Add support for RISC-V 64-bit architecture

Signed-off-by: Rebecca Chang Swee Fun <rebecca.chang@starfivetech.com>
Change-Id: If6424a3b268943a5e2dc847f94b509d4b509df79
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/52765
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>

CMakeLists.txt

@@ -494,6 +494,8 @@ elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "mips")
   set(ARCH "generic")
 elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "ppc64le")
   set(ARCH "ppc64le")
+elseif (${CMAKE_SYSTEM_PROCESSOR} STREQUAL "riscv64")
+  set(ARCH "riscv64")
 else()
   message(FATAL_ERROR "Unknown processor:" ${CMAKE_SYSTEM_PROCESSOR})
 endif()

include/openssl/base.h

@@ -118,6 +118,8 @@ extern "C" {
 #define OPENSSL_32_BIT
 #elif defined(__myriad2__)
 #define OPENSSL_32_BIT
+#elif defined(__riscv) && __riscv_xlen == 64
+#define OPENSSL_64_BIT
 #else
 // Note BoringSSL only supports standard 32-bit and 64-bit two's-complement,
 // little-endian architectures. Functions will not produce the correct answer