Add Smdbltrp

Author: ved-rivos

riscv/csrs.cc

@@ -511,7 +511,10 @@ bool mstatus_csr_t::unlogged_write(const reg_t val) noexcept {
 
   const reg_t requested_mpp = proc->legalize_privilege(get_field(val, MSTATUS_MPP));
   const reg_t adjusted_val = set_field(val, MSTATUS_MPP, requested_mpp);
-  const reg_t new_mstatus = (read() & ~mask) | (adjusted_val & mask);
+  reg_t new_mstatus = (read() & ~mask) | (adjusted_val & mask);
+  if (new_mstatus & MSTATUS_MDT) {
+    new_mstatus = new_mstatus & ~MSTATUS_MIE;
+  }
   maybe_flush_tlb(new_mstatus);
   this->val = adjust_sd(new_mstatus);
   return true;

riscv/insns/mret.h

@@ -13,6 +13,17 @@ if (ZICFILP_xLPE(prev_virt, prev_prv)) {
   STATE.elp = static_cast<elp_t>(get_field(s, MSTATUS_MPELP));
 }
 s = set_field(s, MSTATUS_MPELP, elp_t::NO_LP_EXPECTED);
+
+s = set_field(s, MSTATUS_MDT, 0);
+if (prev_prv == PRV_U || prev_virt) {
+  s = set_field(s, MSTATUS_SDT, 0);
+}
+if (prev_virt && prev_prv == PRV_U) {
+  reg_t vs = STATE.vsstatus->read();
+  vs = set_field(vs, SSTATUS_SDT, 0);
+  STATE.vsstatus->write(vs);
+}
+
 STATE.mstatus->write(s);
 if (STATE.mstatush) STATE.mstatush->write(s >> 32); // log mstatush change
 STATE.tcontrol->write((STATE.tcontrol->read() & CSR_TCONTROL_MPTE) ? (CSR_TCONTROL_MPTE | CSR_TCONTROL_MTE) : 0);

riscv/insns/sret.h

@@ -26,6 +26,21 @@ if (!STATE.v) {
 if (ZICFILP_xLPE(prev_virt, prev_prv)) {
   STATE.elp = static_cast<elp_t>(get_field(s, SSTATUS_SPELP));
 }
+
+if (STATE.prv == PRV_M) {
+  reg_t m = STATE.mstatus->read();
+  m = set_field(m, MSTATUS_MDT, 0);
+  if (prev_prv == PRV_U || prev_virt) {
+    s = set_field(s, MSTATUS_SDT, 0);
+  }
+  STATE.mstatus->write(m);
+  if (prev_virt && prev_prv == PRV_U) {
+    reg_t vs = STATE.vsstatus->read();
+    vs = set_field(vs, SSTATUS_SDT, 0);
+    STATE.vsstatus->write(vs);
+  }
+}
+
 s = set_field(s, SSTATUS_SPELP, elp_t::NO_LP_EXPECTED);
 STATE.sstatus->write(s);
 p->set_privilege(prev_prv, prev_virt);