Move homogeneity detection into pmpaddr_csr_t

3 files changed, 30 insertions, 22 deletions

diff --git a/riscv/csrs.cc b/riscv/csrs.cc
index 8ac71f0..62f207e 100644
--- a/riscv/csrs.cc
+++ b/riscv/csrs.cc
@@ -156,6 +156,30 @@ bool pmpaddr_csr_t::match4(reg_t addr) const noexcept {
 }
 
 
+bool pmpaddr_csr_t::subset_match(reg_t addr, reg_t len) const noexcept {
+  if ((addr | len) & (len - 1))
+    abort();
+  state_t* const state = proc->get_state();
+  reg_t base = tor_base_paddr();
+  reg_t tor = tor_paddr();
+  uint8_t cfg = state->pmpcfg[pmpidx];
+
+  if ((cfg & PMP_A) == 0) return false;
+
+  bool is_tor = (cfg & PMP_A) == PMP_TOR;
+  bool begins_after_lower = addr >= base;
+  bool begins_after_upper = addr >= tor;
+  bool ends_before_lower = (addr & -len) < (base & -len);
+  bool ends_before_upper = (addr & -len) < (tor & -len);
+  bool tor_homogeneous = ends_before_lower || begins_after_upper ||
+    (begins_after_lower && ends_before_upper);
+
+  bool mask_homogeneous = ~(napot_mask() << 1) & len;
+  bool napot_homogeneous = mask_homogeneous || ((addr ^ tor) / len) != 0;
+
+  return !(is_tor ? tor_homogeneous : napot_homogeneous);
+}
+
 // implement class pmpcfg_csr_t
 pmpcfg_csr_t::pmpcfg_csr_t(processor_t* const proc, const reg_t addr):
   logged_csr_t(proc, addr) {
diff --git a/riscv/csrs.h b/riscv/csrs.h
index 306553c..961630b 100644
--- a/riscv/csrs.h
+++ b/riscv/csrs.h
@@ -86,6 +86,9 @@ class pmpaddr_csr_t: public logged_csr_t {
   // Does a 4-byte access at the specified address match this PMP entry?
   bool match4(reg_t addr) const noexcept;
 
+  // Does the specified range match only a proper subset of this page?
+  bool subset_match(reg_t addr, reg_t len) const noexcept;
+
  protected:
   virtual bool unlogged_write(const reg_t val) noexcept override;
  private:
diff --git a/riscv/mmu.cc b/riscv/mmu.cc
index 6d1299b..480b77e 100644
--- a/riscv/mmu.cc
+++ b/riscv/mmu.cc
@@ -256,28 +256,9 @@ reg_t mmu_t::pmp_homogeneous(reg_t addr, reg_t len)
   if (!proc)
     return true;
 
-  for (size_t i = 0; i < proc->n_pmp; i++) {
-    reg_t base = proc->state.pmpaddr[i]->tor_base_paddr();
-    reg_t tor = proc->state.pmpaddr[i]->tor_paddr();
-    uint8_t cfg = proc->state.pmpcfg[i];
-
-    if (cfg & PMP_A) {
-      bool is_tor = (cfg & PMP_A) == PMP_TOR;
-
-      bool begins_after_lower = addr >= base;
-      bool begins_after_upper = addr >= tor;
-      bool ends_before_lower = (addr & -len) < (base & -len);
-      bool ends_before_upper = (addr & -len) < (tor & -len);
-      bool tor_homogeneous = ends_before_lower || begins_after_upper ||
-        (begins_after_lower && ends_before_upper);
-
-      bool mask_homogeneous = ~(proc->state.pmpaddr[i]->napot_mask() << 1) & len;
-      bool napot_homogeneous = mask_homogeneous || ((addr ^ tor) / len) != 0;
-
-      if (!(is_tor ? tor_homogeneous : napot_homogeneous))
-        return false;
-    }
-  }
+  for (size_t i = 0; i < proc->n_pmp; i++)
+    if (proc->state.pmpaddr[i]->subset_match(addr, len))
+      return false;
 
   return true;
 }