diff -ur openjdk/common/autoconf/platform.m4 openjdk.riscv/common/autoconf/platform.m4
--- openjdk/common/autoconf/platform.m4	2017-10-09 09:21:48.000000000 +0000
+++ openjdk.riscv/common/autoconf/platform.m4	2018-03-04 21:30:36.204000000 +0000
@@ -96,6 +96,18 @@
       VAR_CPU_BITS=64
       VAR_CPU_ENDIAN=big
       ;;
+    riscv32)
+      VAR_CPU=riscv32
+      VAR_CPU_ARCH=riscv
+      VAR_CPU_BITS=32
+      VAR_CPU_ENDIAN=little
+      ;;
+    riscv64)
+      VAR_CPU=riscv64
+      VAR_CPU_ARCH=riscv
+      VAR_CPU_BITS=64
+      VAR_CPU_ENDIAN=little
+      ;;
     *)
       AC_MSG_ERROR([unsupported cpu $1])
       ;;
diff -ur openjdk/hotspot/src/os/linux/vm/os_linux.cpp openjdk.riscv/hotspot/src/os/linux/vm/os_linux.cpp
--- openjdk/hotspot/src/os/linux/vm/os_linux.cpp	2017-10-09 09:25:27.000000000 +0000
+++ openjdk.riscv/hotspot/src/os/linux/vm/os_linux.cpp	2018-03-04 21:31:58.308000000 +0000
@@ -1744,6 +1744,10 @@
   #define EM_AARCH64    183               /* ARM AARCH64 */
 #endif
 
+  #ifndef EM_RISCV
+  #define EM_RISCV      243               /* RISC-V */
+  #endif
+
   static const arch_t arch_array[]={
     {EM_386,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
     {EM_486,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
@@ -1766,6 +1770,7 @@
     {EM_PARISC,      EM_PARISC,  ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
     {EM_68K,         EM_68K,     ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
     {EM_AARCH64,     EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
+    {EM_RISCV,       EM_RISCV,   ELFCLASSNONE, ELFDATA2MSB, (char*)"RISC-V"},
   };
 
 #if  (defined IA32)
@@ -1782,6 +1787,8 @@
   static  Elf32_Half running_arch_code=EM_PPC64;
 #elif  (defined __powerpc__)
   static  Elf32_Half running_arch_code=EM_PPC;
+#elif  (defined __riscv)
+  static  Elf32_Half running_arch_code=EM_RISCV;
 #elif  (defined AARCH64)
   static  Elf32_Half running_arch_code=EM_AARCH64;
 #elif  (defined ARM)
@@ -1800,7 +1807,7 @@
   static  Elf32_Half running_arch_code=EM_68K;
 #else
     #error Method os::dll_load requires that one of following is defined:\
-        AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc
+        AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, __riscv, S390, __sparc
 #endif
 
   // Identify compatability class for VM's architecture and library's architecture
@@ -1833,10 +1840,12 @@
   }
 
 #ifndef S390
+#ifndef __riscv
   if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
     return NULL;
   }
+#endif // __riscv
 #endif // !S390
 
   if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
Only in openjdk.riscv/hotspot/src/os/linux/vm: os_linux.cpp.orig