pointer masking: Implement Smnpm (Flush TLB on changing *envcfg.PMM)

Author: YenHaoChen

riscv/csrs.cc

@@ -981,6 +981,9 @@ bool envcfg_csr_t::unlogged_write(const reg_t val) noexcept {
   const reg_t pmm = get_field(adjusted_val, MENVCFG_PMM);
   adjusted_val = set_field(adjusted_val, MENVCFG_PMM, pmm != pmm_reserved ? pmm : 0);
 
+  if (get_field(adjusted_val, MENVCFG_PMM) != get_field(read(), MENVCFG_PMM))
+    proc->get_mmu()->flush_tlb();
+
   return masked_csr_t::unlogged_write(adjusted_val);
 }
 

riscv/mmu.cc

@@ -620,6 +620,8 @@ reg_t mmu_t::get_pmlen(bool effective_virt, reg_t effective_priv, xlate_flags_t
   reg_t pmm = 0;
   if (effective_priv == PRV_M)
     pmm = get_field(proc->state.mseccfg->read(), MSECCFG_PMM);
+  else if (!effective_virt && (effective_priv == PRV_S || (!proc->extension_enabled('S') && effective_priv == PRV_U)))
+    pmm = get_field(proc->state.menvcfg->read(), MENVCFG_PMM);
 
   switch (pmm) {
     case 2: return 7;