sim: revamp unserialization procedure

Replace direct call to unserialize() on each SimObject with a pair of
calls for better control over initialization in both ckpt and non-ckpt
cases.

If restoring from a checkpoint, loadState(ckpt) is called on each
SimObject.  The default implementation simply calls unserialize() if
there is a corresponding checkpoint section, so we get backward
compatibility for existing objects.  However, objects can override
loadState() to get other behaviors, e.g., doing other programmed
initializations after unserialize(), or complaining if no checkpoint
section is found.  (Note that the default warning for a missing
checkpoint section is now gone.)

If not restoring from a checkpoint, we call the new initState() method
on each SimObject instead.  This provides a hook for state
initializations that are only required when *not* restoring from a
checkpoint.

Given this new framework, do some cleanup of LiveProcess subclasses
and X86System, which were (in some cases) emulating initState()
behavior in startup via a local flag or (in other cases) erroneously
doing initializations in startup() that clobbered state loaded earlier
by unserialize().

17 files changed, 59 insertions, 54 deletions

diff --git a/src/arch/alpha/process.cc b/src/arch/alpha/process.cc
index 1c83f64b2..431ef86c0 100644
--- a/src/arch/alpha/process.cc
+++ b/src/arch/alpha/process.cc
@@ -173,19 +173,35 @@ AlphaLiveProcess::argsInit(int intSize, int pageSize)
 }
 
 void
-AlphaLiveProcess::startup()
+AlphaLiveProcess::setupASNReg()
 {
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     tc->setMiscRegNoEffect(IPR_DTB_ASN, M5_pid << 57);
+}
 
-    if (checkpointRestored) {
-        return;
-    }
 
-    Process::startup();
+void
+AlphaLiveProcess::loadState(Checkpoint *cp)
+{
+    LiveProcess::loadState(cp);
+    // need to set up ASN after unserialization since M5_pid value may
+    // come from checkpoint
+    setupASNReg();
+}
+
+
+void
+AlphaLiveProcess::initState()
+{
+    // need to set up ASN before further initialization since init
+    // will involve writing to virtual memory addresses
+    setupASNReg();
+
+    LiveProcess::initState();
 
     argsInit(MachineBytes, VMPageSize);
 
+    ThreadContext *tc = system->getThreadContext(contextIds[0]);
     tc->setIntReg(GlobalPointerReg, objFile->globalPointer());
     //Operate in user mode
     tc->setMiscRegNoEffect(IPR_ICM, 0x18);
diff --git a/src/arch/alpha/process.hh b/src/arch/alpha/process.hh
index 36b25a48e..40d6bf48a 100644
--- a/src/arch/alpha/process.hh
+++ b/src/arch/alpha/process.hh
@@ -36,10 +36,14 @@
 
 class AlphaLiveProcess : public LiveProcess
 {
+  private:
+    void setupASNReg();
+
   protected:
     AlphaLiveProcess(LiveProcessParams *params, ObjectFile *objFile);
 
-    void startup();
+    void loadState(Checkpoint *cp);
+    void initState();
 
     void argsInit(int intSize, int pageSize);
 
diff --git a/src/arch/arm/process.cc b/src/arch/arm/process.cc
index 555fdf56e..e7748ad50 100644
--- a/src/arch/arm/process.cc
+++ b/src/arch/arm/process.cc
@@ -76,6 +76,7 @@ ArmLiveProcess::ArmLiveProcess(LiveProcessParams *params, ObjectFile *objFile,
 void
 ArmLiveProcess::startup()
 {
+    LiveProcess::startup();
     argsInit(MachineBytes, VMPageSize);
 }
 
@@ -114,9 +115,6 @@ ArmLiveProcess::argsInit(int intSize, int pageSize)
     //We want 16 byte alignment
     uint64_t align = 16;
 
-    // Overloaded argsInit so that we can fine-tune for ARM architecture
-    Process::startup();
-
     // load object file into target memory
     objFile->loadSections(initVirtMem);
 
diff --git a/src/arch/mips/process.cc b/src/arch/mips/process.cc
index 2fd9114e9..7f1e94709 100644
--- a/src/arch/mips/process.cc
+++ b/src/arch/mips/process.cc
@@ -67,9 +67,9 @@ MipsLiveProcess::MipsLiveProcess(LiveProcessParams * params,
 }
 
 void
-MipsLiveProcess::startup()
+MipsLiveProcess::initState()
 {
-    Process::startup();
+    LiveProcess::initState();
 
     argsInit<uint32_t>(VMPageSize);
 }
@@ -79,7 +79,6 @@ void
 MipsLiveProcess::argsInit(int pageSize)
 {
     int intSize = sizeof(IntType);
-    Process::startup();
 
     // load object file into target memory
     objFile->loadSections(initVirtMem);
diff --git a/src/arch/mips/process.hh b/src/arch/mips/process.hh
index f1238b41f..a065feb8f 100644
--- a/src/arch/mips/process.hh
+++ b/src/arch/mips/process.hh
@@ -45,7 +45,7 @@ class MipsLiveProcess : public LiveProcess
   protected:
     MipsLiveProcess(LiveProcessParams * params, ObjectFile *objFile);
 
-    void startup();
+    void initState();
 
     template<class IntType>
     void argsInit(int pageSize);
diff --git a/src/arch/power/linux/process.cc b/src/arch/power/linux/process.cc
index 504d0e334..c2587d5e7 100644
--- a/src/arch/power/linux/process.cc
+++ b/src/arch/power/linux/process.cc
@@ -432,9 +432,9 @@ PowerLinuxProcess::getDesc(int callnum)
 }
 
 void
-PowerLinuxProcess::startup()
+PowerLinuxProcess::initState()
 {
-    PowerLiveProcess::startup();
+    PowerLiveProcess::initState();
 }
 
 PowerISA::IntReg
diff --git a/src/arch/power/linux/process.hh b/src/arch/power/linux/process.hh
index db6759a77..bef7e8dae 100644
--- a/src/arch/power/linux/process.hh
+++ b/src/arch/power/linux/process.hh
@@ -44,7 +44,7 @@ class PowerLinuxProcess : public PowerLiveProcess
 
     virtual SyscallDesc* getDesc(int callnum);
 
-    void startup();
+    void initState();
 
     PowerISA::IntReg getSyscallArg(ThreadContext *tc, int &i);
     void setSyscallArg(ThreadContext *tc, int i, PowerISA::IntReg val);
diff --git a/src/arch/power/process.cc b/src/arch/power/process.cc
index 12b216e50..9fb69b9f8 100644
--- a/src/arch/power/process.cc
+++ b/src/arch/power/process.cc
@@ -63,8 +63,10 @@ PowerLiveProcess::PowerLiveProcess(LiveProcessParams *params,
 }
 
 void
-PowerLiveProcess::startup()
+PowerLiveProcess::initState()
 {
+    Process::initState();
+
     argsInit(MachineBytes, VMPageSize);
 }
 
@@ -83,9 +85,6 @@ PowerLiveProcess::argsInit(int intSize, int pageSize)
     //We want 16 byte alignment
     uint64_t align = 16;
 
-    // Overloaded argsInit so that we can fine-tune for POWER architecture
-    Process::startup();
-
     // load object file into target memory
     objFile->loadSections(initVirtMem);
 
diff --git a/src/arch/power/process.hh b/src/arch/power/process.hh
index ede75f05f..473b7e028 100644
--- a/src/arch/power/process.hh
+++ b/src/arch/power/process.hh
@@ -46,7 +46,7 @@ class PowerLiveProcess : public LiveProcess
   protected:
     PowerLiveProcess(LiveProcessParams * params, ObjectFile *objFile);
 
-    void startup();
+    void initState();
 
   public:
     void argsInit(int intSize, int pageSize);
diff --git a/src/arch/sparc/process.cc b/src/arch/sparc/process.cc
index 7e01f6b07..0cd8889a9 100644
--- a/src/arch/sparc/process.cc
+++ b/src/arch/sparc/process.cc
@@ -111,9 +111,9 @@ void SparcLiveProcess::handleTrap(int trapNum, ThreadContext *tc)
 }
 
 void
-SparcLiveProcess::startup()
+SparcLiveProcess::initState()
 {
-    Process::startup();
+    LiveProcess::initState();
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     //From the SPARC ABI
@@ -157,12 +157,9 @@ SparcLiveProcess::startup()
 }
 
 void
-Sparc32LiveProcess::startup()
+Sparc32LiveProcess::initState()
 {
-    if (checkpointRestored)
-        return;
-
-    SparcLiveProcess::startup();
+    SparcLiveProcess::initState();
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     //The process runs in user mode with 32 bit addresses
@@ -172,12 +169,9 @@ Sparc32LiveProcess::startup()
 }
 
 void
-Sparc64LiveProcess::startup()
+Sparc64LiveProcess::initState()
 {
-    if (checkpointRestored)
-        return;
-
-    SparcLiveProcess::startup();
+    SparcLiveProcess::initState();
 
     ThreadContext *tc = system->getThreadContext(contextIds[0]);
     //The process runs in user mode
diff --git a/src/arch/sparc/process.hh b/src/arch/sparc/process.hh
index cca312e0a..2d68fb3fc 100644
--- a/src/arch/sparc/process.hh
+++ b/src/arch/sparc/process.hh
@@ -52,7 +52,7 @@ class SparcLiveProcess : public LiveProcess
     SparcLiveProcess(LiveProcessParams * params,
             ObjectFile *objFile, Addr _StackBias);
 
-    void startup();
+    void initState();
 
     template<class IntType>
     void argsInit(int pageSize);
@@ -87,7 +87,7 @@ class Sparc32LiveProcess : public SparcLiveProcess
         mmap_start = mmap_end = 0x70000000;
     }
 
-    void startup();
+    void initState();
 
   public:
 
@@ -115,7 +115,7 @@ class Sparc64LiveProcess : public SparcLiveProcess
         mmap_start = mmap_end = 0xfffff80000000000ULL;
     }
 
-    void startup();
+    void initState();
 
   public:
 
diff --git a/src/arch/x86/linux/system.cc b/src/arch/x86/linux/system.cc
index 4ae6d0ca4..1a113d365 100644
--- a/src/arch/x86/linux/system.cc
+++ b/src/arch/x86/linux/system.cc
@@ -59,9 +59,9 @@ LinuxX86System::~LinuxX86System()
 }
 
 void
-LinuxX86System::startup()
+LinuxX86System::initState()
 {
-    X86System::startup();
+    X86System::initState();
 
     // The location of the real mode data structure.
     const Addr realModeData = 0x90200;
diff --git a/src/arch/x86/linux/system.hh b/src/arch/x86/linux/system.hh
index e3c52ae50..ae7e93f3d 100644
--- a/src/arch/x86/linux/system.hh
+++ b/src/arch/x86/linux/system.hh
@@ -58,7 +58,7 @@ class LinuxX86System : public X86System
     LinuxX86System(Params *p);
     ~LinuxX86System();
 
-    void startup();
+    void initState();
 };
 
 #endif
diff --git a/src/arch/x86/process.cc b/src/arch/x86/process.cc
index 2a2d43d3b..02cd45478 100644
--- a/src/arch/x86/process.cc
+++ b/src/arch/x86/process.cc
@@ -157,12 +157,9 @@ X86LiveProcess::getDesc(int callnum)
 }
 
 void
-X86_64LiveProcess::startup()
+X86_64LiveProcess::initState()
 {
-    LiveProcess::startup();
-
-    if (checkpointRestored)
-        return;
+    X86LiveProcess::initState();
 
     argsInit(sizeof(uint64_t), VMPageSize);
 
@@ -255,12 +252,9 @@ X86_64LiveProcess::startup()
 }
 
 void
-I386LiveProcess::startup()
+I386LiveProcess::initState()
 {
-    LiveProcess::startup();
-
-    if (checkpointRestored)
-        return;
+    X86LiveProcess::initState();
 
     argsInit(sizeof(uint32_t), VMPageSize);
 
diff --git a/src/arch/x86/process.hh b/src/arch/x86/process.hh
index 8063898d7..34275b2d3 100644
--- a/src/arch/x86/process.hh
+++ b/src/arch/x86/process.hh
@@ -99,7 +99,7 @@ namespace X86ISA
 
       public:
         void argsInit(int intSize, int pageSize);
-        void startup();
+        void initState();
 
         X86ISA::IntReg getSyscallArg(ThreadContext *tc, int &i);
         void setSyscallArg(ThreadContext *tc, int i, X86ISA::IntReg val);
@@ -123,7 +123,7 @@ namespace X86ISA
 
       public:
         void argsInit(int intSize, int pageSize);
-        void startup();
+        void initState();
 
         void syscall(int64_t callnum, ThreadContext *tc);
         X86ISA::IntReg getSyscallArg(ThreadContext *tc, int &i);
diff --git a/src/arch/x86/system.cc b/src/arch/x86/system.cc
index 01416e544..46d17cdb3 100644
--- a/src/arch/x86/system.cc
+++ b/src/arch/x86/system.cc
@@ -109,9 +109,10 @@ installSegDesc(ThreadContext *tc, SegmentRegIndex seg,
 }
 
 void
-X86System::startup()
+X86System::initState()
 {
-    System::startup();
+    System::initState();
+
     ThreadContext *tc = threadContexts[0];
     // This is the boot strap processor (BSP). Initialize it to look like
     // the boot loader has just turned control over to the 64 bit OS. We
diff --git a/src/arch/x86/system.hh b/src/arch/x86/system.hh
index 4a61193e6..0b5da3145 100644
--- a/src/arch/x86/system.hh
+++ b/src/arch/x86/system.hh
@@ -77,7 +77,7 @@ class X86System : public System
     void serialize(std::ostream &os);
     void unserialize(Checkpoint *cp, const std::string &section);
 
-    void startup();
+    void initState();
 
   protected: