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