riscv/processor.h

   1 // See LICENSE for license details.
   2 #ifndef _RISCV_PROCESSOR_H
   3 #define _RISCV_PROCESSOR_H
   4
   5 #include "decode.h"
   6 #include "config.h"
   7 #include "devices.h"
   8 #include "trap.h"
   9 #include <string>
  10 #include <vector>
  11 #include <map>
  12 #include "debug_rom_defines.h"
  13 #ifdef SPIKE_SIMPLEV
  14 #include "sv_decode.h"
  15 #endif
  16
  17 class processor_t;
  18 class mmu_t;
  19 typedef reg_t (*insn_func_t)(processor_t*, insn_t, reg_t);
  20 class simif_t;
  21 class trap_t;
  22 class extension_t;
  23 class disassembler_t;
  24
  25 struct insn_desc_t
  26 {
  27   insn_bits_t match;
  28   insn_bits_t mask;
  29   insn_func_t rv32;
  30   insn_func_t rv64;
  31 };
  32
  33 struct commit_log_reg_t
  34 {
  35   reg_t addr;
  36   freg_t data;
  37 };
  38
  39 typedef struct
  40 {
  41   uint8_t prv;
  42   bool step;
  43   bool ebreakm;
  44   bool ebreakh;
  45   bool ebreaks;
  46   bool ebreaku;
  47   bool halt;
  48   uint8_t cause;
  49 } dcsr_t;
  50
  51 typedef enum
  52 {
  53   ACTION_DEBUG_EXCEPTION = MCONTROL_ACTION_DEBUG_EXCEPTION,
  54   ACTION_DEBUG_MODE = MCONTROL_ACTION_DEBUG_MODE,
  55   ACTION_TRACE_START = MCONTROL_ACTION_TRACE_START,
  56   ACTION_TRACE_STOP = MCONTROL_ACTION_TRACE_STOP,
  57   ACTION_TRACE_EMIT = MCONTROL_ACTION_TRACE_EMIT
  58 } mcontrol_action_t;
  59
  60 typedef enum
  61 {
  62   MATCH_EQUAL = MCONTROL_MATCH_EQUAL,
  63   MATCH_NAPOT = MCONTROL_MATCH_NAPOT,
  64   MATCH_GE = MCONTROL_MATCH_GE,
  65   MATCH_LT = MCONTROL_MATCH_LT,
  66   MATCH_MASK_LOW = MCONTROL_MATCH_MASK_LOW,
  67   MATCH_MASK_HIGH = MCONTROL_MATCH_MASK_HIGH
  68 } mcontrol_match_t;
  69
  70 typedef struct
  71 {
  72   uint8_t type;
  73   bool dmode;
  74   uint8_t maskmax;
  75   bool select;
  76   bool timing;
  77   mcontrol_action_t action;
  78   bool chain;
  79   mcontrol_match_t match;
  80   bool m;
  81   bool h;
  82   bool s;
  83   bool u;
  84   bool execute;
  85   bool store;
  86   bool load;
  87 } mcontrol_t;
  88
  89 // architectural state of a RISC-V hart
  90 struct state_t
  91 {
  92   void reset(reg_t max_isa);
  93
  94   static const int num_triggers = 4;
  95
  96   reg_t pc;
  97   regfile_t<reg_t, NXPR, true> XPR;
  98   regfile_t<freg_t, NFPR, false> FPR;
  99
 100   // control and status registers
 101   reg_t prv;    // TODO: Can this be an enum instead?
 102   reg_t misa;
 103   reg_t mstatus;
 104   reg_t mepc;
 105   reg_t mtval;
 106   reg_t mscratch;
 107   reg_t mtvec;
 108   reg_t mcause;
 109   reg_t minstret;
 110   reg_t mie;
 111   reg_t mip;
 112   reg_t medeleg;
 113   reg_t mideleg;
 114   uint32_t mcounteren;
 115   uint32_t scounteren;
 116   reg_t sepc;
 117   reg_t stval;
 118   reg_t sscratch;
 119   reg_t stvec;
 120   reg_t satp;
 121   reg_t scause;
 122   reg_t dpc;
 123   reg_t dscratch;
 124   dcsr_t dcsr;
 125   reg_t tselect;
 126   mcontrol_t mcontrol[num_triggers];
 127   reg_t tdata2[num_triggers];
 128
 129 #ifdef SPIKE_SIMPLEV
 130   uint64_t vl;
 131   uint64_t mvl;
 132   sv_reg_csr_entry sv_csrs[SV_CSR_SZ];
 133   sv_reg_entry     sv_int_tb[NXPR];
 134   sv_reg_entry     sv_fp_tb[NFPR];
 135   sv_pred_csr_entry sv_pred_csrs[SV_CSR_SZ];
 136   sv_pred_entry     sv_pred_int_tb[NXPR];
 137   sv_pred_entry     sv_pred_fp_tb[NFPR];
 138 #endif
 139
 140   uint32_t fflags;
 141   uint32_t frm;
 142   bool serialized; // whether timer CSRs are in a well-defined state
 143
 144   // When true, execute a single instruction and then enter debug mode.  This
 145   // can only be set by executing dret.
 146   enum {
 147       STEP_NONE,
 148       STEP_STEPPING,
 149       STEP_STEPPED
 150   } single_step;
 151
 152 #ifdef RISCV_ENABLE_COMMITLOG
 153   commit_log_reg_t log_reg_write;
 154   reg_t last_inst_priv;
 155   int last_inst_xlen;
 156   int last_inst_flen;
 157 #endif
 158 };
 159
 160 typedef enum {
 161   OPERATION_EXECUTE,
 162   OPERATION_STORE,
 163   OPERATION_LOAD,
 164 } trigger_operation_t;
 165
 166 // Count number of contiguous 1 bits starting from the LSB.
 167 static int cto(reg_t val)
 168 {
 169   int res = 0;
 170   while ((val & 1) == 1)
 171     val >>= 1, res++;
 172   return res;
 173 }
 174
 175 // this class represents one processor in a RISC-V machine.
 176 class processor_t : public abstract_device_t
 177 {
 178 public:
 179   processor_t(const char* isa, simif_t* sim, uint32_t id, bool halt_on_reset=false);
 180   ~processor_t();
 181
 182   void set_debug(bool value);
 183   void set_histogram(bool value);
 184   void reset();
 185   void step(size_t n); // run for n cycles
 186   void set_csr(int which, reg_t val);
 187   reg_t get_csr(int which);
 188   mmu_t* get_mmu() { return mmu; }
 189   state_t* get_state() { return &state; }
 190   unsigned get_xlen() { return xlen; }
 191   unsigned get_max_xlen() { return max_xlen; }
 192   std::string get_isa_string() { return isa_string; }
 193   unsigned get_flen() {
 194     return supports_extension('Q') ? 128 :
 195            supports_extension('D') ? 64 :
 196            supports_extension('F') ? 32 : 0;
 197   }
 198   extension_t* get_extension() { return ext; }
 199   bool supports_extension(unsigned char ext) {
 200     if (ext >= 'a' && ext <= 'z') ext += 'A' - 'a';
 201     return ext >= 'A' && ext <= 'Z' && ((state.misa >> (ext - 'A')) & 1);
 202   }
 203   reg_t pc_alignment_mask() {
 204     return ~(reg_t)(supports_extension('C') ? 0 : 2);
 205   }
 206   void check_pc_alignment(reg_t pc) {
 207     if (unlikely(pc & ~pc_alignment_mask()))
 208       throw trap_instruction_address_misaligned(pc);
 209   }
 210   reg_t legalize_privilege(reg_t);
 211   void set_privilege(reg_t);
 212   void update_histogram(reg_t pc);
 213   const disassembler_t* get_disassembler() { return disassembler; }
 214
 215   void register_insn(insn_desc_t);
 216   void register_extension(extension_t*);
 217
 218   // MMIO slave interface
 219   bool load(reg_t addr, size_t len, uint8_t* bytes);
 220   bool store(reg_t addr, size_t len, const uint8_t* bytes);
 221
 222   // When true, display disassembly of each instruction that's executed.
 223   bool debug;
 224   // When true, take the slow simulation path.
 225   bool slow_path();
 226   bool halted() { return state.dcsr.cause ? true : false; }
 227   bool halt_request;
 228
 229   // Return the index of a trigger that matched, or -1.
 230   inline int trigger_match(trigger_operation_t operation, reg_t address, reg_t data)
 231   {
 232     if (state.dcsr.cause)
 233       return -1;
 234
 235     bool chain_ok = true;
 236
 237     for (unsigned int i = 0; i < state.num_triggers; i++) {
 238       if (!chain_ok) {
 239         chain_ok |= !state.mcontrol[i].chain;
 240         continue;
 241       }
 242
 243       if ((operation == OPERATION_EXECUTE && !state.mcontrol[i].execute) ||
 244           (operation == OPERATION_STORE && !state.mcontrol[i].store) ||
 245           (operation == OPERATION_LOAD && !state.mcontrol[i].load) ||
 246           (state.prv == PRV_M && !state.mcontrol[i].m) ||
 247           (state.prv == PRV_S && !state.mcontrol[i].s) ||
 248           (state.prv == PRV_U && !state.mcontrol[i].u)) {
 249         continue;
 250       }
 251
 252       reg_t value;
 253       if (state.mcontrol[i].select) {
 254         value = data;
 255       } else {
 256         value = address;
 257       }
 258
 259       // We need this because in 32-bit mode sometimes the PC bits get sign
 260       // extended.
 261       if (xlen == 32) {
 262         value &= 0xffffffff;
 263       }
 264
 265       switch (state.mcontrol[i].match) {
 266         case MATCH_EQUAL:
 267           if (value != state.tdata2[i])
 268             continue;
 269           break;
 270         case MATCH_NAPOT:
 271           {
 272             reg_t mask = ~((1 << cto(state.tdata2[i])) - 1);
 273             if ((value & mask) != (state.tdata2[i] & mask))
 274               continue;
 275           }
 276           break;
 277         case MATCH_GE:
 278           if (value < state.tdata2[i])
 279             continue;
 280           break;
 281         case MATCH_LT:
 282           if (value >= state.tdata2[i])
 283             continue;
 284           break;
 285         case MATCH_MASK_LOW:
 286           {
 287             reg_t mask = state.tdata2[i] >> (xlen/2);
 288             if ((value & mask) != (state.tdata2[i] & mask))
 289               continue;
 290           }
 291           break;
 292         case MATCH_MASK_HIGH:
 293           {
 294             reg_t mask = state.tdata2[i] >> (xlen/2);
 295             if (((value >> (xlen/2)) & mask) != (state.tdata2[i] & mask))
 296               continue;
 297           }
 298           break;
 299       }
 300
 301       if (!state.mcontrol[i].chain) {
 302         return i;
 303       }
 304       chain_ok = true;
 305     }
 306     return -1;
 307   }
 308
 309   void trigger_updated();
 310
 311 private:
 312   simif_t* sim;
 313   mmu_t* mmu; // main memory is always accessed via the mmu
 314   extension_t* ext;
 315   disassembler_t* disassembler;
 316   state_t state;
 317   uint32_t id;
 318   unsigned max_xlen;
 319   unsigned xlen;
 320   reg_t max_isa;
 321   std::string isa_string;
 322   bool histogram_enabled;
 323   bool halt_on_reset;
 324
 325   std::vector<insn_desc_t> instructions;
 326   std::map<reg_t,uint64_t> pc_histogram;
 327
 328   static const size_t OPCODE_CACHE_SIZE = 8191;
 329   insn_desc_t opcode_cache[OPCODE_CACHE_SIZE];
 330
 331   void take_pending_interrupt() { take_interrupt(state.mip & state.mie); }
 332   void take_interrupt(reg_t mask); // take first enabled interrupt in mask
 333   void take_trap(trap_t& t, reg_t epc); // take an exception
 334   void disasm(insn_t insn); // disassemble and print an instruction
 335   int paddr_bits();
 336
 337   void enter_debug_mode(uint8_t cause);
 338
 339   friend class mmu_t;
 340   friend class clint_t;
 341   friend class extension_t;
 342
 343   void parse_isa_string(const char* isa);
 344   void build_opcode_map();
 345   void register_base_instructions();
 346   insn_func_t decode_insn(insn_t insn);
 347
 348   // Track repeated executions for processor_t::disasm()
 349   uint64_t last_pc, last_bits, executions;
 350 };
 351
 352 reg_t illegal_instruction(processor_t* p, insn_t insn, reg_t pc);
 353
 354 #define REGISTER_INSN(proc, name, match, mask) \
 355   extern reg_t rv32_##name(processor_t*, insn_t, reg_t); \
 356   extern reg_t rv64_##name(processor_t*, insn_t, reg_t); \
 357   proc->register_insn((insn_desc_t){match, mask, rv32_##name, rv64_##name});
 358
 359 #endif