diff --git a/CMakeLists.txt b/CMakeLists.txt
index f8df14007..88332464b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -152,6 +152,8 @@ endfunction(link_to_source)
 
 string(REGEX MATCH "Clang" CMAKE_COMPILER_IS_CLANG "${CMAKE_C_COMPILER_ID}")
 
+include(CheckCCompilerFlag)
+
 if(CMAKE_COMPILER_IS_GNU)
     # some warnings we want are not available with old GCC versions
     # note: starting with CMake 2.8 we could use CMAKE_C_COMPILER_VERSION
@@ -168,7 +170,10 @@ if(CMAKE_COMPILER_IS_GNU)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wshadow")
     endif()
     if (GCC_VERSION VERSION_GREATER 5.0)
-        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wformat-signedness")
+        CHECK_C_COMPILER_FLAG("-Wformat-signedness" C_COMPILER_SUPPORTS_WFORMAT_SIGNEDNESS)
+        if(C_COMPILER_SUPPORTS_WFORMAT_SIGNEDNESS)
+            set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wformat-signedness")
+        endif()
     endif()
     set(CMAKE_C_FLAGS_RELEASE     "-O2")
     set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
diff --git a/ChangeLog.d/e2k-support.txt b/ChangeLog.d/e2k-support.txt
new file mode 100644
index 000000000..023b1888e
--- /dev/null
+++ b/ChangeLog.d/e2k-support.txt
@@ -0,0 +1,5 @@
+Features
+   * Support building on e2k (Elbrus) architecture: correctly enable
+     -Wformat-signedness, and fix the code that causes signed-one-bit-field
+     and sign-compare warnings. Contributed by makise-homura (Igor Molchanov)
+     <akemi_homura@kurisa.ch>.
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 88951e544..650bdc3d8 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -2046,7 +2046,7 @@ int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want )
             if( ret < 0 )
                 return( ret );
 
-            if ( (size_t)ret > len || ( INT_MAX > SIZE_MAX && ret > SIZE_MAX ) )
+            if ( (size_t)ret > len || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1,
                     ( "f_recv returned %d bytes but only %lu were requested",
@@ -2100,7 +2100,7 @@ int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
         if( ret <= 0 )
             return( ret );
 
-        if( (size_t)ret > ssl->out_left || ( INT_MAX > SIZE_MAX && ret > SIZE_MAX ) )
+        if( (size_t)ret > ssl->out_left || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1,
                 ( "f_send returned %d bytes but only %lu bytes were sent",
diff --git a/programs/pkey/dh_genprime.c b/programs/pkey/dh_genprime.c
index 796ba4b82..a481e3291 100644
--- a/programs/pkey/dh_genprime.c
+++ b/programs/pkey/dh_genprime.c
@@ -89,7 +89,7 @@ int main( int argc, char **argv )
     {
     usage:
         mbedtls_printf( USAGE );
-        mbedtls_exit( exit_code );
+        goto exit;
     }
 
     for( i = 1; i < argc; i++ )
diff --git a/tests/include/test/macros.h b/tests/include/test/macros.h
index 717715631..f40478070 100644
--- a/tests/include/test/macros.h
+++ b/tests/include/test/macros.h
@@ -73,7 +73,7 @@
 /* A compile-time constant with the value 0. If `const_expr` is not a
  * compile-time constant with a nonzero value, cause a compile-time error. */
 #define STATIC_ASSERT_EXPR( const_expr )                                \
-    ( 0 && sizeof( struct { int STATIC_ASSERT : 1 - 2 * ! ( const_expr ); } ) )
+    ( 0 && sizeof( struct { unsigned int STATIC_ASSERT : 1 - 2 * ! ( const_expr ); } ) )
 /* Return the scalar value `value` (possibly promoted). This is a compile-time
  * constant if `value` is. `condition` must be a compile-time constant.
  * If `condition` is false, arrange to cause a compile-time error. */