Move commit logging check off the critical path

Suppress TLB refill when commit logging is enabled to facilitate this
strategy.

riscv/mmu.cc

@@ -256,6 +256,9 @@ void mmu_t::load_slow_path(reg_t original_addr, reg_t len, uint8_t* bytes, xlate
     bytes += sizeof(reg_t);
   }
   check_triggers(triggers::OPERATION_LOAD, transformed_addr, access_info.effective_virt, reg_from_bytes(len, bytes));
+
+  if (proc && unlikely(proc->get_log_commits_enabled()))
+    proc->state.log_mem_read.push_back(std::make_tuple(original_addr, 0, len));
 }
 
 void mmu_t::store_slow_path_intrapage(reg_t len, const uint8_t* bytes, mem_access_info_t access_info, bool actually_store)
@@ -318,6 +321,9 @@ void mmu_t::store_slow_path(reg_t original_addr, reg_t len, const uint8_t* bytes
   } else {
     store_slow_path_intrapage(len, bytes, access_info, actually_store);
   }
+
+  if (proc && unlikely(proc->get_log_commits_enabled()))
+    proc->state.log_mem_write.push_back(std::make_tuple(original_addr, reg_from_bytes(len, bytes), len));
 }
 
 tlb_entry_t mmu_t::refill_tlb(reg_t vaddr, reg_t paddr, char* host_addr, access_type type)
@@ -327,7 +333,9 @@ tlb_entry_t mmu_t::refill_tlb(reg_t vaddr, reg_t paddr, char* host_addr, access_
 
   tlb_entry_t entry = {uintptr_t(host_addr) - (vaddr % PGSIZE), paddr - (vaddr % PGSIZE)};
 
-  if (in_mprv() || !pmp_homogeneous(paddr & ~reg_t(PGSIZE - 1), PGSIZE))
+  if (in_mprv()
+      || !pmp_homogeneous(paddr & ~reg_t(PGSIZE - 1), PGSIZE)
+      || (proc && proc->get_log_commits_enabled()))
     return entry;
 
   switch (type) {

riscv/mmu.h

@@ -90,9 +90,6 @@ public:
       load_slow_path(addr, sizeof(T), (uint8_t*)&res, xlate_flags);
     }
 
-    if (unlikely(proc && proc->get_log_commits_enabled()))
-      proc->state.log_mem_read.push_back(std::make_tuple(addr, 0, sizeof(T)));
-
     return from_target(res);
   }
 
@@ -131,9 +128,6 @@ public:
       target_endian<T> target_val = to_target(val);
       store_slow_path(addr, sizeof(T), (const uint8_t*)&target_val, xlate_flags, true, false);
     }
-
-    if (unlikely(proc && proc->get_log_commits_enabled()))
-      proc->state.log_mem_write.push_back(std::make_tuple(addr, val, sizeof(T)));
   }
 
   template<typename T>

riscv/processor.cc

@@ -144,6 +144,7 @@ void processor_t::set_histogram(bool value)
 void processor_t::enable_log_commits()
 {
   log_commits_enabled = true;
+  mmu->flush_tlb(); // the TLB caches this setting
 }
 
 void processor_t::reset()