ARM: Fix checkpoint restoration into O3 CPU and the way O3 switchCpu works.

This change fixes a small bug in the arm copyRegs() code where some registers
wouldn't be copied if the processor was in a mode other than MODE_USER.
Additionally, this change simplifies the way the O3 switchCpu code works by
utilizing TheISA::copyRegs() to copy the required context information
rather than the adhoc copying that goes on in the CPU model. The current code
makes assumptions about the visibility of int and float registers that aren't
true for all architectures in FS mode.

1 files changed, 4 insertions, 29 deletions

diff --git a/src/cpu/o3/thread_context_impl.hh b/src/cpu/o3/thread_context_impl.hh
index e7b0540d1..b179ad50e 100755
--- a/src/cpu/o3/thread_context_impl.hh
+++ b/src/cpu/o3/thread_context_impl.hh
@@ -231,36 +231,11 @@ template <class Impl>
 void
 O3ThreadContext<Impl>::copyArchRegs(ThreadContext *tc)
 {
-    // This function will mess things up unless the ROB is empty and
-    // there are no instructions in the pipeline.
-    ThreadID tid = thread->threadId();
-    PhysRegIndex renamed_reg;
-
-    // First loop through the integer registers.
-    for (int i = 0; i < TheISA::NumIntRegs; ++i) {
-        renamed_reg = cpu->renameMap[tid].lookup(i);
-
-        DPRINTF(O3CPU, "Copying over register %i, had data %lli, "
-                "now has data %lli.\n",
-                renamed_reg, cpu->readIntReg(renamed_reg),
-                tc->readIntReg(i));
-
-        cpu->setIntReg(renamed_reg, tc->readIntReg(i));
-    }
-
-    // Then loop through the floating point registers.
-    for (int i = 0; i < TheISA::NumFloatRegs; ++i) {
-        renamed_reg = cpu->renameMap[tid].lookup(i + TheISA::FP_Base_DepTag);
-        cpu->setFloatRegBits(renamed_reg,
-                             tc->readFloatRegBits(i));
-    }
-
-    // Copy the misc regs.
-    TheISA::copyMiscRegs(tc, this);
+    // Prevent squashing
+    thread->inSyscall = true;
+    TheISA::copyRegs(tc, this);
+    thread->inSyscall = false;
 
-    // Then finally set the PC, the next PC, the nextNPC, the micropc, and the
-    // next micropc.
-    cpu->pcState(tc->pcState(), tid);
 #if !FULL_SYSTEM
     this->thread->funcExeInst = tc->readFuncExeInst();
 #endif