diff --git a/util/m5/src/addr_call_type.c b/util/m5/src/addr_call_type.c
index cb269dc5fa..0b3d1fcf43 100644
--- a/util/m5/src/addr_call_type.c
+++ b/util/m5/src/addr_call_type.c
@@ -28,6 +28,8 @@
 #include <string.h>
 
 #include "addr_call_type.h"
+#include "args.h"
+#include "m5_mmap.h"
 
 #define M5OP(name, func) __typeof__(name) M5OP_MERGE_TOKENS(name, _addr);
 M5OP_FOREACH
@@ -42,9 +44,40 @@ M5OP_FOREACH
 int
 addr_call_type_detect(int *argc, char **argv[])
 {
-    if (*argc > 0 && strcmp((*argv)[0], "--addr") == 0) {
+    static const char *prefix = "--addr";
+    const size_t prefix_len = strlen(prefix);
+    uint64_t addr_override;
+
+    // If the first argument starts with --addr...
+    if (*argc > 0 && memcmp((*argv)[0], prefix, prefix_len) == 0) {
+        char *argv0 = (*argv)[0];
         (*argc)--;
         (*argv)++;
+
+        // If there's more text in this argument...
+        if (strlen(argv0) != prefix_len) {
+            // If it doesn't start with '=', it's malformed.
+            if (argv0[prefix_len] != '=')
+                return -1;
+            // Attempt to extract an address after the '='.
+            char *temp_argv[] = { &argv0[prefix_len + 1] };
+            if (!parse_int_args(1, temp_argv, &addr_override, 1))
+                return -1;
+            // If we found an address, use it to override m5op_addr.
+            m5op_addr = addr_override;
+            return 1;
+        }
+        // If an address override wasn't part of the first argument, check if
+        // it's the second argument. If not, then there's no override.
+        if (*argc > 0 && parse_int_args(1, *argv, &addr_override, 1)) {
+            m5op_addr = addr_override;
+            (*argc)--;
+            (*argv)++;
+            return 1;
+        }
+        // If the default address was zero, an override is required.
+        if (!m5op_addr)
+            return -1;
         return 1;
     }
     return 0;
diff --git a/util/m5/src/addr_call_type.h b/util/m5/src/addr_call_type.h
index d1fbfa6e87..6dcdb5bdbc 100644
--- a/util/m5/src/addr_call_type.h
+++ b/util/m5/src/addr_call_type.h
@@ -30,6 +30,7 @@
 
 #include "dispatch_table.h"
 
+// Returns 0 if not detected, 1 if detected successfully, and -1 on error.
 int addr_call_type_detect(int *argc, char **argv[]);
 DispatchTable *addr_call_type_init();
 
diff --git a/util/m5/src/m5.c b/util/m5/src/m5.c
index 11e7d603d5..644acd0337 100644
--- a/util/m5/src/m5.c
+++ b/util/m5/src/m5.c
@@ -290,10 +290,16 @@ usage()
     fprintf(stderr, "\n");
     fprintf(stderr, "Call types:\n");
 #   if ENABLE_CT_addr
-    fprintf(stderr, "    --addr%s\n", DEFAULT_CT_addr ? " (default)" : "");
+    fprintf(stderr, "    --addr %s%s\n",
+#   if defined(M5OP_ADDR)
+            "[address override]",
+#   else
+            "<address override>",
+#   endif
+            DEFAULT_CT_addr ? " (default)" : "");
     fprintf(stderr, "        Use the address based invocation method.\n");
 #   if defined(M5OP_ADDR)
-    fprintf(stderr, "        The address is %#"PRIx64".\n",
+    fprintf(stderr, "        The default address is %#"PRIx64".\n",
             (uint64_t)M5OP_ADDR);
 #   endif
 #   endif
@@ -331,8 +337,12 @@ main(int argc, char *argv[])
     }
 #   endif
 #   if ENABLE_CT_addr
-    if (!dt && addr_call_type_detect(&argc, &argv)) {
-        dt = addr_call_type_init();
+    if (!dt) {
+        int detect = addr_call_type_detect(&argc, &argv);
+        if (detect < 0)
+            usage();
+        if (detect > 0)
+            dt = addr_call_type_init();
     }
 #   endif
 #   if ENABLE_CT_semi
diff --git a/util/m5/src/m5_mmap.c b/util/m5/src/m5_mmap.c
index 79de59baab..4a5aa0f559 100644
--- a/util/m5/src/m5_mmap.c
+++ b/util/m5/src/m5_mmap.c
@@ -49,10 +49,14 @@
 
 void *m5_mem = NULL;
 
+#ifndef M5OP_ADDR
+#define M5OP_ADDR 0
+#endif
+uint64_t m5op_addr = M5OP_ADDR;
+
 void
 map_m5_mem()
 {
-#ifdef M5OP_ADDR
     int fd;
 
     fd = open("/dev/mem", O_RDWR | O_SYNC);
@@ -62,10 +66,9 @@ map_m5_mem()
     }
 
     m5_mem = mmap(NULL, 0x10000, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
-                  M5OP_ADDR);
+                  m5op_addr);
     if (!m5_mem) {
         perror("Can't mmap /dev/mem");
         exit(1);
     }
-#endif
 }
diff --git a/util/m5/src/m5_mmap.h b/util/m5/src/m5_mmap.h
index d32857f0b1..552b400d07 100644
--- a/util/m5/src/m5_mmap.h
+++ b/util/m5/src/m5_mmap.h
@@ -42,9 +42,11 @@
 #define __UTIL_M5_MMAP_H__
 
 #include <fcntl.h>
+#include <stdint.h>
 #include <sys/mman.h>
 
 extern void *m5_mem;
+extern uint64_t m5op_addr;
 
 void map_m5_mem();