monitor: move mainargs to PC_START + 0x1000

include/memory/memory.h

@@ -7,6 +7,7 @@
 extern uint8_t pmem[];
 
 #define IMAGE_START 0x0
+#define MAINARGS_START 0x1000
 
 /* convert the guest physical address in the guest program to host virtual address in NEMU */
 #define guest_to_host(p) ((void *)(pmem + (unsigned)p))

src/monitor/diff-test/diff-test.c

@@ -78,8 +78,6 @@ void init_difftest(char *ref_so_file, long img_size, int port) {
 
   ref_difftest_init(port);
   ref_difftest_memcpy_from_dut(PC_START, guest_to_host(IMAGE_START), img_size);
-  char *mainargs = guest_to_host(0);
-  ref_difftest_memcpy_from_dut(PC_START - IMAGE_START, mainargs, strlen(mainargs) + 1);
   ref_difftest_setregs(&cpu);
 }
 

src/monitor/monitor.c

@@ -11,7 +11,7 @@ void init_wp_pool();
 void init_device();
 void init_difftest(char *ref_so_file, long img_size, int port);
 
-static char *mainargs = "";
+static char *mainargs = NULL;
 static char *log_file = NULL;
 static char *diff_so_file = NULL;
 static char *img_file = NULL;
@@ -60,7 +60,9 @@ static inline long load_img() {
     fclose(fp);
 
     // mainargs
-    strcpy(guest_to_host(0), mainargs);
+    if (mainargs != NULL) {
+      strcpy(guest_to_host(MAINARGS_START), mainargs);
+    }
   }
   return size;
 }