Support debug system bus access.

5 files changed, 230 insertions, 20 deletions

diff --git a/riscv/debug_defines.h b/riscv/debug_defines.h
index 58826f0..0d843b0 100644
--- a/riscv/debug_defines.h
+++ b/riscv/debug_defines.h
@@ -1041,8 +1041,27 @@
 #define DMI_AUTHDATA_DATA_OFFSET            0
 #define DMI_AUTHDATA_DATA_LENGTH            32
 #define DMI_AUTHDATA_DATA                   (0xffffffffU << DMI_AUTHDATA_DATA_OFFSET)
+#define DMI_SBADDRESS3                      0x37
+/*
+* Accesses bits 127:96 of the physical address in {\tt sbaddress} (if
+* the system address bus is that wide).
+ */
+#define DMI_SBADDRESS3_ADDRESS_OFFSET       0
+#define DMI_SBADDRESS3_ADDRESS_LENGTH       32
+#define DMI_SBADDRESS3_ADDRESS              (0xffffffffU << DMI_SBADDRESS3_ADDRESS_OFFSET)
 #define DMI_SBCS                            0x38
 /*
+* 0: The System Bus interface conforms to mainline drafts of this
+* spec older than 1 January, 2018.
+*
+* 1: The System Bus interface conforms to this version of the spec.
+*
+* Other values are reserved for future versions.
+ */
+#define DMI_SBCS_VERSION_OFFSET             29
+#define DMI_SBCS_VERSION_LENGTH             3
+#define DMI_SBCS_VERSION                    (0x7U << DMI_SBCS_VERSION_OFFSET)
+/*
 * When a 1, every write to \Rsbaddresszero automatically triggers a
 * system bus read at the new address.
  */
diff --git a/riscv/debug_module.cc b/riscv/debug_module.cc
index 981e991..2bc480a 100644
--- a/riscv/debug_module.cc
+++ b/riscv/debug_module.cc
@@ -23,18 +23,6 @@ debug_module_t::debug_module_t(sim_t *sim, unsigned progbufsize) :
   debug_abstract_start(debug_progbuf_start - debug_abstract_size*4),
   sim(sim)
 {
-  dmcontrol = {0};
-
-  dmstatus = {0};
-  dmstatus.impebreak = true;
-  dmstatus.authenticated = 1;
-  dmstatus.version = 2;
-
-  abstractcs = {0};
-  abstractcs.progbufsize = progbufsize;
-
-  abstractauto = {0};
-
   program_buffer = new uint8_t[program_buffer_bytes];
 
   memset(halted, 0, sizeof(halted));
@@ -51,6 +39,8 @@ debug_module_t::debug_module_t(sim_t *sim, unsigned progbufsize) :
           jal(ZERO, debug_abstract_start - DEBUG_ROM_WHERETO));
 
   memset(debug_abstract, 0, sizeof(debug_abstract));
+
+  reset();
 }
 
 debug_module_t::~debug_module_t()
@@ -78,6 +68,14 @@ void debug_module_t::reset()
   abstractcs.progbufsize = progbufsize;
 
   abstractauto = {0};
+
+  sbcs = {0};
+  sbcs.version = 1;
+  sbcs.access64 = true;
+  sbcs.access32 = true;
+  sbcs.access16 = true;
+  sbcs.access8 = true;
+  sbcs.asize = sizeof(reg_t) * 8;
 }
 
 void debug_module_t::add_device(bus_t *bus) {
@@ -228,6 +226,87 @@ processor_t *debug_module_t::current_proc() const
   return proc;
 }
 
+unsigned debug_module_t::sb_access_bits()
+{
+  return 8 << sbcs.sbaccess;
+}
+
+void debug_module_t::sb_autoincrement()
+{
+  if (!sbcs.autoincrement)
+    return;
+
+  uint64_t value = sbaddress[0] + sb_access_bits() / 8;
+  sbaddress[0] = value;
+  uint32_t carry = value >> 32;
+
+  value = sbaddress[1] + carry;
+  sbaddress[1] = value;
+  carry = value >> 32;
+
+  value = sbaddress[2] + carry;
+  sbaddress[2] = value;
+  carry = value >> 32;
+
+  sbaddress[3] += carry;
+}
+
+void debug_module_t::sb_read()
+{
+  reg_t address = ((uint64_t) sbaddress[1] << 32) | sbaddress[0];
+  D(fprintf(stderr, "sb_read() @ 0x%lx\n", address));
+  try {
+    switch (sbcs.sbaccess) {
+      case 0:
+        sbdata[0] = sim->debug_mmu->load_uint8(address);
+        break;
+      case 1:
+        sbdata[0] = sim->debug_mmu->load_uint16(address);
+        break;
+      case 2:
+        sbdata[0] = sim->debug_mmu->load_uint32(address);
+        D(fprintf(stderr, "   -> 0x%x\n", sbdata[0]));
+        break;
+      case 3:
+        {
+          uint64_t value = sim->debug_mmu->load_uint32(address);
+          sbdata[0] = value;
+          sbdata[1] = value >> 32;
+          break;
+        }
+      default:
+        sbcs.error = 3;
+        break;
+    }
+  } catch (trap_load_access_fault& t) {
+    sbcs.error = 2;
+  }
+}
+
+void debug_module_t::sb_write()
+{
+  reg_t address = ((uint64_t) sbaddress[1] << 32) | sbaddress[0];
+  D(fprintf(stderr, "sb_write() 0x%x @ 0x%lx\n", sbdata[0], address));
+  switch (sbcs.sbaccess) {
+    case 0:
+      sim->debug_mmu->store_uint8(address, sbdata[0]);
+      break;
+    case 1:
+      sim->debug_mmu->store_uint16(address, sbdata[0]);
+      break;
+    case 2:
+      sim->debug_mmu->store_uint32(address, sbdata[0]);
+      break;
+    case 3:
+      sim->debug_mmu->store_uint64(address,
+          (((uint64_t) sbdata[1]) << 32) | sbdata[0]);
+      break;
+    default:
+      sbcs.error = 3;
+      break;
+  }
+}
+
 bool debug_module_t::dmi_read(unsigned address, uint32_t *value)
 {
   uint32_t result = 0;
@@ -343,6 +422,50 @@ bool debug_module_t::dmi_read(unsigned address, uint32_t *value)
         result = set_field(result, DMI_HARTINFO_DATASIZE, abstractcs.datacount);
         result = set_field(result, DMI_HARTINFO_DATAADDR, debug_data_start);
         break;
+      case DMI_SBCS:
+        result = set_field(result, DMI_SBCS_VERSION, sbcs.version);
+        result = set_field(result, DMI_SBCS_SBREADONADDR, sbcs.readonaddr);
+        result = set_field(result, DMI_SBCS_SBACCESS, sbcs.sbaccess);
+        result = set_field(result, DMI_SBCS_SBAUTOINCREMENT, sbcs.autoincrement);
+        result = set_field(result, DMI_SBCS_SBREADONDATA, sbcs.readondata);
+        result = set_field(result, DMI_SBCS_SBERROR, sbcs.error);
+        result = set_field(result, DMI_SBCS_SBASIZE, sbcs.asize);
+        result = set_field(result, DMI_SBCS_SBACCESS128, sbcs.access128);
+        result = set_field(result, DMI_SBCS_SBACCESS64, sbcs.access64);
+        result = set_field(result, DMI_SBCS_SBACCESS32, sbcs.access32);
+        result = set_field(result, DMI_SBCS_SBACCESS16, sbcs.access16);
+        result = set_field(result, DMI_SBCS_SBACCESS8, sbcs.access8);
+        break;
+      case DMI_SBADDRESS0:
+        result = sbaddress[0];
+        break;
+      case DMI_SBADDRESS1:
+        result = sbaddress[1];
+        break;
+      case DMI_SBADDRESS2:
+        result = sbaddress[2];
+        break;
+      case DMI_SBADDRESS3:
+        result = sbaddress[3];
+        break;
+      case DMI_SBDATA0:
+        result = sbdata[0];
+        if (sbcs.error == 0) {
+          sb_autoincrement();
+          if (sbcs.readondata) {
+            sb_read();
+          }
+        }
+        break;
+      case DMI_SBDATA1:
+        result = sbdata[1];
+        break;
+      case DMI_SBDATA2:
+        result = sbdata[2];
+        break;
+      case DMI_SBDATA3:
+        result = sbdata[3];
+        break;
       default:
         result = 0;
         D(fprintf(stderr, "Unexpected. Returning Error."));
@@ -462,6 +585,8 @@ bool debug_module_t::dmi_write(unsigned address, uint32_t value)
     switch (address) {
       case DMI_DMCONTROL:
         {
+          if (!dmcontrol.dmactive && get_field(value, DMI_DMCONTROL_DMACTIVE))
+            reset();
           dmcontrol.dmactive = get_field(value, DMI_DMCONTROL_DMACTIVE);
           if (dmcontrol.dmactive) {
             dmcontrol.haltreq = get_field(value, DMI_DMCONTROL_HALTREQ);
@@ -469,8 +594,6 @@ bool debug_module_t::dmi_write(unsigned address, uint32_t value)
             dmcontrol.hartreset = get_field(value, DMI_DMCONTROL_HARTRESET);
             dmcontrol.ndmreset = get_field(value, DMI_DMCONTROL_NDMRESET);
             dmcontrol.hartsel = get_field(value, DMI_DMCONTROL_HARTSEL);
-          } else {
-            reset();
           }
           processor_t *proc = current_proc();
           if (proc) {
@@ -506,6 +629,46 @@ bool debug_module_t::dmi_write(unsigned address, uint32_t value)
         abstractauto.autoexecdata = get_field(value,
             DMI_ABSTRACTAUTO_AUTOEXECDATA);
         return true;
+      case DMI_SBCS:
+        sbcs.readonaddr = get_field(value, DMI_SBCS_SBREADONADDR);
+        sbcs.sbaccess = get_field(value, DMI_SBCS_SBACCESS);
+        sbcs.autoincrement = get_field(value, DMI_SBCS_SBAUTOINCREMENT);
+        sbcs.readondata = get_field(value, DMI_SBCS_SBREADONDATA);
+        sbcs.error &= ~get_field(value, DMI_SBCS_SBERROR);
+        return true;
+      case DMI_SBADDRESS0:
+        sbaddress[0] = value;
+        if (sbcs.error == 0 && sbcs.readonaddr) {
+          sb_read();
+        }
+        return true;
+      case DMI_SBADDRESS1:
+        sbaddress[1] = value;
+        return true;
+      case DMI_SBADDRESS2:
+        sbaddress[2] = value;
+        return true;
+      case DMI_SBADDRESS3:
+        sbaddress[3] = value;
+        return true;
+      case DMI_SBDATA0:
+        sbdata[0] = value;
+        if (sbcs.error == 0) {
+          sb_write();
+          if (sbcs.autoincrement && sbcs.error == 0) {
+            sb_autoincrement();
+          }
+        }
+        return true;
+      case DMI_SBDATA1:
+        sbdata[1] = value;
+        return true;
+      case DMI_SBDATA2:
+        sbdata[2] = value;
+        return true;
+      case DMI_SBDATA3:
+        sbdata[3] = value;
+        return true;
     }
   }
   return false;
diff --git a/riscv/debug_module.h b/riscv/debug_module.h
index 00c66cc..be9b8bc 100644
--- a/riscv/debug_module.h
+++ b/riscv/debug_module.h
@@ -56,6 +56,21 @@ typedef struct {
   unsigned autoexecdata;
 } abstractauto_t;
 
+typedef struct {
+  unsigned version;
+  bool readonaddr;
+  unsigned sbaccess;
+  bool autoincrement;
+  bool readondata;
+  unsigned error;
+  unsigned asize;
+  bool access128;
+  bool access64;
+  bool access32;
+  bool access16;
+  bool access8;
+} sbcs_t;
+
 class debug_module_t : public abstract_device_t
 {
   public:
@@ -101,12 +116,21 @@ class debug_module_t : public abstract_device_t
     void write32(uint8_t *rom, unsigned int index, uint32_t value);
     uint32_t read32(uint8_t *rom, unsigned int index);
 
+    void sb_autoincrement();
+    void sb_read();
+    void sb_write();
+    unsigned sb_access_bits();
+
     dmcontrol_t dmcontrol;
     dmstatus_t dmstatus;
     abstractcs_t abstractcs;
     abstractauto_t abstractauto;
     uint32_t command;
 
+    sbcs_t sbcs;
+    uint32_t sbaddress[4];
+    uint32_t sbdata[4];
+
     processor_t *current_proc() const;
     void reset();
     bool perform_abstract_command();
diff --git a/riscv/sim.cc b/riscv/sim.cc
index 81d1307..97697e4 100644
--- a/riscv/sim.cc
+++ b/riscv/sim.cc
@@ -27,10 +27,9 @@ sim_t::sim_t(const char* isa, size_t nprocs, bool halted, reg_t start_pc,
              std::vector<std::pair<reg_t, mem_t*>> mems,
              const std::vector<std::string>& args,
              std::vector<int> const hartids, unsigned progsize)
-  : htif_t(args), debug_module(this, progsize), mems(mems),
-      procs(std::max(nprocs, size_t(1))),
-    start_pc(start_pc),
-    current_step(0), current_proc(0), debug(false), remote_bitbang(NULL)
+  : htif_t(args), mems(mems), procs(std::max(nprocs, size_t(1))),
+    start_pc(start_pc), current_step(0), current_proc(0), debug(false),
+    remote_bitbang(NULL), debug_module(this, progsize)
 {
   signal(SIGINT, &handle_signal);
 
diff --git a/riscv/sim.h b/riscv/sim.h
index ce5fe19..e29cca4 100644
--- a/riscv/sim.h
+++ b/riscv/sim.h
@@ -38,8 +38,6 @@ public:
   processor_t* get_core(size_t i) { return procs.at(i); }
   unsigned nprocs() const { return procs.size(); }
 
-  debug_module_t debug_module;
-
 private:
   std::vector<std::pair<reg_t, mem_t*>> mems;
   mmu_t* debug_mmu;  // debug port into main memory
@@ -92,6 +90,7 @@ private:
 
   friend class processor_t;
   friend class mmu_t;
+  friend class debug_module_t;
 
   // htif
   friend void sim_thread_main(void*);
@@ -105,6 +104,12 @@ private:
   void write_chunk(addr_t taddr, size_t len, const void* src);
   size_t chunk_align() { return 8; }
   size_t chunk_max_size() { return 8; }
+
+public:
+  // Initialize this after procs, because in debug_module_t::reset() we
+  // enumerate processors, which segfaults if procs hasn't been initialized
+  // yet.
+  debug_module_t debug_module;
 };
 
 extern volatile bool ctrlc_pressed;