reduce sig_len constraint to 4 bytes (#569)

* reduce sig_len constraint to 4 bytes

Spike currently asserts that the signature length should always be a multiple of 16-bytes. However, the compliance suite has agreed to upon the signature being a multiple ot 4-bytes. This prevents some of the tests to run on spike since it fails the assertion.

The proposed change fixes this issue and reduces the assertion to 4 bytes.

* Added size argument to htif arguments and zero padding for signature output. Defaultline size-16.

* Modified type of line_size to unsigned.

* Renamed size to granularity.

* Rename granularity to signature-granularity.

Co-authored-by: dracarys99 <spawan1999@gmail.com>

fesvr/htif.cc

@@ -64,7 +64,8 @@ htif_t::htif_t(const std::vector<std::string>& args) : htif_t()
   for (unsigned int i = 0; i < args.size(); i++) {
     argv[i+1] = (char *) args[i].c_str();
   }
-
+  //Set line size as 16 by default.
+  line_size = 16;
   parse_arguments(argc, argv);
   register_devices();
 }
@@ -174,12 +175,13 @@ void htif_t::stop()
     assert(sigs && "can't open signature file!");
     sigs << std::setfill('0') << std::hex;
 
-    const addr_t incr = 16;
+    for (addr_t i = 0; i < sig_len; i += line_size)
-    assert(sig_len % incr == 0);
-    for (addr_t i = 0; i < sig_len; i += incr)
     {
-      for (addr_t j = incr; j > 0; j--)
+      for (addr_t j = line_size; j > 0; j--)
-        sigs << std::setw(2) << (uint16_t)buf[i+j-1];
+          if (i+j < sig_len)
+            sigs << std::setw(2) << (uint16_t)buf[i+j-1];
+          else
+            sigs << std::setw(2) << (uint16_t)0;
       sigs << '\n';
     }
 
@@ -275,6 +277,10 @@ void htif_t::parse_arguments(int argc, char ** argv)
         break;
       case HTIF_LONG_OPTIONS_OPTIND + 4:
         payloads.push_back(optarg);
+        break;
+      case HTIF_LONG_OPTIONS_OPTIND + 5:
+        line_size = atoi(optarg);
+
         break;
       case '?':
         if (!opterr)
@@ -310,6 +316,10 @@ void htif_t::parse_arguments(int argc, char ** argv)
           c = HTIF_LONG_OPTIONS_OPTIND + 4;
           optarg = optarg + 9;
         }
+        else if(arg.find("+signature-granularity=")==0){
+            c = HTIF_LONG_OPTIONS_OPTIND + 5;
+            optarg = optarg + 23;
+        }
         else if (arg.find("+permissive-off") == 0) {
           if (opterr)
             throw std::invalid_argument("Found +permissive-off when not parsing permissively");

fesvr/htif.h

@@ -63,6 +63,7 @@ class htif_t : public chunked_memif_t
   std::vector<std::string> hargs;
   std::vector<std::string> targs;
   std::string sig_file;
+  unsigned int line_size;
   addr_t sig_addr; // torture
   addr_t sig_len; // torture
   addr_t tohost_addr;
@@ -100,6 +101,8 @@ class htif_t : public chunked_memif_t
        +rfb=DISPLAY          to be accessible on 5900 + DISPLAY (default = 0)\n\
       --signature=FILE     Write torture test signature to FILE\n\
        +signature=FILE\n\
+      --signature-granularity=VAL           Size of each line in signature.\n\
+       +signature-granularity=VAL\n\
       --chroot=PATH        Use PATH as location of syscall-servicing binaries\n\
        +chroot=PATH\n\
       --payload=PATH       Load PATH memory as an additional ELF payload\n\
@@ -121,6 +124,7 @@ TARGET (RISC-V BINARY) OPTIONS\n\
 {"signature", required_argument, 0, HTIF_LONG_OPTIONS_OPTIND + 2 },     \
 {"chroot",    required_argument, 0, HTIF_LONG_OPTIONS_OPTIND + 3 },     \
 {"payload",   required_argument, 0, HTIF_LONG_OPTIONS_OPTIND + 4 },     \
+{"signature-granularity",    optional_argument, 0, HTIF_LONG_OPTIONS_OPTIND + 5 },     \
 {0, 0, 0, 0}
 
 #endif // __HTIF_H