add support for mcountinhibit CSR

We hardwired mcountinihibit to 0 previously. Now, we implemented it.

Signed-off-by: Yangyu Chen <cyy@cyyself.name>

riscv/csr_init.cc

@@ -86,7 +86,6 @@ void state_t::csr_init(processor_t* const proc, reg_t max_isa)
       add_csr(which_mevent, mevent[i]);
     }
   }
-  add_csr(CSR_MCOUNTINHIBIT, std::make_shared<const_csr_t>(proc, CSR_MCOUNTINHIBIT, 0));
   add_const_ext_csr(EXT_SSCOFPMF, CSR_SCOUNTOVF, std::make_shared<scountovf_csr_t>(proc, CSR_SCOUNTOVF));
   add_csr(CSR_MIE, mie = std::make_shared<mie_csr_t>(proc, CSR_MIE));
   add_csr(CSR_MIP, mip = std::make_shared<mip_csr_t>(proc, CSR_MIP));
@@ -134,6 +133,7 @@ void state_t::csr_init(processor_t* const proc, reg_t max_isa)
   add_supervisor_csr(CSR_MIDELEG, mideleg = std::make_shared<mideleg_csr_t>(proc, CSR_MIDELEG));
   const reg_t counteren_mask = (proc->extension_enabled_const(EXT_ZICNTR) ? 0x7UL : 0x0) | (proc->extension_enabled_const(EXT_ZIHPM) ? 0xfffffff8ULL : 0x0);
   add_user_csr(CSR_MCOUNTEREN, mcounteren = std::make_shared<masked_csr_t>(proc, CSR_MCOUNTEREN, counteren_mask, 0));
+  add_csr(CSR_MCOUNTINHIBIT, mcountinhibit = std::make_shared<masked_csr_t>(proc, CSR_MCOUNTINHIBIT, counteren_mask & (~MCOUNTEREN_TIME), 0));
   add_supervisor_csr(CSR_SCOUNTEREN, scounteren = std::make_shared<masked_csr_t>(proc, CSR_SCOUNTEREN, counteren_mask, 0));
   nonvirtual_sepc = std::make_shared<epc_csr_t>(proc, CSR_SEPC);
   add_hypervisor_csr(CSR_VSEPC, vsepc = std::make_shared<epc_csr_t>(proc, CSR_VSEPC));

riscv/encoding.h

@@ -4,7 +4,7 @@
 
 /*
  * This file is auto-generated by running 'make' in
- * https://github.com/riscv/riscv-opcodes (048218e)
+ * https://github.com/riscv/riscv-opcodes (6a1be96)
  */
 
 #ifndef RISCV_CSR_ENCODING_H
@@ -223,6 +223,17 @@
 #define MHPMEVENTH_MINH  0x40000000
 #define MHPMEVENTH_OF    0x80000000
 
+#define MCOUNTEREN_CY_SHIFT    0
+#define MCOUNTEREN_TIME_SHIFT  1
+#define MCOUNTEREN_IR_SHIFT    2
+
+#define MCOUNTEREN_CY      (1U << MCOUNTEREN_CY_SHIFT)
+#define MCOUNTEREN_TIME    (1U << MCOUNTEREN_TIME_SHIFT)
+#define MCOUNTEREN_IR      (1U << MCOUNTEREN_IR_SHIFT)
+
+#define MCOUNTINHIBIT_CY    MCOUNTEREN_CY
+#define MCOUNTINHIBIT_IR    MCOUNTEREN_IR
+
 #define HENVCFG_FIOM  0x00000001
 #define HENVCFG_LPE   0x00000004
 #define HENVCFG_SSE   0x00000008
@@ -3008,6 +3019,7 @@
 #define INSN_FIELD_MOP_RR_T_30 0x40000000
 #define INSN_FIELD_MOP_RR_T_27_26 0xc000000
 #define INSN_FIELD_C_MOP_T 0x700
+#define INSN_FIELD_RS2=RS1 0x1f00000
 #endif
 #ifdef DECLARE_INSN
 DECLARE_INSN(add, MATCH_ADD, MASK_ADD)

riscv/execute.cc

@@ -364,10 +364,12 @@ void processor_t::step(size_t n)
       in_wfi = true;
     }
 
-    state.minstret->bump(instret);
+    if (!(state.mcountinhibit->read() & MCOUNTINHIBIT_IR))
+      state.minstret->bump(instret);
 
     // Model a hart whose CPI is 1.
-    state.mcycle->bump(instret);
+    if (!(state.mcountinhibit->read() & MCOUNTINHIBIT_CY))
+      state.mcycle->bump(instret);
 
     n -= instret;
   }

riscv/processor.h

@@ -99,6 +99,7 @@ struct state_t
   csr_t_p medeleg;
   csr_t_p mideleg;
   csr_t_p mcounteren;
+  csr_t_p mcountinhibit;
   csr_t_p mevent[N_HPMCOUNTERS];
   csr_t_p mnstatus;
   csr_t_p mnepc;