nativetrace.cc

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#include "arch/arm/nativetrace.hh"
 
#include "arch/arm/regs/cc.hh"
#include "arch/arm/regs/int.hh"
#include "arch/arm/regs/misc.hh"
#include "arch/arm/regs/vec.hh"
#include "base/compiler.hh"
#include "cpu/thread_context.hh"
#include "debug/ExecRegDelta.hh"
#include "params/ArmNativeTrace.hh"
#include "sim/byteswap.hh"
 
namespace gem5
{
 
using namespace ArmISA;
 
namespace trace {
 
[[maybe_unused]] static const char *regNames[] = {
    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
    "r8", "r9", "r10", "fp", "r12", "sp", "lr", "pc",
    "cpsr", "f0", "f1", "f2", "f3", "f4", "f5", "f6",
    "f7", "f8", "f9", "f10", "f11", "f12", "f13", "f14",
    "f15", "f16", "f17", "f18", "f19", "f20", "f21", "f22",
    "f23", "f24", "f25", "f26", "f27", "f28", "f29", "f30",
    "f31", "fpscr"
};
 
ArmNativeTrace::ArmNativeTrace(const Params &p)
    : NativeTrace(p), stopOnPCError(p.stop_on_pc_error)
{}
 
void
ArmNativeTrace::ThreadState::update(NativeTrace *parent)
{
    oldState = state[current];
    current = (current + 1) % 2;
    newState = state[current];
 
    memcpy(newState, oldState, sizeof(state[0]));
 
    uint64_t diffVector;
    parent->read(&diffVector, sizeof(diffVector));
    diffVector = letoh(diffVector);
 
    int changes = 0;
    for (int i = 0; i < STATE_NUMVALS; i++) {
        if (diffVector & 0x1) {
            changed[i] = true;
            changes++;
        } else {
            changed[i] = false;
        }
        diffVector >>= 1;
    }
 
    auto values = std::make_unique<uint64_t[]>(changes);
    parent->read(values.get(), changes * sizeof(uint64_t));
    int pos = 0;
    for (int i = 0; i < STATE_NUMVALS; i++) {
        if (changed[i]) {
            newState[i] = letoh(values[pos++]);
            changed[i] = (newState[i] != oldState[i]);
        }
    }
}
 
void
ArmNativeTrace::ThreadState::update(ThreadContext *tc)
{
    oldState = state[current];
    current = (current + 1) % 2;
    newState = state[current];
 
    // Regular int regs
    for (int i = 0; i < 15; i++) {
        newState[i] = tc->getReg(intRegClass[i]);
        changed[i] = (oldState[i] != newState[i]);
    }
 
    //R15, aliased with the PC
    newState[STATE_PC] = tc->pcState().as<ArmISA::PCState>().npc();
    changed[STATE_PC] = (newState[STATE_PC] != oldState[STATE_PC]);
 
    //CPSR
    CPSR cpsr = tc->readMiscReg(MISCREG_CPSR);
    cpsr.nz = tc->getReg(cc_reg::Nz);
    cpsr.c = tc->getReg(cc_reg::C);
    cpsr.v = tc->getReg(cc_reg::V);
    cpsr.ge = tc->getReg(cc_reg::Ge);
 
    newState[STATE_CPSR] = cpsr;
    changed[STATE_CPSR] = (newState[STATE_CPSR] != oldState[STATE_CPSR]);
 
    for (int i = 0; i < NumVecV7ArchRegs; i++) {
        ArmISA::VecRegContainer vec_container;
        tc->getReg(vecRegClass[i], &vec_container);
        auto *vec = vec_container.as<uint64_t>();
        newState[STATE_F0 + 2*i] = vec[0];
        newState[STATE_F0 + 2*i + 1] = vec[1];
    }
    newState[STATE_FPSCR] = tc->readMiscReg(MISCREG_FPSCR) |
                            tc->getReg(cc_reg::Fp);
}
 
void
ArmNativeTrace::check(NativeTraceRecord *record)
{
    ThreadContext *tc = record->getThread();
    // This area is read only on the target. It can't stop there to tell us
    // what's going on, so we should skip over anything there also.
    if (tc->pcState().as<ArmISA::PCState>().npc() > 0xffff0000)
        return;
    nState.update(this);
    mState.update(tc);
 
    // If a syscall just happened native trace needs another tick
    if ((mState.oldState[STATE_PC] == nState.oldState[STATE_PC]) &&
            (mState.newState[STATE_PC] - 4 == nState.newState[STATE_PC])) {
            DPRINTF(ExecRegDelta, "Advancing to match PCs after syscall\n");
            nState.update(this);
 
    }
 
    bool errorFound = false;
    // Regular int regs
    for (int i = 0; i < STATE_NUMVALS; i++) {
        if (nState.changed[i] || mState.changed[i]) {
            bool oldMatch = (mState.oldState[i] == nState.oldState[i]);
            bool newMatch = (mState.newState[i] == nState.newState[i]);
            if (oldMatch && newMatch) {
                // The more things change, the more they stay the same.
                continue;
            }
 
            errorFound = true;
 
#ifndef NDEBUG
            const char *vergence = "  ";
            if (oldMatch && !newMatch) {
                vergence = "<>";
            } else if (!oldMatch && newMatch) {
                vergence = "><";
            }
 
            if (!nState.changed[i]) {
                DPRINTF(ExecRegDelta, "%s [%5s] "\
                                      "Native:         %#010x         "\
                                      "M5:     %#010x => %#010x\n",
                                      vergence, regNames[i],
                                      nState.newState[i],
                                      mState.oldState[i], mState.newState[i]);
            } else if (!mState.changed[i]) {
                DPRINTF(ExecRegDelta, "%s [%5s] "\
                                      "Native: %#010x => %#010x "\
                                      "M5:             %#010x        \n",
                                      vergence, regNames[i],
                                      nState.oldState[i], nState.newState[i],
                                      mState.newState[i]);
            } else {
                DPRINTF(ExecRegDelta, "%s [%5s] "\
                                      "Native: %#010x => %#010x "\
                                      "M5:     %#010x => %#010x\n",
                                      vergence, regNames[i],
                                      nState.oldState[i], nState.newState[i],
                                      mState.oldState[i], mState.newState[i]);
            }
#endif
        }
    }
    if (errorFound) {
        StaticInstPtr inst = record->getStaticInst();
        assert(inst);
        bool ran = true;
        if (inst->isMicroop()) {
            ran = false;
            inst = record->getMacroStaticInst();
        }
        assert(inst);
        record->traceInst(inst, ran);
 
        bool pcError = (mState.newState[STATE_PC] !=
                        nState.newState[STATE_PC]);
        if (stopOnPCError && pcError)
            panic("Native trace detected an error in control flow!");
    }
}
 
} // namespace trace
} // namespace gem5