Add bootargs command-line option to Spike

We add bootargs command-line option to Spike which allows us to
provide custom kernel parameters to Linux and Xvisor.

Signed-off-by: Anup Patel <anup.patel@wdc.com>

riscv/dts.cc

@@ -11,6 +11,7 @@
 
 std::string make_dts(size_t insns_per_rtc_tick, size_t cpu_hz,
                      reg_t initrd_start, reg_t initrd_end,
+                     const char* bootargs,
                      std::vector<processor_t*> procs,
                      std::vector<std::pair<reg_t, mem_t*>> mems)
 {
@@ -25,12 +26,22 @@ std::string make_dts(size_t insns_per_rtc_tick, size_t cpu_hz,
          "  model = \"ucbbar,spike-bare\";\n"
          "  chosen {\n";
   if (initrd_start < initrd_end) {
-    s << "    bootargs = \"root=/dev/ram console=hvc0 earlycon=sbi\";\n"
-         "    linux,initrd-start = <" << (size_t)initrd_start << ">;\n"
+    s << "    linux,initrd-start = <" << (size_t)initrd_start << ">;\n"
          "    linux,initrd-end = <" << (size_t)initrd_end << ">;\n";
+    if (!bootargs)
+      bootargs = "root=/dev/ram console=hvc0 earlycon=sbi";
   } else {
-    s << "    bootargs = \"console=hvc0 earlycon=sbi\";\n";
+    if (!bootargs)
+      bootargs = "console=hvc0 earlycon=sbi";
   }
+    s << "    bootargs = \"";
+  for (size_t i = 0; i < strlen(bootargs); i++) {
+    if (bootargs[i] == '"')
+    s << '\\' << bootargs[i];
+    else
+    s << bootargs[i];
+  }
+    s << "\";\n";
     s << "  };\n"
          "  cpus {\n"
          "    #address-cells = <1>;\n"

riscv/dts.h

@@ -8,6 +8,7 @@
 
 std::string make_dts(size_t insns_per_rtc_tick, size_t cpu_hz,
                      reg_t initrd_start, reg_t initrd_end,
+                     const char* bootargs,
                      std::vector<processor_t*> procs,
                      std::vector<std::pair<reg_t, mem_t*>> mems);
 

riscv/sim.cc

@@ -28,7 +28,7 @@ static void handle_signal(int sig)
 
 sim_t::sim_t(const char* isa, const char* priv, const char* varch,
              size_t nprocs, bool halted, bool real_time_clint,
-             reg_t initrd_start, reg_t initrd_end,
+             reg_t initrd_start, reg_t initrd_end, const char* bootargs,
              reg_t start_pc, std::vector<std::pair<reg_t, mem_t*>> mems,
              std::vector<std::pair<reg_t, abstract_device_t*>> plugin_devices,
              const std::vector<std::string>& args,
@@ -42,6 +42,7 @@ sim_t::sim_t(const char* isa, const char* priv, const char* varch,
     procs(std::max(nprocs, size_t(1))),
     initrd_start(initrd_start),
     initrd_end(initrd_end),
+    bootargs(bootargs),
     start_pc(start_pc),
     dtb_file(dtb_file ? dtb_file : ""),
     dtb_enabled(dtb_enabled),
@@ -230,7 +231,7 @@ void sim_t::make_dtb()
 
     dtb = strstream.str();
   } else {
-    dts = make_dts(INSNS_PER_RTC_TICK, CPU_HZ, initrd_start, initrd_end, procs, mems);
+    dts = make_dts(INSNS_PER_RTC_TICK, CPU_HZ, initrd_start, initrd_end, bootargs, procs, mems);
     dtb = dts_compile(dts);
   }
 }
@@ -271,7 +272,7 @@ void sim_t::set_rom()
 
     dtb = strstream.str();
   } else {
-    dts = make_dts(INSNS_PER_RTC_TICK, CPU_HZ, initrd_start, initrd_end, procs, mems);
+    dts = make_dts(INSNS_PER_RTC_TICK, CPU_HZ, initrd_start, initrd_end, bootargs, procs, mems);
     dtb = dts_compile(dts);
   }
 

riscv/sim.h

@@ -25,7 +25,7 @@ class sim_t : public htif_t, public simif_t
 public:
   sim_t(const char* isa, const char* priv, const char* varch, size_t _nprocs,
         bool halted, bool real_time_clint,
-        reg_t initrd_start, reg_t initrd_end,
+        reg_t initrd_start, reg_t initrd_end, const char* bootargs,
         reg_t start_pc, std::vector<std::pair<reg_t, mem_t*>> mems,
         std::vector<std::pair<reg_t, abstract_device_t*>> plugin_devices,
         const std::vector<std::string>& args, const std::vector<int> hartids,
@@ -64,6 +64,7 @@ private:
   std::vector<processor_t*> procs;
   reg_t initrd_start;
   reg_t initrd_end;
+  const char* bootargs;
   reg_t start_pc;
   std::string dts;
   std::string dtb;

spike_main/spike.cc

@@ -51,6 +51,7 @@ static void help(int exit_code = 1)
   fprintf(stderr, "  --dump-dts            Print device tree string and exit\n");
   fprintf(stderr, "  --disable-dtb         Don't write the device tree blob into memory\n");
   fprintf(stderr, "  --initrd=<path>       Load kernel initrd into memory\n");
+  fprintf(stderr, "  --bootargs=<args>     Provide custom bootargs for kernel [default: console=hvc0 earlycon=sbi]\n");
   fprintf(stderr, "  --real-time-clint     Increment clint time at real-time rate\n");
   fprintf(stderr, "  --dm-progsize=<words> Progsize for the debug module [default 2]\n");
   fprintf(stderr, "  --dm-sba=<bits>       Debug bus master supports up to "
@@ -191,6 +192,7 @@ int main(int argc, char** argv)
   size_t nprocs = 1;
   size_t initrd_size;
   reg_t initrd_start = 0, initrd_end = 0;
+  const char* bootargs = NULL;
   reg_t start_pc = reg_t(-1);
   std::vector<std::pair<reg_t, mem_t*>> mems;
   std::vector<std::pair<reg_t, abstract_device_t*>> plugin_devices;
@@ -301,6 +303,7 @@ int main(int argc, char** argv)
   parser.option(0, "disable-dtb", 0, [&](const char *s){dtb_enabled = false;});
   parser.option(0, "dtb", 1, [&](const char *s){dtb_file = s;});
   parser.option(0, "initrd", 1, [&](const char* s){initrd = s;});
+  parser.option(0, "bootargs", 1, [&](const char* s){bootargs = s;});
   parser.option(0, "real-time-clint", 0, [&](const char *s){real_time_clint = true;});
   parser.option(0, "extlib", 1, [&](const char *s){
     void *lib = dlopen(s, RTLD_NOW | RTLD_GLOBAL);
@@ -351,7 +354,7 @@ int main(int argc, char** argv)
   }
 
   sim_t s(isa, priv, varch, nprocs, halted, real_time_clint,
-      initrd_start, initrd_end, start_pc, mems, plugin_devices, htif_args,
+      initrd_start, initrd_end, bootargs, start_pc, mems, plugin_devices, htif_args,
       std::move(hartids), dm_config, log_path, dtb_enabled, dtb_file);
   std::unique_ptr<remote_bitbang_t> remote_bitbang((remote_bitbang_t *) NULL);
   std::unique_ptr<jtag_dtm_t> jtag_dtm(