mem-cache: Support for page crossing prefetches

Prefetchers can now issue hardware prefetch requests that go beyond
the boundaries of the system page. Page crossing references will need
to look up the TLBs to be able to compute the physical address to be
prefetched.

Change-Id: Ib56374097e3b7dc87414139d210ea9272f96b06b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/14620
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

src/mem/cache/prefetch/base.cc

@@ -96,7 +96,7 @@ BasePrefetcher::BasePrefetcher(const BasePrefetcherParams *p)
       masterId(p->sys->getMasterId(this)), pageBytes(p->sys->getPageBytes()),
       prefetchOnAccess(p->prefetch_on_access),
       useVirtualAddresses(p->use_virtual_addresses), issuedPrefetches(0),
-      usefulPrefetches(0)
+      usefulPrefetches(0), tlb(nullptr)
 {
 }
 
@@ -254,3 +254,10 @@ BasePrefetcher::addEventProbe(SimObject *obj, const char *name)
     ProbeManager *pm(obj->getProbeManager());
     listeners.push_back(new PrefetchListener(*this, pm, name));
 }
+
+void
+BasePrefetcher::addTLB(BaseTLB *t)
+{
+    fatal_if(tlb != nullptr, "Only one TLB can be registered");
+    tlb = t;
+}