util-m5: Add default M5OP_ADDR to arm64 (#977)

As pointed out here [1], the expected M5OP_ADDR for arm64 arch is
0x10010000. This change reflects that.

[1] https://github.com/gem5/gem5/pull/725

util/m5/src/abi/arm64/SConsopts

@@ -32,3 +32,6 @@ get_abi_opt('QEMU_ARCH', 'aarch64')
 env['CALL_TYPE']['inst'].impl('m5op.S', 'verify_inst.cc', default=True)
 env['CALL_TYPE']['addr'].impl('m5op_addr.S')
 env['CALL_TYPE']['semi'].impl('m5op_semi.S', 'verify_semi.cc')
+
+env.Append(CXXFLAGS='-DM5OP_ADDR=0x10010000')
+env.Append(CCFLAGS='-DM5OP_ADDR=0x10010000')

util/m5/src/m5_mmap.c

@@ -69,6 +69,10 @@ map_m5_mem()
         exit(1);
     }
 
+    if (m5op_addr == 0) {
+        fprintf(stdout, "Warn: m5op_addr is set to 0x0\n");
+    }
+
     fd = open(m5_mmap_dev, O_RDWR | O_SYNC);
     if (fd == -1) {
         fprintf(stderr, "Can't open %s: %s\n", m5_mmap_dev, strerror(errno));