERCASE_CMAKE_SYSTEM_PROCESSOR MATCHES "^mips")
     set(WTF_CPU_MIPS 1)
 elseif (LOWERCASE_CMAKE_SYSTEM_PROCESSOR MATCHES "sh4")
diff --git a/ChangeLog b/ChangeLog
index 0d6f60874205..9d9ce29a2286 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2017-09-20  Alberto Garcia  <berto@igalia.com>
+
+        Fix HPPA and Alpha builds
+        https://bugs.webkit.org/show_bug.cgi?id=177224
+
+        Reviewed by Alex Christensen.
+
+        * CMakeLists.txt:
+
 2017-09-19  Carlos Alberto Lopez Perez  <clopez@igalia.com>
 
         [CMake] Add ENABLE_WEB_CRYPTO option and make ENABLE_SUBTLE_CRYPTO depend on it.
diff --git a/Source/JavaScriptCore/CMakeLists.txt b/Source/JavaScriptCore/CMakeLists.txt
index caebf2297d96..095a76505948 100644
--- a/Source/JavaScriptCore/CMakeLists.txt
+++ b/Source/JavaScriptCore/CMakeLists.txt
@@ -1525,6 +1525,7 @@ list(APPEND JavaScriptCore_HEADERS ${DERIVED_SOURCES_JAVASCRIPTCORE_DIR}/Injecte
 
 if (WTF_CPU_ARM)
 elseif (WTF_CPU_ARM64)
+elseif (WTF_CPU_ALPHA)
 elseif (WTF_CPU_HPPA)
 elseif (WTF_CPU_PPC)
 elseif (WTF_CPU_PPC64)
diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index 3f14d25a9f90..84b7fe2ffb09 100644
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,12 @@
+2017-09-20  Alberto Garcia  <berto@igalia.com>
+
+        Fix HPPA and Alpha builds
+        https://bugs.webkit.org/show_bug.cgi?id=177224
+
+        Reviewed by Alex Christensen.
+
+        * CMakeLists.txt:
+
 2017-08-30  Saam Barati  <sbarati@apple.com>
 
         semicolon is being interpreted as an = in the LiteralParser
diff --git a/Source/WTF/ChangeLog b/Source/WTF/ChangeLog
index 10961fa6cb6c..40157a775645 100644
--- a/Source/WTF/ChangeLog
+++ b/Source/WTF/ChangeLog
@@ -1,3 +1,12 @@
+2017-09-20  Alberto Garcia  <berto@igalia.com>
+
+        Fix HPPA and Alpha builds
+        https://bugs.webkit.org/show_bug.cgi?id=177224
+
+        Reviewed by Alex Christensen.
+
+        * wtf/Platform.h:
+
 2017-08-22  Chris Dumez  <cdumez@apple.com>
 
         Introduce a new CompletionHandler type and use it for NetworkDataTaskClient's completion handlers to help catch bugs
diff --git a/Source/WTF/wtf/Platform.h b/Source/WTF/wtf/Platform.h
index 802f52579f8b..1c1b9a61570a 100644
--- a/Source/WTF/wtf/Platform.h
+++ b/Source/WTF/wtf/Platform.h
@@ -353,7 +353,7 @@
 
 #endif /* ARM */
 
-#if CPU(ARM) || CPU(MIPS) || CPU(SH4)
+#if CPU(ARM) || CPU(MIPS) || CPU(SH4) || CPU(ALPHA) || CPU(HPPA)
 #define WTF_CPU_NEEDS_ALIGNED_ACCESS 1
 #endif