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 debugint;
  39   bool ebreakm;
  40   bool ebreakh;
  41   bool ebreaks;
  42   bool ebreaku;
  43   bool halt;
  44   uint8_t cause;
  45 } dcsr_t;
  46
  47 // architectural state of a RISC-V hart
  48 struct state_t
  49 {
  50   void reset();
  51
  52   reg_t pc;
  53   regfile_t<reg_t, NXPR, true> XPR;
  54   regfile_t<freg_t, NFPR, false> FPR;
  55
  56   // control and status registers
  57   reg_t prv;
  58   reg_t mstatus;
  59   reg_t mepc;
  60   reg_t mbadaddr;
  61   reg_t mscratch;
  62   reg_t mtvec;
  63   reg_t mcause;
  64   reg_t minstret;
  65   reg_t mie;
  66   reg_t mip;
  67   reg_t medeleg;
  68   reg_t mideleg;
  69   reg_t mucounteren;
  70   reg_t mscounteren;
  71   reg_t sepc;
  72   reg_t sbadaddr;
  73   reg_t sscratch;
  74   reg_t stvec;
  75   reg_t sptbr;
  76   reg_t scause;
  77   reg_t dpc;
  78   reg_t dscratch;
  79   dcsr_t dcsr;
  80
  81   uint32_t fflags;
  82   uint32_t frm;
  83   bool serialized; // whether timer CSRs are in a well-defined state
  84
  85   reg_t load_reservation;
  86
  87 #ifdef RISCV_ENABLE_COMMITLOG
  88   commit_log_reg_t log_reg_write;
  89   reg_t last_inst_priv;
  90 #endif
  91 };
  92
  93 typedef enum {
  94       HR_NONE,
  95       HR_STEPPED,       // A single step was completed
  96       HR_SWBP,          // sbreak was executed
  97       HR_INTERRUPT,     // Execution interrupted by debugger
  98       HR_CMDLINE,       // Command line requested that the processor start halted
  99       HR_ATTACHED       // Halted because a debugger attached
 100 } halt_reason_t;
 101
 102 // this class represents one processor in a RISC-V machine.
 103 class processor_t : public abstract_device_t
 104 {
 105 public:
 106   processor_t(const char* isa, sim_t* sim, uint32_t id);
 107   ~processor_t();
 108
 109   void set_debug(bool value);
 110   void set_halted(bool value, halt_reason_t reason);
 111   void set_single_step(bool value);
 112   void set_histogram(bool value);
 113   void reset(bool value);
 114   void step(size_t n); // run for n cycles
 115   bool running() { return run; }
 116   void set_csr(int which, reg_t val);
 117   void raise_interrupt(reg_t which);
 118   reg_t get_csr(int which);
 119   mmu_t* get_mmu() { return mmu; }
 120   state_t* get_state() { return &state; }
 121   extension_t* get_extension() { return ext; }
 122   bool supports_extension(unsigned char ext) {
 123     if (ext >= 'a' && ext <= 'z') ext += 'A' - 'a';
 124     return ext >= 'A' && ext <= 'Z' && ((isa >> (ext - 'A')) & 1);
 125   }
 126   void set_privilege(reg_t);
 127   void yield_load_reservation() { state.load_reservation = (reg_t)-1; }
 128   void update_histogram(reg_t pc);
 129
 130   void register_insn(insn_desc_t);
 131   void register_extension(extension_t*);
 132
 133   // MMIO slave interface
 134   bool load(reg_t addr, size_t len, uint8_t* bytes);
 135   bool store(reg_t addr, size_t len, const uint8_t* bytes);
 136
 137 private:
 138   sim_t* sim;
 139   mmu_t* mmu; // main memory is always accessed via the mmu
 140   extension_t* ext;
 141   disassembler_t* disassembler;
 142   state_t state;
 143   uint32_t id;
 144   unsigned max_xlen;
 145   unsigned xlen;
 146   reg_t isa;
 147   std::string isa_string;
 148   bool run; // !reset
 149   // When true, display disassembly of each instruction that's executed.
 150   bool debug;
 151   // TODO: Should this just be rolled into `run`?
 152   bool halted;  // When true, no instructions are executed.
 153   halt_reason_t halt_reason;        // Why is halted true?
 154   // When true, execute exactly one instruction (even if halted is true), then
 155   // set halted to true and single_step to false.
 156   bool single_step;
 157   bool histogram_enabled;
 158
 159   std::vector<insn_desc_t> instructions;
 160   std::map<reg_t,uint64_t> pc_histogram;
 161
 162   static const size_t OPCODE_CACHE_SIZE = 8191;
 163   insn_desc_t opcode_cache[OPCODE_CACHE_SIZE];
 164
 165   void check_timer();
 166   void take_interrupt(); // take a trap if any interrupts are pending
 167   void take_trap(trap_t& t, reg_t epc); // take an exception
 168   void disasm(insn_t insn); // disassemble and print an instruction
 169
 170   friend class sim_t;
 171   friend class mmu_t;
 172   friend class rtc_t;
 173   friend class extension_t;
 174   friend class gdbserver_t;
 175
 176   void parse_isa_string(const char* isa);
 177   void build_opcode_map();
 178   void register_base_instructions();
 179   insn_func_t decode_insn(insn_t insn);
 180 };
 181
 182 reg_t illegal_instruction(processor_t* p, insn_t insn, reg_t pc);
 183
 184 #define REGISTER_INSN(proc, name, match, mask) \
 185   extern reg_t rv32_##name(processor_t*, insn_t, reg_t); \
 186   extern reg_t rv64_##name(processor_t*, insn_t, reg_t); \
 187   proc->register_insn((insn_desc_t){match, mask, rv32_##name, rv64_##name});
 188
 189 #endif